Sexual Reproduction In Flowering Plants - One Shot Lecture | CHAMPION - NEET CRASH COURSE 2022

Summary

In this comprehensive lecture on sexual reproduction in flowering plants, Arjuna dives deep into the intricacies of angiosperms, focusing on their reproductive units—the stamen and carpel. The lecture breaks down both the male and female reproductive structures, explaining their components and functions. Arjuna explores the processes of microsporogenesis and megasporogenesis, detailing how pollen grains and embryo sacs are formed. Additionally, the megaspore mother cell's journey to forming a functional megaspore is highlighted. Through vivid diagrams and clear explanations, this lecture provides an in-depth understanding of the complex processes involved in the reproductive cycle of flowering plants.

Highlights

• Arjuna provides an in-depth look at the reproductive structures of flowering plants, particularly focusing on the stamen and carpel. 🌿
• The lecture covers the intricacies of pollination and fertilization within angiosperms. 🌼
• Detailed explanations of microsporangium and megasporangium processes are presented. 🎓
• Arjuna discusses the importance of microscope mother cells and their role in sexual reproduction. 🌺
• Throughout the lecture, vivid diagrams help illustrate complex biological processes. 📚

Key Takeaways

• Discover the unique world of angiosperms and their reproductive units! 🌸
• Learn how different parts of the stamen and carpel contribute to plant reproduction. 🌺
• Get insights into microsporogenesis and megasporogenesis processes! 🌼
• Understand the importance of the pollen grain and embryo sac formations. 🎉
• Deep dive into the fascinating journey of megaspore mother cells! 🌻

Overview

Arjuna kicks off the lecture with an engaging introduction to the world of flowering plants' sexual reproduction, focusing on the roles of the stamen and carpel within angiosperms. The lecture sets the stage for a detailed exploration of the various parts of a flower and their roles in reproduction.

The lesson dives into the process of microsporogenesis and megasporogenesis, essential biological phenomena that explain how pollen grains and embryo sacs are formed. With step-by-step explanations, Arjuna makes these complex processes accessible and fascinating, emphasizing the development from microspore mother cells to pollen grains and from megaspore mother cells to embryo sacs.

Throughout the session, viewers are guided through intricate diagrams which illustrate the complex structures and processes discussed. Arjuna’s clear breakdown of key concepts ensures that by the end of the lecture, students have a comprehensive understanding of how sexual reproduction occurs in flowering plants, equipping them for academic excellence.

Chapters

• 00:00 - 00:30: Introduction In the Introduction chapter, the speaker, Arjuna, begins by greeting the students and expressing hopes that they are doing well. The chapter focuses on sexual reproduction in flowering plants, specifically angiosperms, which are characterized as flowering plants. The discussion is set to explore the flower as the reproductive unit in these plants.
• 00:30 - 05:00: Parts of a Flower The chapter 'Parts of a Flower' focuses on the unique features of angiosperms, emphasizing that flowers are exclusive to this group in the plant kingdom. It introduces the different parts of a flower, specifically mentioning the 'thalamus' (also known as the receptacle) and the 'pedicel', which is the stalk supporting the flower.
• 05:00 - 16:10: Stamen: Male Reproductive Unit The chapter introduces the various parts of a flower, focusing on its male reproductive unit: the stamen. It sets the stage for discussing the process of reproduction in flowering plants.
• 16:10 - 25:00: Development of Anther This chapter focuses on the development of the anther, a crucial part of the male reproductive unit in plants known as the stamen. It briefly touches on the role of petals and sepals in protecting the flower and attracting insects, before diving into the details of the stamen's structure and function.
• 25:00 - 43:00: Microsporogenesis and Development of Male Gametophyte The chapter discusses the structure of a stamen, including the filament and anther. The typical questions related to this structure are explored, emphasizing the parts present towards the thalamus. The content likely includes diagrams to aid understanding.
• 43:00 - 56:00: Female Reproductive Part: Carpels and Ovules The chapter focuses on the female reproductive parts of a flower, specifically the carpels and ovules. It explains the structure of the thalamus and its connection to the filament, emphasizing the distinction between the proximal and distal ends of the filament. The proximal end is located near the thalamus, while the distal end is away from it. This structural understanding is crucial for comprehending the functioning of female reproductive parts in plants.
• 56:00 - 72:00: Megasporogenesis and Development of Female Gametophyte In this chapter, the focus is on the process of megasporogenesis and how the female gametophyte develops. A specific detail highlighted is about the attachment of the anther to the filament, which is a common question derived from this area of study. It is emphasized that the anther is attached proximally, based on information from the reference text NCERT (National Council of Educational Research and Training).
• 72:00 - 91:00: Pollination: Types and Agents The chapter explains the concept of pollination, focusing on the types and agents involved in the process. A particular emphasis is placed on the structure of flowers, notably how the filament is attached to the thalamus through its proximal end, which is often examined in related questions.
• 91:00 - 116:00: Fertilization and Double Fertilization The chapter discusses the reproductive structures in plants, focusing on the anther. It clarifies that while the filament does not have a reproductive function, the anther does. A direct question might ask about the structure of the anther, which is described as tetragonal, meaning it has four sides.
• 116:00 - 135:00: Post-fertilization Changes and Embryo Development The chapter discusses the post-fertilization changes and embryo development, primarily focusing on the structure and characteristics of certain reproductive organs. It highlights that the structure in question is bilobed, meaning it has two lobes. Further, each lobe is dithicus, indicating that it contains two thicker regions, which are described as microsporangia in the latter stage of development. The explanations are made in the context of each lobe's features and its significance in the reproductive process.
• 135:00 - 153:00: Seed and Fruit Formation The chapter discusses the structural characteristics of anthers in angiosperms, focusing on their tetra sporangiate nature. Anthers have four microsporangia, are characterized as tetragonal, bilobed, and diethicus.
• 153:00 - 166:00: Apomixis and Polyembryony The chapter begins with a focus on tetrasporangite, which is characterized by containing four microsporangium. The narrative progresses to explain the developmental stages as the anther matures, affecting these microsporangium.
• 166:00 - 166:35: Conclusion and Review The chapter focuses on the maturation process of anthers, highlighting the transformation of microsporangiums into pollen sacs as they mature. It stresses the importance of remembering this transition.

Sexual Reproduction In Flowering Plants - One Shot Lecture | CHAMPION - NEET CRASH COURSE 2022 Transcription

• 00:00 - 00:30 hello students how you all are i hope you all are doing very good myself arjuna and today the chapter we are going to start is sexual reproduction in flowering plants so let's continue with the chapter when talking that we are going to deal with the flowering plants that means we are going to deal with the angiosperms and that means we are going to deal with the flower the reproductive unit in the
• 00:30 - 01:00 angiosperms so when i talk about a flower which is only the characteristic of angiosperms it is not found anywhere else in the whole plant kingdom so when i talk about the flower what are the different parts of a flower it has a thalamus it has a thalamus which is called as receptacle also and it has a stalk which is called as the pedicel
• 01:00 - 01:30 right and over that it has sepals it has petals it has the stamen and it has the carpel right so these are the various parts of the flower we are going to deal with right okay just a second there is a reflection on the boot yes beta so now we are going to deal with the process of reproduction in the flowering plants that means we are going
• 01:30 - 02:00 to deal with these two parts that is the stamen and the carpal the petals and the sepals are the protective units of the flower sepals protect the flower protect these inner worlds and the petals they attract the insects right so we are going to deal with the stamen so let's first deal with the stamen male reproductive unit stamen is the male reproductive unit in the plant right
• 02:00 - 02:30 so let's uh draw a diagram of stamen the typical diagram of a stamen this is the filament and this is the anther so what type of question comes from this portion regarding the structure of the stamen so understand beta that whatever whatever is present towards these thalamus whatever part is present towards the
• 02:30 - 03:00 thalamus this part is the is the proximal part of the filament and whatever is present away from the thalamus this is the distal end of the filament so remember this point that this is the proximal end of filament okay proximal end of filament which is towards the thalamus and this one is the distal end of
• 03:00 - 03:30 the filament which is away from the thalamus so what question comes from this part that the anther is attached to the filament from the proximal end or from the distal end so what will be your answer that the anther is attached this is the line of ncrt and the question also comes right anther is attached to
• 03:30 - 04:00 the filament by distal end through its distal end okay this is important line and the filament is attached to the thalamus the filament is attached to the thalamus via or through its proximal end okay so this is the question which comes from this part right
• 04:00 - 04:30 now the filament has not the reproductive function the reproductive the reproductive function is present in the anther now what kind of question comes from the part of anther direct question comes direct question comes regarding the structure of anthon first of all the structure of anther is tetragonal what is the meaning of tetragonal that it has four sides it has four sides tetragonal
• 04:30 - 05:00 then second important thing it is bilobed it is bilobed it has two lobes one lobe second law then it is dithicus because in each lobe is it has two thicker in each lobe it has two thicker and these thicker will be representing microsporangium later on right so each lobe has two thicker each lobe we say it in context of each lobe so each
• 05:00 - 05:30 lobe has two thicker so diet thickest and then it is tetra sporangiete it is tetra sporangiae that means it has a total of four micro sporangium within it okay so if anyone asks you what is the nature of anther you will say that in angiosperms the nature of anther is tetragonal bilobed diethicus and
• 05:30 - 06:00 tetrasporangite okay clear so this is important and it has a total of four it has a total of four microsporangium in it okay then later on these microsporangium when the enter matures when the enter matures then these microsporangium
• 06:00 - 06:30 are called as pollen sacs an anther has four microsporangium and when the enter gets matured these microsporangiums they are called as pollen sacs this is important line and must be remembered right when the answer gets matured the microscope angium are called as the pollen sacs okay okay now let's discuss now we understand
• 06:30 - 07:00 what is the and yes one more thing that a stamen can also be called as microsporophyll the another name of stamen can also be called as microsporophyll okay so stamen has this typical structure filament and third filament is attached to the thalamus via the proximal end and to the enthalpy then the structure of anther you know
• 07:00 - 07:30 tetragonal bilobed diathicus tetrasporangite and when the anther gets matured the microsporangium are called as the pollen sac okay now what is important in uh anthon is development of enter how the enter gets developed in case of angiosperms so development of anther the development of anther occurs through
• 07:30 - 08:00 special cells called as the archaesporial cells these are the special cells which ultimately give rise to the anther okay so these cells they divide like this they divide periclinally that means horizontally and give rise to two layers the outer layer is called as the parietal layer and the inner layer is called as the sporo genus layer
• 08:00 - 08:30 that means these special cells the archaesporial cells they ultimately give rise to two layers the outer layer is the parietal layer and this outer layer ultimately give rise to this parietal layer ultimately give rise to the anther wall this layer after many divisions forms the anther wall and this anther wall contains four layers that is epidermis
• 08:30 - 09:00 which we are going to deal in detail epidermis then comes the endothelium middle layers and the tape atom middle layers and the tape atom so these four layers ultimately forms the wall of the anther and protects the enter and several other functions we will be going to discuss
• 09:00 - 09:30 sporogenous layer ultimately give rise to the sporogenous tissue and this sporo genus tissue ultimately forms the microsporangium and within these microsporangium there will be development of microspores and then those microspores will give rise to pollen grains okay so this is how development of enter occurs right these special cells give rise to two layers the parietal layer
• 09:30 - 10:00 gives rise to the wall of the anther and the sporo genus layer give rise to ultimately it give rise to the pollen grains now let's discuss the structure of the anther right so i've just told you that yes so this is a ncrt diagram very beautiful diagram here you can see the filament and this is the anther right so ultimately pollen grains will be formed inside the microsporangium and then the
