The role of auxin in cell separation in the dehiscence zone of oilseed rape pods

Abstract

Concentrations of both free and conjugated indole-3-acetic acid (IAA) were studied during development of pod wall, dehiscence zone and seeds of Brassica napus pods. A decrease in auxin content prior to moisture loss in the pods was observed specifically in the dehiscence zone, which was correlated with a tissue specific increase in β-1,4-glucanase activity. Furthermore, treatment of the pods with the auxin mimic 2-methyl-4-chlorophenoxyacetic acid resulted in a delay of 10 d of β-1,4-glucanase activity and con-comitant cell separation in the dehiscence zone. This indicates that the activity of hydrolytic enzymes involved in cell separation in the dehiscence zone is regulated by auxin activity.