BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Gibberellins promote growth in different ways. These hormones are mainly involved in controlling and promoting stem elongation, flowering, and leaf expansion as well as seed germination. They are used in suspension cultures to enhance the growth of cells.

Detailed explanation-2: -Evidence suggests that gibberellins stimulate the growth of main stems, especially when applied to the whole plant. They are also involved in the bolting (elongation) of rosette plants (e.g., lettuce) after exposure to certain environmental stimuli such as long periods of daylight.

Detailed explanation-3: -Physiological studies and phenotypic characterization of mutants impaired GA biosynthesis. It revealed that GA plays an important role in stem or internode elongation. It stimulates cell division and expansion in response to light or dark.

Detailed explanation-4: -Gibberellin appears to induce its effect on stem elongation by de-repressing negatively regulated genes Le., by deactivating or degrading the repressors of GA response so that GA induced genes are transcribed and stem elongation or growth occurs.

Detailed explanation-5: -(i) In light, hormone auxin, helps the cells to grow longer in plants. (ii) Plant hormone gibberellins help in growth of a stem.