Heat and salinity induced oxidative stress and changes in protein profile in Amaranthus Lividus L.

Treatment of Amaranthus lividus L. (a tropical leaf crop) seedlings separately with NaCl (50, 100 & 150 mM) and heat shock for different durations (45°C for 4, 8 & 12 hours) during early germination induced oxidative stress and exhibited coinducibility of some stress proteins. Exposure of Amaranthus seeds to elevated temperature and NaCl salinity caused significant accumulation of reactive oxygen species such as superoxide radicals, hydrogen peroxide and TBARS contents with a reduction of membrane protein thiol level. Both forms of abiotic stress were related to significant reduction of antioxidative efficiency (viz. catalase, peroxidase, superoxide dismutase) and total thiol content. A comparative study of qualitative protein profiles of salinity stressed and heat shock raised seedlings by 8 to 15% gradient SDS-PAGE exhibited, expression of some similar polypeptides having molecular masses 90 and 110 kDa. Both forms of abiotic stress also showed coinducibility of some over expressed proteins. The results clearly suggest that heat and salinity imposed a similar kind of oxidative stress, which might induce the expression of common set of stress proteins.