Some Effects of 2,4-Dichlorophenoxyacetic Acid on Starch Digestion and Reducing Activity in Bean Tissue Cultures

Abstract

Sections 1.5 mm. in thickness of the first internode of young plants of Red Kidney bean were grown on nutrient agar containing 10 g. of starch and 10 mg. of 2,4-D per liter. After 15 days they showed extensive undifferentiated proliferation. Starch degradation in the medium containing 2,4-D was more extensive than in medium without 2,4-D. A high level of reducing activity was demonstrated, by use of triphenyl tetrazolium chloride, in the endodermis, phloem, cambium, and xylem parenchyma, a pattern of enzyme activity corresponding to the pattern of meristematic activity induced by certain growth substances. Intracellular localization of reducing activity to the mitochondria was suggested.