• 10:00 - 10:30 anther will dehyze it will dehyze and the pollen grains will come out of it right see here pollen sac is written instead of microsporangium pollen sac is written why because when the enter matures the microsporangium are called as the pollen sac okay yes now this is the typical diagram of the anther which is important so here you can see beta that there is one two three four four sides that is why tetragonal
• 10:30 - 11:00 structure it has one two three four four microsporangium that is why tetrasporangiate now i have just told you that the anther has the anther wall the wall which has four layers in it right so if see this is the part here we are focusing on the anther wall so this is the anther wall the wall of the anther and we are when we are
• 11:00 - 11:30 focusing on it then we see this then the outermost layer is the epidermis inner two epidermis there is endothelium inner two endothelium there are middle layers inner two middle layers there is the tape atom and finally inner two tape atom there is the sporo genus tissue which ultimately forms the microspore mother cells so if someone says that arrange the layers of anther wall from outside to inside what
• 11:30 - 12:00 you will say first the outermost layer of the anther wall is epidermis then endothelium then middle layers and then tip it okay and finally inside microsporangium microsport mother cells are developed from sporogenous tissue and then from microspore mother cells microspores and then ultimately the pollen grains and when the anther gets mature the pollen grains the anther it gets ruptured and the pollen grains come out
• 12:00 - 12:30 sorry so let's first discuss the anther wall let's first discuss the anther wall and when i talk about the anther wall the outermost layer the first layer is the epidermis so what is important regarding epidermis is that it is a single layer structure it is single layered
• 12:30 - 13:00 and epidermis is protective in nature the outermost layer of the anther wall is single layered which is protective in nature and is called as the epidermis okay then below the epidermis comes the endothelium below epidermis comes the endothelium endothelium again is single layered and what is important regarding
• 13:00 - 13:30 endothelium is that there is some deposition of special material on the walls of endothelium and this is the deposition of alpha cellulosic fibers the cells of endothelium has alpha cellulosic fibers and what is the nature of these alpha cellulosic fibers they are hydroscopic in nature what is the
• 13:30 - 14:00 meaning of hygroscopic that they are moisture absorbing and they absorb uh they absorb a whole amount of water in them and when the anther gets matured they lose their water and when they lose their water then they get shrinked and when they get shrinked they pressurize the wall of the anther and the anther gets ruptured that means what is the function of
• 14:00 - 14:30 endothelium what is the function of endothelium it helps in the dehysense it helps in the d hyacinths of anther right dehyscense means rupturing of anther because of this layer the anther gets ruptured it gets dehyzed and thus this is helpful
• 14:30 - 15:00 in dispersal of pollen grains when the anther will get ruptured only then the pollen grains will come out right so endothelium the main function is the dihysims or the rupturing of anther then let's discuss about the middle layers the middle layers are approximately three to five layered
• 15:00 - 15:30 they are three to five layered and they are fe miral what is the meaning of fe miral that means short-lived short-lived the middle layers they are short-lived that means when they get formed after a short point of time they gets degenerated and when they gets degenerated they help in the nourishment of developing pollen grains so they are short lived and help
• 15:30 - 16:00 in providing nourishment to the developing pollen brains and health in providing nourishment to the developing holding grains okay so this is important regarding the middle layers now the most important the last but not the least that is tapitum now tapitum what is important about tapitum first of all beta
• 16:00 - 16:30 as you have read the plant kingdom now you know what is a sporophyte and what is a gametophyte right until and unless i will do meiosis in any cell the cells will be the part of sporophyte that means the stamen the stamen is a part of flower and flower is a part of sporophyte that means every part of stamen is deployed every part of stamen is a part of
• 16:30 - 17:00 sporophyte and it will be a deployed structure until and unless we will perform meiosis in it so obviously epidermis is a deployed structure endothelium is a deployed structure because all of them are part of sporophyte middle layers deployed but tapitum but tapitum is polyploid it is polyploid or sometimes
• 17:00 - 17:30 it is also called as a triploid right that means something which has ploidy level greater greater than deployed ploidy level it is termed as polypoloid right and moreover the cells all the cells of the epidermis endothelial middle layers each cell contain only one nucleus that means they are uni nucleated but the tapitum the cells of tibitum they are multi-nucleated they are multi-nucleated or in ncrt it
• 17:30 - 18:00 is written as bin nucleated that means the cells of the tape atom the cells of the tape atom they have more than one nucleus in them so these two points are very important regarding tapitum that the ploidy level is polypoloid and it contains more than one nucleus in each cell and what is the reason behind it the reason is failure of cytokinesis
• 18:00 - 18:30 that means in a cell when keryokinesis will occur that means division of a nucleus will occur and just after that division of cytoplasm will not occur that means it will be going to be multi-nucleated okay so these two points are very important regarding tapered emitter very important now what is the function of tippetum what is the main function of tapitum providing nourishment to the developing
• 18:30 - 19:00 pollen grains it is the major function nourishment to pollen grains right this is the major function of the tibetan but apart from that there are several other functions of the tapeton and what are those what are the other functions of tapitum let's see this step atom is also responsible for formation of pollen kit
• 19:00 - 19:30 the second function is formation of colon kit now what is this pollen kit see better you you know basic structure of a pollen grain it has in tine it has exained right a pollen grain has in time and exign right every pollen grain but but those flowers which are pollinated by insects
• 19:30 - 20:00 they have an additional layer around the exam they have an additional sticky yellow colored layer around the egg sign and this is called as pollen kit this is a sticky yellow colored covering around the exam which is present only in entomophilus flowers
• 20:00 - 20:30 this kind of covering around the exign is present only in entomophilus flowers that means the flowers which are pollinated by the insects only they have pollen kit and the pollen kit how it helps when the insect sits on the flower because the pollen grains are sticky the pollen grains get stick to their legs and when they you know move the pollen grains move with them so pollen kit is formed by tapitum then
• 20:30 - 21:00 third function is it also helpful in the formation of yubish bodies it is responsible for the formation of yubish bodies and these special yubish bodies they in turn forms a very special chemical that is called as sporopo lenin sporopolenin this is sporopolenin is the
• 21:00 - 21:30 hardest substance hardest and most resistant substance of whole universe literally nothing literally nothing no enzyme no acid no alkali no pathogen can harm this substance sporophyllanin so this is very resistant and very hard substance and ultimately this sporopolanine forms exign forms the outermost covering of
• 21:30 - 22:00 the pollen grain that is exained so this is understood that ultimately the exign of the pollen grain is formed by tapitum how because tapatum forms yubish body you wish body forms poropylenine and sporopolarine form the exain of the pollen grain okay then what are the rest functions of tapitum it is helpful in the formation of some hormones some hormones like auxin iaa
• 22:00 - 22:30 which will be helpful in the growth of colon tube later on then it is also responsible for formation of some enzymes some enzymes like cellulase cellulase pectinase and calais these are some enzymes which are formed by the tipitum and finally it is responsible for the formation of compatibility
• 22:30 - 23:00 proteins these compatibility proteins are helpful in pollen pistil interaction that means pollen carries the compatibility proteins with it and when it lands on this stigma it convinces the stigma that yes i am the member of your species and please allow me to form the pollen tube so it convinces the stigma with the help of these compatibility proteins okay so these are the major functions of tapeterm nourishment to pollen grains then it
• 23:00 - 23:30 forms the pollen kit in the entomophilus flowers then formation of sporopal onion then hormones enzymes and compatibility proteins so this is about the anther wall now let's move to the microsporangium we know beta that microsporangium is formed by a special tissue called as the sporo genus tissue right now what will happen this is poro genus tissue the cells
• 23:30 - 24:00 some cells of this tissue this is poro genus tissue forms the microsporangium and some cells of this tissue they gets differentiated right some cells are obviously this is 2n some cells of this tissue gets differentiated they gets mature they gets different from the rest of the
• 24:00 - 24:30 tissue and they form specialized cells called as the micro spore mother cells so this is sporogenous tissue after differentiation it give rise to special cells called as the microspore mother cells okay right so the i i'm telling you what is happening at the center i've just talked about the anther wall now i'm discussing what is happening at the center where
• 24:30 - 25:00 microscope microsporangium is present in that microsporangium sporogeneous tissue is present which has formed specialized cells called as the microspore mother cells now we are going to study a special process occurring inside the anther and that is microgenesis that means formation of microspores in the anther
• 25:00 - 25:30 formation of microspores inside the anther now let's see how these microscopes are formed inside the anthra so inside each microsporangium inside each microsporangium there are four microsporangium so inside each microscore engine there are many microspore mother cells and i am taking only one of them out so
• 25:30 - 26:00 i am taking one microspore mother cells and we will see that how microspore will be formed so i am taking here single microspore mother cell there are many microspore mother cells right so what will happen here in the microspore mother cell meiosis will occur okay meiosis will occur and what will be
• 26:00 - 26:30 formed after meiosis in the microspore mother cells there will be formation of four microspores four microspores and obviously these microspores are haploid because they are the result of meiosis now these four microspores the microspore mother cell has a special type of you know compound in its cell wall the cell wall of microspore mother cell have a special compound in it
• 26:30 - 27:00 called as calors calories is a type of carbohydrate so what will happen one microspore mother cell when it will undergo meiosis it will form four microspores right and these four microspores they remain attached to each other right these four microspores they remain attached to each other
• 27:00 - 27:30 one will be behind it right so this is the these are the four microspore mother cells which are remain attached this is a tetrad tetrad means four microspores are attached to each other four microspores they remain attached to each other by and what is the thing which is responsible that these four
• 27:30 - 28:00 microscopes are attached to each other is callose callose was present in the wall of microspore mother cell and when it give rise to four microspores these four microspores remain attached to each other and they form a tetrad and why they're attached to each other because of the this compound callose okay so here what kind of shape you can see here this is the iso bilateral
• 28:00 - 28:30 shape this is the iso bilateral shape which is seen in case of monocots right but the shape of the tetrad the shape of the tetrad can be tetrahedral also and this is seen in case of dicots okay so what is happening at the center the sporogenous tissue it gave rise to
• 28:30 - 29:00 microspore mother cell and each microspore mother cell undergo meiosis to form four microspores and those four microscopes are haploid structures which remain attached to each other and they form a tetrad now from these microspores we have to form the gametophyte if you have attended the lecture of plant kingdom i have told you that what is the function of spores the spores they give rise to gametophyte
• 29:00 - 29:30 now these micro spores they will give rise to male gametophyte and who is the male gametophyte the pollen grain so now let's discuss development of male gametophyte development of male gametophyte and what is the another name of male gametophyte
• 29:30 - 30:00 pollen grain microspore will give rise to pollen grain which is a male gametophyte so what are the changes that will occur while the microspore now first of all when the four microspores they are attached to each other i have just told you the four microspores they are attached to each other because of the cellos now what will happen that there will be an enzyme which will come
• 30:00 - 30:30 and that enzyme is calais and you know who have formed the enzyme calais the layer tape atom the kelly's enzyme will dissolve the kelos will dissolve the calories and when this calais enzyme will dissolve the calories these microspores will be separated these microspores
• 30:30 - 31:00 will be separated from each other like this they will be separated and each microspore each microspore will develop into a pollen grain each microspore will develop into a pollen grain right that means that means
