Plant and Animal Hormones Important points

Plant and Animal Hormones Important Points

1) Name some plant hormones:-

1) Auxins

2) Cytokinins

3) Gibberellins

4) Abscisic Acid (ABA)

5) Ethylene

2) What are the two types of Auxins ?

Auxins are classified into two types, namely natural auxins and synthetic auxins

1) Natural Auxins : Auxins produced by the plants are called natural auxins. Example IAA (Indole - 3-Acetic Acid )

2) Synthetic Auxins: Artificially synthesized auxins that have properties like auxins are called as synthetic auxins. Example : 2,4D (2,4 Dichlorophenoxy Acetic Acid)

3) What is apical dominance

The auxins produced by the apical buds suppress growth to lateral buds. This is called apical dominance.

4) What is Richmond Lang effect?

Application of cytokinin delays the process of ageing in plants. This is called Richmond Lang effect

5) What is bolting ?

Treatment of rosette plants with gibberellin induces sudden shoot elongation followed by flowering. This is called bolting

6) Which hormone is called as stress hormone?

Abscisic acid (ABA) is a growth inhibitor which regulates abscission and dormancy. It increases tolerance of plants to various kinds of stress. So it also called as stress hormone

7) Write the physiological effects of ethylene

1) Ethylene promotes the ripening of fruits. eg. Tomato, Apple, Mango, Banana etc.,

2) Ethylene inhibits the elongation of stem and roots in dicots.

3) Ethylene hastens the senescence of leaves and flowers.

4) Ethylene stimulates formation of abscission zone in leaves, flowers and fruits. This leads to premature shedding

5) Ethylene breaks the dormancy of buds, seeds and storage organs