Identification of Leaf Based Physiological Markers for Drought Susceptibility during Early Seedling Development of Mungbean

Abstract

Drought is a recurrent phenomenon in many of the countries. Moisture stress during seedling stage is very critical in determining the establishment of the crop and its further development and yield. Identifying drought tolerance mechanism and physiological markers of drought susceptibility is this crop during seedling stress would be useful tool in future genetic manipulation programme to establish drought tolerance in this crop. Thus the present study aimed for quickly identifying reliable physiological markers for drought susceptibility through evaluation of physiological and biochemical changes in leaves of two contrasting mungbean ( Vigna radiata L. Wilczek) cultivars i.e. K 851 (drought tolerant) and PDM 84-139 (drought susceptible) during seedling development. A range of four external water potentials ( i.e. -1.0, -2.0, -3.0 and -4.0 bars), besides glass distilled water as control (0.0 bar), w as used. Parameters like leaf area, relative leaf water content, chlorophyll content, chlorophyll stability indices in both the cultivars were decreased with the increasing magnitude of stress. By and large phenols and ascorbic acid content were increased with the stress level but the trend was not consistent. A steady rise in proline, hydrogen peroxide content and lipid peroxidation was found with water stress. Out of two cultivars tested, drought tolerant cultivar K 851 was better in leaf water balance and higher accumulation of phenols, proline and ascorbic acid than PDM 84-139. The correlation study indicated lipid peroxidation and H 2 O 2 content as valuable physiological markers for screening of drought susceptibility .