Biochemical and Physiological changes in groundnut (Arachis hypogaea L.) in response to stem rot (Sclerotium rolfsii) infection

Studies on biochemical aspects of groundnut and Sclerotium rolfsii interaction are sparse, probably due to complex biology and nature of the biotropic parasitim. The present investigation was carried out on stem rot (Sclerotium rolfsii) of groundnut with two varieties (GG-20 and GJG-22) and sampling of leaf tissues were done at 2 days after inoculation (DAI), 7 DAI, and 14 DAI from inoculated soil (T2) and sampling time was kept for normal soil (T1) to observe the changes in physiological and biochemical parameters as well as altered enzyme activities due to stem rot infection in groundnut. Physiological parameters in leaf tissues of groundnut collected from inoculated soil showed reduction in their values by 13.24 %, 17.21 % and 20.08 % in chlorophyll a, chlorophyll b and total chlorophyll respectively compared to normal soil. Significant interaction effect was observed for treatment and stages of groundnut in respect to all physiological parameters. Biochemical parameters like total phenol and ascorbic acid in leaves and oxalic acid in stem were increased due to infection. Leaf samples from inoculated soil showed rise in the biochemical parameters like phenol, ascorbic acid and oxalic acid by 77.08 %, 50.94 %, and 95.68 %, respectively. Same trend of increase or decrease was observed with the stage wise progress of disease from S1 to S3 stage as well as same result were found in the interaction of treatment and stages from T2S1 to T2S3 treatments.