# Plant Physiology Lesson 6: Crop Nutrition and Mineral Nutrients Absorption

**Channel:** ScenseMe
**Source:** https://www.youtube.com/watch?v=q1hbdVbWW6I
**Transcript page:** https://www.withtranscript.ai/video/q1hbdVbWW6I

## Chapters

- 0:03 — Course Introduction and Overview
- 2:11 — Nutrient Concepts and Plant Nutrition
- 12:14 — Alternative Plant Nutritional Modes Explained
- 19:45 — Crop Cultivation and Macronutrient Sources
- 25:34 — Mineral Nutrient Sources and Absorption Basics
- 29:00 — Essential and Beneficial Plant Nutrients
- 42:23 — Biochemical Classification of Nutrients
- 47:13 — Root Uptake Mechanisms and Lecture Wrap-Up

## Transcript

**[0:03]:** Right. I think we should make a start because I need to finish a bit early today, so. Good morning. Welcome back from your long holiday. Hope that you have had a good time with your family and. Yes, that's good. That's good. Did you get lots of diraya or are you too old now to get such things?

**[0:42]:** All right, so we're going to resume our lesson for the second half of the remaining semester. So basically what's gonna happen for the next seven, eight weeks is you're going to learn, basically you have to learn three important things, namely the plant crop nutrition, introduction to it, and then you're going to learn about the plant growth regulators, the hormones, and then you're going to learn about the general plant development, especially in relating to fruit, flower and fruit development. Okay? We would like to make everything into context so that you can see that, okay, this is the overview of what you have learned and eventually this is the thing that you get from this course. Okay? All right, so let's make a start. I hope most of you have joined. Please wake up your friends, make them join.

**[2:11]:** Okay, so our lesson today is about crop nutrition and mineral nutrients absorption. Admittedly, these. Sorry, I need to share my screen. I forgot to do that.

**[2:31]:** All right, Keshe C. My screen now. Just checking. Yes, doctor. Okay.

**[2:43]:** Okay, so we're going to have a look at the crop nutrition and mineral nutrients absorption. I think to some degree you have learned very basic, very fundamental about these two topics. Okay. Crop nutri, nutrition in general, you have learned about that and mineral nutrients. I think if you have taken your soil science, you should be familiar enough with the concept of minerals, elements, anions, cations and so on, and also the concept of absorption and adoption, absorption to the soil particles. Okay, Right.

**[3:32]:** My quick advice is when it comes to learning nutrition, regardless of which direction that you're going to go after you're done with your program, you know, you know, you're not necessarily interested with crop nutrition. Maybe you are more into breeding, maybe some of you more into biochemistry or crop physiology like I am. I'm a plant physiologist. Maybe some of you are more interested with the modeling, biostatistics and so on. Regardless of that, I would like to advise you to have a good understanding about nutrition because not only for the sake of your exams for this cause from nutrition, but because this is going to be of benefit to you as well at the human level. You see, when you understand the nutrients, what is meant by that and also the requirements in the plants and of course by ourselves, not Only that you can take care of your plants.

**[4:49]:** You maybe now it's not really the problem because you're still young. In the later part of life, you know how to take good care of yourself, okay? Because living in the modern age now, we are exposed in various highly processed food and this can actually hamper our health and our general vitality. So have a, I would say encourage yourself, persuade yourself to like and understand nutrition. Okay? Not just for the sake of your exams now, but for the sake of you at the individual level. Okay, so what is meant by nutrients? Nutrients basically the components of food. So, so depending on what organisms you are or depending which part of the world you from, you're going to have different kind of food. Okay, Maybe for, for the Chinese, they have the Chinese food, right? They have all the dim sum, they have all the noodles wonton me.

**[6:06]:** And for the Indian, they have all the roti, they have all the, you know, tandoori and so on. And for the Malay as well. Regardless of the kind of foods presented to you, these foods actually contains nutrients. And these nutrients fall into major categories that we are familiar with, namely carbohydrates, fats, protein, vitamins, minerals, water and so on. Okay, so nutrients, the components that need to build the bodies to grow. It's true, okay, for both of you and also for the plants. Okay. And the nutrients are also needed to repair the damaged part of the bodies and provide energy to carry out life processes. Okay. When you are living organism, you carry out life processes, your cells are living a meta, metabolizing actively just to repair, to divide, to differentiate and so on. Okay, so these all require nutrients and energy to do that. And when you study about all these nutrients, this is the field that we call as the study of nutrition.

**[7:26]:** We understand the mode of food taking by organism and then how does it get utilized in the body of that particular organism? So it can be whatever that you're learning now. It's. We call it crop nutrition. We learn what is important to be consumed by the crops and then how this is get metabolized in the crop to what functions. Okay, for example, you take nutrient a get into the body of a plant. What does it do? There are so many nutrients out there and each nutrient has its own role and function. Okay. To differentiate between us human mammals with plants, we. That is known, nutritionally known as the heterotrophic organism in our nutrition type, because we cannot manufacture our own food, we have to obtain it from other sources, external sources. But for the front, it's called autotrophic, okay? Because plants can basically, well, you know, plus do not have to go to cafeteria or go to, to call or for, for panda food.