• 31:00 - 31:30 one microspore mother cell one microspore mother cell ultimately give rise to four pollen grains now let's see that what are the changes that uh a microspore mother cell show when it ultimately gave rise to pollen grain so in this diagram this is a microspore a single microspore right this is a single microspore
• 31:30 - 32:00 okay this is the diagram of ncrt which is important so right now we are discussing development of male gametophyte or formation of pollen green first of all all the four microspores they got separated from each other and then ultimately each microspore will develop into a pollen grain so how each microspore forms the pollen grain let's check it out so this is a microspore right a haploid structure now the first change that occurs in the
• 32:00 - 32:30 microspore is the development of vacuole is the development of vacuole so the first change occurs is vehiculation the first change is vehiculation that means a vacuole is developed in the microspore so nucleus is pushed towards periphery towards side now what will happen spindle fibers will be formed that means asymmetric mitosis will be seen here
• 32:30 - 33:00 a symmetric or unequal mitosis will be seen because of the formation of asymmetric spindle the spindle form towards the upper side they are larger and the spindle towards the lower side they are smaller because of the formation of asymmetric spindle fibers the mitosis over here is unequal and because of that
• 33:00 - 33:30 one single microspore gets divided into two cells into two cells and these two cells are unequal they are not equal why because the unequal mitosis has just occurred so ultimately the microspore first undergo evacuation then unequal mitosis occurs in microspore and then it forms a two celled structure then it forms
• 33:30 - 34:00 a two cell structure and this two cell structure is called as a pollen grain a pollen grain or the male gametophyte so this is how a single microspore gets changed into a male gametophyte so what are you seeing over here it's a two-celled structure which is called as a pollen grain the above cell is called as the vegetative cell and the shorter the
• 34:00 - 34:30 smaller cell is called as the generative cell right now when when the pollen grains gets formed inside the anther the anther then is ready for rupturing for dehysins and which layer was responsible for dehysins endothelium so anther will get ruptured and the pollen grains will come out this is called as shedding of pollen grain that means when they come out of
• 34:30 - 35:00 anther so in sixty percent of angiosperms in sixty percent of angiosperms heading of pollen grain shedding of pollen grain occurs at
• 35:00 - 35:30 two-celled stage when the pollen green it has two cells within it it has two cells then the anther will get ruptured and the pollen grains will come out so in 60 percent of angiosperms it is like that but in forty percent of angiosperms but in forty percent of angiosperms shedding of pollen grain
• 35:30 - 36:00 heading off poland grains occur at pre-celled stage that means when the pollen grain it will be a three-celled structure after that the anther will get ruptured and the pollen grains will come out so this is an important point in six six
• 36:00 - 36:30 sixty percent of angiosperms it occurs at two cell stage and in forty percent it occurs at three cell stage now what is the meaning of three cell stage what happens that this generative cell this generative cell again undergoes mitosis again so this generative cell when it will undergo mitosis it will form two cells and those two cells are called as male gametes so finally how many cells will be there in the pollen grain three
• 36:30 - 37:00 one vegetative cell and the generator cell has given rise to two male gametes so ultimately the pollen grain is going to be a three cell structure in all the angiospermic plants but what happens that in 60 of angiosperms when the pollen grain lands on the stigma lands on the stigma and forms the pollen tube after that the generative cell divides to give two male gametes but in 40 percent of the
• 37:00 - 37:30 angiosperms this happens inside the anther only you got the point okay in sixty percent of the angiosperms the three cell stage occurs when it lands on the stigma but in forty percent angiosperms the generator cell divides to give two male gametes inside the ampere only okay now some important points regarding the generative cell and the vegetative cell okay
• 37:30 - 38:00 so see here this is very important now let me first draw a diagram of a typical pollen grain if i draw the diagram of a typical pollen grain of angiosperms this is this the outermost layer is called as the exign and you know exain is composed of which substance sporopolis and i have just told you that sporopolanine is formed by tapitum
• 38:00 - 38:30 right and this is the most hard substance of the whole universe then this is the point where sporopolanine is absent right because because it has to give away the way to for pollen grain to come out poland tube to come out right so there is a space in the enzyme from which the pollen tube will come out and the point where sporopolenin is absent
• 38:30 - 39:00 the point where sporopolanine is absent in exign is called as germapore right is called as germapur so this jarvapour is the point in the exam where sporopolymer is absent and and from this pore poland tube will come
• 39:00 - 39:30 out from this pore colon tube will come out will come okay now the inner layer is the in time the inner layer is the intane and this in time is pectocellulosic because it is composed of pectin and cellulose so this is pectocellulosic in
• 39:30 - 40:00 nature and it gives rise to pollen tube extension of intane is pollen tube what you have to do if you take this in time and stretch it if you take the in time and stretch it then pollen tube will be formed then pollen tube is nothing but extension of enzyme that is why the nature of pollen tube is also ectocellulosic so extension of intane is poland tube
• 40:00 - 40:30 extension of indian is poland tube the smaller cell is the germ cell and the larger cell is the vegetative cell so this larger cell is called as the vegetative or the tube cell and what is the function of this vegetative cell or tube cell it will form the pollen tube later on and this smaller cell is called as the germ or the generative cell and what is the
• 40:30 - 41:00 function of generative cell to give rise to two male gametes after mitosis so this is a typical structure of pollen grain let's see what ncrt has to say about this when the polar green is mature see the lines when the pollen grain is mature it contains two cells the vegetative cell and generative cell okay the vegetative cell is bigger okay learn these words with me the
• 41:00 - 41:30 vegetative cell is bigger has abundant food reserve right that means the food reserve in the pollen grain is due to the presence of vegetative cell it has a large irregularly shaped nucleus so what are the three properties of vegetative cell according to ncrt it is a larger cell it has abundance of reserved food material and the nucleus of the vegetative cell is large and irregularly shaped
• 41:30 - 42:00 now the generative cell is small and floats into the cytoplasm of the vegetative cell the generative cell is so small and it has very less amount of cytoplasm that this generative cell floats in the cytoplasm of the vegetative cell now what is the shape of the generative cell generative cell is a spindle shaped spindle shape is not the shape of the nucleus of the generative cell but it is the shape of the cell of the generative
• 42:00 - 42:30 cell okay and it has dense cytoplasm and a nucleus okay this i have told you so are you clear with it clear okay so what we can say here that for two celled stage of pollen grain for two celled stage of pollen grain if i talk about the two-celled stage of
• 42:30 - 43:00 pollen grain then how many meiosis and how many mitosis will be required see if you have to form a two-celled pollen grain then how many meiosis and how many mitosis you'll have to do answer so for two cell stage of pollen grain one meiosis and one mitosis is required remember meiosis y
• 43:00 - 43:30 microspore mother cell will undergo meiosis to form microspore and then in that microspore mitosis will occur to form a two-celled pollen grain then for three celled stage of pollen grain that means pollen grain that means the pollen green when it will contain two male gametes then how many meiosis and mitosis will be required one
• 43:30 - 44:00 meiosis and two mitosis will be required why two mitosis because first by first mitosis generative cell and a vegetative cell will be formed and after second mitosis the generative cell will divide to give two milligametes that is why two mitosis so remember this for two cell stage one meiosis one mitosis for three cell stage one meiosis two mitosis okay so now we have formed the pollen grains and when
• 44:00 - 44:30 the pollen grains are formed inside the anther the anther this is the line of ncrt when pollen grains are formed inside anther then what are the changes that occur in the anther when pollen grains are when pollen grains formed inside anther then the anther will dehydrate then the anther will dehydrate that mean it will lose its water and when it will lose its water there will be shrinkage
• 44:30 - 45:00 of cells and the anther will rupture the anther will dehydrate and there will be dehydrator rupturing of anther and which layer will be helping out it helping it out endothelium right and then the pollen grain will be dispersed okay so this is how now what we have understood up till now what is stamen what is anther what is the structure of anthon how anther wall is formed what are the four layers present in the anther wall what are their functions
• 45:00 - 45:30 what are their what is their nature and then how microspores are formed inside microsporangium and how those microsport give rise to the male gametophyte that is sporting grade now there are certain things which are given in ncrt regarding the pollen grain and they are the pollen allergy pollen allergy the pollen grains of some plants are
• 45:30 - 46:00 pollen grains of some plants are allergic they cause bronchitis or asthma right and this phenomenon is called as colon allergy and direct question comes the examples of those plants whose pollen grains can cause bronchitis or asthma and the examples are amaranthus amaranthus chinopodium
• 46:00 - 46:30 is also called as the carrot grass the carrot crust okay so important amaranthus chunopodium and the parthenium then comes the pollen products poland products as the pollens are rich in nutrients
• 46:30 - 47:00 i have just told you that the vegetative cell has enough amount of reserved food materials so the pollen grains they are very rich in nutrients and nowadays it is fashionable the pollen grains are available in the form of cough syrups they are available in the form of tablets and these pollen grains are taken by the athletes and the horses to increase their performance so these are the pollen products then comes the pollen banks
• 47:00 - 47:30 what are the poland banks the pollen grains of certain species they are preserved they are preserved in the laboratories for various experiments and this is called as a pollen bank and what is done in the poland banks the cryo preservation what is cryo preservation the pollen grains are preserved at minus 196 degree centigrade
• 47:30 - 48:00 pollen grains are preserved at minus 196 degree centigrades in liquid nitrogen in liquid nitrogen this question comes very important the pollen grains are preserved at minus 196 degree centigrade at liquid nitrogen this is cryo preservation and then comes the important thing that is pollen viability
• 48:00 - 48:30 colon viability what is poland viability that when the pollen grains they come out of the anther when they come out of the anther then the time period the time period up to which they are capable of forming pollen tube that time period is called as the pollen viability okay and the pollen viability is different in different plants like in cereals it is given in ncrt that
• 48:30 - 49:00 in cereals like wheat rice right the members of the gramini family they have pollen viability of just 30 minutes half an hour that means when the pollen grains comes out of the pollen comes out of the anther then within half an hour it has to reach the stigma if it doesn't then it is wasted it will not be able to form poland tube after that
• 49:00 - 49:30 then the pollen viability can be of several months that means after coming out of anthra the colon grain is capable of forming the poland tube even after several months and the examples given in ncrt are three families the solan ac family that is the potato family the rose ac family that is the rose family and the leguminacy family that is the
• 49:30 - 50:00 p family or the soya bean family these families the these three families has the pollen viability for several months okay so this is regarding the male reproductive part now let's move on to the female reproductive part and the female reproductive part is represented by the couple and also called as the pistol right
• 50:00 - 50:30 and the collection of carpal or pistol in the flower is called as the gynotium [Music] it is called as the gynocim now what sort of questions comes from this part okay now according to ncrt the gynosium can be monocarpillary monocapillary means when the gynosium contains only one carpal
• 50:30 - 51:00 right it has only one carpal in it but it can be bicarbonate if the gynoscium contains two carpels tricarpillary tetracarpillary upto and so on right so it can be up to and so on more than two is counted in multicarbonary more than two is counted in multicapillary that is tri tetrapenta right so
• 51:00 - 51:30 if there are two carbons if there are two carpels within the same flower right two carpels that means if there are two carpels in the gynosium then they can be fused or they can be free if there are three four or five that means if there is more than one carpal in the gynosium then they can be either in the fused condition or in the so if this condition is there because single if it is single then how it can be fused or free it will be free but if
