Pretreatment effects of Nitric oxide on antioxidant responses of Pea plants during decreasing night temperatures

Nitric oxide (NO) as a gaseous molecule has a central role in plant responses to biotic and abiotic stresses. Low temperature is an important factor that limits the survival، productivity and geographical distribution of plants in large areas of the world. Low temperatures by a variety of biochemical، physiological and molecular changes are leading to oxidative stress. In this experiment، the effects of 0. 1 mM nitric oxide pretreatment were studied on pea plant (Cicer arietinum) during low night temperatures (5، 15، 25℃). The experimental design was completely randomized factorial with four replications for evaluate the amounts of hydrogen peroxide، lipid peroxidation، soluble and insoluble phenolic compounds، total antioxidant capacity، peroxidase and superoxide dismutase enzyme activities. The results showed that nitric oxide pretreatment was effective on the content of hydrogen peroxide، soluble and insoluble phenolic compounds، total antioxidant capacity، but it was effective on the content of lipid peroxidation، peroxidase and superoxide dismutase enzymes activity. Night temperatures were effective on all of them. Interaction between nitric oxide and temperature has significant effect on the content of total antioxidant capacity and superoxide dismutase enzyme activity. The hydrogen peroxide content، lipid peroxidation، soluble and insoluble phenolic compounds amount and peroxidase enzyme activity was not affected by interaction between nitric oxide and temperature.