**[8:48]:** They can just manufacture their own food by gathering all these basic building units. And they are very much capable to live on their own. Okay, but we can't, we. We rely very much on plant. So the very first process that enable plan to do so to pick up autotrophic is. I hope you still remember from your lectures before you underwent your semester break, mid semester break. It's the photosynthesis, okay? So this is why I keep telling you photosynthesis, that is the basic of all plant studies, okay? This is the start of everything. Whenever you study about crop, about the plants, about agriculture, even if you go to, to the non direct listening kind of field in agriculture, like the global economics, I mean like, okay, that, that doesn't go to the farm. No, but you still need to understand the photosynthesis because this is give what gives impact to how agricultural inputs is utilized and managed globally.

**[10:09]:** Okay? So please recall back from your photosynthesis machinery lesson about your photosynthesis. I hope still remember this. So we have the light ration and also the light independent reaction, the products from each of these and how they function, okay? Right. So being the autotrophic organism also means that the plant is able to synthesis proteins, meaning that they can make their own proteins. Can we make our own protein? Yes, but not all. Because the building block of proteins, namely the amino acids. So proteins is made from.

**[10:57]:** Amino acid? Yes, amino acids, okay? There are 20amino acids, I think 8amino acid is called the essential amino acid. Essential amino acid. Because our bodies cannot make these amino acids, okay? We have to obtain it from the plastic. But the plants can pretty much survive on their own, okay? Because they have the ability to absorb nitrogen, which is the elements utilized a lot in making proteins, okay? So now you understand why you have to eat various type of foods, okay? Because each type of food will cater to various nutritional needs that your body cannot meet or cannot manufacture at all. Like the essential amino acids, vitamin C. Our body cannot make vitamin C, okay? We're not some kind of lizard in the, in, in the desert. Those animals, they can manufacture their own vitamin C, but we can't, okay? Right.

**[12:14]:** However, bear in mind not all plants photosynthesize predominantly, okay? Some plants are parasitic, they are parasite, okay? They don't really photosynthesize, but they, they get their nutrients, food from, from other plants, okay? And these plants of course, since they are not photosynthesizing, they join us in the nutrition Modes there are heterotopic. For example, the daughter plant. You see this stringy looking plant covering this whole tree? Yeah. This is a daughter plant. This is not a tropical plant. You can't see it here. I've got some, another example here. This is called the dalu down leper. Okay. And this is the dalu plant. Okay. This is the plant and this is the host plant. You can see how, how different it looks, but somehow if you don't pay close attention, you think it's part of the same tree, but actually it's not. Okay. It's parasitic. Its living off the life essence of its host tree.

**[13:38]:** Okay, Right.

**[13:42]:** What are the common example? There are many other example. Okay, so please bear in your mind, not all plants are autotrophic. When, when, when people keep saying that the plants are autotrophy plant or photosynthesizing, that is in general speaking, meaning like 95% perhaps of the whole plant's population. Photosynthesizing. Okay. But not all of them. Okay. There is always exception because you're dealing with biology, you're dealing with nature. There is always exception, hence the word. Okay? Right. Okay, look at this plant. This is the, the mistletoe, that's the host tree. And this is the mistletoe you can see here. All right? And mistletoe. We, we have our tropical version of mistletoe, but this is the mistletoe, the actual mistletoe. What, what, what plant is this? Mistletoe? I think in the western culture it's quite, it has got some, some, quite, quite a significant impact on the culture.

**[14:54]:** I'm not encouraging you to do this, but if you watch the, the western movies, if, if the movie got some kind of Happy New Year scenes, you can see that the actor, actress is kissing right, under something. Usually that's something. They will have the new year kiss under the mistletoe. It's for the good luck. Okay. So this one, even though it's parasitic, it's regarded as good luck for some reason. Okay. All right.

**[15:25]:** Another thing that you need to bear in mind, just because the plants are living on another plants doesn't mean that they are parasitic. Sometimes there are epiphytes, okay? They just live there to support their growth needs. They're not parasitic. Okay. And we have loads of them as well. All right? They just, they live symbiotically sometimes or mutually. Sometimes commensurately, sometimes with, with the host plants. Okay. We have this staghorn plants, we have this bromelain. I'll just read the name. Okay. This is the Staghorn, fern, stag horn. Fernando. This is the bromeliads. Bromeliads. This is, I think I know. This is tillandsia.

**[16:23]:** So these, these are all the example of epiphyte plants. Okay. Some plants, they are neither heterotrophy or autotrophy, but they are rather carnivorous because they live in such a nutrient lacking kind of environment. Meaning that for example, they live in an acid box. Acid box. This is equivalent to our region, it's called the pit or the gambut. Meaning that when you're standing on the land, that actually is not the land, this is actually the decayed plant materials. Okay. So in general it's called the box, okay. And it's very acidic. It's very acidic. So even the nutrients are there. They are not available to the plants because they're just too acidic. So the plants need to supplement their nutritional needs by becoming carnivorous. So they modify the leaf, it becomes the trap, and then some insect get attracted to it and then it will be trapped and then digested.

**[17:41]:** There are a few examples. You got your Venus fly trap here. Okay. You got your Venus fly trap here. Fly trap. I think the Latin name for this is Dionia saracenia. This is Saracinia. And then this is Nephent. This Nephetis Nephetes. What's that? Emily. I think I know there's an Emily Keep.

