Abstract:

The purpose of this study was to explore the effects of spraying 2,4-epibrassinolide （EBR） at high temperature during rice grain filling stage on yield components and quality of rice, the high-quality rice variety Zhehexiang 2 was used as the test material. At the beginning of grain filling stage, high temperature （HT） and normal treatment （NT） were carried out for 15 days in automatic temperature- and humidity-controlled climate chambers. Plants were sprayed with 0.15 mg·L^-1 2,4-epibrassinolide （EBR）, or the BR biosynthesis inhibitor brassinazole （BRZ）, or the same volume of distilled water （H₂O, control） at the beginning of the temperature treatments. The results showed that the high temperature treatment during the grain filling stage significantly reduced the spikelet fertility rate of Zhehexiang 2, but had a small effect on the grain weight. Meanwhile, high temperature treatment reduced the processing quality, grain appearance quality and eating quality of rice. Exogenous spraying of EBR under high temperature could increased the yield of Zhehexiang 2, and increased the brown rice recovery, milled rice recovery, and head rice recovery of rice, but the EBR treatment decreased significantly the chalky grain rate, chalkiness and protein content. The results provides a theoretical basis for further clarifying the effects of EBR on alleviating high temperature damage in rice.

Key words: rice, high temperature, grain filling stage, 2, 4-Epibrassinolide, yield, grain quality

摘要：

为明确水稻灌浆期高温下喷施2,4-表油菜素内酯（2,4-epibrassinolide, EBR）对水稻产量构成因素及品质的影响，以优质稻品种浙禾香2号为试验材料，在灌浆期进行15 d高温（HT）和适温（NT）处理，同时喷施浓度为0.15 mg/L的EBR和相同浓度的油菜素内酯合成抑制剂油菜素唑（Brassinozole, BRZ），以喷施相同量的清水为对照。结果表明，灌浆期高温处理显著降低浙禾香2号的结实率，但对粒重的影响较小;高温处理降低稻米的加工品质、外观品质和食味品质;高温下外源喷施EBR能够显著提高浙禾香2号的产量、糙米率和整精米率，显著降低垩白粒率、垩白度和蛋白质含量。试验结果为进一步明确EBR缓解水稻高温热害的效应提供理论基础。

关键词: 水稻, 灌浆期, 高温, 2, 4-表油菜素内酯, 产量, 稻米品质