14-Hydroxybrassinosteroids(Cas No.:457603-63-3) is a class of broad-spectrum, highly active plant growth regulators. Its activity is mainly manifested in promoting plant growth, increasing fruiting rate, increasing yield, improving quality, and resisting stress. This active ingredient and other brassinosteroid substances with similar structures and functions are known as the sixth type of plant hormone after auxin, gibberellins, cytokinins, abscisic acid and ethylene. It has high physiological activity and unique role in regulating growth and development. It can show good regulatory effects at extremely small doses. Its mode of action is mainly to promote cell elongation and division, regulate leaf shape; change cell membrane potential and enzyme activity, enhance photosynthesis; promote the biosynthesis of DNA, RNA and protein, and improve the tolerance of plants to environmental stress.