**[18:07]:** It's the peaches plant. It's the perio. Okay, so it's very slippery. Got some insect. The insects pretty much cannot escape. Once it's trapped the digestive nutrients of the peaches plants going to digest it and become, become the nutrients for the plant. Okay, right. So some plants, you can see it's got this symbiotic relationship because they live together with the host plant. Okay, so for example, in here the, the plants, they kind of provides, and I mean the host, it provides the nutrients needed by the. Its partner, symbiotic partner. And in return, the symbiotic partner gives some kind of protections to the host blood or give other nutrients that the host plant can, cannot manufacture and, and so on. Okay, so this is a very beautiful way the nature has been designed. You can see there's a diversity of nutrition modes present in the nature. Okay, so these are summary of what we have seen so far.

**[19:36]:** So you got your epiphyte, you've got your parasite plant and also the carnivorous plants. Okay, right.

**[19:45]:** What about crops? Okay, so when you talk about crops, crops pretty much are grown in such a way we call it as the monoculture.

**[19:59]:** Okay. And when this happens naturally, the nutrients that are present in the soil cannot be sufficient or enough to cater for the continuously growing monoculture crops. So in order to replenish back all the nutrients, that's why the farmers keep fertilizing the land. Because for the nutrients in the soil to become available, it takes time. As you can learn, as you have learned, it's through the process of weathering, okay, Breaking, breaking down of soil, breaking down of, I would say, minerals. Minerals, rocks to get sign nutrients.

**[21:04]:** However, this, this process is rather slow and it takes time to happen. Okay, but in the monoculture, you need to grow things very fast, right? So that's why you have the fertilization program. Okay. All right. Okay, so just a quick summary for this section. Regardless of the nutrients that the plants require, they still have to gather all these nutrients, various elements or vitamins or something in order to form these three macronutrients. Okay? So this is what we call as macronutrients.

**[21:54]:** Why? Because they are the combination of all these elements together to form a more complex structure. And this story is of course true for both the plants and also us, the human. Okay, so the macronutrients that the plants need, Earth need as well, is the carbohydrates, fat, oil or lipids, and also the protein. Okay. So because the plants is able to make all of these various macronutrients from this building blocks, that's why we get the proteins from the plant. Okay, Protein example from these are all animal sources like the soy, the beans. Yeah, okay, you got the bean. Okay. And then the carbohydrates, that's the, your starch, your lipids, your oil, we get like your oil pump, right? Your oil pump produce palm oil. Okay. And that is needed by us humans and not just for our nutritional needs, but for various other industries as well.

**[23:18]:** And also water. Okay? Yes. In some part of. Of the world, they don't have the luxury like us. We have access to water all the time. Sometimes, you know, water is so scarce that you get the water from the thing that you eat. So, for example, like the, the watermelon. Right.

**[23:40]:** I hope I'm drawing this correctly. So watermelon also. Watermelon is about 95% water. So when you eat watermelon, not that only you get this protein, carbohydrate and lipid, but you get the water as well. Okay, so that is a very, very plus point. All right, okay. So what about the mineral nutrition and plants? So plants, as you know, very capable to Manufacture their own food because they are autotrophic as long as they are being provided with all the building blocks for the foods. Okay. As you can see, these are the building blocks for the food. It's pretty much the same thing. Okay? Carbon, hydrogen, hydrogen and oxygen. Okay? So these you can regard as the framework, frame work, nutrients, because regardless of any macronutrients that comes later, this is always the building block, the framework. Okay. Or the backbone. Sometimes people call this the backbone as well.

**[24:59]:** The backbone nutrient, Carbon, hydrogen, oxygen, the cho. Okay? And for the proteins, of course, protein, it's. It's more complicated and it's got many structure and function as well. So sometimes all this cho, it's going to be attached with various other elements like the nitrogen, sulphur and phosphate group as well.

**[25:30]:** So where do plants get all of these elements?

**[25:34]:** So in basic, it comes from the soil, okay. And also the atmosphere.

**[25:46]:** Because remember, plan plants has the two part. It has got.

**[25:56]:** Has got the ground, the canopy, and also the underground. And nutrient can get into the plant using various entries. Okay, Remember, plan plants do not only absorb nutrients through roots, okay? Plants can also absorb nutrients through leaf, through stem. Okay? There are openings.

**[26:32]:** So why is it important to study the mineral nutrition? So basically, mineral is inorganic elements. I hope you still remember from what you have learned in your soil science.

**[26:47]:** And the nutrient is the substance needed to do the necessary synthesis or of organic compounds. Okay? So minerals is usually the combination of two things. Two or three things. I'll give you. I'll give you one. See, simple example. You have your magnesium. Magnesium, right. So stand alone. This is called the element. Yeah. However, in nature, magnesium not present as an individual element like this, okay. You don't suddenly find, okay, there is a magnesium. Loss of magnesium in the soil, it is always bound to something. It's creating a mineral. So usually you're going to find something like magnesium chloride. Okay? Magnesium chloride, okay. And this is a type of mineral, okay. Some people want to call it salt. That is correct as well.

**[28:03]:** And of course, this has to be broken down first before the plant can utilize each of this magnesium and also the chlorine. Okay? Chloride is not element, okay. That is the form of this compound. When it's in the form of salt, the element is chlorine. Okay? So I would like to urge you to get your terminologies correct. Okay. When it comes to this chemistry stuff, for example, stuff like silicon or silica, which one is the element stain or silica? Stuff like that, Please get it correct. Okay? Right. So the mineral nutrition, of course, this is needed to promote your crop yield.

