Question

Explain brefly about Auxin, Gibberellins, Cytokinins and abscisic acid.

Answer 1

Auxins, gibberlins, cytokinins and abscisic acid are phyto-hormones. Auxins promote cell enlargement and cell differentiation in plants.They also promote fruit growth.
Gibberlins promote cell enlargement and cell differentiation in presence of Auxins. they also help in Breaking dormancy in seeds and buds. they also promote fruit growth.
Cytokinins promote cell division, help in Breaking dormancy of seeds and buds, delay the ageing in leaves, promote the opening of stomata and promote fruit growth.
abscisic acid promotes the dormancy in seeds and buds, promotes the closing of stomata and promotes the wilting and falling of leaves.

Answer 2

Answer:

AUXIN

Auxin is a plant hormone produced in the stem tip that promotes cell elongation. Auxin moves to the darker side of the plant, causing the cells there to grow larger than corresponding cells on the lighter side of the plant.

What is the role of auxin in plants?

Auxin is a key regulator of plant growth and development, orchestrating cell division, elongation and differentiation, embryonic development, root and stem tropisms, apical dominance, and transition to flowering.

What is the action of auxin?

The plant hormone auxin triggers complex growth and developmental processes. Its underlying molecular mechanism of action facilitates rapid switching between transcriptional repression and gene activation through the auxin-dependent degradation of transcriptional repressors.

Why is auxin not a hormone?

Although auxin may act at low concentrations and can be transported, it is not produced in a specific tissue. Auxin may also be too pleiotropic to be considered a hormone. ... In fact, auxin rather appears to be a signal that triggers a pre-set system than a hormone with a specific function.

Gibberellin

Gibberellins (GAs) are plant hormones that regulate various developmental processes, including stem elongation, germination, dormancy, flowering, flower development, and leaf and fruit senescence. GAs are one of the longest-known classes of plant hormone.

Cytokinin

Cytokinins (CK) are a class of plant growth substances (phytohormones) that promote cell division, or cytokinesis, in plant roots and shoots. They are involved primarily in cell growth and differentiation, but also affect apical dominance, axillary bud growth, and leaf senescence.

Abscisic acid

Abscisic acid (ABA) is a plant hormone. ABA functions in many plant developmental processes, including seed and bud dormancy, the control of organ size and stomatal closure.

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