 We have already discussed about the main reproductive part of a flower and we looked deep down into how the anther looks, what is inside the anther and the detailed cross-sectional structure of an anther. And the main purpose of that video was to see how the microspores are formed here. So let me bring this part outside. So this is the one which has sporogenous cells, the spring cells that you see inside are sporogenous cells and we saw how these sporogenous cells divide meotically to form microspores. Now in this video we will look into what are the changes that takes place inside these microspores so that a pollen is formed and then how this anther bursts and pollens are released. So let's begin. Let's begin by talking about the changes that takes place in the microspores and for that we will have to look into this part. So the tipatum layer and the pink cells that you see inside which later forms microspore. Let us enlarge that part now. So here it is. This is the tipatum layer. Let me write down. This is tipatum and why is it so important because the cells here are big. It has a lot of cytoplasm and it provides nourishment to the cells that's growing inside. Along with that it has many other functions and we will discuss about them when we come across those functions. So inside this tipatum layer we will have microspores which are formed by meotic division and therefore they are haploid and we discussed how these cells are formed in our previous videos already. Now we will look into the changes that takes place in the microspores and for that let us just keep one cell and look into the changes that's taking place in that cell. So let's get rid of all these cells and just keep one. Here it is. This is also a haploid microspore. Now this microspore has a membrane which is just like a cell's membrane. So it is similar to plasma membrane but around this plasma membrane this microspore now starts secreting another layer which is called the intine. This intine is made of cellulose and cellulose plus pectin. Okay so these are the substances that makes up this layer and who produces this intine this microspore itself. Now what is the need of this microspore to even produce a layer outside it because it already has a plasma membrane right? So what is the need of another layer? What do you think? Well the answer is this microspore which later will turn into a pollen now will be released outside in the environment to go and fuse with the female gamut right? So to protect the content inside the microspore it needs layers outside so that it is not destroyed when it is released in the environment. Now this tipatum layer which is outside which provides nourishment to the to the growing cells inside this tipatum layer thinks that this intine layer is not sufficient for the microspores. So this tipatum layer now secretes a substance which is called a sporopollenin. This sporopollenin aggregates around this microspore producing another layer which we call exine. So this exine is secreted by this tipatum layer and this sporopollenin this long biological term is actually a chemical substance which is one of the most resistant organic compounds known and this sporopollenin makes up the exine so imagine the kind of resistance or the kind of protection this microspore or the pollen gets. So if an animal happened to ingest this pollen this exine will make sure that the digestive juices of this animal won't digest the pollen and also if this pollen happened to fall on parts where it should not fall like on water or on soil then this exine layer will make sure that this pollen is not degraded or destroyed. So these two layers are basically to protect this pollen when it is released outside and now with two layers on the outside of this microspore this microspore is now called a pollen. We have already been calling it a pollen but any microspore that has an entine and an exine outside it we call it a pollen so now it has become a proper pollen. Alright now as we have discussed about the different layers that is outside a pollen it's now time we look what's happening inside. So this pollen which is formed from a microspore is also haploid because microspores were haploid and we have not seen any cell division here so this will also be haploid but now mitosis will take place inside the cell and like any mitotic division first the nucleus will divide so the nucleus will divide into two but things happen differently when it comes to the cytoplasmic division because the cytoplasmic division is not equal. As you can see a large cell is formed which has more cytoplasm and more cellular content and a small cellular section is formed which gradually gradually forms a complete cell that floats inside this large cell. Now as we can see that this cell is divided into two one large cell and a small cell. This large cell is now called the vegetative or the tube cell. Can you guess why we call it a tube cell? Well this is because this cell can rise to what we call a pollen tube. So if we consider this to be a pollen and here are the eggs of a flower then from this this part of the cell pollen tube develops. So this is the pollen tube that reaches the egg and through this tube the male gamutified travels. So this is the cell the tube cell which give rise to this yellow color long pollen tube that you see here and we also call it vegetative because it do not directly take part in the fusion or it do not give rise to the male gamutified. So this vegetative or the tube cell we just saw give rise to a long pollen tube. Then what is the job of this smaller cell here? This cell we call it the generative cell because this cell give rise to the male gamuts and most pollens are released in this stage. This two cell stage one which we call vegetative or tube cell and the other one which we call generative cell that gives rise to the male gamutified. So in this in this stage the pollens are released. Now let us see how these pollens are actually released. And for that let us bring in the transverse section of the anther again and as we have discussed this pink sporogenous cells inside finally grows into proper pollen and we and we saw how pollens are finally formed but during the course of the formation of pollens the layers outside the pollen particles slowly becomes fibrous and and somewhere here and here on both sides the the tension kind of increases and the anther bursts out releasing the pollen and that is how we see the pollen being released outside by the anthers. So this was all about how pollens are formed from microspores and how the anther bursts and releases the pollen outside.