**[29:00]:** That is the sole point. Okay? It just. It's not because to make your plants happy, of course, this do make your. Your crops are very happy. Hence the production of crop yield. You can see that with the increment of fertilizer, the crop yield kind of increase as well, but only to a certain point. Only after that. If you increase the fertilizer, you're going to get some increment, but not as much as here. The slope is not as steep as here. Why? Because the utilization is low here.

**[29:43]:** Low nutrient utilization, very high nutrient utilization. That's why there's so many studies to study to know a crop nutrition for various crops and plant. Because if each crop and plants utilize nutrients differently, it depends on various things. Environment, soil type, soil type, the crop species, and so on. High nutrients utilization.

**[30:18]:** All right, okay. Still remember this. This is your beloved periodic tables of elements. Okay? How many, how many, how many elements do we have? You know what, let's ask Google. How, how many, how many elements do we have?

**[30:43]:** How many elements are there?

**[30:47]:** 118. Okay, we have 118 elements. Okay, this thing keeps increasing, okay, Depending on what else has been found or being managed to be manufactured in the labs. Okay? Not all elements are present in nature. Okay? Some elements are only lab made. So out of the 118 elements, Okay, plants require about nine plus eight. Plants require about 17 elements, 17 out of 118 as the essential nutrient to complete its life cycle. Okay, so and these elements, they reside in various group, okay, they are from group one, group two, you can see here from, from. From this size of the periodic table as well and also in the middle as well. Okay, so what is meant by essential nutrients? Elements which are required for the plant to grow from seed and to produce the seed again to complete its life cycle. Okay? Sometimes if you take one of the elements, the plants, it can grow vegetatively, producing all the leaves, stems, but it cannot produce the flowers because the nutrients are not enough.

**[32:25]:** Okay? So if you provide the nutrients which is lacking, then the plant can flower and then complete the life cycle. All right, so 17 elements. How do we know 17? So this came from a very long time ago, the experiment. Okay? I would like to remind you one thing depends on the books that you read. Some books say that you need 16 elements. Some books say that you need 17, some books say that you need 18. Okay? So we like to stay on the fence. So that's why we use the 17. If there's only 16, it doesn't take into account it minus nickel.

**[33:16]:** Okay, here we plus the nickel.

**[33:22]:** If it's 18, it can plus with the nickel, of course, nickel plus it can be very stick. It can be silicon, it can be vanadium, it can be cobalt and so on. Or sodium. Sodium. Okay. Sodium.

**[33:51]:** So depending on the school of thoughts that you go to, they're going to call within these numbers only. Okay. But I would say that 70 is good number. I mean, pretty much across the crop species around the world, plus whatever kind of soil that you're dealing with regularly. When you do the, the plants elemental analysis, you're going to find that these 17 regularly present in, in a plant. Right? Okay. So there's a concept of macronutrients and micronutrients. Okay? So from, from these 17 elements, you get the macro, you get the micronutrients with relations to the abundance of these elements inside the plants. Okay? Right. Okay, so there's a story down here when the nickel was added to this 17 elements school of thought. It's. Well, it's not, it's not very long time ago. Actually, it's only about 30 years ago. Okay. And there's a chronology how this is found.

**[35:24]:** Found. Okay. Scientists do not just one day decide, okay, this we have decided from the table, periodic table of elements. 17 elements are needed for the plant growth and reproduction. No, this is a continuous process. You can see from the chronology the element and when scientists found its essentiality in plants, okay, it started in the 1800s. You can see this is like 200 years ago. Right? So it gets progressively. Start with the, See, start with what? It start with the cho. The framework, okay? And then progressively all the way until nickel, okay. In the 1987, right. So how, how, how, how, how scientists know this? So they use the, the hydroponic technique. Okay? They can use the hydroponic technique or just the, the regular soil culture. They, they provide everything. Then they just take out one element each time to see if this element is removed, can the plant complete the life cycle?

**[36:46]:** Okay, so that's why it's a, it's a lengthy process. You need to see the effects of eliminating these elements to the plant. Okay, Right, So here's the summary of the essential plant nutrient. We're using the 17 elements, okay?

**[37:10]:** Three framework elements. Carbon, hydrogen, oxygen. And then you have the macronutrients, you have the micronutrients. For the micronutrients, you have your primary and secondary nutrients. Okay, Primary, secondary. And for the micronutrients, you will have these eight. Okay. Bear in Mind micronutrients, at least you need eight. But sometimes if your fertilizer can provide more, that can be beneficial to the plant. But in essence you only need this micronutrient. Okay?

**[37:58]:** So that's. That's when the terminologies of essential and beneficial comes in place. Okay. When nutrients are essential, it means the absence of the nutrients will prevent the plants from completing its life cycle. Okay? So it's needed regardless beneficial. If it's not present, it's fine. The plant can complete the life cycle. But if it's present, it can stimulate the growth and development. The plants is happier.

