| 摘要: |
| 【目的】研究灌浆初期高温胁迫对水稻籽粒活性氧积累及产量形成的影响，为耐热水稻种质资源的筛选和鉴定提供理论依据。【方法】以长江中下游地区普遍推广种植的8个水稻品种为材料，在灌浆初期进行高温胁迫（38 ℃/32 ℃，昼/夜），研究各水稻品种在灌浆初期高温胁迫下的ROS含量、抗氧化酶活性、淀粉合成相关酶活性、产量及其构成要素以及稻米品质的差异。【结果】与对照相比，灌浆初期高温胁迫导致水稻籽粒O-2·和H2O2含量及抗氧化酶活性显著增加。在不同水稻品种中，淀粉合成相关酶活性对灌浆初期高温胁迫的响应具有差异性。高温胁迫下，产量损失较大水稻品种的O-2·和H2O2含量增幅较大，淀粉合成酶活性受高温胁迫影响也较大。灌浆初期高温胁迫导致水稻结实率、千粒质量、收获指数和产量显著下降，其中黄华占和湘两优900的产量损失较小，在灌浆初期的耐热性较强；粤王丝苗、泰优390和湘两优2号的产量损失较大，在灌浆初期的耐热性弱。灌浆初期高温胁迫导致糙米率、精米率和淀粉含量显著下降，垩白粒率和垩白度增加。高温胁迫下，产量损失较大水稻品种的淀粉含量下降幅度较大，稻米品质受高温胁迫影响也较大。在高温胁迫下，水稻产量与ROS含量显著负相关，而与抗氧化酶活性显著正相关。产量、籽粒加工指标、淀粉含量和淀粉合成酶活性的抗逆系数与ROS含量的抗逆系数显著负相关，而与抗氧化酶活性的抗逆系数显著正相关。【结论】灌浆初期高温胁迫导致水稻籽粒ROS过量积累是降低淀粉合成酶活性和淀粉含量，进而导致产量和稻米外观加工品质下降的重要因素。ROS的增加量可作为灌浆初期水稻耐热性评价的参考指标。 |
| 关键词: 水稻；高温胁迫；籽粒产量；抗逆系数 耐热品种 |
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| 基金项目:江西省自然科学基金资助项目（20232ACB205019,20202BABL213046）；国家自然科学基金项目（32260803） |
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| Effect of heat stress during early filling stage on ROS accumulation and yield formation in rice grain |
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LIU Xiaolong,YE Shihe,LIAO Junjie,et al
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| Abstract: |
| 【Objective】This study analyzed the effect of heat stress during early filling stage on reactive oxygen species (ROS) accumulation in rice grain and yield formation to provide basis for selecting and identifying heat tolerant rice varieties.【Method】Eight rice varieties widely planted in the middle and lower reaches of the Yangtze River were treated at early filling stage by heat stress (38 ℃/32 ℃ for day/night) to investigate differences in ROS contents,activities of antioxidant enzymes and starch synthesis related enzymes,grain yield and its component,as well as rice quality of different rice varieties.【Result】Compared with CK,O-2· and H2O2 contents and activities of antioxidant enzymes were significantly increased by heat stress at early filling stage.There were differences in activities of starch synthesis related enzymes among rice varieties in response to heat stress.Contents of O-2· and H2O2 and activities of starch synthesis related enzymes of varieties with higher yield loss were larger.The percentage of filled spikelets,1 000-grain weight,harvest index and grain yield were significantly decreased by heat stress during early filling stage. The yield losses of Huanghuazhan and Xiangliangyou 900 were less than other varieties,indicating higher heat tolerance.Yuewangsimiao,Taiyou 390 and Xiangliangyou-2 had higher yield losses,indicating that they were heat sensitive.The brown rice,milled rice and starch content were significantly decreased under heat stress,while chalky kernel and chalkiness were increased.Rice varieties with higher yield losses also had larger decreases in starch contents.There were significantly negative correlations between yield and ROS contents and significantly positive correlations between yield and activities of antioxidant enzymes.The resistance coefficients of ROS contents had significantly negative correlations with yield,grain milling indices,starch content and activities of starch synthesis enzymes,while they had significantly positive correlations with activities of antioxidant enzymes.【Conclusion】Over-accumulation of ROS in rice grain caused by heat stress during early filling stage was an important factor for decreasing activities of starch synthesis related enzymes and starch contents and it further led to decreases of yield and rice quality.ROS increases could be a reference index for evaluating heat tolerance of different rice varieties at early filling stage. |
| Key words: rice heat stress grain yield resistance coefficient heat resistant variety |
