Question

What are the functions of the following?

1)Auxins

2)Cytokinins

3)Abscisic Acid

4)Gibberellins

5)Ethylene

please fast, I have exams day after tomorrow

Answer 1

Both auxins and gibberellins are plant hormones that function to promote plant growth through cell elongation. Auxins, in particular, respond to the influences of light availability and gravity, and also promote the differentiation of vascular tissue. Gibberellins are more responsible for growing shoots and promoting cell division in addition to cell elongation.
Cytokinins help in cytokinesis. Actually, kinetin was first discovered, not naturally from plants but differently. When scientists were in search for natural substances with cytokinin like activities, they isolated zeatin (from corn kernels) and coconut milk. After the discovery of zeatin, several naturally occurring cytokinins were finally discovered. It was found that these cytokinins were synthesised naturally in regions where rapid cell division takes place.

Abscisic acid
Application of minute quantity of abscisic acid to leaves shall reduce transpiration to a great extent through partial closure of stomata. It conserves water and reduces the requirement of irrigation. Photosynthesis is reduced to a lesser extent (Transpiration 56%: Photosynthesis 14%


Ethylene
Kerosene lamps and hay were previously used for stimulating colour development and ripening of some fleshy fruits, e.g., Banana, Mango, Apple, and Tomato. The effect is due to ethylene. Ethylene lamps are now specifically used for this purpose.