Journal of Plant Biochemistry & Physiology
Open Access

Abstract

Interaction of Hormones with Reactive Oxygen Species in Regulating Seed Germination of Vigna radiata (L.) Wilczek

Chaudhuri A, Singh KL and Kar RK

Regulation of seed germination is quite complex and is further complicated by interaction of hormones like
gibberellin (GA), abscisic acid (ABA) and ethylene. Moreover, the involvement of reactive oxygen species (ROS)
in hormone signaling for such regulation is still less understood. The aim of the present study was to explore the
interactive role of GA, ABA and ethylene and possible involvement of ROS in mediation of hormone action during
seed germination of Vigna radiata. Seeds of V. radiata were germinated in presence of hormones, their biosynthesis
or action inhibitors and in combinations with hydrogen peroxide and at intervals germination percentages were
determined. Treated seeds were also tested for production of superoxide by NBT staining and analysed for NADPH
oxidase (NOX) activity by in-gel assay. ABA and paclobutrazole (GA biosynthesis inhibitor) inhibited germination of
non-dormant V. radiata seeds. GA recovered germination from inhibition by Ag+ (ethylene action inhibitor) whereas
paclobutrazole-induced inhibition could not be recovered by ethylene. But ethylene could recover significantly ABA-
inhibited germination. Treatment with H2O2 rescued germination from inhibition by ABA, paclobutrazole and Ag+ with
efficiency in the order ABA> Ag+>paclobutrazole. Superoxide (O2.-) production, as revealed by NBT staining, was
found mostly in the apical part of the axis in control and ethylene treated seeds and to a less extent in GA treated
seeds while almost no stain was found in case of treatments with ABA, Ag+ and paclobutrazole. In-gel assay of
NOX activity showed three bands in control and in case of treatments with ethylene, GA and fluridone while intensity
became less for one or more bands in case of paclobutrazole, ABA and Ag+ treatment. It appears that ethylene and
ABA is antagonistic to each other while GA is partially independent in regulating germination of Vigna radiata seeds
through mediation of ROS.

Published Date: 2013-02-20; Received Date: 2013-01-21