Water temperatures during vegetative growth affect cold tolerance at the booting stage of rice under controlled environmental conditions

摘要

We tested the effect of water temperature (rw) during vegetative growth on the cold tolerance of rice under fully controlled environmental conditions. We grew seedlings of the rice cultivar 'Hayayuki' in a growth chamber, and at the four-leaf stage exposed some of the seedlings to T_w of 18°C (low T_w treatment) for 14 days, and the rest to T_w of 23°C (control). At the booting stage, plants were subjected to low air temperature (12°C for 4 or 5 days) in another growth chamber to induce spikelet sterility. Palea length, which is an indicator of the pollen developmental stage, increased linearly with increasing auricle distance, and there was no difference in this relationship between treatments. Spikelet sterility was significantly higher in plants exposed to low T_w during vegetative growth. These results suggest that T_w during vegetative growth affects the degree of physiological cold tolerance of rice during the booting stage.