Just like in animals, after fertilization, the plant zygote will undergo cell divisions. But here's where things get a little different. This zygote undergoes asymmetric cell divisions, meaning that the two resulting daughter cells don't get the same amount of cytoplasm and other stuff, so they are different sizes and we can see that happening in this image. First, we have our zygote, and then it divides unevenly resulting in this 2-cell stage right here, and you can see that one is about twice the size of the other. We call these cells the apical cell and the basal cell. And I bet you can guess why thinking back to that apical basal axis. It turns out that the apical cell actually is what forms the plant itself. The basal cell forms what's known as the suspensor, which contributes to the supportive structures of the embryo, kind of like the placenta in mammals. So, you could almost think of this parallel as like the inner cell mass versus the trophoblast. Now, only one cell in the suspensor contributes to the plant embryo. Just one, so we can basically just say that the basal cell forms support structures and the apical cell forms the plant embryo. There's that one cell exception, but it's really not a big deal, so it's okay for us to just make those generalities. In addition to these apical-basal divisions, there are also radial divisions. So, you can see, going along this way, there are divisions in an outward fashion. We have these cells here dividing outward to form this pattern, which is an example of a radial division, dividing outward instead of just up and down.
Now, in addition to the structures we've talked about, the embryonic plant has some structures that we haven't given names to. Namely, we have the cotyledons, which are basically embryonic leaves, and you can see them right here. The hypocotyl, which is basically the embryonic stem, you can see that labeled right here. And, there is the shoot, which is made up of the hypocotyl and the cotyledons. So, this is our shoot. And, then we have our root, which is the underground portion of the plant that forms from what's known as the radicle. And, to go back to our image up here, you can see that these two images are actually like zoomed-in pictures that are specifically looking at the top of this developing embryo, but we can see the full image here, right? Before, we were kinda cutting it off like this and like this, but you can see that there's actually this long string of cells coming off the bottom that's going to form those support structures whereas these colored cells on top will actually form the embryonic plant. Here we have what's known as the heart shape and here the torpedo, and these are just names given to the particular shapes that the developing plant embryo takes during the course of its development.
Now, let's get back to the meristem, which, if you recall, is where those plant stem cells are located, which can give rise to the various structures of the plant like the roots, the leaves, new stalks, what have you. So, before I said that there were more, there was more than one meristem and that we'd get to what those specific meristems are. Well, now we're getting to it. There is the shoot apical meristem, sometimes abbreviated SAM, like that, and you can see it located right here, denoted by this red dot, and you can see where it arises from during development right here. There's also the root apical meristem, which you can see is highlighted in purple and is present during development here and here. The shoot apical meristem gives rise to organs like flowers and leaves. The root apical meristem gives rise to the roots, as the name implies, and meristems ensure that plants can have lifelong growth, which is very important because many plants continue to grow throughout their entire lives.