[Music] welcome to another episode of the notes live i'm your host aishwarya and today we will be discussing transport implants and we have a friend with us over to your friend hello everyone so like ashwiria said we're discussing igcc biology chapter 8 that is transport implants the first part is xylem and phloem so these are basically the two main vessels in plants so the syllabus states that you need to know the functions of these two vessels and you need to be able to identify them in different diagrams and in different parts of the plants and then you have to be able to relate the structure of these vessels to their functions so they're just three main points for that part which we will look into later so let's get started first of all what's xylophone xylem and phloem are the two main vessels that transport nutrients in throughout the plant we have already discussed this um the xylem is responsible for transport of water and mineral ions as well as supporting the plant while the phloem the flowing vessel it's responsible for the transport of sucrose and amino acids so these are two different vessels they contain two different um sorts of nutrients and they are different in composition and also in positions in diagrams as you'll see now so if you look at the first picture that's the root you'll see how this phloem and the xylem is situated so the xylem is in the center that's the plus sign kind of thing that's the xylem while the four circles of the four oval shaped thingies uh at the edge are the fluents so usually you'll try to think about like this the outer thing is the phloem while the inner part is the xylem so you'll see that trend in the next picture too that's the stem if you look at it the red part inside those small oval uh thingies there's the red and the blue so the red is the xylem vessel while the blue is the fluorine vessel so you'll see the two of to the two different plants root and stem they have that similar pattern the xylem is on the inside while the form is on the outside don't try this in the paper it's just a little trick that i use to learn uh to be able to identify these in the diagrams so it's a little tip here but you need to be able to state that okay so that is the flow man this is the xylem don't say the one on the inside is the one on the outside is flown because it's not going to make sense and the examiner might not give you marks for that now we go to the third image uh it's the leaf so this one kind of defines the trend because there's nothing really outside or inside here it's just that the top part and the bottom part so you can see over here you kind of have to learn it though the top part is flowing and the bottom part is xylem so always remember when you're learning it when you're making notes try to color code it so like in these images like in these diagrams the blue part is flowing and the red part is stylum and when you keep looking at it you'll get a hang of it and then you just know it by heart so the next part is the structure and function of xylem vessels so you need to know more about the xylem vessels in a little more detail so first point you need to know is that xylem have xylem vessels have thick walls which are made of lignin and you don't need to know the details of this part you just have to know that the walls are thick and it's made of lignin the second part the second point that you need to know is that these the cells have no cell content except for maybe a little bit of cytoplasm and that's about it and then the next part is the cells are joined end-to-end with no cross walls to form a continued long continuous tube so if you'll remember from a previous chapter firm vessels have a safe kind of structure in between the transportation while for xylem vessels the transportation happens only in one direction and there's no safe kind of uh barricades or barriers it's just one long hollow tube uh for continuous movement of water so that that's what it's that's what's different about the foam apart from the contents itself it's the structure so xylem vessels are one long hollow tube while the flowing vessels have separations uh made by these walls of dead remains of the cells but you don't need to know the details of that okay so that was the first part now we go to the second part the second part is an extension of the first part that is this is water of teeth so like i said uh water is transported into xylem vessels so in this part the syllabus needs you to know uh what is a root hair cell i need to do you need to be able to state its functions and its adaptations and you need to know the path taken by water from the root to the leaves and then how it exists the plan and then yeah that's about it the second the last part is a paper six question you'll be able to figure that out out by the end of this part okay so first of all this is the root hair cell the large surface area of root hair cell increases the uptake of water and mineral ions so when you look at this um extension to the pla nor ordinary looking plant cell you should know that the function of this extension is to increase the surface area and when you think about extended surface area you'll think about um maximum absorption of water and mineral ions over here you'll note that the root hair cells have no chloroplast because first of all it's underneath the ground so there's no sunlight reaching the plant uh thus that that part of the plant and thus there's no photosynthesis happening so chloroplasts are not required um that's why that part of the plant the roots are not green it's because of the absence of the chloroplast um like i said it's long it has a large surface area so that most of the maximum absorption of water is possible uh and also maximum absorption of mineral ions so these uh nutrients are transported in the xylem vessels like i said the xylem vital the xylem vessel transports water and mineral ions so that was the root hair cell so the the root yourself is basically the first step in the plant that the water goes through and then it just is transported throughout the plant to the leaf and then outside the leaf which is what we will discuss here the pathway of the water water enters root hair cell via bio osmosis osmosis is the movement of water particles from a high concentration to low concentration we have done this and uh this osmosis is possible this water potential is higher in soil than in cytoplasm so the water tries to move from high water potential to low water potential to in order to reach an equilibrium however this equilibrium is never really reached because the water is constantly um evaporating from the leaf so there's always a deficiency of water that's why osmosis is constantly occurring so that there's always a supply of water to the plant um water passes through the cortex cells by osmosis but mostly by suction now this suction is created because of a process known as transpiration this is something we will look into in the further in the coming slides um you don't need to know what's a cortex cell this is an extra bit of information but you just have to know that water passes through the plant uh by osmosis and mostly by