Once our plant embryo is formed and our seed is all set, it still has to somehow turn into a fully formed plant. This begins with germination, which is the process by which a plant forms from a seed. And it usually occurs after water is absorbed by the seed, through a process known as imbibition. Now, the seed coat, as we've said before, is that protective outer layer, and it forms from the integument, which you might recall as a structure found in the ovule. Now that outer layer is tough, and while sometimes imbibition will be able to cause enough swelling that it can break the seed coat open and sort of free the plant to develop, some seed coats are actually too thick to absorb water and require some type of physical penetration in order to germinate. In some cases, this could actually require being, you know, for example, chewed up and digested a little by an animal or something before the seed can actually germinate.
Now, the way a seed will sprout depends on whether the plant is a monocot or a eudicot. See, eudicots will have a hypocotyl that curves and grows towards the surface, and essentially pushes the cotyledons out of the soil. So you can kinda see that happening in this diagram here, where this hypocotyl will be curved, and it will grow up, and push its way out of the soil, and once it's out of the soil the cotyledons will actually sprout out of this seed. Now, in monocots this happens a little differently. Monocots will actually push their shoots straight up through the soil, whereas in the case of eudicots, the hypocotyl, that embryonic stem, is curved, and you can almost think of this as like a process of the plant arching its way out of the ground. In monocots, this is more of a straight shot. And because of that, monocots actually have to have these protective structures that help their emerging roots and shoots. And we call those the coleorhiza and coleoptile. The coleorhiza is the first structure to actually emerge from the seed, let me hop out of the way here, you can see it here, and it is protecting the radicle, and you might, I hope, you caught the spelling mistake in this figure, radicle is supposed to be spelled like that. I just liked the spelling mistake too much to take it out of the figure, because this is basically spelled like, you know, like radical dudes. So, anyhow, the coleorhiza protects the radicle, and the coleoptile protects the cotyledons, which you can see as these little structures here inside the coleoptile.
Now, hopefully, as you can see in this image here, here's our seed, it's going to stay where it is. And from here, its shoots are going to push up, and its roots are going to push down. So whereas the eudicot, again, did that curving, pushing out of the soil. Right? This is going to have the seed stay where it is, and it's going to push its shoots and roots out from that point. Now, how do these seeds get where they need to go? Well, seed dispersal is the technical term for the transport of seeds away from the parent plant, and there is a number of ways this can happen. You can have wind disperse your seeds, water, also animals, as we can see with this dog here that is covered in burrs, which are seed pods for plants. And oh, here also you can see these little plumes from a dandelion. Here is the seed, and this tuft on top is to help the seed be dispersed by wind. Now, seeds don't germinate right away when they land in dirt. They actually can enter a period of dormancy and will actually wait to germinate until the conditions are favorable. And in the case of some seeds, this could be years of dormancy before germination. Alright. Let's turn the page.