• 51:30 - 52:00 the gynosim contains more than one carpel then it can be either fused the carpals present in the gynosim they can be fused or they can be free if they are fused this condition is called as the sym carpus condition and if they are free this condition is called as the echocarpus condition and this makes the important question
• 52:00 - 52:30 this is the most common condition found in the flowering plants when the carpels in the gynoshim they are present in the fused condition but when they are present in the free condition there are very few examples one is the example of michelia lotus rose etc these are some examples of the plants in which there is multi-carpillary gynosium and the carpals in the gynoshem they all
• 52:30 - 53:00 are free from each other and the most common condition is when the carpals are fused with each other so this makes an important question from this part here is the diagram given in the ncrt right so this is the last diagram this one is the diagram of meshalia and what is important about vishalia that it has multicartilary apocarpus
• 53:00 - 53:30 that means it has many carpals in it gynocim and all are free from each other all are free from each other and in case of the rest two examples are of hibiscus hibiscus also called as china rose and papavar papa were so many ferum so
• 53:30 - 54:00 hibiscus hibiscus is the china rose in both of them the gynosium is multi-carpillary and syncarpus that means fused and the most common condition is fused right so this makes the important question from this part okay
• 54:00 - 54:30 now let's discuss the structure of a carpel or a piston if i draw the diagram of a carpel or a pistol then you know this is a typical diagram this part is a stigma on which the pollen grain comes and lands on this is the style through which the pollen grain pollen tube sorry travels and this is the ovary okay so the ovary
• 54:30 - 55:00 the space this is uh ovary is hollow from inside and the space within the ovary is called as locule is called as locule right and this locule if there is single space then unilocular if there is two spaces bilocular multilocular trilocular okay and within this space what are present within the space of the ovary what
• 55:00 - 55:30 important structures are present ovules ovules are present which are also called as megasporangium inside the anther microsporangium were present but inside the ovary megasporangium are present which are also called as the ovules okay and how ovules are present here they are attached with the wall of the ovary with
• 55:30 - 56:00 a special structure called as funicle the ovules are attached with the wall of the ovary with a special structure with a special stock-like structure called as funicle okay so an ovule is present inside the ovary and an ovary can have single obule an ovary can have a single ovule
• 56:00 - 56:30 inside an ovary there can be single ovule or there can be many ovules it depends from plants to plants okay all those plants which have single seeded fruits all these cereals mango they have single ovule within the ovary and all the plants which are many seeded like papaya watermelon that means their ovary has many opals okay so this can be the example of
• 56:30 - 57:00 cereals and mango and here there are several examples papaya watermelon etc right okay now now we know it now let's move on to ovule let's have a typical diagram of ovule and this is the typical diagram of an ovule
• 57:00 - 57:30 and ovule in case of angiosperm is also called as integumented megasporangium integum megasporangium that means the megasporangium which has protective covering around itself is integumented ovule so this integrated
• 57:30 - 58:00 ovule has and yes what is the nature of a typical angiospermic ovule it is anatropus in nature what is the meaning of anatos that means the ovule body gets rotated by 180 degree the ovule body gets rotated by 180 degree the ovule body rotates by 180 degree uh over funicle this is an
• 58:00 - 58:30 atropus ovule so a typical angiospermic plant has anatopus ovule and these are the several parts of the ovule let's understand this is the funicle this is the funicle or the stock of the ovule with the help of which i've just told you the stock of the ovule with the help of which the ovule gets attached to the wall of the ovary so this is the stock of the ovule called as the funicle now the point at which the
• 58:30 - 59:00 ovule body is attached to the funicle is called as hilum this point is called as hilum the point of attachment what is hilum this question directly comes point how point of attachment of punical with ovule is hilum so hilum is point of attachment of punical with ovule
• 59:00 - 59:30 that point of attachment is called as hilum okay now the ovule has two coverings the outer integument and the inner integument that is why it is called as a bi-tegmic structure it has two integuments then inside the integument it has a mass of parenchymatous cells which is called as new cellulose and ultimately when the
• 59:30 - 60:00 ovule gets matured embryo sac formed inside the ovule right the chalazal end the base of the ovule the base of the ovule is called as chalazal end and this is the opening which is called as the micropile so this is a typical structure of the ovule right funicle is the stalk hilum is the point of attachment of you nickel with the fuel it has two
• 60:00 - 60:30 integuments inside the ovule there is a mass of parenchymatous tissue called as new cells which ultimately give rise to embryo sac and microbiology okay now let's see what happens inside this ovule now let's understand the process of mega sporogenesis let's understand the process of megasporogenesis or formation of
• 60:30 - 61:00 megaspore or formation of megaspore so we know that inside the ovule new cellulose is present right nucellus is present which is a deployed structure so let's take this this is the ovule right this is the micropillar end this is the
• 61:00 - 61:30 chalazal end okay now a mass of cells this ovule is all filled up with the mass of cell called as the new cells which is a sporophytic tissue a deployed tissue right now what will happen listen carefully only one single cell of new cells only one single cell of nucellus towards the micro piler end gets differentiated and
• 61:30 - 62:00 forms megaspore mother cell this question directly comes megaspore mother cell now what sort of question comes from here a single cell of new cells a single cell of new cellulose towards micro piler end towards
• 62:00 - 62:30 micro finer end now they confuse it they will say that a single cell of new cells towards the chalazal end forms megaspore mothers are falls megaspore mother cell is formed towards the micro pilar end so a single cell of nucleus towards micro piler and gets differentiated to form the megaspore mother cell and ncrt says
• 62:30 - 63:00 that this megaspore mother cell has a dense cytoplasm this is large cell and it has a prominent nucleus so these are the properties of see the difference inside the microsporangium in anther many microspore mother cells were formed but inside the megasporangium or ovule
• 63:00 - 63:30 only one megaspore mother cell is formed and now what will happen [Music] this megaspore mother cell this megaspore mother cell will undergo meiosis right to form 4 mega spores it forms 4 mega spores but what happens
• 63:30 - 64:00 that out of the four mega spores the three three towards the micro pilot end gets degenerated three of them degenerates and only this remains only one remains and that is called as the functional megaspore so out of the four megaspores three gets degenerated and only one and this is
• 64:00 - 64:30 important the functional megaspore is presence towards chalazza this is important megaspore mother cell was formed towards microbiol but megaspore is formed the functional megaspore is present towards chalaza now from this single megaspore we will form the female gametophyte remember the microspore gave rise to the male gametophyte that is pollen grain now the
• 64:30 - 65:00 single megaspore will give rise to the female gametophyte that is the embryo sag so now let's understand formation of female gametophyte formation of female gametophyte or embryo sac
• 65:00 - 65:30 which is a haploid structure now what will happen this functional megaspore will undergo many changes so this is a functional mega score which was present towards the chalazar it will undergo first pre-nuclear division first pre-nuclear division and what kind of free nuclear division is this
• 65:30 - 66:00 mitotic division what kind of free nuclear division is called as a free nuclear division a division in which only the nucleus divides and not the cytoplasm so this is a kind of mitosis in which only nucleus will divide and just after the division of nucleus the division of cytoplasm will not be there so in the first mitosis only the cytoplasm will divide so it will be a binucleated
• 66:00 - 66:30 structure two nucleus will be formed then second free nuclear division second mitotic division which is again will be free nuclear that means only the nucleus will divide so it will become tetra nucleated then third mitotic division third mitotic division
• 66:30 - 67:00 again free nuclear so it will become octa nucleated one two three four five six seven eight so ultimately this becomes an eight nucleated structure so in a functional mega spore three free nuclear division occurs three free nuclear mitotic division occurs to ultimately give rise to a eight nucleated structure and then what will happen in this eight nucleated structure polarization
• 67:00 - 67:30 polarization what is the meaning of polarization that out of the eight nuclei one two three three will go towards the if i am taking it as the chalazal end you can take any and as chalazal in any and as micro pilot but you have to remember what kind of cell are present towards micro pilorin and what kind of cell are present towards the chalazar land right so if i'm taking this as the micro micropilot three will go towards the micropiler end
• 67:30 - 68:00 and the two nuclei will remain at the center so this is called as polarization then out of the eight three will go towards the character end three nuclei will migrate towards the micropillar end and two will remain at the center now what will happen after this after this cell wall development will happen after this cell wall development will happen three nuclei are present this and three
• 68:00 - 68:30 nuclei descended two at the center so just uh see carefully what i'm gonna write over here out of the eight nuclei this is the line of ncrt out of the eight nuclei six nuclei undergo undergo cell wall formation this is the line of the ncrt and important
• 68:30 - 69:00 out of the eight nuclei six nuclei undergo cell wall formation that around the upper three cell wall will be formed around the upper three cell wall will be formed around these upper lower three cell wall will be formed so now there will not there will not be called as nuclei they will be called as cells because of the cell wall development so what will happen with these two the cell wall will not be formed around them no
• 69:00 - 69:30 because the rest of the cell is theirs whatever the property has to be distributed it was distributed amongst these six and the rest of the property is with these two these two nuclei that means the rest of the cell is the cell of these two polar nuclei and this is called as the central cell so this is important line that out of the eight only six nuclei undergo cell wall formation and what is the result
• 69:30 - 70:00 three cells towards chalaza these are now cells they are not nuclei now they are cells and three cells towards microbial and two at the center this largest cell this largest cell is called as the central cell is called as the central cell having two
• 70:00 - 70:30 polar nuclei these are the three antipodals these three cells are the three antipodal cells present towards chalazza and this is a three-celled structure called as egg apparatus egg apparatus has one egg cell in it one egg cell and two synergies
• 70:30 - 71:00 so the question asks egg apparatus is how many celled structure egg apparatuses free cell structure contains one egg cell and two synergies and it is present towards the micropilot end and these are the two polar nuclei which is present in the largest cell of the embryo sac now the structure which are
• 71:00 - 71:30 present over here this structure is called as the embryo sac the embryo sac or also called as the female gametophyte the embryo sac or the female gametophyte right so you can see count the number of cells with me one two three four five six and this is the largest cell seven
• 71:30 - 72:00 so embryo sac is seven celled and eight nucleated structure why eight nucleated because the central cell has two nuclei in it and this kind of embryo sac is called as polygonum type of embryo sac why it is called as polygonum type of embryo sag because this kind of embryo sac was first studied in the plant
• 72:00 - 72:30 polygonum right and this kind of embryo sac is monosporic embryo sac this is very important this kind of embryo sac is monosporic embryo sac what is the meaning of monosporic embryo sac that the embryo sac develops only from one megaspore develops only from
• 72:30 - 73:00 one megaspore because the three of the mega sports the rest three of the mega sports they were degenerated but the one single mega spore ultimately gave rise to the female gametophyte so you have to remember these things about the embryo sac right it is a seven cent eight nucleated structure it is polygonum type and it is monosphoric in nature now
• 73:00 - 73:30 what kind of question comes for development of for development of embryo sac to form an embryo sac how many meiosis and how many mitosis are required so you have just seen that for development of embryo sag one meiosis and three mitosis remember three mitosis i have just shown you occurs
• 73:30 - 74:00 one meiosis three mitosis okay now what another sort of question comes that what is the function of synergids in embryo sac synergids are also called as the helper cells why because they have a special structure in them the synergids have a special structure present in them that is called as the philly form apparatus
