Embryonic tissues form during plant development along the radial axis, and these embryonic tissues are kind of like the germ layers that form during animal development. So, in animal development, we have the ectoderm, mesoderm, and endoderm. In plant development, we have the epidermis, ground tissue, and vascular tissue. The epidermis is the outermost layer of cells and these are cells that are specialized to protect the organism. You can see them labeled here and represented by these bright green cells surrounding this cross section. Inside those, we have the ground tissue, and these are cells that will differentiate into specialized cells like photosynthetic cells. So, these are going to be the cells that have a very wide range of differentiating possibilities. Now, within the ground tissue, we have vascular tissue, which you can see right here. And these are cells that are going to differentiate into specialized transport cells for the movement of food and water around the plant. You might know of xylem and phloem. Those particular types of vascular tissues found in plants well, these arise from the vascular tissue and, embryonic tissue. Now, plant embryos, just like animals, have their development governed by chemical signals which lead to differential expression. So, just like we saw with the fly embryo where bicoid was released and diffused and developed a concentration gradient, the same thing happens in plants, and a nice example of that is with the hormone auxin, which is a common morphogen that provides positional information in developing plants. And you can see in this image, we have the diffusion of auxin at first upward and then, eventually, later in development, downward. And, of course, remember that these chemical signals are reused during development all the time. Now, the major difference between plants and animals in terms of development is that, unlike animal cells which have their fates sealed, you know, they have that permanent differentiation. Some plant cells can actually dedifferentiate to become different types of cells and this is why humans have been able to cultivate plants from clippings for so long. It's because of this ability for plant cells to dedifferentiate. So, here in our example, you can see we're cutting two portions, zoomed in, and you can see that the bottom of portion 1 has been marked by a red dot and the top of portion 2 has been marked by a blue dot. So, before we cut this stem, those blue and red dots were right next to each other, and those cells were, basically, the same types of cells and they were right next to each other. However, we place our clippings differently so that the cells on the red dot end go into the ground and become the roots, whereas the cells from the blue dot end are placed out of the ground and grow into the shoot. So what does that mean? Well, because the red and blue dots, the cells near the red and blue dots were basically the same types of cells, but they, after the clipping was made, developed into different structures. This shows us that plant cells can dedifferentiate and then become different types of cells, which is very different from animals who have their cell fate sealed. Alright. That's all I have for this lesson. I'll see you guys next time.