Question

what are plant hormone ? write their functions​

Answer 1

Explanation:

Plant hormones are signal molecules produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of growth and development, from embryogenesis, the regulation of organ size, pathogen defense, stress tolerance and through to reproductive development.

The plant growth is controlled by certain chemical substances called the plant hormones. These are also known as the growth factors, growth substances, plant growth regulators (PGR) or phytohormones. These can either promote or inhibit the growth of the plant.

On the basis of the function there are five types of plant hormones:

1. Auxin

2. Gibberellin

3. Cytokinin

4. Ethylene

5. Abscisic acid (ABA)

Answer 2

Functions of plant hormones:

${ \red{ \bf{ Auxins: }}}$

${ \green{ \bf{ Site\: of \: Synthesis:}}}$

Synthesized primarily in shoot apical meristems and young leaves.

${ \green{ \bf{ Functions: }}}$

Promote cell elongation.

Suppress the growth of lateral buds.

Delay fall of leaves.

Induce formation of parthenocarpic fruits.

${ \red{ \bf{Gibberellins: }}}$

${ \green{ \bf{ Site\: of \: Synthesis:}}}$

Synthesized primarily in the meristems of apical buds and roots.

${ \green{ \bf{ Functions: }}}$

Help in stem-elongation.

Break dormancy of seeds and buds.

Delay senescence.

Induce parthenocarpy.

${ \red{ \bf{ Cytokinins: }}}$

${ \green{ \bf{ Site\: of \: Synthesis:}}}$

Synthesized primarily in roots and transported to other organs.

${ \green{ \bf{ Functions: }}}$

Stimulate cell-division and cell enlargement.

Prevent ageing of plant parts.

Inhibit apical dominance.

${ \red{ \bf{ Ethylene:}}}$

${ \green{ \bf{ Site\: of \: Synthesis:}}}$

Synthesized in senescent leaves and flowers, germinating seeds and ripening fruits.

${ \green{ \bf{Functions: }}}$

Induces fruit ripening.

Promotes senescence.

${ \red{ \bf{ Abscisic \: acid: }}}$

${ \green{ \bf{ Site\: of \: Synthesis:}}}$

Synthesized in green fruits and seeds at the beginning of the wintering period.

${ \green{ \bf{ Functions: }}}$

Induces dormancy of buds and seeds.

Inhibits seed-germination and development.

Stimulates closing of stomata.