FUNCTIONAL STATE OF MITOCHONDRIA IN VARIOUS PEA SEEDLING CULTIVARS DIFFERING IN RESISTANCE TO WATER DEFICIENCY AND INFLUENCE OF IRON TETRANITROSYL COMPLEX WITH THIOSULFATE LIGANDS ON IT

Different cultivars of plants have various ability to tolerate adverse environmental effects without a sharp decrease ingrowth processes and yields. The present study was carried out to study the effect of water deficiency (WD) on themorphological, biochemical and bioenergetic characteristics of two cultivars of pea seedlings differing in resistance to WD. Atthe same time, the effect of nitric oxide donor a tetranitrosyl iron complex with thiosulfate ligands (TNIC-thio) on theresistance of pea seedlings to insufficient moisture was studied.The functional state of the mitochondria was studied per rate respiration of mitochondria, by the level of lipid peroxidationby the spectrofluorimetry, and a fatty acid composition of mitochondrial membranes with the chromatography technique, bythe study of mitochondrial morphology with the method of atomic force microscopy.Water deficiency (WD) led to the activation of lipid peroxidation, which caused swelling of mitochondria and changes inthe content of C18 and C20 fatty acids (FA) in the membranes of these organelles. Wherein there was a decrease in the contentof linolenic acid by 15% in the mitochondrial membranes of the less resistant cultivar, while in the resistant cultivar itdecreased by only 6%. Note that in the membranes of mitochondria more resistant to water deficiency there were 3,23 timesmore unsaturated C20 FA. The water scarcity was accompanied by an increase in the content of these fatty acids. Differences inthe FA composition of mitochondrial membranes affected the bioenergetic characteristics of mitochondria. WD caused adecrease in the maximum oxidation rates of NAD-dependent substrates by mitochondria of seedlings. At the same time, therate of oxidation of NAD-dependent substrates and the efficiency of oxidative phosphorylation in the more resistant cultivarwere higher. Treatment of pea seeds with 10-8M TNIC-thio restored the bioenergetic characteristics of mitochondria in peaseedlings of both cultivars. However, the efficiency of oxidative phosphorylation in the respiratory chain of mitochondria ofthe water-deficiency more resistant cultivar was 15,7% higherThe increased content of unsaturated VLCFAs in the mitochondrial membranes of pea seedlings contributes to maintainingthe bioenergetic characteristics of mitochondria, and, consequently, the energy metabolism of the cell under stress conditions.