Enhancement of Overall Plant Growth,a New Response to Brassins

SPECIFIC responses involving plant growth and behaviour are obtained with plant hormones and synthetic growth-regulating substances¹. Enhancement of overall growth involving all parts of the plant has not been demonstrated with these substances. Using the fatty hormones, brassins, we increased repeatedly the overall growth of bean and some other kinds of plants in greenhouse conditions during the past 3 yr². These findings have broad implications for the existence of hormone control factors of a new type.