Phytohormone (植物激素)

Phytohormones, also known as plant endogenous hormones or plant natural hormones, are a class of organic compounds synthesized by specific tissues within plants that regulate plant physiological activities in minute quantities. These hormones modulate various physiological processes in plants by either promoting or inhibiting them, thereby controlling plant growth, development, environmental adaptation, and different stages of the plant lifecycle. The major classes of known phytohormones include six categories: auxins, gibberellins, cytokinins, abscisic acid, and ethylene. Although these phytohormones are generally small, structurally simple molecules, their physiological effects are highly complex and diverse, influencing basic processes such as cell division, elongation, and differentiation. They also play a broad role in regulating important physiological phenomena such as germination, root formation, flowering, fruiting, sex determination, dormancy, and abscission^[1].