Auxin and Gibberellin

Plant growth regulators are generally divided into five categories: auxins, gibberellins, cytokinins, abscisic acid and ethylene. Today I mainly talk about the functions of auxin and gibberellin

(1) Auxin

Auxin in plants is mainly produced in new shoots, young leaves and developing embryos, and has the characteristics of polar transport. Auxin controls the speed of cell expansion by affecting the elasticity of the cell wall, promotes cell elongation, and when it is transported downward from the shoot, it can stimulate the cell division of the shoot and stem cambium, and also inhibit the growth of lateral buds. development, and also has the effect of preventing aging. Auxin is mainly used to promote rooting of fruit tree cuttings, flower thinning and fruit thinning, and it is also widely used in preventing pre-harvest fruit drop and controlling the occurrence of sprouting tillers.

(2) Gibberellin

Gibberellins in plants are mainly produced in young leaves, young embryos and roots, and have no obvious polar transport characteristics. When gibberellin is applied externally to fruit trees, its mobility is also poor and its efficacy has obvious limitations. The main function of gibberellin is: to promote the elongation of new shoots of fruit trees, thereby promoting the growth of new shoots; to break the dormancy of buds and seeds, to promote the germination of seeds and buds; to inhibit the formation of flower buds and reduce the amount of flowers; Use together with vitamins to prevent young fruits from falling off and promote fruit enlargement. In addition, gibberellins also have the effect of delaying fruit ripening.