Welcome to Eprints@IARI

Abstract

The root carbohydrates, their mobilization and metabolism were examined in green gram (Vigna radiata (L.) Wilczek) genotypes in relation to their waterlogging tolerance. Experiment was conducted with two contrasting green gram genotypes, viz. MH 96-1 (tolerant) and (MH 1K-24) (susceptible). Waterlogging treatment was given by placing earthen pots with 25 days old plants in plastic troughs measuring 100 x 70 x 35 cm (L x B x H) and filled with water to a height just 1-2 cm below the soil level in pots. Treatments consisted of control, 2, 4, 6 and 8 days waterlogging and recovery. Waterlogging resulted in decline in relative water content (RWC), membrane stability index (MSI) in root and leaf tissues and leaf chlorophyll (Chl) content. The decline was greater in MH 1K-24 than MH 96-1. MH 96-1 also showed better recovery than MH 1K-24. Waterlogging resulted in decline in total and non- reducing sugar content in both genotypes and reducing sugar content in MH 1K-24. Comparatively tolerant genotype MH 96-1 had greater total, reducing and non-reducing sugar content than MH 1K- 24. Reducing sugar actually increased in MH 96-1 upto 4 days of waterlogging. Waterlogging also caused an increase in sucrose synthase (SuSy) activity in MH 96-1 upto 6 days and slightly declined in the 8 days of waterlogging. The variation in reducing sugar content was parallel to sucrose synthase activity. Waterlogging resulted in increase in alcohol dehydrogenase (ADH) activity and MH 96-1 showed greater increase than MH 1K-24. The results suggest that waterlogging tolerance of green gram genotypes depends on the availability of sufficient sugar reserve in the roots, activity of sucrose synthase to provide reducing sugars for glycolytic activity and ADH for the recycling of NADH for the continuation of glycolysis, the major source of energy under hypoxia. This led to better RWC and Chl content in leaves and membrane stability of leaf and root tissue in tolerant type.