An Atypical Growth of Cabbage-Seedling Roots. I. Morphology, Histology, and Induction Conditions

Abstract
Seedling roots of Brassica oleracea were observed to produce abnormal outgrowths, or tumors, when grown in the presence of para-chlorophenoxyacetic acid (I). The outgrowths were observed histologically to consist of plates of non-divergent lateral roots, in rows one or more deep. Halogenated phenoxy-acetic acids other than I were active, but other synthetic growth substances were inactive. Formation of the outgrowths was much enhanced by feeding various N sources, alone or in mixtures, and was inhibited by buffering at a pH of 6 or above.