suction destruction happens because of a process called transpiration water and minerals are forced to cross the end endomes endodermis so this is again an extra information not really something you need to know at this level but once again these it's really to uh reinforce that it's water and minerals we're not looking at amino acids and sucrose here because that's another process we will look into later and then the last part is water enters xylem then leaves and then it gets to when it gets to the mesophyll cells so like i said the final destination in the plant is the leaf so it goes from the root hair cell to the along the stems and along the um veins of the leaf to get to the leaf the cells of the leaf where uh respiration and photosynthesis can occur that that's really the purpose of for the water okay so transpiration like i said water is moving along the plant because of a suction motion created by transpiration so we will look at what is transformation here so first of all the syllabus needs you to know what is transpiration and how water evaporates from the surface of the leaf and then you look at why why water evaporates and we'll look at the a little bit into detail about the mechanisms of the mechanism of the process and then we'll look at effective external environmental changes over that that has the effects of external um changes on the rate of transpiration and then we will look at why wilting occurs well thing um yeah it's just slightly related to this first of all transpiration is the loss of water vapor from the leaves so this is a very basic definition you need to memorize this this could come in paper four paper two paper six as well maybe but really don't take it take your chances it's a simple definition learn it water transpiration is the loss of water vapor from the leaves a key word water vapor you have to mention the vapor if you just say water it the examiner may or may not accept the answer so mention water vapor to stay safe the next point is water evaporates from the surfaces of the mesophyll cells into the air spaces and then diffuses out of the leaf through the stomata as water vapor so water evaporates from the measurable cells so if you remember the structure of the leaf the top part is the mesophyll cells and the bottom part has air spaces so basically the water evaporates from the measurable cells into the air spaces where um excess gases are stored or waste gases are stored and these gases are weighted basically waiting to exit the leaf through the stomata stomatas are basically entryways to the leaf these are tiny holes that are open and closed by the guard cells this was discussed in another in the previous chapter so yeah you should probably revise that before coming here so yes water is used up in the mesophyll cells and the excess so the waste is evaporated into the air spaces that through which uh from which it evaporates through the stomata the water vapor loss is related to the large internal surface area provided by the interconnecting air spaces between the mesophyll cells and the size and number of stomata so like i said there the stomata has a very large surface area which allows for water to evaporate quickly uh and so that as the water evaporates quickly the stock this suction motion is created because water is cohesive in nature so when some of the water leaves it kind of pulls the water in another part of the plant forward to bring it to the leaf to make up for the absence of the water that was that's not there you know what i mean this water is constantly needed so as soon as the some of the previous the old water leaves leave there's a demand for some more water so which comes from the stem or whatever basically through the pathway that was taken by the water from the root hair cell to the leaf and this is why transpiration is so important because it basically facilitates the whole process of uptake of water this is the most important process here because without this um transport of water would not be as efficient if it was possible at all so yeah yeah that's about it okay the next part is wilting building occurs if water loss is greater than water uptake like i said when water evaporates it creates demand for more water but what happens if that demand is not met um the cells become flaccid the tissues become limp and the plant is no longer supported so basically the look if you look think about the plant cell and the vacuole vacuole is basically a very very large relatively large space that contains water so when it's full it gives the cell a robust shape however when it's empty the cell loses that robustness it loses uh it's no longer rigid and a full it becomes smaller and um it starts to limp which may and when it's happening in a larger scale when it's happening to many uh cells it happens to the entire plant and that's where you'll notice the plant starts to build but as soon as you give it some water as soon as you water the plant you'll see that the water supply has been replenished so the plant is no longer wilting okay so once again we're looking at uh uptake of water we looked at the path a pathway of water now we're looking at the uptake of water once again very important process in this is transpiration okay so the uptake of water is caused by water loss in the leaves like i said that's transpiration when that happens the water potential is lowered and then the water moves from xylem to leaf tissues once again via osmosis whenever you see anything about to do with movement of water it's always osmosis because that's the that's the way uh water moves from one part to another that's osmosis water moves up the stem in the xylem due to tension tension is basically because of the cohesive nature of water water molecules so when like i said when this part of the water moves this part will try to follow it basically it's like it's kind of like a magnet but don't think of it that way really something to just clear the concept but yes that's basically what's happening and then the whole process basically ends with the gain of water through the roots so you think about it this way the water is leaving the plant through the leaf and as while that is happening simultaneously water is entering the plant through the roots so it's a constant cycle it's a constant process that's always happening and it could be hindered by many factors by many external environmental conditions which we will look at later but this uh upward flow of water from the root to the leaf it's called the transformation stream okay here's the external factors that i was talking about the factors affecting rate of transpiration so there's three main factors that you need to know for igcc biology there's temperature humidity and light intensity so the first factor is temperature higher temperatures increase water holding capacity of air and then it increases the transpiration rate so it's basically what's written here higher temperature increases the water it increases how much water can be carried by the air and so since that's happening more water can leave the leaf so more water is exiting the leaf so the rate of transpiration increases so higher the