Question

State the role performed by plant hormones. Name a plant hormone which is essential for cell division.

Answer 1

Hint: Plant hormones are signal molecules that regulate cellular processes like growth, development and nutrition in targeted cells locally and they also move from one location to another.

Complete answer:
Plant hormones are signal molecules which are produced inside the plant at very low concentrations.
> Role of plant hormones:
Plant hormones control all aspects of plant growth and development, from embryogenesis, the regulation of organ size, pathogen defense, stress tolerance and through to reproductive development. Plants produces several hormones and their roles are mentioned below:

Sr. No.	Hormones	Function
1.	Auxin	Root growth, stem elongation and fruit development
2.	Cytokinins	Root growth, help in germination and cell division
3.	Gibberellin	Seed and bud germination, stem elongation and fruit development
4.	Brassinosteroids	Inhibit root growth
5.	Abscisic acid	Promote seed dormancy, inhibit root growth
6.	Ethylene	Fruit ripening

We can see from the table that cytokinin is essential for cell division. Cytokinin is a photo hormone. Cytokinins are synthesized in the roots. They move upward in the xylem and reach to the leaves and fruits. It is involved primarily in cell growth and cell division. It also helps in root growth, regulates axillary bud growth and apical dominance.

Additional information:
Cytokinins are produced in the root apical meristems at the tip of the roots and travel upward with water and travel up the stem through the xylem.

Note: Division of cells in plants is promoted by both auxins and cytokinins as they act synergistically. They are secreted mainly in growing areas of plants and act locally while cell growth is controlled by auxins, gibberellins and cytokinins.