Plant Hormones
Biology · पादप हार्मोन · 12 facts
Auxin: promotes cell elongation; phototropism(grow toward light); apical dominance
Gibberellin: stem elongation, seed germination, flowering
Cytokinin: cell division, delays aging(senescence) of leaves
Ethylene: fruit ripening; leaf fall(abscission); gaseous hormone
Abscisic acid(ABA): stress hormone; inhibits growth; closes stomata in drought
Phototropism: plant grows toward light (positive); root away(negative)
Geotropism: root grows toward gravity(positive); shoot away(negative)
Hydrotropism: root grows toward water
Artificial ripening of fruits uses ethylene gas(calcium carbide releases it)
Charles Darwin first studied phototropism in plant shoots
Weedicides(2,4-D): synthetic auxin kills weeds; used in agriculture
Plant hormones coordinate growth, development, and response to environment