RESUMO
Aims: To better understand the physiological and biochemical mechanisms in the light of antioxidative enzymes activity under salinity stress between tolerant and susceptible genotypes of groundnut. Study Design: Completely Randomized Design. Place and Duration of Study: The laboratory experiment was carried out in the departmental laboratory of Plant Physiology, Bidhan Chandra Krishi Viswavidyalaya (BCKV), Mohanpur, Nadia, and West Bengal during the year 2017-18. Methodology: A controlled study was conducted to screen 26 genotypes of groundnut under 200 mM NaCl salinity stress. Fourteen-day old seedlings were subjected to salinity treatment. For this, the modified Hoagland nutrient solution containing 200 mM NaCl (osmotic potential: -0.8 MPa) was applied in each case and the pH was adjusted to 6.3. The treatments were repeated on every third day. Control set without salinity stress was also maintained similarly in each case for comparison of results. Results: The salt tolerance index or STI of the genotypes ranged from 47.57% to 96.40%. Out of all the genotypes KDG-197 (STI= 96.40%) was found to be the most tolerant under a salinity stress of 200 mM NaCl and it was closely followed by R 2001-2 (STI=87.92%), VG 315 (STI=84.05%), TCGS 1157 (STI=77.59%) and TG 51 (STI=73.67%). While the genotypes Girnar 3 (STI= 47.57%), OG 52-1 (STI=49.09%), TVG 0856 (STI= 49.28%) and J 86 (STI= 50.66%) were the most susceptible genotypes based on their relative performance under stress in respect of total dry weight. It has been noted further that, out of the nine genotypes, enhancement of antioxidative enzyme like super oxide dismutase (SOD), guaiacol peroxidase (GPOX) and catalase (CAT) activity was recorded maximally in tolerant genotype KDG 197 (64.18%, 71.74% and 52.82% increase over control respectively) and R 2001-2 (53.68 %, 93.48% and 53.96 % increase over control respectively) but the activity of these enzyme in the four susceptible genotypes declined considerably under salinity treatment. Conclusion: Tolerant genotypes of groundnut in general registered much higher activities of antioxidative enzymes in their leaves as compared to the susceptible genotype under high salinity stress.