制御環境下における水稲の開花反応について

A series of experiments were conducted to investigate the difference of flower opening in rice plants between under the controlled environments (the natural-light growth room and the artificial-light growth cabinet) and in the outdoors on a clear day.
1. The peak time of flower opening was delayed mostly one hour in the natural-light growth room and one or two hours in the artificial-light growth cabinet, compared with the peak time in the outdoors on a clear day (Fig. 4, 5 and 6).
2. Rice plants which had been kept under light condition through day and night came to flower continuously throughout the day (Fig. 7 and 9). The circadian rhythm of flower opening was maintained for at least six days after the continuous dark treatment was started (Fig. 8 and 9).
3. The flower opening time was regulated by the circadian rhythm which was mainly caused by diurnal changes of temperatures (Fig. 4 to 9).
4. Flowers usually remained open about 60 minutes in the outdoors on a clear day, but 80 to 90 minutes under the controlled environments (Table 3 and 4).
5. In the artificial-light growth cabinet, some anthers did not seemed to dehisce, and some spikelets were sterile (Table 2 and 5).