Protein metabolism in leaves and developing grains of rices differing in grain protein content

Four semi-dwarf rices (Oryza sativa L.) differing in percentage of grain protein, grown in a flooded field receiving basal N fertilization, had a peak activity of root glutamate dehydrogenase 4 weeks after transplanting. A lower peak occurred during panicle formation 10 weeks after transplanting. The percentage of N of the active leaf blades was also highest 4 weeks after transplanting. The activity of nitrate reductase in the leaf blades was low and decreased after transplanting.