[Mitochondria respiration in developing sunflower seeds]. / Dykhanie mitokhondrii razvivaiushchikhsia semian podsolnechnika.

ABSTRACT

We studied the oxidative and phosphorylative activity of mitochondria in the seeds of three sunflower cultivars (Polevik, Peredovik, and Yubileinyi) during development of the seed embryo within 1 to 54 days after flowering. The rates of succinate oxidation by the mitochondria were 1.5-2 times those of malate or alpha-ketoglutarate oxidation. The ratio of substrate oxidation rates underwent changes during the seed growth. The differences were recorded between cultivars as concerns the times when the maximum oxidation rates were reached. Oxidation was coupled with phosphorylation during the entire period of seed development the value of respiratory control after Chang changed from 1.4 to 7. By the time of transition to maturation, the rates of oxidation of both substrates and the values of respiratory control and ADP/O decreased. The results we obtained suggest that by days 13-15 of seed embryo growth, the rate of ATP production decreases upon oxidation of Krebs cycle products.