Original video: https://youtu.be/xtAOUytuyiU
This video introduces plant hormones (phytohormones or PGRs), the chemical messengers that regulate plant growth, development, and reproduction. Learn about the major classes of hormones, including promoters and inhibitors.
Video Transcript:
These are the hormone classes. There are many hormones, let's say 10,000. All these hormones belong, more or less, under these five main classes: auxin, cytokinin, ABA (abscisic acid), gibberellin, and the gas hormone, ethylene. All are in the form of fluid, liquid, except ethylene. Ethylene is the only gaseous hormone.
Do humans have gaseous hormones? What about pheromones? Humans have pheromones too. Babies, when first born, don't really open their eyes. Notice that? Blind babies in the first weeks of life like to cry a lot. But when the mom is closer, it stops crying. The mom doesn't have to make a sound, just stands next to it, prepares the baby diaper, and the baby will stop crying. That is evidence the baby is sensing the mom, not involving any contact.
It's the mom releasing pheromones. Some people, when they have a crush on somebody, they like to stay next to the person. That's the pheromone talking. You just like the presence. Maybe the guy or the girl is wearing expensive perfume. I'm not talking about the perfume. It's just you like to sit next to the person. If you hate to sit next to the person, probably that's an evading pheromone.
All these hormones in humans, we can produce gaseous hormones, but I do not know how far scientists have studied it. There are studies involving that. For plants, surely ethylene is there. There are an abundance of studies involving ethylene, it's very fascinating.
From these five classes of hormones, they are further divided into two: growth promoters and inhibitors. Promoters incite growth, like elongation, expansion, proliferation. These include auxin, cytokinins, and gibberellins. Inhibitors stop, make it less young, like senescing, or completely stop it from acting in a usual manner.
Certain tissues in plants, especially reproductive tissue, if ethylene is applied, you can kill the male tissue. That is inhibiting. In agriculture, if you apply ethylene, you can change the sex of the flower. Not because the hormone is doing surgery, it prevents the growth and kills the male tissue, leaving only female.
There are types of PGR. One is the promoter: auxin, gibberellin, cytokinin. There are two groups: one promoting growth, such as cell division, cell enlargement. I mentioned this earlier. Why do plants need all these various hormones just to promote growth? Can it be just one hormone?
Because plants want to be specific in either division, enlargement, or targeting specific organs: flowering, fruiting, seed formation, or vegetative growth. It's not like humans. Your red blood cells, can they enlarge? No, it doesn't have a cell wall. If it enlarges, it's going to pop.
Your liver cells, heart cells, myocardial cells, can they enlarge? You're going to burst the cell. Plants, because of cell walls, the cell can swell out, enlarge, double. Many things, dimensionally speaking, can happen to the cell. This is not possible for humans.
Many neuron cells have been around since your birth, pretty much that way. The cells in your eyes. I don't know whether this is true or not, they said that your eyeball is pretty much that size as you were born. They don't enlarge. If they enlarge like your hand, your baby hand is like one-tenth of this hand now. If your eyeball becomes 10 times bigger, instead of, are you having what? Coconut? That will make you look weird, alien-like.
Not all cells in your body grow or expand proportionately. Some stay that way since your birth. What stays the same since your birth? It doesn't increase in number, meaning it does not proliferate. It stays the same from the day you were born.
What? You were born, you got that much. By the age of 40, you got that much as well. Fingers? Not cells. Ears, so your ear do not get bigger. Actually, your ears, as you get older, will grow longer. Your earlobe will go longer. Look at a 100-year-old person, you can see the ear is coming down. The corneas actually get replaced every seven or eight years. The entire atom in your body actually got replaced with a new one. You are not you.
Egg cells. When you first form in the fetus, you got something like 2 million eggs. When you are about to be born, it's got reduced to 200,000 eggs. Then when you are born, you are only left with around 300, and these are the eggs that are going to mature and become your ova. So, it stays the same. At the age of 15, because you got excited, you go to a concert, your egg multiplies. No, that's not happening. No matter how much you got excited seeing your favorite band, it's not going to get multiplied, it stays 300 from the beginning. That's what you get. Humans can't do that. The eggs do not get multiplied, but they do get mature in the corpus luteum, in the ovary. The guys cannot appreciate this. Before your red days happen, you are like just joining a cult. So, if your friend, your best friend is unreasonable, they cannot control that, that's evolution.
Another type is the inhibitors. I have said the fundamental of it, it's to inhibit. Inhibiting is not necessarily a bad thing. Inhibit to do one process in order to allow another process to happen. If you are not getting inhibited, you are as tall as a coconut tree now. Tell me, which supermarket is going to sell your clothes? So, inhibition is not a bad thing, after all. But we don't want it to happen before the time. We want it to happen at the right time so that the organism, including yourself, can function beautifully.
Keywords: Plant Physiology, Plant Hormones, PGRs, Plant Growth, Promoter, Inhibitor
Watch fill video: https://youtu.be/wuspDfZHpho
Attribution 4.0 International — CC BY 4.0 - Creative Commons
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