**[38:36]:** Okay, so these elements include the sodium, silicon and also se. This is selenium.

**[38:52]:** So this is quite different with us humans nutritional needs, okay. Because selenium, this is essential to us, especially for male. Okay. For male, this is of essence because this involves with the reproduction. Okay? So without wish, probably you cannot appropriate the species further. Right? So remember, we have different word nutrients, the cho. And then we have the macronutrient. This is just to. To review again, right? So that when you are on your own, when you read this, you do it repeatedly so that it can get into your head. Right? Okay. Oh yeah, Special note here. Cobalt, sodium vanadium and silicon or something called beneficial plant nutrients. Okay. Not required. Okay, but if they are present, then that's good, right? And they belongs under the micronutrients category. Okay. In addition to the original, how many original? Eight micronutrients. What are the original? I. I expect you to memorize this.

**[40:18]:** Okay. All these 17 elements. Okay? So the micronutrients include the iron, manganese, zinc, boron, copper, chloride. It's not chloride, actually, this is chlorine.

**[40:41]:** Let's see.

**[40:44]:** Chlorine chloride.

**[40:54]:** Not choline. Choline is something chlorine sometimes Google suggestion. Really not helping.

**[41:15]:** Let's see.

**[41:20]:** Okay. Chlorine, it's the element. Chloride is an anion. This. This guy here got this charge here. Okay. Right. So this is the one that comes with the minus one. Alright, so some nomenclature can be confusing. I, I can understand that. But please bear in mind they might sound alike, but chemically they act differently. Okay? Chlorine is the element that you see on the periodic table of element. Chloride is what you have when. What the plants absorb. Okay? So please get your terminologies correct. Okay? Right. So how you. You can see here. And the plants nutrients, the elements are classified based on the abundance.

**[42:23]:** Abundance in plants.

**[42:30]:** Abundance in plant. That's why we use the words as the framework. Macronutrients and micronutrients. Meaning that for the framework elements, these present the most macronutrient the second and micronutrient least. There is another way to scientists use to classify the these elemental needs of the plant. Okay, so the classification of plant nutrient can be also be based on the biochemistry and also the physiology. Okay. For the biochemical classification, we have four groups, okay? We have group one, group two, group three and group four. Okay? So these are be basing on the biochemicals roles of these elements in the plant. Okay. For the group one, these are just, these are just the description go straight to the table. So the group one is the nutrients that are part of the carbon compound. So this is the backbone the fundamentals of the organisms. Okay, so you, you have your nitrogen and also sulfur, okay?

**[43:55]:** And then group, group two, these nitrogen, sulfur attach to the, your framework. Okay? And then group two nutrients that are important in energy storage and structural integrity. So you have your phosphate, silicon and also boron. And then you have group three, which is in ionic form. Okay? You can see here Group 3, yeah, they are in ionic state. Okay. They are not like elements in, from. From other group. Okay? In, in other group, they. They involve in the reactions. For there are many biochemical reactions, okay? I, I think you from your biochemistry lesson, you know, there are many reactions that happen. The hydrolysis, esterification, you know, there's so much going on each of these elements involving that, right? So but when they have different roles or react differently in terms of biochemistry, they are grouped together based on the same behavior. That's why we get all of this grouping system.

**[45:25]:** Okay? So and finally for the group number four, these are the elements presented in the chelates. Keylets means chelate from the word claw. Claw. They are, they are bound, bound, bound to something.

**[45:47]:** Meaning that they don't. They are not present on their own, but they are rather chelated or clothed to other substance. Okay? Right. So much of these are actually involved.

**[46:04]:** For the enzyme reactions, they are required in a very small amount. But if one is not present, for example, let's take one, the zinc. If the zinc is not happen, some of the biochemical reactions in the photosynthesis can happen as well. Right? So when, when, when this is happening, the plants cannot function. Well, just imagine if photosynthesis cannot happen, can the plants grow? Eventually the growth will stop and the plant will look stunted and sadly it's going to die very soon as well. Right. So these elements, according to the biochemical classification, they are required. Okay? But depending on the rules that they have. Okay, right. I, I Don't go into detail about this classification because this is not crop nutrition course.

**[47:13]:** I did teach crop nutrition a few years back. If you are interested with this course to learn further about this nutrients classification and absorption in the plant, maybe you can take it in your. I think in your start your third year you can take AGR 4401. All right? Not. Not with me. I don't think they will because we have more lecturers now. I thought that before because the faculty didn't have lots of lecture to teach this. So that's why I had to teach that. Right? Okay. Right. So when you have a plant presented like this, you can now know each nutrients, number one, each nutrients, they have functions in certain parts of the plant. Some nutrients are always functioning present throughout the plants like the framework nutrients. It is present in the stem, it is present in the leaf, it is present in the flower, it's present in the fruit.

**[48:16]:** Okay? Some nutrients, they are present for this specific function of the plant. For example, to create a more root mass, you need phosphorus, okay. To to make a leaf, lots of leaf you need. And lots of nitrogen. Okay? And for the reproduction you need the zinc, magnesium, boron, phosphorous. And for the stress management you need potassium, zinc, copper, calcium, iron and to some degree actually silicon as well. Right? Okay. Now what impact can the soil have on the plant nutrients?

**[49:04]:** You see, in the soils there are various elements present. There are various nutrients present. However, not all of them are available to the plant. Just because they are present the nutrients does not mean they are available.

**[49:30]:** They can be available for the plant to uptake and absorb into the body if certain criteria are met. First, one of the criteria that affects nutrient availability.

