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Conference publicationsAbstractsXXI conferenceAntistress Properties of Plant Growth Regulators Are a Result of Lowering the ROS Generation by MitochondriaEmanuel Institute of Biochemical Physics, ul. Kosygina 4, 119334, Moscow 1 pp. (accepted)Under stress conditions, the main sources of ROS are mitochondria. In this regard possible to put forward the assumption that the preparations-adaptogens should affect primarily the generation of ROS by these organelles, and consequently to lower the intensity of lipid peroxidation (LPO) in biological membranes and, mainly, in mitochondrial membranes. The supposition tested for preparations, which influence the growth and development of plants, i.e., plant growth regulators (PGRs). The subjects of study were melaphen (melamine salt of bis(oxymethyl)phosphonic acid) and pyraphen (salt of bis(oxymethyl)phosphonic acid of 2,4,6-triaminopyrimidine) synthesized at the Arbuzov Institute of Organic and Physical Chemistry, Russian Academy of Sciences, Kazan Science Center. The stress impact was effectuated on a model of insufficient moistening; the test subjects were mitochondria of 6-day etiolated pea germs. The aim of the work was to establish whether the bioenergetic properties of mitochondria will change under conditions of water deficiency after the treatment of the seeds with a 2× 10-12 M solution of melaphen or 10-8 M solution of pyraphen. The introduction of PGRs in these concentrations into the incubation medium caused a decrease in the LPO intensity to control values in mitochondrial membranes. The insufficient moistening resulted in a 3-fold increase in the content of products of lipid peroxidation (LPO) in the mitochondrial membranes of pea germs. The treatment of the seeds with melaphen or pyraphen reduced the content of LPO products. Melaphen appeared the most efficient: it decreased the intensity of fluorescence of the LPO products to the control values. Changes in physicochemical properties of mitochondrial membranes affect the activity of membrane-bound enzymes. The insufficient moistening resulted in a decrease in the maximum rates of oxidation of NAD-dependent substrates: the oxidation rates of glutamate+malate in the presence of ADP or FCCP were 29-30% lower than the control values and respiratory control rate (RCR) decreased from 2.27±0.01 to 1.70±0.02. The melaphen treatment of the seeds prevented changes in the bioenergetic properties of mitochondria. It was found out that the treatment with pyraphen, which affects the LPO intensity to a lesser degree, nearly does not affect the maximum rates of oxidation of NAD-dependent substrates. The maximum rates of oxidation of NAD-dependent substrates were measurable with the corresponding values of oxidation of these substrates by mitochondria of germs under conditions of insufficient watering and untreated with pyraphen. However, the efficiency of oxidative phosphorylation increased by 12%. Thus, PGRs upgrade the plant resistance to stresses by lowering the AOS generation by mitochondria
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