The expression of complex I and two homologues of bacterial and yeast NADH dehydrogenases, NDA and NDB, have been studied in potato leaf mitochondria. The mRNA level of NDA is completely light dependent and shows a diurnal rhythm with a sharp maximum just after dawn. NDA protein quantity and internal rotenone-insensitive NADH dehydrogenase activity are also light dependent. These findings sugge...

The occurrence of photorespiration in soybean (Glycine max [L.] Merr.) leaf cells was demonstrated by the presence of an O(2)-dependent CO(2) compensation concentration, a nonlinear time course for photosynthetic (14)CO(2) uptake at low CO(2) and high O(2) concentrations, and an O(2) stimulation of glycine and serine synthesis which was reversed by high CO(2) concentration. The compensation con...

The light responsiveness of mitochondrial function was investigated through changes in mitochondrial composition and metabolism in rice (Oryza sativa) shoots. The mitochondrial proteome and metabolite abundances under low light, (LL, 100 μmol m(-2) s(-1) ), and high light (HL, 700 μmol m(-2) s(-1) ) were measured along with information on shoot photosynthetic, respiratory and photorespiratory a...

The flow of glyoxylate derived from glycolate into various metabolic routes in the peroxisomes during photorespiration was assessed. Isolated spinach leaf peroxisomes were fed [(14)C] glycolate in the absence or presence of exogenous glutamate, and the formation of radioactive glyoxylate, CO(2), glycine, oxalate, and formate was monitored at time intervals. In the absence of glutamate, 80% of t...

It was shown in the previous study that phosphinothricin (glufosinate) causes an accumulation of ammonia and inhibition o f photosynthesis. The extent to which there is a connection between these two processes is now investigated in the present study. First of all, the role of N H 3 per se in the impairment of photosynthesis was to be clarified. For this purpose, the inhibition of photosyn­ the...

We compared the structural, biochemical, and physiological characteristics involved in photorespiration of intergeneric hybrids differing in genome constitution (DtDtR, DtDtRR, and DtRR) between the C3-C4 intermediate species Diplotaxis tenuifolia (DtDt) and the C3 species radish (Raphanus sativus; RR). The bundle sheath (BS) cells in D. tenuifolia included many centripetally located chloroplas...

P.1 ABBREVIATIONS – P.2 LIST OF PAPERS – P.5 INTRODUCTION. 1 The photosynthetic processes – P.7 1.1 Light reactions. 1.2 Carbon reactions. 2 Regulation of photosynthetic processes – P.8 2.1 Non photochemical dissipation mechanisms. 2.2 Photochemical dissipation mechanisms. 3 Reactive oxygen species (ROS) and antioxidant system – P.11 3.1 ROS production sites and homeostasis. 3.2 Low molecular w...