AP BIOLOGY

Detailed explanation-1: -Ethylene can be utilized in agriculture to promote faster and more uniform postharvest ripening. 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.

Detailed explanation-2: -Gibberellins have striking growth-promoting effects. They speed the elongation of dwarf varieties to normal sizes and promote flowering, stem and root elongation, and growth of fruit. Such elongation resembles in some respects that caused by IAA, and gibberellin also induces IAA formation.

Detailed explanation-3: -The plant hormone gibberellin (GA) controls major aspects of plant growth such as germination, elongation growth, flower development, and flowering time.

Detailed explanation-4: -(i) In light, hormone auxin, helps the cells to grow longer in plants. (ii) Plant hormone gibberellins help in growth of a stem.

Detailed explanation-5: -Gibberellins cause seed germination by breaking the seed’s dormancy and acting as a chemical messenger. Its hormone binds to a receptor, and calcium activates the protein calmodulin, and the complex binds to DNA, producing an enzyme to stimulate growth in the embryo.