so in this particular video we are going to be looking at the xylem tissue just the structure and an introduction to its function I will not go into the detail of the xylem's function yet because I will need to explain the structure part first a common problem that students face when they're talking about xylem tissue is the fact that they can't imagine uh what does zym tissue actually looks like so this video is just to shed some light into what the xylem tissue is all about the first thing to know about xylm tissue is it's categorized as something called a vascular tissue and if you remember in a previous video vascular tissues just basically means tissues that are involved in the transport of substances so the xylm tissue itself contain tube like structures and they involved in in uh the transport of water and minerals so the question here is where exactly are the xylem tissues if you look at this cross-section of the roots stem and leaf right here cross-section or transfer section that's what TS means I'm highlighting the vascular tissues in pink that's where the xylem and Flo are located but this video is just focusing on the xylm so if you look at the parts where I'm just highlighting in blue that's where the xylem tissues are actually located in The Roots stem and leaf so as a student you have to know where the location of the xylem is specifically for all these three areas of the plant so the question here is what exactly is found in the xylm tissue let's just take this root cross-section and I've removed out the every other tissue except the xylem and I'm going to magnify the xylem uh tissue when we magnify it if we would to look at it under the microscope we will see these weird looking geometrical shapes and you can also see these tiny little green spots that I'm drawing out so you see the xylem tissue itself is actually made out of parenchima tissues which are not important but those hexagonal large tube like structures those are the important ones because they are known as something called xyum vessels these are important that's why I'm putting two stars there so they form so let's talk a little bit about the formation of the xylem vessels you see you do not need to know the formation of the xylm vessels in the exam they will not ask you how these xylem vessels are formed but the reason why I want to explain it is because it actually gives us an idea of what the xylem vessel is all about you see what I'm doing here is I'm just drawing out a plant okay you can see the stem and leaf when the stem is still quite young they will actually have many live plant cells within them so if you can see that um with square I'm just taking out a section within the stem and I'm drawing out many life plant cells and you can see that for some of the plant cells they are connected through something known as the plasmodesma if you have forgotten what the plasmodesma is all about please go refer back to this particular video in chapter one so during the development of the young stem to become mature what will start happening is surrounding the plant cells you will start to see this brown color structure that I'm drawing starting to form around the cells and that is known as something called lignin lignin is this particular material that is rigid and waterproof waterproof meaning to say water cannot go into the cell nor can water go out of the cell so what happens is the cells within the liif area will be deprived of minerals and important nutrients and what will happen here is those cells will actually die keep in mind that this is just normal development so then I'll ask my students is this good that it's happening to the plant most of my students will say well it's bad because the cells are dying right but for plants in this case it's actually quite good the reason why it's quite good is because those cells will be broken down and it will then form this kind kind of hollow uh rigid structure or tube like structure within itself and those Hollow tube like structures within itself is basically known as the xylem vessel that's where the xylem vessel actually comes from and if I were to just take out one section of the xylem vessel and just throw it out where it's made out of those dead cells that dead cell is referred to as the xylm vessel element it's a deadified cell lii meaning to say surround Ed by Lin and there are no end walls no end walls meaning to say wherever I'm highlighting in yellow there is no restriction anymore it's just a continuous space and when you join one xylem vessel element with another xylem vessel element with another xylem vessel element that's when you get something called the xylm vessels and notice where the plasmodesma used to be where the plasmodesma used to be which I'm are circling in red in the light plant cells that areas will not get liquified however that areas will contain something known as pits pits are just basically referred to as unlignified spaces in the xylm the longitudinal section is what you are looking at on the left part of the screen that's how you that's how the xylems look like when you are seeing it from the side but if we were to see the TS or transfer section of the xylem this is what it will look like this weird geometrical almost hexagonal shapes with very thick cell wall the reason why it's quite thick is not just because of the cell wall because it is also thick because of the extra liin deposits outside the plant which I'm coloring in right now so if I were to just draw out a 3D just a simple 3D section of a xylem this is how we think the xylem vessel element looks like and that green color section is known as the pit so remember the xylem itself is lignified surrounded by liin it's made out of dead cells and the inside of the xylem is hollow this is just to introduce how the xylem looks like okay uh now some you may look at the textbook and they'll say that oh the lignification has different patterns it's anular spiral reticulate you do not need to know all that in detail all right you just need to know that for now the xylm vessel is something that is made out of dead cells called xylem vessel elements the inside of the xylem is hollow the xylem wall itself is lignified with a structure known as liin that is rigid and waterproof and interspersed within the xylem vessel are tiny little portals or section known as pits that's all we have to know for now why are these structures important in the transport of water and minerals I will talk about that in a later video