• 74:00 - 74:30 the filiform apparatus is present towards the micropiler and in the synergids and what is the function of this filiform apparatus to guide pollen tube into the embryo sac to guide pollen tube into the embryo sac that pollen tube has not to go anywhere but to come inside the embryo sac okay antipodals they ultimately degenerates
• 74:30 - 75:00 to give the to provide the nourishment right so now we have formed the female gametophyte and the male gametophyte the female gametophyte is called as the embryo sac which contains the egg cell and the male gametophyte is the pollen grain which contains the male gametes now what will happen fertilization but before fertilization what will happen pollination so let's see what is pollination
• 75:00 - 75:30 okay so let's see so before fertilization what we'll have to do we'll have to disperse the pollen grains from anther to the stigma pollination is transfer of pollen grains from anther to stigma now this pollination can be further of three types pollination can be further of three types it can be autogammy
• 75:30 - 76:00 or the self pollination autogammy or self pollination then g tonogami and then comes the alogami alogami or xenogamy or
• 76:00 - 76:30 cross pollination okay now what is autogammy autogammy means when a splat has stamen as well as the carpal and the pollination occurs within the same flower the pollination occurs within the same flower so when i talk about autogammy then there will be involvement of same
• 76:30 - 77:00 plant and same flower that means it's a plant and the pollen grain of the same flower will be landed on the pole on the stigma of the same flower it will occur within the same plant within the same flower okay within same flower so it will be done by itself auto means by itself nobody is required pollinating agent is not
• 77:00 - 77:30 required even wind is not required wind is also a pollinating agent that is also not required pollinating agent is not required this kind of pollination occurs by itself this kind of pollination occurs by itself because the pollen grain of the same flower lands on the carpel or the stigma of the same flower then what happens on in juton origami that the plant is same but the flowers are different
• 77:30 - 78:00 the plant is same but the flowers are different that means on the same plant the polar grain of this flower lands on the pollen grain of this flower that means same plant but a different flower when the pollination occurs between the different flowers of the same plant then this is g tonogamy and obviously here pollinating agent will be required so here
• 78:00 - 78:30 pollinating agent is required okay cross pollination means different plant different flower different plant and different flower this flower is present on different
• 78:30 - 79:00 plant and this flower is current present on different plant right so this is xenogamy aloe vera cross pollination and obviously pollinating agent without pollinating agent cross pollination will not be occurring the pollinating agent is required over here also so these are the three types of pollination orthogamy g tonogamy and elogami clear now what is important about jeter nogamy a very important line that jitonogami is functionally
• 79:00 - 79:30 functionally or you can say ecologically ecologically it is cross pollination jeter nogamy is functionally or ecologically it is cross pollination why functionally or ecologically it is cross pollination because pollinating agent is required it is not occurring by itself but genetically but genetically the jito nogami is
• 79:30 - 80:00 self pollination why because same plant is involved because same plant is involved and the genetics of the pollen grain will be similar to the genetics of the carpel so genetically jutonogamy is self-pollination but ecologically it is cross pollination okay so now what kind of questions comes from this part like what are the conditions that promote
• 80:00 - 80:30 what self-pollination contrivances or conditions that promote self-pollination all those conditions which promote self-pollination they are called as the inbreeding device in breeding devices why they are called
• 80:30 - 81:00 as the inbreeding devices because the genetics because in this context if the plant will continue to self-pollinate there will be right there will be no change in the genetics so it will be inbreeding so all those devices all those conditions that promote self-pollination they promote inbreeding depression right that is why they're called ingraining devices so what are the various ingredient devices first bisexual flower
• 81:00 - 81:30 bisexual flower also called as the monoclinus flower this is opposite remember this is opposite a monoclinus flower is a bisexual flower bisexuality of flower is very essential for self pollination if the flower is not bisexual self pollination will not occur right second important thing is homogamy what is homogamy that both
• 81:30 - 82:00 carpel and stamen mature at same time both carpel and stamen mature at same time if they get mature at same time then homogemy then it will promote self pollination then comes the klistogamy what is clisto gaming please to gemmy is
• 82:00 - 82:30 a phenomenon where flower remains closed that means the flower will never be opened up and when the flower will always be remain closed it will be never opened up then it will obviously show self-pollination right so please togemi what is the disadvantage of please taught the disadvantage of klistogamy is that it may lead to inbreeding depression
• 82:30 - 83:00 because there will be no change in the genetics of the plant there will be no variation so it may lead to inbreeding depression but what is the advantage of histogaming that without the requirement of pollinating agent there will always be formation of seed there is assurance that seed will be formed even in the absence of pollinating agent right and the last one is the bud pollination in some plants when the
• 83:00 - 83:30 flower is a bud when the flower is a bud and it has not bloomed up the reproductive bar the reproductive parts they get mature and they show self pollination this is called as bud pollination this is often seen in pea plant and in rice plant okay so these are the four conditions bisexual flower homogeneistogamy and bud pollination that promotes the self pollination now
• 83:30 - 84:00 let's see the conditions that promotes the conditions that promote the cross pollination and all those conditions that promotes cross pollination they are called as the out breeding devices
• 84:00 - 84:30 and what are the out breeding devices let's see first unisexual flower if a flower that doesn't means that a bisexual flower cannot show cross pollination i am citing a line listen it carefully a bisexual flower can show cross-pollination jutenogamy or self-pollination but self-pollination will always be shown by bisexual flower are you getting my point a bisexual
• 84:30 - 85:00 flower can show can show self-pollination cross-pollination g tonogamy but ortogamy will always be seen in bisexual flower and in unisexual flower obviously jito nogami and uh cross pollination can be seen how we will see it so unisexual flower cross pollination then heterogamy what is the meaning of heterogamy that carpal and stamen matures at different
• 85:00 - 85:30 time they are not they do not get mature at similar time carpal and stamen matures at different times this is heterogamy then comes heterostyle what is heterostyle that means the position there is very much difference between the length of the style and the length of the stamen
• 85:30 - 86:00 right so it uh the pollen grain will not be able to you know um land on the stigma so there will be difference between the length of statement and the length of the style so this is heterostyle then self sterility in some plants the pollen grain of the stigma of the same flower do not recognizes its own pollen grain so it will support cross pollination and then chasmo gaming
• 86:00 - 86:30 what is chasmogamy when the flower gets opened up and the flower opens up or blooms then it supports the cross pollination so these all are the out breeding devices which supports the cross pollination now in ncrt there are three plants given there are three plants given which have both the types of flowers in
• 86:30 - 87:00 them pleisto gammas as well as chasmo gammas and the examples are viola pomelina pomelina and oxalis and oxalis right in all these three plants they have both the kind of flowers on them they have chasm gammas which gets opened up as well as klystro gametes which do not get opened up they have both the kinds of flowers in them okay
• 87:00 - 87:30 okay now let's see what kind of question comes from this portion they will ask that in papaya in papaya and date palm what is possible and what is not possible in papaya and date palm what is possible and what is not possible i have told you this in the chapter reproduction what i have which i have just you know taken the part that there are two kinds of plants
• 87:30 - 88:00 dioecious a diocese plant has only one type of unisexual flowers but a monoasius plant can have bisexual flower or it can have two types of unisexual flowers over the same plant right i have told you this in the reproduction implant and i told you that it will be used up again in the chapter sexual reproduction so papaya and date palm they are diocese plants that means on a single plant they have only male flower on one plant they will having all the
• 88:00 - 88:30 flowers will be male flowers and on the other flower all the flowers on the other plant all the flowers will be female flowers so what is possible in them what is possible in these kind of plants obviously jito nogami will not be possible because jitono gaming happens between two flowers of the same plant and when all the flowers are male flowers then gito nogami will not be possible
• 88:30 - 89:00 obviously auto gaming will also not be possible because for otto yami you must have bisexual flower that means only one thing is possible and that is xenogamy this kind of questions comes very often so in date palm in papaya which are diocese plants only only what is possible xenogame and then comes in maize and cucurbits what is possible
• 89:00 - 89:30 so you'll say maize is a monoicious plant it's the monoicious plant they are monoicious plants which have unisexual flowers of both the types on them some flowers are male flowers and some flowers are female flowers they have unisexual flowers but those unisexual flowers are present on the same plant so
• 89:30 - 90:00 apply your mind and tell me will uh autogammy will occur or not autogammy obviously not because auto gaming happens only in bisexual flower but they have unisexual plant geotonogamy will happen or not obviously it will happen because they have male and female flats both so it will happen between the different flowers of the same plant cross pollination yes obviously there will be room for cross pollination
• 90:00 - 90:30 also okay so these are some famous questions which come from this part from the pollination now let's talk about the pollinating agents pollinating agents there are two kinds of pollinating agents biotic or abiotic biotic are the living agents right and the most common type of pollinating
• 90:30 - 91:00 agents is insect insect are the most common pollinating agents right and in the insects also the bees are the most common there are so many type of insects on earth there are seven insects on every 10 organisms on the earth so there are so many types of insects but the bees are the most common pollinating agents insects then there can be snail
• 91:00 - 91:30 then there can be lamers monkeys elephant humans they all help in the snake birds humans these all are the biotic pollinating agents and the most common one are insects abiotic are wind and water wind and water and amongst wing and
• 91:30 - 92:00 water wind is more common wind pollination is more common amongst wind and water but the most common pollinating agent is insect okay now let's discuss each one of them one by one first of all let's discuss the wind pollination wind pollination is also called as animophilly do not get
• 92:00 - 92:30 do not get confused in it any more animal world not animal it is wind pollination now what are the properties of flower which shows wind pollination this is important obviously the flowers which show wind pollination they will be orderless there will be no aroma or smell in them there will be nectar less right nectar-less odorless nectar-less okay then
• 92:30 - 93:00 they will be colorless also because they need not to attract the insects then what is the important part their pollen grains are light they are light so that they can easily move with the help of air light and non-sticky light and non-sticky this is important then their stigma their stigma is well exposed towards the
• 93:00 - 93:30 air so that it can easily receive the pollen grain and the stigma should be feathery it should not be sticky it should be feathery feathery means it should have you know brush like structures in it so can it it can easily receive the pollen grains so it should be well exposed and feathery and what is more important is that the ovary ovary of the flowers contains single
• 93:30 - 94:00 ovule this is very important point ovary contains single ovule always all those plants which show animophilly their ovary will always contain single ovule this is a very important point and the flowers are often packed into inflorescence the flowers of the wind pollinated flowers they are tagged into in
• 94:00 - 94:30 fluorescence in fluorescence is a group of flowers present on the planet so these are the important points which wind which the flowers which show wind pollination they have all these points are important light and non-sticky well exposed feathery contains single ovule okay and one more thing that wind pollination is a directionless and wasteful process it's a directionless there's no certain direction and wasteful process
• 94:30 - 95:00 because there is no surety that the wind will take the uh pollen grains to the desired destination so that is why all those plants which are animophilus they form a large amount of pollen grains okay and their ovary has only single ovule now the question is wind pollination what is the example given in ncrt wind pollination is shown by cereals wind pollination is shown by
• 95:00 - 95:30 cereals this is pretty important cereals cereals belongs to which family grammy grammy or oasi family wheat maize rice right these all are the members of gramini family in them the wind pollination will be seen right and
