 In our previous video, we discussed about meristematic tissues, right? Tissues that had cells which could actively divide. In this video, we are going to talk about mature meristematic cells which differentiated and lost their ability to divide and we now call them permanent tissues. Well, in this video, we will look into the details of permanent tissue. So permanent tissues are again divided into two further types. Simple permanent tissue and complex permanent tissue. Simple permanent tissues are the ones which are made up of just one type of cells, okay? And complex permanent tissues are the ones which are made up of different types of tissues which together performs one particular function, okay? For example, let's consider this. Here, you can see it is all same cells forming one tissue and we can call it simple permanent tissue. But here, all these different colored cells are different tissues actually. They are coming together performing one particular task and we can call it complex permanent tissue. Now in reality, these tissues look nowhere near to what I have made on the screen, okay? I have oversimplified stuff here just for the sake of explaining, okay? Now if we take a plant and cut it somewhere here, we will do a cross section, okay? The shoot area and if we look at it under the microscope, obviously we will have to do a very thin slice from there. It would look somewhat like this, okay? Now, we zoom in even further. Maybe this particular part here, we will zoom in even further. Then it would appear like this. Now, a major part or a major portion of this section is made up of simple permanent tissue and just a small part here and here is made up of complex permanent tissue, okay? Now, we will look into those complex parts later in the video. But if we look at the other parts which are made of simple permanent tissue, you will be able to observe that it is of different shapes and also of different color, which indicates that simple permanent tissues are again of different types. So, here are the three types of simple permanent tissue. We call them perenkaima, kolenkaima and sclerenkaima. The most abundant of the simple permanent tissues are perenkaima, which is also called the filler tissue. So, if a plant needs to fill up any area in the plant body, it is mostly perenkaima tissue, okay? These are living cells and they have very thin cell wall and are loosely arranged. You can see the intercellular spaces between the cells, right? They are mainly responsible for storage of food. So, these are their function. Now, there are perenkaima cells which are found in the leaf and they perform the function of photosynthesis because they have chlorophyll in them and because of the presence of chlorophyll, those perenkaima cells are called chlorenkaima. And again in plants that floats on water, these perenkaima cells are arranged in such a way that it creates air pockets between them. Like in case of lotus, if you look closely, you will see that these perenkaima cells are arranged in such a way that it provides buoyancy and helps the plant to float. So, such kind of perenkaima tissue are called erenkaima. Now, the next type of simple permanent tissue is called cholenkaima. They are again living cells, but their cell wall is not as thin as the perenkaima. Instead, there is deposition of cellulose, hemicellulose and pectin in the corners of the cell, making their cell wall a little thick and leaves a very little intercellular spaces in the cholenkaima tissue. The main job of this tissue is to provide flexibility to the plant. For example, you must have seen how coiled and flexible tendrils are of climbers. It is all because of the cholenkaima. Now, let's move on to the third and the final type of simple permanent tissue called sclerenkaima. Now, unlike the other two, sclerenkaima is made up of dead cells. Yes, interesting, right? A living plant having dead cells. But before we proceed, let me tell you, plants have more dead cells than living cells inside of them. Do you know we humans also have a lot of dead cells in our body? Our hair? Dead cells. Nails? Dead cells. But we are pretty much living, right? So, living organisms can be called living even if they have some amount of dead cells in them. Now, these sclerenkaima or dead tissues, they make the plant parts hard and stiff and provide strength to the plant. For example, the husk of the coconut. How hard it is, right? It is made up of sclerenkaima. Now, the sclerenkaima is so hard because the cell walls are thickened due to the deposition of a chemical called lignin in them. Often, the cell walls are so thick that there is no internal space inside. The lignin deposition is so much that it fills up the entire cell. Making it a super hard tissue. This tissue is present in the stems around the vascular bundle, in the veins of leaves and the hard covering of seeds and nuts.