Published online by Cambridge University Press: 12 June 2017
Studies with plant growth-regulators are severely handicapped unless methods are available for quantitative determinations of these chemicals. Beginning with the classical work of Went, several techniques have been developed to obtain a quantitative measure of plant growth-regulating chemicals. Brown and Weintraub, Hitchcock and Zimmerman and Frankton have discussed the use of biological assays as quantitative tests for various hormone-type chemicals. Thus far, the only biological methods developed beyond the semi-quantitative stage are those depending on cell elongation in shoots, inhibition or elongation of roots, and the stimulation of ovary development.