BIOMOLECULES AND ENZYMES

Detailed explanation-1: -The gaseous hormone ethylene plays a key role in plant growth and development, and it is a major regulator of stress responses. It inhibits vegetative growth by restricting cell elongation, mainly through cross-talk with auxins.

Detailed explanation-2: -Abscisic acid is a hormone which inhibits growth. It is responsible for wilting of leaves, dormancy of seeds and buds and inhibition of seed germination and development. Hence it is not associated with the growth of plants. Auxin, gibberellins and cytokinins are plant hormones associated with the growth of plants.

Detailed explanation-3: -Auxin and cytokinin are critical growth hormones in plant development and are naturally present within the plant at variable concentrations throughout the season.

Detailed explanation-4: -Auxin induces ethylene production, and many effects of exogenous auxins are, in fact, ethylene responses (Abeles et al., 1992).