水稻种子室温贮藏最适含水量及其热稳定蛋白的研究

【目的】通过使用在不同气候区室温保存8年的两个不同类型水稻品种，测定水稻室温贮藏的最适含水量，以及在贮藏过程中种子中的热稳定蛋白的变化。【方法】通过发芽试验和热稳定蛋白的测定，比较贮藏8年后种子的发芽率、活力指数和热稳定蛋白的变化。【结果】在北京地区贮藏种子，籼稻桂早2号（Oryza sativa L. ssp. indica Kato）最适种子含水量为5.5%～6.0%，而粳稻幸实（Oryza sativa L.ssp.japonica Kato）为6.5%～7.0%。在南昌地区，籼稻最适种子含水量为4.5%左右，而粳稻为5.5%～6.0%。耐超干的籼稻品种桂早2号种子中有一条分子量为39.4 kD的特异性蛋白条带，而不耐超干的粳稻品种幸实却没有这条带。当桂早2号种子发芽率为零时，该特异性热稳定蛋白条带消失。在分子量为41.6 kD处，桂早2号和幸实品种间的热稳定蛋白电泳图谱也存在差异。当幸实种子发芽率降至零时，该热稳定蛋白条带消失。【结论】在同一地区室温贮藏条件下，其最适含水量水平粳稻幸实高于籼稻桂早2号。而对于在不同气候地区贮藏，其最适含水量水平随该地区年平均温度和大于0℃积温升高而降低。发现的两类热稳定蛋白可能与水稻种子耐脱水性及其种子活力丧失有关。

Studies on Optimum Moisture Content and Heat-Stable Protein of Rice Seeds Stored at Room Temperature

Japonica rice (Xingshi) and Indica rice(Guizao 2) seeds were used to investigate the germination rate，vigor index and heat-stable proteins after stored at room temperature for 8 years. Results showed that the optimum moisture contents of Indica rice seeds stored in Beijing were 5.5% and 6.0%, but for Japonica rice seeds they were 6.5% and 7.0%. The optimum moisture contents were 4.5% for Indica rice seeds and 5.5%and6.0% for Japonica rice seeds stored in Nanchang. .It indicated that the level of the optimum moisture content of Japonica rice seeds was higher than Indica rice seeds stored at room temperature in the same area. But the level of the optimum moisture content will decrease with the increase of average temperature and above zero accumulate temperature in the storage. The result of SDS-PAGE electrophoresis showed that 39.4kD heat-stable protein appeared only in seeds of Indica rice that was tolerant of ultra-drying, but did not appear in seeds of Japonica rice that was untolerant of ultra-drying . The heat-stable protein disappeared when the germination percentage of Indica rice seeds was zero. The SDS-PAGE electrophoresis of 41.6kD heat-stable protein was also different between the two cultivars. The spectrum disappeared when the germination percentage of Japonica rice seeds was zero. These results suggested that the two kinds of heat-stable proteins might be related to dehydration tolerance and vigor lost of seeds.