不育系稻穗开颖不整齐原因的探讨

不育系稻穗的呼吸强度、H#-（2）O#-2酶活性和颖花的ATP含量均比保持系低。通常雌雄蕊的呼吸使颖内CO#-2浓度上升至5%，从而导致鳞片吸水膨大推开外颖。不育系花药败育，呼吸弱，颖内CO#-2浓度不易提高是其开颖不整齐的主要原因。外源CO#-2能显著地加速不育系稻穗的颖花大量开放。

STUDIES ON UNEVENNESS OF SPIKELET-OPEN IN MALE-STERILE LINE OF RICE

The respiratory rate of spikelets and catalase activity of anthers in rice plant were determined with oxygen electrode. The ATP concentration of the spikelets was measured with luciferase method and the process of the spikelet-open on panicles was detected with infrared CO_2 gas analyser. The results are as follows:The respiratory rate of spikelets, the catalase activity of anthers and the ATP concentration of the spikelets in male-sterile line were all lower than that in maintainer line of rice (Table 1). Under normal conditions, the CO_2 concentration in spikelets would reach 5 percent by the respiration of pistil and stamens, which caused lodicule cells uptaking water, extending and the spikelet opening. But the anthers of malesterile line were abortive, and their respiratory rate was very low. So the main reason for unevenness of the spikelet-open was that CO_2 concentration inside spikelets was difficult to increase. A large number of spikelet-open in male-sterile line could be significantly accelerated by the application of carbon dioxide (Table 2, Fig. 3).