A new auxin-inhibiting substance, 4-Cl-6,7-dimethoxy-2-benzoxazolinone, from light-grown maize shoots

Abstract

Two auxin-inhibiting substances were isolated from light-grown maize shoots. One was a new compound and determined from its spectral data as 4-Cl-6,7-dimethoxy-2-benzoxazolinone (Cl-DMBOA). Another was identified from its spectral data as a known compound, 6,7-dimethoxy-2-benzoxazolinone (DMBOA). Above concentrations of 10 −5 M, Cl-DMBOA inhibited the auxin-inducing elongation in the Avena coleoptile section test. Its inhibitory activity was almost comparable to that of DMBOA and higher than that of 6-methoxy-2-benzoxazolinone (MBOA) which we previously isolated.