植物生长和发育、除了需要水分和营养物质外,还需要有一些数量甚微、但对生长有着特殊作用的活性物质,这些活性物质被称为植物激素。植物激素是植物正常代谢的产物,它们对植物的生长、分化、开花、成熟、休眠、脱落和衰老都有调节作用,对植物的生长会产生强烈的影响。到目前,已发现了五大类激素,它们是生长素、赤霉素、细胞分裂素、脱落酸和乙烯。 Plant growth and development, in addition to the need for water and nutrients, but also need to have some small but growing growth has a special role of the active substance, these active substances are called plant hormones. Plant hormones are the products of normal metabolism of plants. They regulate the growth, differentiation, flowering, maturation, dormancy, shedding and senescence of plants and have a strong effect on the growth of plants. So far, five major classes of hormones have been discovered: auxin, gibberellins, cytokinins, abscisic acid and ethylene.