EFFECTS OF ANOXIA ON GROWTH AND CARBOHYDRATE-METABOLISM IN SUSPENSION-CULTURES OF SOYBEAN AND RICE

The aim of this work was to compare the carbohydrate metabolism of sus pension cultures of soybean (Glycine max), intolerant of anoxia, with that of cultures of rice (Oryza sativa), tolerant of anoxia. Soybean c ells in anoxia showed no increase in fresh weight, dry weight or extra ctable protein, and labelled few proteins when supplied with [S-35]met hionine. There were modest (50%) increases in the maximum catalytic ac tivities of sucrose synthase, phosphofructokinase, pyruvate kinase and phosphoenolpyruvate carboxylase. There was a three-fold increase in a lcohol dehydrogenase and no detectable change in lactate dehydrogenase and pyrophosphate:fructose 6-phosphate 1-phosphotransferase [PFK(PP(i ))]. The rates of respiration (O2 uptake and CO2 production in air) an d fermentation (CO2 production in nitrogen), all declined with time in anoxia and the cells died after six days in anoxia. Rice cells in ano xia showed small increases in weight and protein content, and labelled many proteins with [S-35]methionine. Increased maximum catalytic acti vities were found for sucrose synthase (x 2), PFK(PP(i)) (x 6), pyruva te kinase (x 2), alcohol dehydrogenase (x 5) and lactate dehydrogenase (x 2). When rice cells were grown in anoxia, respiration declined ste adily. Fermentation increased after four days in anoxia and then decli ned steadily. However, both respiration and fermentation were still ap preciable even after 52 days in anoxia.