Hydro-Priming Methods for Initiation of Metabolic Process and Synchronization of Germination in Mung Bean (Vigna Radiata L.) Seeds

Seed priming is a commercially applied technique for improving seed vigor under variable field conditions. The present study was carried out to optimize the methods (direct: soaking in water 1:1 W/V and indirect: preconditioning under high RH ≥ 85%) and duration (hours)of hydro-priming, attempting to correlate the critical seed water content with priming-induced metabolic-restart in dry mungbean (Vigna radiata L.)seeds. Although the rate of water absorption and the amount of water absorbed was more by direct compared to the indirect imbibition method, the priming-induced germination responses were identical after 6hof priming treatment. The seed water content absorbed during this period was crucial for initiating the chain of biochemical events, required for early synchronized germination in primed seeds which was evident by improved membrane permeability, high activity of catalase and superoxide dismutase, and more integrated chloroplast and mitochondria in primed seeds. We demonstrate that the critical water content, required for priming-induced benefits for germination vigor, is a relative unit with respect to the duration of priming and the rate of water absorption. Seed priming is a co-ordinately regulated mechanism for controlling germination capacity of seeds by modifying the permeability characteristics of biological membranes and enzyme activity. This study helps to enhance our understanding on the potential of seed priming for synchronized germination and early seedling establishment in the field and beneficial for the resource poor farming community for better return of their limited financial/farm resources under variable environmental/field conditions.