**[49:50]:** Is the phone. Alright, so let's look at here. This is the, this is the midline. This is the PH neutral, as you can see here. When the PH is too acidic, like in here, it's like in too acidic here. Meaning that below, below 5, towards this side, much of the macronutrients are like insufficient macro. Okay. But when it's too alkaline, as you can see here, Much of the micro insufficient.

**[50:50]:** So the best bet for the plant is to have slightly acidic. It is around here, this region here.

**[51:01]:** So when you have your PH of your soil or your nutrient solution, if you're dealing with hydroponic, if the PH still stays within this region, you're going to get your best bet because both of your macronutrients and also your micronutrients are going to be available for the plants. Okay? So the ph of the soil, the PH of the water, they're going to change over time. Okay, that. But the plants have the mechanism to balance this so that these nutrients are present to the plant when it's needed. Okay, so how the ions of these elements. Okay, remember one thing. The elements that you have learned, the 70 elements that you learn, some of them, they are absorbed in the form of ions, specifically cation. Okay. How plants, There are many mechanism to this. Okay. But we're not going to go into deep. But one of the methods, there are many methods of how plants, the roots of the plants absorb the, the nutrients.

**[52:24]:** One of the method is the root has released lots of this hydrogen. When this hydrogen is released, it will displace all this cation. Cation. Cations. Remember, this is the plus positive. So these cations includes nutrients like potassium, magnesium, calcium and copper. So when this happen, this hydrogen will displace all these cations. And when they are displaced from where? From the soil particles, they are going to be available to be absorbed into the roots. Okay. Right. So this is one way of nutrient absorption by the root. That, that is all you need to know up to this point. Actually, bear in mind there, there are more methods to this. Okay. Yeah. So it shows you that the root hair is very important. So let's look at the root hair. What, what's the deal with the plant root? Okay, so this is your, your root, the regular root that you always see.

**[53:49]:** Remember roots got the zone, various zones. Okay. We have the meristematic zone, we have the elongation zone and the maturation zone. So the meristematic zone is actually right in this region. Okay. Not the apex. Okay. This is not the youngest or the meristematic zone. Okay. This is actually part of the structure that is called the root cap. Okay. So you got the meristematic zone, then you got your elongation zone and got. You get your maturation zone. So in the maturation zone you will have this special structure called the root hair. Root hair actually is the outgrowth out growth out the epidermis.

**[54:45]:** There are so many root hairs. Why? Because this improve the surface area. When the surface area increase, the plants can absorb more water and nutrients.

**[54:58]:** Right.

**[55:03]:** So you can see from here there are various elements actually in the ionic forms that can be absorbed throughout the root regions. For example, the calcium is typically absorbed in the apical regions and potassium nitrate, ammonia absorbing the elongation region and so on. This is not at the universal for like every single species follow this kind of absorption scheme. No, but kind of in general to to show you that the roots is actually a very active location. Deals with the absorption of these various nutrients depending on the region of the root. This is very small. Okay. This is maybe like from here to here, maybe like 1 millimeter only. But you can see the complexity of the structure, how it gets so complex to the point all these elements and nutrients can be absorbed very efficiently. Okay. So at this point, I expect you to familiar enough with this anatomy of the root, the regions of the roots, meristematic elongation and maturation, and also the roots.

**[56:26]:** Maybe you need to be able at this level to understand and to know the structure. For example, in the middle here, this is your vascular structure. So your vascular, you got your phloem and your xylem. Okay. And then you have your root hairs, you got your epidermis. And then right after the epidermis you get your ground tissue of your root, which is the cortex.

**[56:57]:** Cortex, okay. And then you will have your endodermis. Why do you need to know this? Because this have impact on the, on the journey of the nutrients absorbed. Okay. Which you're going to see in a bit, right. And then you're going to see right in the middle your vasculars system. Right? Yeah. So look at, look at the, the graph, the graph here. This is your root going up this way. This is the nutrient concentration in the soil going this way. This is distant from the root surface. You can see here. When you are farther from the root surface, the nutrients concentration is also depleting. Okay? It's also depleting. So what's the problem here?

**[58:02]:** Can you see there is a gap here? There is a gap and there's a gap here. So the plant actually, even though it can on its own absorb lots of nutrients, but it's still not efficient. Okay. Some regions still are not accessible to the roots. Okay. Hence that's why you get this.

**[58:31]:** So how do plants deal with this? This is when the symbiotic relationship with other micro, especially fungus, come into play. Okay. The mycorrhizal association, okay. When the roots have some kind of association with other organism, for example, this mycorrhizal fungi, it improves the nutrients absorption in terms of the area.

**[59:10]:** See, the fungus can grow into the region, So it can, even though the distance from the root surface is farther. Now these fungus can act like the extra head. So to grab the nutrients from the farther region. So there is a few types of the mycorrhizal interaction. The first type is the ectotrophic mycorrhizal ectotrophic Meaning that this mycorrhiza ecto means outside, trophic, it means surface. Meaning that these mycorrhiza do not penetrate the cells or the tissue inside the root. They just live on the surface that you see here. It's just on the surface or in between cell, in the crevices of the cell, but never inside the cell. You can see all these, all these fungal, fungal sheath here. They're just growing among the cells, in between the cell and on the surface of the cell or the root tissue, but never inside of it.

