Plant growth is an entirely natural process, one that is seemingly out of our hands. As we water, fertilize, compost and watch, we can only hope that the plant grows according to our needs, at least in some way. However, if you don’t know about PGR and what they are supposed to do, then plant growth is entirely out of your control.
Put simply, PGR is known as Plant Growth Regulators and are plant hormones that can regulate, i.e. speed up or slow down the growth or ripening of plants.
The plants themselves produce these hormones internally, but that is done in minuscule concentration. These hormones do the same foundational functions as human DNA – they determine plant growth, the direction of growth, determining sex, plant life cycle, and even death. Without these hormones, a plant would not be able to function.
But PGR on the other hand, are synthesized by us externally, which is why they are known as exogenous plant hormones. They are widely used in the process of Agriculture to regulate crop growth and ensure fruitful agriculture production. However, these chemically synthesized growth hormones have to be used carefully and in selected quantities because too much would make the fruit ripen fast on the outside while keeping it raw in the middle.
This is exactly why some of the fruits that you eat appear so good on the outside while being horrible on the inside!
Now, let’s talk in brief about some well-known plant hormones.
1. Auxins
Produced at the terminal or last buds in the plant, their job is to suppress lateral bud growth. This ensures that a plant initially grows tall before it branches out to a more rounded appearance. Auxins also stimulate root growth to keep the plant base secure.
2. Cytokinins
Probably a name that you remember hearing back in school, cytokinins are essential to plant hormones. They work together with Auxins and form a significant influence on the plant’s growth and development. They also help in the process of cell division.
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3. Abscisic acid
The ‘stress reliever’ and a plant’s best friend, abscisic acid or ABA is one of the most important among the PGR. It acts as an inhibitor whenever the plant is feeling or will most likely be feeling some stress or pressure. For example, it inhibits leaf growth during unfavorable conditions, closes the stomata whenever there is a shortage of water, etc.
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4. Gibberellins
Carrying out the opposite functions to the ABAs, Gibberellins or GAs, instigate growth and development in the plant. They mobilize enzymes that assist in food production that occurs during plant growth. They have a hand in cell division, flowering, increasing the size of leaves and fruits, etc.
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Knowing what these hormones do and how exactly they affect the plant is crucial when you’re trying to cultivate a garden of your own. Even though it might be a natural process, you will need to get involved at times and steer the plant in the right direction.
