 Gymnosperms are a group of plants that do not produce flowers so how do they reproduce? Their reproductive organs are the cones. So there are two types of cones in every gymnosperm the female cones and the male cones. So we already have a video on the male cone I would recommend you go back and look at it and this video we are going to look at the female cone and explore how reproduction happens in gymnosperms. This is a female cone and what we are going to do is we are going to take a longitudinal section of it by that I mean we are going to cut it from top to bottom and remove the front part so this is what we will see when we do that. So this is the LS the longitudinal section the cone has a technical name it's called the female strobilus or the female cone and if you look at the longitudinal section you see these things these parts that seem to arise from this central axis and each of these parts is a sporophyll the female sporophyll which is also called the mega sporophyll. So each of these is a mega sporophyll. Why mega? Mega means big and micro means small micro sporophyll would be the sporophyll present in the male cone that's because microspores are present in male cones and mega spores are present in female cones. We call them so because the male spores are much smaller than the female spores. So each of these is a mega sporophyll and why is it called sporophyll? Spore you know and fill stands for leaf. So these are modified leaves each of these is a modified leaf which contains spores in it that's why it's called the sporophyll. So now we are going to take a look at this little bump over here in each sporophyll. This bump is nothing but the ovule so this is the ovule and this right here you see there's a gap over here this gap is present towards the base of the sporophyll and is called the micropile. We will see later why the micropile is so important. So inside the ovule a lot of interesting things are going on. So we have this mega spore mother cell there is a cell there are a lot of cells inside the ovule but there is this one special cell which is the mega spore mother cell okay I'll just label it over here this is the mega spore mother cell and this as the name suggests is responsible for making spores. So what happens is this mega spore mother cell divides by meiosis and gives rise to four spores right here. So meiosis so the mega spore mother cell was diploid and after meiosis the spores that it results in these spores each of them are haploid. So all of these are spores but with time three of the spores degenerate okay and there is this one spore that remains standing and that's the spore that's important that gives rise to the female gametophyte. So this spore right here it divides and divides by mitosis to give rise to this larger structure and this is called the female gametophyte. Now you might remember from bryophytes and pteridophytes that the gametophyte is supposed to be a plant it's a green plant which can survive on its own it can do photosynthesis make its own food but this here is a really really tiny structure the ovules themselves are very tiny and the gametophyte is inside it it's even smaller. So this is much smaller than the gametophytes that are there in the bryophytes and the pteridophytes not only that they are not green and they are not independent plants they're completely dependent on the sporeophyte whereas the sporeophyte the female cone that is a part of the gymnasperm tree which is the sporeophyte. So the female gametophyte is completely dependent on the sporeophyte and so is the male gametophyte by the way. So this is what happened with evolution the gametophyte became smaller and smaller until it became completely dependent on the sporeophyte. So anyway you see these two smaller structures inside the female gametophyte these two are the archegonia singular is archegonium and plural is archegonia i'm going to enlarge this a bit you see these tiny dots over here these two are the eggs so each of these is an egg there is an egg in each archegonium now let's see what happens in fertilization so for fertilization of course the male gamete is required which is present in the male gametophyte and the male gametophyte is nothing but the pollen grain so this right here is the pollen grain the pollen grains in gymnasperms reach the female gametophyte by pollination and the pollination always occurs in gymnasperms with the help of the wind so once the pollen grain reaches the ovule it enters the ovule through the micro pile that is why the gap was there as you saw above there the gap was there for the male gametophyte to enter so when the pollen grain comes and sits at the base of the ovule it germinates let's just bring this down a little bit so this right here is the pollen tube and let me make this a little bit bigger so you see these tiny dots over here these are the two male gametes that are there in the pollen grain so the pollen tube grows and reaches one of the archegonia and one of the two male gametes goes and fuses with the egg that is there in the archegonia and hence the zygote is formed after the zygote is formed it grows by mitosis the zygote divides by mitosis repeatedly to form the embryo so this is the embryo and this entire thing which was the ovule once has become the seed and if you take a look at the entire cone and that too has matured so it become more woody and these right here are the seeds which were ovules once so this is pretty much what happens in the reproduction of gymnosperms we start the ovule where there is a megaspore mother cell which divides by myosistiform spores only one of which survives with which grows into the gametophyte the female gametophyte which has the archegonia with the eggs when pollination happens the pollen grain comes in through the microbiome in the ovule and the pollen grain germinates to form the pollen tube and the pollen tube discharges one of the male gametes into the egg in one of the archegonia and that forms the zygote and the zygote develops to form the embryo