Effects of growth temperature on photosynthetic carbon metabolism in green plants III. Differences in structure, photosynthetic activities and activities of ribulose diphosphate carboxylase and glycolate oxidase in leaves of wheat grown under varied temperatures

摘要

The rate of ferricyanide photoreduction in broken chloroplasts isolated from leaves of wheat acclimatized to a low temperature (mean temperature, 5–7°C) was similar to that in chloroplasts from wheat acclimatized to a high temperature (20–25°C).There was no practical difference in glycolate oxidase activity in leaf extracts of wheat plants grown at low and high temperatures. In contrast, the ribulose diphosphate carboxylase activity of chloroplasts from low temperature sample was less than half that for the high temperature sample.Chloroplasts having a high rate of photosynthetic CO2-fixation were obtained from wheat acclimatized to a low temperature, whereas the CO2-fixation activity in chloroplasts isolated from high temperature-acclimatized wheat was very low.Electron microscopy revealed that chloroplasts in high temperature-acclimatized wheat were ellipsoidal, electron dense and contained starch granules. Those in low temperature-acclimatized leaves were round and did not contain starch gr