Evaluation of some defense enzymes activities in chickpea plants under cold stress

Plants require different defensive mechanisms for being survive and tolerance to environmental stresses. In present study, activity of defensive enzymes such as alternative oxidase (AOX), superoxide dismutase (SOD), catalase (CAT), electrolyte leakage index (ELI) and hydrogen peroxide (H2O2) amount as a cellular damage indices in two genotypes of chickpea, susceptible (ILC533) and tolerant (Sel96Th11439) under 4°C cold stress was evaluated. Statistical analyses results showed that there is a significant difference between genotypes under cold stress. Under cold stress, decrease in damage indices was accompanied with an increase in AOX activity. The maximum activity of AOX was seen in tolerant genotype on sixth day of cold stress, whereas under such conditions AOX activity in susceptible genotype significantly was lower compared to tolerant genotype. The increase in AOX activity which was accompanied with a decrease in cellular damage (ELI and H2O2 results) particularly on sixth day of cold stress showed the significance of AOX enzyme in tolerance of chickpea plants to cold stress. The simultaneous and significant increase in SOD and CAT activities along with confirmation the results of AOX activity increased degree of genetic tolerance of chickpea to cold stress or plant recovery after exposure to cold stress. These indices may be useful in assessment of chickpea genotypes under cold stress or utilization them in breeding programs.