【摘要】 本省在1978年7—8月间,出现长期持续高温,使杂交中稻发生严重空壳减产。我们从1979年开始,采用两个杂交中稻组合——四优2号和汕优2号——通过花期逐穗挂牌和每天开花时用多色油漆标记每一颖花的方法,详细研究杂交水稻结实性与天然高温(日最高气温>35℃)和低湿的关系,主要结果如下。1.天然高温对杂交稻结实率的影响主要是影响授粉受精作用,从而增加空壳率,降低结实率,并扰乱穗部枝梗上颖花的开花顺序及结实率的分布规律。2.在自然高温条件下杂交稻每一颖花受高温为害最敏感的时期是:(1)开花当日当时;(2)开花后1—3日。第二个敏感时期,显著不同于常规水稻品种。3.开花时致害的临界高温,四优2号约为34℃以上,汕优2号约为36℃以上。表明汕优2号较耐高温,具有较广的适应性。4.开花时穗层的空气相对湿度也明显影响着杂交稻的结实性。空壳率高是高温低湿同时作用的结果。如果空气湿度维持在60—80%,可减弱高温影响。更多还原

【Abstract】 There was a continuous long period of high-temperature(M. H. T. >35℃) in July-Aug 1978, in Hubei province. It induced a higher spikelet sterility and a lower yield.Since 1979, we have intensively studied the spikelet fertility of two combinations of hybrid-midprice——"4-you No. 2", "Shan-you No.2"——in relation to natural high-temperature (M. H. T. >35℃.) and low relative humidity of air, by hanging a plate on every panicle in flowering time and signing every spikelet with colour paint at anthesis time every day. Some important results obtained are as follows.1. Effects of natural high-temperature on spikelet ferility of hybrid rice are essentially due to the pollination and fertilization of rice flowers being affected directly by natural high-temperature, which induced a higher steriliy and a lower fertility of spikelets. Moreover, it was observed that the normal anthesis sequence on the panicles was confused.2. Under natural conditions the most sensitive periods of every spikelet susceptible to high-temperature are: (1)the due time at anthesis in that day; and (2)the time 1-3 days after anthesis. The second period sensitive to high-temperature is apparently different from that of the conventional varieties of rice.3. The critical susceptible high-temperature inducing empty grains may be>34℃. on hybrid rice combination "4-you No.2" and>36℃. on "Shah-you No.2." Thus "Shan-you No.2" is. more tolerant to hightemperature than "4-you No.2" and could adapt to broader cultural conditions.4. At the due time of anthesis, the air relative humidity (R. H.) in panicle layer could also affect the fertility of hybrid rice evidently. The higher spikelet sterility is the result caused by high-temperature and low-humidity simutaneously. If the air R. H. level could be maintained in 60-80%, the affection of high-temperature would be weakened.更多还原