• 95:30 - 96:00 that means wind pollination is seen by monopods the members of the gramini family all of them are monocots okay this is important so wind pollination is shown by the monocots the cereals the members of the gramini family and these are the characteristics now let's go to the water pollination water pollination or hydrophili
• 96:00 - 96:30 okay water pollination or hydrophilic that what is important regarding them that pollen grains have both pollen grains and stigma both of them have mucilaginous covering around them so that the water will not be able to cause any damage to the pollen grains and the stigma so they have
• 96:30 - 97:00 mucilaginous covering now what is important regarding the water pollination is that this is very rare in angiosperms hydrophilic is very rare in angiosperms it is seen only in hattie genera there are lacks of species of plants present on earth and out of them hydrophilic is seen only in 30 genus of the angiospermic plants only 30 genus
• 97:00 - 97:30 and amongst those 30 genus mostly monocots are there this is important line hydrophilic is very rare restricted only to 30 genera of angiospermic plants and those plant are mostly monocots now there is a question comes that in hydrophytes hydrophytes are the plants which are present in the water so is this a common sense to say that
• 97:30 - 98:00 hydrophytes will show hydrophilic no even in hydrophytes hydrophil is least common because most of the hydrophytes that present on the surface of water and most of the hydrophytes they show entomophily most of the hydrophytes they are pollinated by insects because most of them are present on the water surface so hydrophili hydrophili is the examples of hydrophili
• 98:00 - 98:30 are only very few like vallisneria hydrilla and zeus terra these are the three hydropites or aquatic plants which show hydrophilic
• 98:30 - 99:00 otherwise many hydrophytes they show either wind pollination or insect pollination right so these are the three examples of hydrophytes which show a hydrophilic okay so many hydrophytes show either so entomophily
• 99:00 - 99:30 or animophilly either wind pollination or water pollination sorry and entomophily is more common insect pollination is more common in case of hydrophytes like water hyacinth you must have heard the name of water hyacinth that is icornia and water lily so in most of the hydrophytes
• 99:30 - 100:00 entomophily is seen and in very few hydrophytes hydrophilic seen that is i have given you the three examples which you have to remember this is the diagram of ncrt in ncr it is given that vallisneria this is the depiction of the plant vallisneria which show hydrophili and in the vallis area the hydrophili the kind of hydropony which is present is epihydrophili what is the meaning of epihydrophily that the hydrophili is occurring at the
• 100:00 - 100:30 surface at just at the surface of water right these are the female flowers these are the female flowers and what happens the female flowers the stigma of the female flower is just present at the surface it is not exposed to the air but it is present just at the surface of the water and the male flower the male flower will be you know will be detached from the male plant and they come towards the stigma at the surface and the pollination the pollination will occur
• 100:30 - 101:00 at the surface of water this is epihydrophilly and vallisneria again is a diocese plant that means male plant is different and the female plant is different okay in zostera in zeus terra hypohydrophyll is seen that means pollination occurs below the water surface in vallisneria it is occurring at the water surface it occurs below the water surface
• 101:00 - 101:30 okay and now comes the most important one that is entomophily or the insect pollination or the insect pollination what are the features this is the most common type what are the features the flowers will have an order
• 101:30 - 102:00 that is a smell they will have color they will have nectar and the pollen grains of the insect pollinated flowers they are very special because they have remember they have pollen kit around them who formed the pollen kit the tape item which is a sticky layer and they gets sticked to the legs of the insect then
• 102:00 - 102:30 stigma stigma is also sticky okay so these are the characteristics if the flowers are small generally the flowers are large sized generally the insect pollinated flowers are large sized with bright color to attract the insect but if the flower are small if they are small then they will
• 102:30 - 103:00 be packed into inflorescence so that they will be easily visible to the insect otherwise generally they are large sized flowers but if they are small they will be packed into in fluorescence so that they can easily be conspicuous or visible to the insect okay so these are the features of insect pollinated flower now the insects they do not have this
• 103:00 - 103:30 feeling of doing the social service for the flowers they do it for their own sake that means they do it for the floral rewards they get some rewards they get some you know something only because of that they do the pollination so what they get they get nectar the floral rewards they get pollen grains or they get the safe place to lay their
• 103:30 - 104:00 eggs the insects they lay their egg into the flower into the gynoshem of the flowers so that their eggs they get the safe place right safe place to lay their eggs right and the example of this when the insect come towards plant so that they get the safe place to lay their eggs is amorphous
• 104:00 - 104:30 amorphous then fig or tulaka these are the plants which in which the plants the flower the insect come to lay their egg there is an association between fig and vast big and vast this is the obligate association
• 104:30 - 105:00 this is the obligate association that means they cannot live without without each other fig and vast pig is the ficus right the plant and vasp is the insect they are so closely associated with each other that they cannot live without each other and this is an obligate association this question is also given this cbsc sample paper of term two okay so these are the plans which show obligate association
• 105:00 - 105:30 now so this is all about the pollination now after pollination what will happen the pollination is done now the stigma has after pollination what will happen the pollen grain has landed on the stigma this is the pollen grain and it is present on the it is present on the stigma
• 105:30 - 106:00 of the carpal right so now what will happen here here at the stigma there will be a colon pistol interaction there will be a pollen pistil interaction now what is the meaning of pollen pistil interaction the pollen grain will convince the stigma that i am the pollen grain of your own species please allow
• 106:00 - 106:30 me to form the pollen tube then the stigma will say okay just a second let me recognize you whether you are of my own species or not so the pollen grain carries the compatibility proteins formed by the tape atom and convinces the stigma when the stigma gives the green light the pollen tube will be formed so poland pistol interaction is the dialogue occurs between the pollen grain and the stigma and when the compatibility is proved
• 106:30 - 107:00 when the compatibility is found when the compatibility proteins are matched between stigma and the pollen grain then pollen tube gets formed then pollen tube gets formed and you know who will form the pollen tube who will form the pollen tube
• 107:00 - 107:30 the pollen tube will be formed by the tube nucleus right so this is the pollen grain this was the germ pore remember now the intane will be extended remember colon tube is nothing but the extension of enzyme so here now colon tube will be formed and the nature of pollen tube is also pectocellulosic
• 107:30 - 108:00 why because it is formed by in time and who will help in the formation the tube nucleus this is the tube nucleus the vegetative nucleus it will help in the formation of colon tube right now the generative cell the generative cell divides to give rise to two male gametes generative cell divides to
• 108:00 - 108:30 give rise to two male gametes right so this generative cell will form two male gametes so ultimately these are the two male gametes present in the and these are non-motile that means flagella is not present in them the two
• 108:30 - 109:00 male gametes they do not have flagella okay now this is a mature male gametophyte when it forms the pollen tube and it carries the two male gametes so who is the carrier of male gametes in case of angiosperms the carrier of male gametes is the pollen tube who carries the male gametes pollen tube and who carries the pollen grains many pollinating agents so this is aubry
• 109:00 - 109:30 inside ovary what is present inside ovary there is obule right so this is obule and in cytovol what we have just formed up we have formed the embryo sac which is waiting for the male gametes to come so inside the ovule
• 109:30 - 110:00 so this pollen tube will grow towards the ovule right towards the ovule but who ensures but who ensures that the colon tube will enter into the embryo sac towards the micro piler side only who ensures this synergets so now synergids
• 110:00 - 110:30 will guide the pollen tube synergids will guide the pollen tube to enter to enter into embryo sac to enter into embryo sac through micro piler side through micro
• 110:30 - 111:00 filer side it just so that these synergets they guide the pollen tube that they have to enter into the embryo sac only through the micro piler side okay and during this process one of the synergids gets degenerated one of the synergids gets degenerated before the entry of colon tube gets
• 111:00 - 111:30 degenerated before the entry of colon tube just before the entry of pollen tube out of the two synergids one of the synergids gets degenerated okay now what will happen now what will happen ultimately
• 111:30 - 112:00 this is the embryo sac the three antipodals they will degenerate the antipodals will degenerate one of the synergids has already degenerated one of the synergies has already degenerated before the entry
• 112:00 - 112:30 of colon tube right this is the egg cell and just before the entry of colon tube now the pollen tube is about to enter the pollen tube is about to enter the embryo sag and just before its entry what will happen that the two polar nuclei fuses polar nuclei gets fused
• 112:30 - 113:00 to form secondary nucleus to form secondary nucleus which is a diploid structure so these two polar nuclei which were haploid they fused to form the secondary nucleus so this is the secondary nucleus and then ultimately
• 113:00 - 113:30 the pollen tube takes entry into the degenerated synergy the pollen tube takes entry into the degenerated synergy and from the degenerated synergy it takes entry into the cytoplasm of the other synergy and ultimately the other synergy would also die okay other synaptic would also die so what will be present here after this thing that
• 113:30 - 114:00 inside the embryo sac nothing is left anti-portals degenerated both of the synergists degenerated so now we have this secondary nucleus in the central cell this is the secondary nucleus and this hole is the central cell right antipodals degenerated synergets degenerated and what is left here just
• 114:00 - 114:30 excel antipodals also degenerated and the pollen tube has released two male gametes these are the two male gametes which are present in the embryo sac so one of the male gametes one of the male gametes will get fused with the secondary nucleus and one of the male gametes will fused with the egg cell so
• 114:30 - 115:00 one of the male gametes so this is male gamete and this is secondary nucleus and their fusion their fusion is called as the triple fusion their fusion is called as the triple fusion right why triple fusion because two polar nuclei fuse to form secondary nucleus and then male gamete fused to
• 115:00 - 115:30 form the structure that means ultimately three nuclei are involved two polar nuclei and one male gamete right so triple fusion then other male gamete and egg cell this is the male gamete other male gamete and this is the egg cell and their fusion is called as thin gammy so within the same embryo sag there are
• 115:30 - 116:00 two fusions one fusion between male gamete and secondary nucleus other fusion between male gamete and egg cell and this is called as sim syngami and triple fusion together is called as double fertilization within the single embryo sac there are two fusions that is called as double fertilization and this is seen only in case of angiosperms okay so what will be the result now
• 116:00 - 116:30 the result will be the fertilized egg cell the fertilized egg cell forms zygote and the fertilized central cell the fertilized central cell the central
• 116:30 - 117:00 cell got fertilized with the other male gamete so the fertilized central cell forms peck what is pec peck is primary endosperm cell and this primary endosperm cell contains pen that is primary endosperm nucleus
• 117:00 - 117:30 and this primary endosperm nucleus is a triploid nucleus 3n because it was a result of two fusion three triple fusion okay so ultimately we have peck primary endosperm cell and we have zybot now what we have to see is post fertilization development that is how embryo is formed from zygote and how endosperm is formed from
• 117:30 - 118:00 pec so i hope until now everything is clear to you so now let's move on to the post fertilization development we will first see that how endosperm is formed from the peck so post fertilization changes and
• 118:00 - 118:30 in the post fertilization changes let's discuss how pec the primary endosperm cell which contains the primary endosperm nucleus ultimately forms the endosperm which is a triploid structure in the angiosperms and what is the function of endosperm to provide nourishment to the growing embryo so on the basis of kind of divisions occur
• 118:30 - 119:00 in pec the endosperm can be of two types it can be free nuclear endosperm it can be pre-nuclear endosperm or it can be cellular endosperm now what is the difference between the two in free cellular free nuclear endosperm what happens that the pin
