Question

What are the roles of plant hormones?

Answer 1

Plant hormones or phytohormones:

1. Plant hormones are the chemical messengers present in plants.
2. Plant hormones play a similar role to hormones in the human body by regulating an array of physiological and biochemical pathways in plants.
3. Plant hormones are of the following types: Auxins, gibberellins, cytokinin, abscisic acid, and ethylene.

Role of plant hormones:

Auxins:

1. Auxins regulate plant growth.
2. Auxins lead to the elongation of the apical meristem, flowering in plants like pineapple, as well as phototropism.

Gibberellins:

1. Gibberellins phytohormones are responsible for the germination of dormant seeds.
2. Gibberellins lead to flowering and an increase in the girth of plants and their fruits.

Cytokinin:

1. Cytokinins lead to vascularisation and lateral branching causing an overall dense growth of leaves by reducing the accumulation of sugar and increasing the synthesis of chlorophyll.
2. They facilitate cell division and the formation of new buds, stems, etc.

Abscisic acid:

1. Abscisic acid hormone is crucial for maintaining seed and bud dormancy, the control of organ size, responding to abiotic factors, and regulating stomatal closure.
2. Thus, they act as growth inhibitors.
3. Abscisic acid is important as an immunological defense of plants against fungal pesticides.

Ethylene:

1. Ethylene is an inhibitory phytohormone that reduced growth and leads to senescence or aging of the plant.
2. It also leads to the ripening of the fruits.