temperature higher the rate of transpiration okay next point is humidity low humidity increases the water potential gradient between leaf and that atmosphere what this basically means is water potential is lower in the air than the leaf so like i if you remember osmosis water moves from high water potential to low water potential so if the air has low water potential water moves from the leaves to the air so it's a natural movement no energy required and that's why when the humidity is lower rate of transpiration increases so high humidity transpiration rate decreases it's uh inverse related inversely related next point is the light intensity highlight intensity causes stomata to open more often which increases the rate of transpiration why does highlight intensity cost to water to open to increase the rate of photosynthesis so if you remember when the light intensity is higher rate of photosynthesis is also higher similarly when the light intensity is higher rate of transformation is higher because the stomata is opening more often and for longer periods of time so water has more time to exit the leaf and that's about that so now we'll look at the last part this is translocation um 8.4 of this chapter this part four of chapter eight uh this is only extended so if you're doing the core curriculum this part is not important for you but if you're going for the extended version you have to know this part so first of all you need to know what is translocation and you need to know this you need to be able to describe some of the specifics of this process and you need to be able to describe why the sync and the source are changing in different times of the year we will look at what is the sync and source now so first of all part location is the movement of sucrose and amino acids in phloem from sources to sinks so we've talked about transpiration we've talked about water we've talked about xylem vessels and that was that now we're looking at the foreign vessels and what's transport in film vessels it's the supremes and the amino acids so translocation is the movement of sucrose and amino acids in phloem foam vessels you have to be you have to make sure you mention that part from sources to sinks this is the definition you need to memorize this could come it could come as a direct question for like two marks um it could come in paper two as multiple choice you can't really predict this one because it's so straightforward forward it's just easier to learn it it will also help you it will also like strengthen your theory so it's better off if you you're better off to learn it now sources to sings sources is basically where the sucrose and amino acids are made and sinks are the part of the plant where it's used uh it's sort of self-explanatory but we look at it here sources are parts of the plant that release sucrose in amino acid sinks or parts of the plant that use or store sucrose or amino acids now if you if you look at some plants like tubers potato plants uh super starch is stored and then you can and sometimes the start the stores become smaller because they are the sources okay we'll look at that later but first of all you need to know in a for example potato plant believe there are the sources and the potato itself the tubers are the sinks because sucrose's uh supersonic amino acids are released from the leaf and they're stored in the tubers so that should help you understand what's a source and what's a sink translocation in different seasons now translocation happens the source and the sink changes depending on the season now photosynthesis would be greatest in the summer because of maximum sunlight maximum temperature all of these are really favorable for photosynthesis worker so that's why you'll notice in this season plants are the while the tubers are the sinks however if we go to monsoon seasons the rainy seasons or winter um it's it's cloudier it's darker it's colder it's not the best time for plants to grow so you'll notice that the sources are the tubers because they've been storing the sucrose and amino acids right so now the these this this part of the plant is releasing these nutrients to the rest of the plant to keep the plant alive and healthy at at least long enough so that the season changes and once again the leaves can start photosynthesizing and the tubers can start storing these nutrients in times of in case of um unfavorable conditions so let's look here spring the first that's the first line spring sucrose transported from stores in roots to leave so sucrose is in the spring sucrose is transported from the roots to the leaf so the roots are the source here however in summer and early autumn sucrose goes from photosynthesizing leaf to root stores so this is basically what i just explained when the conditions are favorable the sources are the leaves and they transport nutrients to the stores and it's vice versa when the conditions are not favorable so that's translocation and i think that's it let's look at some questions so this is may june 2018. a student is investigating the effect of temperature on the rate of transpiration which environmental conditions should be kept constant during this investigation okay so we're looking at trade of transpiration the effect of temperature and the rate of transpiration so in these questions you should know that only the only thing that should that should be changing is the the the condition itself while everything else should be constant so the correct answer would be everything should be constant except for the temperature which is option b okay so this is october november 2017. what is the function of translocation to move leaf towards the light for photosynthesis nope to move water into leaves of photosynthesis nope to transport amino acids for the growth of new leaf to transport starch to all parts of the plant so you can you can get confused between part c uh option c and d however it is option d because amino acids are not really required because when the plant is struggling it's not really going to grow new leaf because the focus is going to survive so the logical answer would be to transport starch to all parts of the plant because this is starch is what's really required to survive and that's what you'll notice some parts don't really grow in off seasons yeah that's that's basically that okay what is a description of transpiration exchange of gases between the leaf and the atmosphere atmosphere loss of water vapor from leaves and stem of a plant movement of water from the roots to the leaf movement of water through the cells of the wave so this is right of the get-go you should be able to know you see loss of water you should think about transformation so what is the best description of transportation loss of water vapor that that's really the answer nothing to explain here and yeah that's igc biology chapter 8 transport and plans where i think would appear okay thank you thanks for your time today and the both of us hope that you had a better understanding of transport and sound after watching this lesson and our social media handles will be appearing on the next slide so you can follow them thank you so much