**[1:00:36]:** Okay, so that's why it's called the ectotrophic mycorrensa. Okay. Collectively this is form when it's formed. The netting structure like this, this is called the heartic net.

**[1:00:53]:** Okay, so what's the, the value of having this kind of microsociation? So the fungal hyphae this year, this hyphae is finer than the root has. So it can reach beyond nutrient depleted zones in the soil near the root. Meaning that the regions where the roots are not able to reach the hyphae of the fungus, they can do the job instead. So what, what do the roots, the fungus get from this? Well, this is an association. So the fungus can get, number one, they can get a home. And secondly, they can get whatever that the roots secrets. So the root is going to secrete lots of things as you can, as you have seen earlier, it secretes hydrogen. It can also secrete various amino acids, sugars and ex, lots of exudates. We call it exudates, exudate. So this can be the food for the fungus. Right, so the fungus is very, very happy.

**[1:02:07]:** The roots is also very, very happy. So this is a happy, happy relationship. The second type is, it's the vesicular arbuscular mycorrhizal fungi. This is a bit different because this guy here, they never penetrate. They are ectotrophic, meaning that they live outside the surf or just on the surface, but for this vesicular arborusicular day, penetrate inside. Okay. The hyphae growth inside the cells in the cortex here. So this is your epidermis, this is your cortex. Okay. So it grows on the surface as the ectotrophic mycorrhiza here. And also it grows inside the cortex tissue. Okay, so what does it do? Why the name is like this? So vesicular, Vesicular, referring to the vesicles that this mycorrhiza produce in the cortex cell. This is the vesicles, okay, the small balloons here, arbuscular. This is actually Latin. I think it's arbor Arbo means tree. Where is the tree looking?

**[1:03:35]:** This region here. You see, when it penetrates, besides creating the vesicles looking structure, it also create this branch looking structure that we call as the arbuscule. So what does this do?

**[1:04:03]:** It improves the absorption by the hyphae. Okay. Reaching beyond the nutrient depleted zone. Okay. So the function is the same, but the anatomy, the structure is different than the atomic trophic. But the very important thing is this type of mycorrhizal association. It grows inside the cortex in addition to the surface. Okay? Right. Okay. So this is the summary of it. Alright, so ectotrophic simple diffusion from the hyphae in the hatinet to the root of the cell. Okay. For the vesicular arbuscular mycorrhiza you have the simple division like the ectotrophic mycorrhiza. And also the arbuscules degenerate as new, as new ones are forming. So the nutrients release into the host cell. So this structure here, they're not going to be in here forever. When, when they degenerate or degrade, the nutrients are going to be released into the cells. Whose cells? The root cell, the cortex cell.

**[1:05:20]:** And this can be absorbed by the root. Okay. So it's going to be a heavy happy situation eventually for the symbiotic relationship. I think this is a very, very fascinating phenomenon in nature. So at first it looks like this fungus kind of like, oh, I just want to, it looks parasitic at first, but eventually when it has managed to create the reproductive structure, this part is going to die eventually. The dead part actually is the part that is going to be beneficial to the root cortex. But in the process they're going, they are helping with the nutrient absorption as well. Okay, all right. About the nutrients. So the nutrient has been absorbed now you learn that the nutrient has been absorbed by the roots, you know, release some, some kind of substance like the hydrogen to displace the cations from the soil surface. And also there's some mycorrhizal association with the roots.

**[1:06:39]:** So how, how the nutrient travel from the soil now into the root and then to the rest of the planet. So there, there's a several pathway that you're going to see now. So that's, number one is called the apoplast pathway. This is the continuous system of, in the cell wall. Okay, so this is your, let me put it this way. So this is your soil.

**[1:07:13]:** So your nutrient get absorbed into your root hair and that is going to travel across these various cells along the way. So it's going to meet with the epidermis, it's going to meet with the cortex cells, and then it's going to meet with the, okay, this guy here, the endodermis pericycle, and then eventually the xylem and phloem right in the middle. Right. When it only go across. Across the cell wall, it is called the apoplastic pathway. Okay, how do. Let me.

**[1:08:01]:** You can see here, it doesn't get into the cell here, not in the middle of cell. It kind of detouring.

**[1:08:18]:** Around the cells using the cell wall pathway. So apoplast is actually the cell wall path.

**[1:08:32]:** Then you have the second one, which is the trans membrane, and the third one is the simplus. So what's the difference now is for the simplastic pathway, instead of going along the cell wall like you saw earlier, now it goes through the cell, from one cell to another cell to another cell to another cell, across the. What you have in the middle here across the cytoplasm.

**[1:09:13]:** Okay. If it does not penetrate the plasma membrane, but only through the tunnel that you see here. Can you see the tunnel here? This tunnel here that connects all this cell here, this. These are called plasmod plasmodesmata. So these are the tunnels when the movement of the nutrients and water go through the cytoplasm and through the tunnels to the next cells without going through the plasma membrane cell wall. This is called the simplus pathway. But when it goes through the plant membrane, like here, I'm just going to.

**[1:10:20]:** Yeah, something like this. The movement you can see, you. You can see here. Does it use the plasmodesmata? No, it just goes through this. So when it goes through like this, it is called truss membrane because it crosses the plasma membrane.

