Plant growth regulators (also called plant hormones) are numerous chemical substances that influence the growth and differentiation of plant cells, tissues and organs. Plant growth regulators function as chemical messengers for intercellular communication .
Auxins: Auxins stimulate cell elongation and influence a host of other developmental responses, such as root initiation, vascular differentiation, tropic responses, apical dominance and the development of auxiliary buds, flowers and fruits.
There are several uses of auxins such as—
(i) enhancing the formation of roots.
(ii) development of parthenocarpic fruits.
(iii) thinning of flowers and fruits for healthy growth of remaining ones.
(iv) control of preharvest fruit drop.
(v) control of apical dominance.
(vi) stimulate the growth of lateral buds.
Give two differences each between :
(i) Active absorption and Passive absorption
(ii) Transpiration and Guttation.