Question

What are phytohormones? Give examples of these hormones and at least one function.

Answer 1

Hint: Plant hormones are organic molecules found in plants at very low concentrations. These hormones are formed in nearly every part of the plant and are distributed throughout the plant.

Complete solution:
Phytohormones, also known as plant growth regulators, are chemical compounds secreted by plants that control their growth and development.
Here are some examples of phytohormones:
1. Auxin, which is a plant growth hormone secreted by the plant's tip of the shoot. It stimulates the plant's linear growth.
2. Abscisic acid is also a hormone that inhibits plant development. The wilting of leaves is caused by it. Also, this hormone is in control of stomata closure, seed dormancy, among other stuff.
3. Gibberellins stimulate the development of the plant's stem, and break seed dormancy.
4. Cytokinin is a hormone that stimulates cell division. It can be seen in environments where cell division occurs at a faster rate.

Note:
We know that all growth and development processes, such as cell division, enlargement, flowering, seed forming, dormancy, and abscission, are regulated by plant hormones. Thus the plant hormones are classified into two groups based on their actions and they are: Promoters of Plant Growth and Inhibitors of Plant Growth. They will work together or independently. Hence, different hormones may play either complementary or antagonistic roles. Thus it is clear that hormones, along with extrinsic causes, play an essential role in processes such as vernalisation, phototropism, seed germination, and dormancy.