高温下不同施肥量对水稻产量品质形成的影响及其与能量代谢的关系分析

Effect of Different Fertilizer Application Rates on Rice Yield and Quality Formation and Its Relationship with Energy Metabolism at High Temperature

【目的】近年来极端高温天气频发,严重抑制水稻产量品质形成,优化植株营养状态,改善能量代谢可减缓高温热害,但高温下不同施肥量对籽粒能量代谢的影响及其与产量、品质及耐热性形成的影响仍未见报道,其作用机制的阐明可为水稻耐热性抗风险栽培技术研发提供重要理论依据。【方法】以浙江省推广大面积较大的单季杂交籼稻品种中浙优8号为材料,采用人工气候室盆栽的试验方法开展研究。设置不施肥(0-NPK)、1/2肥料(1/2-NPK)和正常施肥(1-NPK)三个肥料用量处理,开花当天移至人工气候室高温处理15d(高温处理设置昼/夜分别为36/28℃,常温对照设置昼/夜分别为28/25℃)。【结果】无论常温或高温下,在供试肥料水平下随着施肥量增加,中浙优8号产量、结实率及千粒重均呈逐渐增加的趋势;高温下,结实率、千粒重的下降幅度随施肥量增加而下降。然而,整精米率随施肥量增加而下降,垩白度则呈增加的趋势。高温处理后籽粒可溶性糖、MDA、H_(2)O_(2)、腺苷三磷酸酶(ATPase)及PARP[poly(ADP-ribose)polymerase]含量高于常温对照处理,淀粉、非结构性碳水化合物、抗氧化酶活性及ATP含量则低于常温对照。无论常温或高温下非结构性碳水化合物、抗氧化酶活性、ATP及ATPase均随着施肥量的增加而提高,而MDA、H_(2)O_(2)及PARP含量则呈下降趋势。常温下,能量感受器基因SnRK1A及SnRK1B相对表达量随施肥量增加而下降,而TOR则呈增长趋势。与常温对照相比,高温处理后SnRK1A上调表达,而TOR相对表达量随施肥量增加而上调。【结论】增施肥料能有效缓解花期高温对水稻结实率及千粒重的影响,但外观品质与加工品质存在变劣的趋势。常温下,增施肥料品质变劣可能与籽粒灌浆速率加快有关,而高温导致品质下降主要在于能量不足,难以满足产量及品质形成的需求。

【Objective】In recent years,frequent occurrence of extreme high temperature weather severely inhibited the formation of rice yield and quality.Optimizing plant nutritional status and improving energy metabolism can alleviate thermal damage.However,the effects of fertilizer application rates on grain energy metabolism and its relationship with yield,quality and thermal resistance at high temperature have not been reported,and elucidating the mechanism can lay an important theoretical basis for the research and development of rice heat-resistant and risk-resistant cultivation technology.【Method】In this study,a single cropping indica hybrid rice variety Zhongzheyou 8,which was widely planted in Zhejiang Province in recent years,was pot-cultivated in a climate chamber.Three fertilizer treatments were set:no fertilization(0-NPK),1/2 normal fertilization(1/2-NPK)and normal fertilization(1-NPK).On the day of flowering,they were moved to the artificial climate chamber for high temperature treatment for 15d(for high temperature treatment,36℃in daytime and 28℃at night;for the normal temperature treatment,28℃in daytime and 25℃at night).【Result】The yield,seed-setting rate and 1000-grain weight of Zhongzheyou 8 followed a trend of increasing with the increaing fertilizer application at normal temperature or high temperature,with a shrinking decreasing amplitude at high temperature.However,head rice rate decreased with the increase of fertilizer application,and chalkiness degree showed an upward trend.The contents of soluble sugar,MDA,H_(2)O_(2),ATPase and poly(ADP-ribose)polymerase(PARP)in the grains after high temperature treatment were higher than those in the normal temperature control,but contents of starch,non-structural carbohydrate,antioxidant enzyme and ATP were lower than those in the normal temperature control.Both at normal temperature and high temperature,the activities of non-structural carbohydrates,antioxidant enzymes,ATP and ATPase increased with rising fertilizer application level,while contents of MDA,H_(2)O_(2) and PARP decreased.At normal temperature,relative expression levels of energy receptor genes SnRK1A and SnRK1B decreased with the increase of fertilizer application,while TOR showed an increasing trend.Compared with normal temperature treatment,after high temperature treatment,the expression of SnRK1A was upregulated,while TOR was downregulated with the increase of fertilizer amount.【Conclusion】Increased fertilizer application could effectively alleviate the negative effect of high temperature on seed setting rate and 1000-grain weight of rice during flowering,but appearance quality and processing quality tended to deteriorate.At normal temperature,the quality deterioration caused by increased fertilizer application may be related to the acceleration of grain filling,while the quality deterioration caused by high temperature is mainly due to the lack of energy,which is difficult to meet the demand of yield and quality formation.