Genotypic Differences in Some Physiological and Biochemical Parameters Symptomatic for Nickel (Ni) Induced Stress in Groundnut (Arachis hypogaea L.)

An excess concentration of nickel (Ni) in soil significantly affects the growth and yields of crop plants. Physiological functions and antioxidative enzyme status of the plants are also altered by this stress. The present study aimed to evaluate nickel induced physiological and biochemical changes in a set of thirteen groundnut genotypes to identify the nickel tolerant genotype. Accumulation of free proline and the activities of Catalase (CAT) and Ascorbate Peroxidase (APX) significantly increased in Ni treated plants. Our results indicate that all the genotypes were differing in their growth parameters, concentrations of free proline, electrolyte leakage and antioxidative enzymes. Ni sensitive genotypes correlated with decrease in shoot: root ratio, increase in electrolyte leakage and decrease in antioxidative enzymes. In contrary tolerant genotypes showed better shoot: root ratios, high free proline content, less electrolyte leakage, optimum CAT and APX activities. The study leads in grouping the genotypes into three categories, i.e. tolerant genotypes- Abhaya, Anantha, Greeshma, ICGV-91114 and Dharani; moderately tolerant- K-1375, K-6 and TG-47 and sensitive genotypes- JL-24, Narayani, Prasuna, Rohini and TPT-4 for Ni induced stress.