**[1:10:42]:** I have this summary of this movement. Okay, so you have three. You have your apoplastic represented by the dotted line. You see the movement of the water. So this is your soil again, this is your root hair. It only uses the cell wall.

**[1:11:03]:** Okay. Only use the cell wall. All right. Up to this point in the endodermis, this is what you need to pay attention to. In the endodermis, there is a presence of an impermeable structure. It's called casparian strip.

**[1:11:30]:** So this is impermeable. So the apoplastic pathway can only be true from the root hair up to the cortex. When it comes to the endodermis, this is the movement of the nutrients. And water is forced to undergo this movement here, which is the simplest pathway. So the simplest pathway Gets absorbed, you go through your cytoplasm and then you go through the tunnel. This is the tunnel here. This is your plasmodesmata. Plasmodesmata. Okay? And then you're going to see that it goes through the plasmodesmata all the way until the xylem vessel. Okay. And the third one is the transmembrane. This guy here, it doesn't care. It just get absorbed into the cell wall and then goes through the cytoplasm and then it penetrates this. You can see the blue line here. This is your plasma membrane.

**[1:12:39]:** Sorry, plasma membrane.

**[1:12:45]:** And then it goes through all the way until the xylem vessel. Okay, so please remember this, this pathway of the nutrients and water. Okay, if it's transmembrane, it can be that way from the root hair all the way until the xylem vessel. But if the apoplast is not possible, it only possible from the cortex. And then when it comes to endodermis, apoplastic pathway is stopped. Okay, but from the pericycle to the parenchyma and to the sinovacle, it can be the apoplasty again for the simplus. Yes. It can be from the root hairs for the cross cortex, endodermis and so on, as long as you have splasmodesmata.

**[1:13:41]:** If suddenly one of these cells do not have plasmodesmata, it is forced to use the transmembrane or apoplastic pathway. Okay, so please remember this is your root anatomy. You have various cells in here and then you have your special endodermis that contains the casparin strip. This is the casparin strip. It is in the cell wall. That's why the apoplastic pathway is stopped and the journey of the nutrients is prevented. Forced to use the transmembrane or the symplastic pathway. Right, so what do you get from all of this after you have understood this so far? It shows that you can manipulate mineral transport in the plants to increase the plant growth yield, increase the plant nutritional quality and density, and also to increase the removal of soil contaminants. Okay, this is actually for. For, not for the yield, but for the environment.

**[1:14:58]:** You can use crop to clean contaminated land. Okay, we can use that. And the, the process is called phyto remediation. Okay. Yeah. All right. Okay. I think for, for degree level, that is all that you need to know because from this part here until all this down here, this is actually meant for the postgraduate or the crop nutrition class. However, I would strongly suggest you to read beyond this, it's not difficult. It tells you about what kind of nutrients present in the plants that you actually do it. You have no, but you know by now and the relative concentration and also the, the amount of micronutrients in terms of dry matter. Okay. And this is actually for the crop nutrition class. Okay, you can read, you can read. It does. Maybe it can help for your further understanding. Okay. But one thing, if it's good for you to know, some elements in the plants, they are mobile and immobile.

**[1:16:36]:** Okay. So mobile elements, meaning that they can move from one tissue to another tissue, meaning that if the tissue is old and senescent, it can be remobilized to much younger and actively growing tissue. So these are the mobile elements. But however, some elements are immobile like this calcium, sulfur, iron, boron. So meaning that they stay in the tissue forever. They just do not live. So that's why this is important for the. When you are diagnosing the plants. When the symptoms are showing in the old leaves, usually it involves the mobile nutrients. But when the symptoms, by symptoms here I mean the symptoms of insufficiency is seen in young leaves or young parts of the plant. It involves the immobile nutrients. Okay. All right. I think that is all for, for today. Yep, yep. That is all for today. So I hope you have learned something.

**[1:18:00]:** I think maybe lots of things you have learned. Okay? All right. What's the time now? Okay. 8:48. So I'll be wrong until I give you another five minutes or so until 8:53. If you have any question you can ask, okay.

**[1:18:22]:** Or maybe you can ask when you see me again on Wednesday to relap.

**[1:18:36]:** So I'll be here, okay? You got any question, just ask until 8:53 it.

**[1:19:17]:** Oh please, please do your assignment, okay? From, from before the mid semester break, your photo respiration assignment. Remember you have a couple of questions you need to answer. So yes, yeah, that's. Please do that with your groupmate. So this Wednesday when you come to the, to the lab, let's see what have you answered? Okay. Because this is going to be your carry mark. So if you have done your lab report or you want to ask me about your lab reports, if you're uncertain about anything, you can ask me on this Wednesday, okay? If you're done, you let me know that you're done. I'll just mark all your lab reports, okay? Just submit in the folders provided, okay. If you have time, do it right away, okay? I don't want you to be too busy at the end of the semester. Okay. It's just too bustling.

**[1:20:25]:** Don't do that. If you're done, you want to get it over with. Whenever you see me during the lab, you have your. Maybe you want to let bring your laptop, show it to me. If it's good, it's good. Just submit. Right?

**[1:20:46]:** Remember you got your first test. Okay. Please do that as well.

**[1:22:53]:** Okay. If you have haven't got any more further question. I think that's all for today. So thank you for joining in and I'll see you again on Wednesday.