• 119:00 - 119:30 the pin initially undergoes many free nuclear divisions and now you understand what is the meaning of pre-nuclear division that only the nucleus will divide and not the cytoplasm so after many free nuclear division a multi-nucleated structure is formed after many free nuclear division a multi-nucleated structure is formed
• 119:30 - 120:00 and then ultimately this in this multinucleated structure the cell wall will form ultimately the cell wall formation will occur and the endosperm will be fought right that means initially there were only free nuclear divisions initially only nucleus divides and when the cell contains many nucleus then ultimately cell wall development occurs this kind of
• 120:00 - 120:30 endosperm is called as free nuclear endosperm and this is most common type of endosperm found in angiosperms most common then what happens in cellular endosperm the pec the peg divides and [Music] karyokinesis after nuclear division the cytoplasmic division occurs immediately that means
• 120:30 - 121:00 it's a kind of division where after nuclear division the cytoplasmic division will occur immediately that means karyokinesis will be immediately formed by cytokinesis here karyokinesis immediately followed by cytokinesis okay will be followed by cytokinesis
• 121:00 - 121:30 and this kind of endosperm is not very common in angiosperms this kind of endosperm is seen only in some members of a solar nac family like petunia petunia is a member of the family solanaceae right so these are the two major types of endosperms pre-nuclear cellular in the pre-nuclear division only in the free nuclear endosperm most common and cellular endosperm is seen in some
• 121:30 - 122:00 members of solanaceae now there is a case called as coconut coconut is a case where two types of endosperm are present in the same in the same seed two types of endosperm are present that means the liquid endosperm when you drink the water from the coconut from the green coconut the liquid endosperm
• 122:00 - 122:30 the liquid which you drink from coconut is nothing but the pre nuclear endosperm and the white kernel around it the white portion around it the white kernel around it that is the cellular endosperm or the solid endosperm right so the white kernel the solid part in the green coconut which is white that is the cellular endosperm but the liquid
• 122:30 - 123:00 you drink is the free nuclear so coconut has two types of endosperm right now let's see how embryo is formed from zygote and that is called as embryogenesis formation of embryo from zygote so in your syllabus there is description of embryogenesis in case of dicot
• 123:00 - 123:30 right but i'll tell you the case of monocots also so let's take zygot this is the zygote right now first of all there will be unequal mitosis in the zygote first of all there will be unequal mitosis in the zygote and what will be formed two cells will be formed
• 123:30 - 124:00 one is the larger cell called as the suspensor cell and the another one is the smaller cell called as the embryonal cell so it give rise to two cells larger cell is the suspensor cell and the smaller cell is the embryonal cell this cell will ultimately give rise to suspensor and the embryonal cell will
• 124:00 - 124:30 give rise to embryo what is the function of suspensor suspensor will derive the nourishment from the endosperm and the embryonal cell will form the embryo so what will happen this suspensor cell this suspensor cell which is formed towards the micro piler side
• 124:30 - 125:00 this suspensor cell which is formed towards the micro piler side this undergoes several divisions this undergo many transverse divisions what are transverse divisions like this the periclinal or the horizontal
• 125:00 - 125:30 divisions are the transverse divisions so after many transverse divisions the suspensor forms a 6 to 8 cell structure and this is called as the suspensor six to eight cell structure so in the suspensor cell in the suspensor
• 125:30 - 126:00 cell many parallel or periclinal or horizontal or transverse division occurs to form a six to eight cell structure called as suspensor and what is the function of suspensor to derive nourishment from the endosperm and provide it to the embryo this embryonal cell this embryonal cell will undergo this embryonal cell
• 126:00 - 126:30 will undergo two longitudinal divisions and one transverse division two longitudinal that means this is the embryonal cell one division will occur like this so two
• 126:30 - 127:00 cell will be formed and then another division will occur like this longitudinal four cells will be formed and then transverse division so four cells will be formed upper side and four cells will be formed towards lower side so eight celled structure is formed right so after two longitudinal divisions and one transverse division how many celled structure is formed eight said structure
• 127:00 - 127:30 is formed and this eight celled structure four cells towards the lower side and four cells towards the upper side so this is an octant right octant and this octant is called as a pro embryo it is called as pro embryo are you getting octant so this is pro
• 127:30 - 128:00 embryo right which has how many cells structure eight cell structure so i hope until here the process is clear suspensor cell after many transverse divisions give rise to suspensor and embryonal cell after two longitudinal and one transverse division give rise to the pro embryo or the octant now this octant the suspensor will remain like this
• 128:00 - 128:30 but the octant will further in the octant many divisions will occur and it will form a globular embryo after pro embryo globular embryo will be formed okay oh before that let me tell you some important thing
• 128:30 - 129:00 before telling you the globular embryo let me tell you about the octent stage so one two three four four towards the upper side one two three four towards the lower side so this is an octant right so let's explain the various part of the embryo this upper part up till here is the suspensor right and this is the pro embryo
• 129:00 - 129:30 the uppermost cell of the suspensor is called as the hostorial cell and what is the function of the hostorial cell it derives the nourishment from endosperm and the lowermost cell of this suspensor is called as hypophysis hypophysis is the lowermost cell of the
• 129:30 - 130:00 suspensor what is the function of hypophysis hypophysis later on forms the root cap it forms the root cap and a part of radical you know what is radical radical is present in the seed which ultimately give rise to the root when you sow a seed into the soil then this is the embryonal octant the four cells towards the hypophysis these four
• 130:00 - 130:30 cells are called as hypo hypophysial tire right this is called as hypophyseal tire and the four cells the four cells which are present away from the hypophysis they form the epi basal tire hypo basal tire sorry this is called as the hypo
• 130:30 - 131:00 basal type and this is the epi basalt tire right the hypobasal tire will later on will form hypocotyl hypocotyl and it will form the remaining part of the radical it will form the remaining part of the radical and
• 131:00 - 131:30 the four cells here the epi basal tire these four cells will ultimately form three main important structures they will form first the plemule and you know plymouth give rise to shoot then it gives epicotyl and it gives cotyledons okay so these are the various functions the high the hypophysis of suspensor
• 131:30 - 132:00 cell will give rise to root cap and the part of radical hypobasal tire will give hypo and remaining part of radical and these four cells they will give rise to premule epicotyl and cotyledons right okay now after further divisions after further divisions in the embryonal octant we will have the globular embryo
• 132:00 - 132:30 now globular embryo will be formed and in this globular embryo there will be different layers the outermost layer is called as the dermatogen or the protodermal and this dermatogen or protoderm will ultimately give rise to the epidermis then the
• 132:30 - 133:00 next layer is the layer of the ground mary stem which ultimately will give rise to ground tissue and as you have read the anatomy now you know what is ground tissue everything except epidermis and xylem and phloem everything is ground tissue and inside the center towards the center pro cambium is present which will give rise to the vascular cylinder the xylem and the chlorine
• 133:00 - 133:30 these are the different layers which will give rise to the different parts and now this embryo is called as the globular embryo now after further divisions after further division what will happen the cotyledons will start to form these are the cotyledons right they start to form they start storing the reserved food material and now this stage is called as the heart
• 133:30 - 134:00 shaped stage and after further divisions ultimately what will happen we will have the cortisol and these are the two cotyledons this is the mature embryo which have proper two cotyledons right these are the two cotyledons which you can see properly over here and ultimately the suspensor will
• 134:00 - 134:30 degenerate ultimately after providing nourishment to the embryo the suspensor will degenerate ultimately right and this embryo will give rise to a new plant okay so what question is asked arrange the various stages of embryo development arrange
• 134:30 - 135:00 various stages of embryo development and how will you arrange beta first stage is the pro embryo after pro embryo comes the globular embryo after globular embryo comes the
• 135:00 - 135:30 heart shaped embryo and then ultimately the quartilinary or the mature embryo so these are the stages which generally comes to arrange okay so these are the various stages in the development of embryo is it clear okay now everything in monocots also everything happens as in dicots
• 135:30 - 136:00 in monocots the embryo development is similar to that of dicots but what is the difference first difference is that in monocots the suspensor is single celled over there the suspensor was six to eight cent but here the suspensor is single celled and the next difference is that there are two cotyledons here also
• 136:00 - 136:30 there are two cotyledons here also but one is rudimentary what is the meaning of rudimentary highly reduced the second cotyledon is so much reduced that we do not even count it that is why we say that in monocots only one cotyledon is present right so the second cotyledon is so rudimentary and reduced that it is not
• 136:30 - 137:00 even counted and that reduced cotyledon is called as epiblast and the second cotyledon is developed the second cotyledon or the single cotyledon we count it as the single cotyledon because it is well developed so the single cotyledon which is developed in case of monocots is called as skew tellum
• 137:00 - 137:30 so if the question comes that the second rudimentary or highly reduced uh cotyledon monocots is called as you will say epiblast and the single cotyledon which is properly developed is called as skeutelum so apart from these differences monocot embryogenic is similar to dicot embryogeny okay now let's see the diagram of ncrt identify which one is the dicot embryo which one
• 137:30 - 138:00 is the monogatard embryo obviously this one is the dicot embryo this one is the dicot embryo you can see over here this is plumule these are two cotyledons these are two cotyledons right this is hypocrite this is radical and this is root cap this is a monocot embryo and you can see that there is a single
• 138:00 - 138:30 cotyledon the single cotyledon is called as cute ellum this is the caulioptile right this is shoot apex this is epiblast see the second cotyledon is so reduced that we do not even count it radical colu riser now what are collierize and red cauliptile cauliptile is a special leaf-like appendage which surrounds the plymouth lemuel forms the shoot and the plymouth is protected by a leaf like
• 138:30 - 139:00 structure called as colloctile and cholioriza surrounds the radical okay this is not present in case of dicot embryo coliorizer and coluptile is present only in case of monocot embryo right okay so now let's see structures formed after fertilization
• 139:00 - 139:30 structures formed after fertilization what are the several structures that are formed after fertilization so we have just read first endosperm now we know how endosperm gets formed up and what is the function of endosperm second embryo right then the third is
• 139:30 - 140:00 the seed then the fruit right so these are the structures which are formed after fertilization so now let's discuss first let's discuss the seed a seed is called as a fertilized ovule as soon as fertilization occurs inside the ovule the ovule no longer called as a
• 140:00 - 140:30 seed or ovule but it is called as a seed so we can say that ultimately the integuments of ovule after fertilization the integument of ovule forms what seed coat and as the integuments of the ovule form seed coat and as there are two integuments so
• 140:30 - 141:00 that is why the seed coat are also two the outer seed cold is called as testa and the inner seed coat is called as kegmen so an angiospermic seed has two seed coats testa and tegmin right and what is present inside the seed the endosperm the embryo the embryo will give rise to a new plant
• 141:00 - 141:30 okay and what is another important point is hilum remember hailam hail remain as a scar even on seed a scar which can be seed on sea which can be seen on seed is hylam and micro pile the opening which was present in the ovule it is also present in the seed also micro pile present and through
• 141:30 - 142:00 this micro pile the new seedling comes out the new small plant comes out of this micro pile okay okay so now this you must have read in the chapter morphology also but uh let's uh see that types of seed seed can be of two types they can be endospermic
• 142:00 - 142:30 endospermic or albuminous seed oh what's happening albuminous seed or they can be non-endospermic or they can be [Music] known endospermic
• 142:30 - 143:00 ah what is happening why this is overwriting these technical things non-endospermic or non-albuminous non-albuminous or x-albuminus or x-albuminus okay
