The Effect of Certain Benzazole Compounds on Plant Growth and Development

Abstract

Klingensmith, M. J. (Colgate U., Hamilton, N. Y.) The effect of certain benzazole compounds on plant growth and development. Amer. Jour. Bot. 48(1): 40–45. Illus. 1961.—A number of benzazoles, in particular benzimidazole, benzothiazole, and benzotriazole, were examined for their effects on growth of seedlings and established plants. Benzothiazole was the most active in repressing elongation of the primary root of cucumber. Benzimidazole and benzotriazole were about 1/10 as active. Adenine was without effect in reversing the benzazole‐induced inhibition of cucumber root elongation and, in fact, supplemented the inhibition caused by benzimidazole and benzothiazole. Application of benzotriazole to the root medium of bean, coleus, tomato, oat and wheat caused a pronounced inhibition of internodal elongation with a stimulation of axillary development. Distinct morphological changes were observed which did not correspond to those produced by other growth regulators. Application of benzimidazole to the root medium of several genera of plants resulted in injury to laminar tissue followed by desiccation, with no concomitant effect on the stem. Application of benzothiazole to the root medium induced development of adventitious roots in bean and tomato. This compound also caused initiation of roots on cultures of tobacco‐stem segments, while not suppressing bud development. The benzazoles tested seem to be of a different class of compounds from other growth regulators which have been studied. The responses elicited by treatment with each of the 3 benzazoles are distinctly characteristic and are dependent on the structure of the azole portion of the molecule.