Temperature Stress and Consequences of its Influence on Functional Activity of Mitochondria in Maize Etiolated Seedlings

Treatments of 30-min influences of high (32, 37, 42, 47, 52 °С) and low (0, 17, 22 °С) temperatures on viability of shoots, common activity of peroxidase, content of reactive oxygen species (ROS), intactness and oxidative activity of mitochondria from etiolated maize seedlings have been studied. It has been shown that 17, 32, 37 и 42 °С temperatures cause intensification of peroxidase activity, and 52 °С depresses this enzyme activity and then led to total death of shoots. ROS content in mitochondria increased during the treatment of seedlings with 0, 17, 22, 37 и 42 °С temperatures. All temperature exposures led to decrease of succinate oxidation rates in mitochondria, at that 47 и 52 °С temperatures inhibited mitochondria respiration to an even greater degree. However, if after the action of the temperature 47 °C the phosphorylating activity was maintained in the mitochondria, after 52 °C it was absent and mitochondria had reduced intactness of outer mitochondria membrane. Low temperatures led to uncouple of oxidative phosphorylation and activating of cyanide-resistant respiration. Role of mitochondria in plant response on the temperature stress has been discussed