开放式增温对华南双季稻稻米品质的影响

Effect of Free Air Temperature Increase on Grain Quality of Double-cropping Rice in South China

【目的】华南双季稻区是我国优质籼稻的主产区之一,研究气候变暖对华南双季稻稻米品质的影响具有重要意义,【方法】采用稻田开放式主动增温系统对早稻(合丰丝苗,2020年;粤禾丝苗,2021年)和晚稻(粤禾丝苗,2020和2021年)进行全生育期昼夜不间断增温处理,分析增温对早、晚稻加工、外观、营养和食味品质的影响。【结果】与不增温处理相比,增温(早稻,1.5~1.8℃;晚稻1.9~2.0℃)对早、晚稻糙米率均无显著影响。增温条件下,早稻精米率和整精米率均显著降低,而晚稻精米率和整精米率无显著变化。增温对垩白粒率和垩白度的影响在早、晚稻之间呈相反趋势;增温显著提高早稻垩白粒率和垩白度,而降低晚稻垩白粒率。增温条件下,早、晚稻直链淀粉含量均显著降低,而蛋白质含量呈升高趋势。此外,增温提高早、晚稻稻米峰值黏度和米饭黏性,降低其消减值及晚稻糊化温度和米饭硬度。相关分析表明,增温条件下,早、晚稻糊化特性和米饭质构的改变主要与直链淀粉含量的降低有关。【结论】增温导致早稻加工和外观品质变差,而有利于改善其营养和食味品质。增温条件下,晚稻外观、营养和食味品质均有改善。

【Objective】The double cropping rice growing area in South China is one of the main producing areas of high-quality indica rice.However,the impact of global warming on rice quality of double-cropping rice in South China remains unclear.【Method】A field experiment was designed with ambient temperature treatment(CK)and whole growth period warming treatment(W).The warming treatments were generated with free air temperature increase(FATI)facilities.The milling,appearance,nutritional and eating quality of early rice(i.e.,Hefengsimiao in 2020 and Yuehesimiao in 2021)and late rice(i.e.,Yuehesimiao in 2020 and 2021)were compared and analyzed between CK and warming treatments.【Result】Compared to the CK,the warming treatment(early rice,1.5–1.8℃;late rice,1.9–2.0℃)had no significant effect on the brown rice rate of early and late rice.The milled rice rate and head rice rate of early rice decreased significantly,while the milled rice rate and head rice rate of late rice did not change under warming conditions.The warming effects on the chalky grain rate and chalkiness fallowed opposite trends between the early and late rice.Warming significantly increased the chalky grain rate and chalkiness of early rice,but decreased the chalky grain rate of late rice.The amylose contents of early and late rice decreased,while the protein contents increased under warming conditions.In addition,warming increased the peak viscosity and stickiness of early and late rice,while decreased their setback,pasting temperature and hardness of late rice.Correlation analysis showed that the changes in rice flour pasting property and cooked rice texture of early and late rice were mainly related to the reduction in amylose content under warming conditions.【Conclusion】Warming worsens the milling and appearance qualities of early rice,but it is beneficial to improving its nutritional and eating quality.The appearance,nutritional and eating quality of late rice are improved under warming conditions.