Tag: plant growth

Ethylene is considered as the growth hormone which regulates promoter and inhibitor as it is used to make the fruit ripen, breaks bud dormancy, initiates flowering. It acts as inhibitor as it retards the mitotic division in root and shoot meristem and also for axillary buds.

ABA inhibits seed germination. ABA stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses.

The plant hormone ethylene is growth inhibitor and is released in plant organs that are to undergo ripening or senescence. Ethylene triggers climacteric ripening of the fruit and induces insensitivity of senescent organs to auxins due to which the nutrients are channelized to other growing parts of the plant resulting in withering away of the plant part.

Gibberellic acid increases the yield of sugarcane crop. Cytokinins inhibit apical dominance and act antagonistically to auxins which promote apical dominance. Rhizomes, corms, tubers, seeds (e.g., peanut) and other storage organs can be made to sprout early by exposing them to ethylene. Abscisic acid is a plant growth inhibitor, which inhibits seed germination.

Presence of cytokinin in an area causes preferential movement of nutrients towards it. When applied to lateral buds, they help in their growth despite the presence of apical bud. They thus act antagonistically to auxin which promotes apical dominance. Therefore cytokinin can overcome apical dominance, caused by auxins.

The most important function of cytokinins is the promotion of cell division. The varying amounts of cytokinins, along with sufficient auxins is required for the growth of callus in tissue culture experiments. Cytokinins delay the senescence of leaves and other organs by mobilisation of nutrients. It is known as Richmond-Lang effect.

Presence of cytokinin in an area causes preferential movement of nutrients towards it. When applied to lateral buds, they help in their growth despite the presence of apical bud. They thus act antagonistically to auxin which promotes apical dominance. Therefore, cytokinin can overcome apical dominance, caused by auxins.

ABA induces seed dormancy in unfavorable environmental condition, its function is antagonistic to gibberillin which promotes seed germination. It is regarded as the stress hormone as it brings about closure of stomata during water stress to prevent water loss from transpiration.

Cytokinins (Letham, 1963) are plant growth hormones which are basic in nature, either aminopurine or phenyl urea derivatives, That promote cytokinesis (= cell division) either alone or in conjunction with auxin. Coconut milk is a rich source of cytokinin.