• 143:00 - 143:30 so what happens beta that when inside the seed the embryo grows during the growth of embryo if the endosperm is totally consumed up and it is not present in the seed later on then the seed is called as non-endospermic seed if the endosperm is totally consumed up by the
• 143:30 - 144:00 embryo if the endosperm is totally consumed by the embryo then it is non-endospermic seed and non-endospermic seed is mostly seen in dicots that means in dicots the embryo consumes the endosperm during development and later on inside the seed endosperm is
• 144:00 - 144:30 not present but in monocots but what happens that mostly in monocots mostly in monocots the endosperm remains in the seed that means the embryo do not consume up the whole endosperm during development right so it remains in the
• 144:30 - 145:00 seed and it is seen mostly in monocots so remember this that mostly in dicots what kind of seed is seen non-endospermic and in monogardts endospermic seed is seen right but there are some exceptions to it and these exceptions are important what are the exceptions first orchid orchid is a monocot right so what sort of seed should be present in it
• 145:00 - 145:30 endospermic but no it is a monocot but still it has non-endospermic seed so these exceptions are important then second is castor castor poppy or sunflower right these are dicots
• 145:30 - 146:00 these are dicots but still they have endospermic seed so in dicots non-endospermic seed is found but these are dicots but still they have endospermic seed and orchid is monocot but still it has non-endospermic seed okay this is important then another kind of seed which is important is perispermic seed
• 146:00 - 146:30 then what is this perisparmic seed the seed in which perry sperm is present the seed in which peri sperm is present that is called as perispermic seed now what is perisperm perisperm is remains of new cellulose
• 146:30 - 147:00 when there is fertilization in the ovule during the development of ovule the nucleus gets consumed nucellus is never found in the seed it is all consumed up but sometimes new cells remains in the seed and that new cellus which is present in the seed is given an important term that is called as perisperm so perisperm is nothing but the remains of new cells which are present in the seed
• 147:00 - 147:30 right and perispermic seed are found in plants like castor castor has perispermic seed then black pepper then beet okay so these are some examples of berry spermic seed okay so this makes an important question now seed
• 147:30 - 148:00 seed show two property which are very important seed show two properties which are very important first is dormancy and the second one is dehydration a seed will not germinate until and unless it
• 148:00 - 148:30 gets all the requirements fulfilled both external and internal until then until then the seed will remain dormant and when the seed matures it loses its water right it gets dehydrated both of these qualities are very good for a farmer because because of these two qualities a farmer can store the seed
• 148:30 - 149:00 right because it will not germinate until and unless it will get the favorable conditions so it is easy to store it and it gets dehydrated because wherever their water is present water gives you know gives the possibility of pathogenic infections but because the seed showed dehydration and dormancy these are very two important properties for farmers right to store seed
• 149:00 - 149:30 because of these two properties the farmers can easily store the seed okay so these are the properties of now let's move on to the another topic that is seed viability seed viability is the capacity of the
• 149:30 - 150:00 seed after the seed is formed then for how much time after the formation of seed for how much time the seed is capable of giving rice to a new plant that is called as the seed viability and the some plants the lose some plants have seed viability only for few you know months like oxalis the seed is formed and within few months
• 150:00 - 150:30 it should be it will be able to give rise to a new plant after that it will not be able to give rise to a new plant but it can be up to several years one example is of lupine lupine it was excavated from arctic tundra right and when it was excavated from arctic tundra with the help of carbon dating system its age was calculated and
• 150:30 - 151:00 it was 10 000 years old and even after excavation when it was sown it gave rise to a new plant that means this plant lupine has a seed viability of 10 000 years and the second example given in ncrt is of the date palm also called as the scientific name is called as phenix it was excavated from dead sea
• 151:00 - 151:30 and the seed which was excavated was 2 000 years old and the seed even after being so much old gave rise to a new plant that means the seed viability can be up to several years okay then what is formed after fertilization fruit and what is a fruit a fruit is a
• 151:30 - 152:00 fertilized ripened obi fertilized ripened ovary after fertilization the ovary gets ripened up to form the fruit right and the ovary wall the wall of the ovary after fertilization give rise to the fruit wall and the fruit wall is called as the pericarp
• 152:00 - 152:30 the pericarp right now the fruit can be of three types this you must have read in the morphology the fruit can be a true fruit it can be a false fruit or it can be a parthenocarpic fruit probe root is a fruit in whose formation only ovary is
• 152:30 - 153:00 involved the fruit in whose formation only ovary is involved that is a true fruit but false fruit is a fruit in which along with ovary along with ovary other floral parts are also involved like thalamus or inflorescence so along with ovary other floral parts are also
• 153:00 - 153:30 involved like the apple the pear the strawberry and most of the fruits are the true fruits and the parthenocarpic fruits are the fruits which are formed without fertilization right this question is coming neat fruits which are formed without fertilization and
• 153:30 - 154:00 the example is banana okay so these are all the structures which are formed after fertilization now the last topic of the chapter and that is apple mixes before apple mixes let me tell you let me show you some diagrams of ncrt yes
• 154:00 - 154:30 this is the diagram of the seed right this is the seed of monocot what you can see here in the seed of monocot seed of monocot this is endosperm and around the endosperm there's a special layer around endosperm there is a special layer called as the elerone layer right which has some important enzymes
• 154:30 - 155:00 hydrolytic enzymes which helps in seed germination scutalum this is the single cotyledon right colorizer collectile and this is the seed of dicot okay so these are the example diagrams of ncrt now let's discuss what is epomixes amphi mixes means the division of gametes amphi means not
• 155:00 - 155:30 division fusion amphi means two mixes means mixing when the two gametes gets mixed up they form zygote right and the zygote forms the embryo this is normal sexual reproduction but what is epo mixes epo mixes is formation of seed without fertilization without fertilization
• 155:30 - 156:00 when do you call uh ovule a seed as soon as within the ovune an embryo is present then that ovule is not called as ovule but seed if that embryo is the product of fertilization then the seed is the proper sexual seed but sometimes what happens that inside the ovule embryo
• 156:00 - 156:30 forms embryo forms directly from integument or from new cells directly embryo forms directly from integument integrament remember the coating of the ovule or new cell as the parent gametes tissue present in it right without fertilization so that ovule will now be called as seed but but the seed is not the product of sexual reproduction but it is formed asexually so what is called epomexus is called as
• 156:30 - 157:00 develop formation of seed without fertilization right and this is a type of asexual method this is line of ncrt this is the type of asexual method which mimics sexual reproduction because formation of seed is a sexual reproduction right so epo mixes is asexual reproduction which is trying to be sexual reproduction okay this line is important
• 157:00 - 157:30 in ncrt there are two families which are given in which epo mixes is commonly seen two families in which epomyxis is seen and these two families are esther ac family and the
• 157:30 - 158:00 grammy family gram in your oac family esther ac family is the sunflower family sunflower marigold chrysanthemum xenia right and yeah this is the family of cereals so epo mixes this is important epo mixes is formation of seed without fertilization it's a type of asexual method which mimics sexual reproduction and it is commonly seen in two families
• 158:00 - 158:30 esther ac the sunflower family and the grammy the cereal family okay now what happens here the embryo is formed without fertilization inside the ovule and this give rise to poly embryoni what happens in the seeds of some plants that inside the embryo sac inside the embryo sac the normal embryo which is a
• 158:30 - 159:00 product of sexual reproduction forms but but an extra embryo also gets formed up by new cells or integument so that the seed contains more than one embryo so poly embryonic is a phenomenon where seed contains more than one embryo
• 159:00 - 159:30 feed contains more than one embryo and the extra embryo the main embryo the main embryo which is formed inside the embryosic is the product of sexual reproduction but the extra embryos are the product of epo mixes right how see the extra embryos which are present in the seed are formed
• 159:30 - 160:00 are formed directly directly through through new cells or integument without fertilization this is epo mixes right so due to epo mixes poly embryonic is seen in some plants where the embryo is formed without
• 160:00 - 160:30 fertilization the extra embryos are formed without fertilization by directly directly from the cell of new cells or directly from the cell of integument and this kind of poly embryoni is called as adventive polyembryonine when the extra embryos are formed either by the new cellular cell or the cells of the integument that is called as
• 160:30 - 161:00 adventif polyembryony and this adventive polly embryoni was first discovered by anton warren lewinhawk polly embryoni was first discovered by anton vaughn leubenhawk
• 161:00 - 161:30 in citrus fruits citrus fruits are lemon or orange so poly embryonic was first discovered in citrus fruits and it is also found in mango so this question often comes that in citrus fruits and in mango the extra embryos comes from which part so you will go to say new cells or integument because they show adventive poly embryonic clear
• 161:30 - 162:00 so this is poly embryonic now uh there are some you know advantages of epo mixes given in ncrt and what are those advantages because if you find the scientists are searching on the apomictic genes the scientists are working on the apomatic genes if they will get the genes which are responsible for epo mixes then that would be
• 162:00 - 162:30 that would be a revolution in the history of the plant breeding program because if the scientist will find the apomictic genes they will insert those apomictic genes in the hybrid varieties in the hybrid seeds right and when they will inject the apomictic genes into the hybrid seed then that seed will form the embryos only by asexual reproduction and not by sexual reproduction then that hybrid plant
• 162:30 - 163:00 will give all the seeds by asexual reproduction and all the seeds will be similar to the parent so the farmer will not have to buy the hybrid seeds again next year because there will be no segregation of traits why because the epimetic genes will not allow the segregation of traits segregation of traits is seen during sexual reproduction right but when due to epi mixes the embryo will be formed
• 163:00 - 163:30 there will be no segregation of traits and the seed will be clone of the hybrid plant so that would be very easy for the farmers they will not have to buy the what they will not have to buy the seeds every year right so what is seen here what we can see here in the ncrt which what question comes from this point let's see
• 163:30 - 164:00 let's see here it's saying that hybrid varieties of our food crops are being extensively cultivated cultivation of hybrids has tremendously incr now we know this that hybrids are you know hybrid seeds are sown so extensively in agriculture these days one of the
• 164:00 - 164:30 problems of hybrids is that hybrid seeds have to be produced every year that means farmer have to buy the hybrid seeds every year from the market why because the hybrid seed he has taken from the market he will sow it in the field then it will form a hybrid plant then if that hybrid plant will sexually reproduce then all the seeds formed on that plant will not be similar to the hybrid plant right so we will the farmer do not take the risk of
• 164:30 - 165:00 sowing these seed in the in the next year because these seeds will be the product of sexual reproduction and they will not be similar as the hybrid plant so will he will buy the seed again in the next year but if we will inject the apomiptic genes into this hybrid variety then the all the seeds will be formed epimetically they will be cloned to the hybrid plant and the farmer will not have to buy the seeds again and again every year so there's a hot
• 165:00 - 165:30 research in the epimetic genes if they will be found they will be injected in the hybrid seeds if the seeds collected from hybrids are sown in the plant there will segregate and do not maintain hybrid characters right generally what happens the seeds they do not retain the characters because they are product of sexual reproduction because there is segregation of traits but if these hybrids are made into apomics but if we inject acometic gene to these hybrids there is no segregation of
• 165:30 - 166:00 characters because there will be no sexual reproduction and that is why farmer will not have to buy the seeds every year okay so this will be the advantage of discovery of epimetic genes so i hope you have understood the chapter well all the points of ncrt are covered listen through the lecture carefully then read your ncrts and then solve the questions and your chapter
• 166:00 - 166:30 will be prepared so we'll meet up in the next chapter until then bye bye love you all you