稻米外观与加工品质对大气CO2浓度升高的响应

【目的】大气CO2浓度升高会降低水稻的外观与加工品质。为探明其下降机制并予以缓解，【方法】采用开放式大气CO2浓度升高(FACE)平台、两种栽培品种及其三种不同的基因调控遗传材料 (中花11及其蒸腾调节材料ZmK2.1-15、ZmK2.1-20、OsKAT3-26、OsKAT3-30; 中花11及其促冠根生长材料ERF3-7和ERF3-12; 日本晴及其促硝酸盐吸收材料NIL)，研究稻米外观与加工品质对CO2浓度升高的响应。【结果】稻米外观品质与加工品质对CO2浓度升高的响应因品种不同而异。CO2浓度升高下，中花11的垩白粒率和垩白度增加9.2%和4.4%，整精米率降低5.3%；而日本晴的垩白粒率和垩白度降低11.1%和7.9%，整精米率提升9.8%。蒸腾调节材料显著改善了CO2浓度升高对中花11外观与外观品质的负面效应，与当前CO2浓度相比，CO2浓度升高，ZmK2.1-15、 ZmK2.1-20、OsKAT3-26、OsKAT3-30的垩白粒率相对变化量为−2.7%、−16.3%、−14.8%，+7.4%，垩白度为−8.7%、−22.3%、−15.1%、−3.0%，整精米率为+2.1%、+6.4%、+3.6%、−7.0%。促冠根生长材料加大了CO2浓度升高对中花11号外观与加工品质的负面效应，ERF3-7、ERF3-12的垩白粒率在CO2浓度升高下分别增加17.7%和11.5%，垩白度增加34.4%和19.1%，整精米率分别降低10.1%和0.8%。促硝酸盐吸收材料(NIL)的垩白粒率和垩白度在CO2浓度升高下无明显变化，整精米率下降4.2%。NIL的外观品质较日本晴明显改善，CO2浓度升高下垩白粒率和垩白度分别下降16.5%和17.9%，当前CO2浓度条件下分别下降26.3%和28.9%。【结论】未来CO2浓度升高条件下，通过基因改良促进水稻蒸腾作用和硝酸盐吸收是提升稻米外观与加工品质的有效途径之一。

Responses of Rice Appearance and Processing Quality to Elevated Atmospheric CO2 Concentration

【Objective】Rice appearance and processing quality will be reduced by elevated atmosphere CO2 concentration ([CO2]). To ascertain the mechanism behind this decline and then alleviate it, 【Method】we used a Free-air Carbon Dioxide Enrichment (FACE) facility, two kinds of cultivars and its three kinds of genetically modified materials (Zhonghua 11 and its transpiration-promoting genetic materials, ZmK2.1-15, ZmK2.1-20, OsKAT3-26, OsKAT3-30; Zhonghua 11 and its crown root-promoting genetic materials, ERF3-7 and ERF3-12; Nipponbare and its nitrate absorption-promoting genetic material, NIL) to study the responses of appearance and processing quality of different rice genetic materials to elevated [CO2]. 【Results】The responses of rice appearance and processing quality to elevated [CO2] varied among these genotypes. The chalky grain percentage and chalkiness degree of Zhonghua11 increased by 9.2% and 4.4% under elevated [CO2] compared with ambient [CO2], and head rice percentage decreased by 5.3%, while the chalky grain percentage and chalkiness degree of Nipponbare decreased by 11.1% and 7.9%, and head rice percentage increased by 9.8%. Transpiration-promoting genetic materials significantly mitigated the negative effect of elevated [CO2] on the appearance and processing quality of Zhonghua11. As compared with ambient [CO2], the changes in chalky grain percentages for ZmK2.1-15, ZmK2.1-20, OsKAT3-26 and OsKAT3-30 under elevated [CO2] were −2.7%, −16.3%, −14.8%, +7.4%, and that of chalkiness degree was −8.7%, −22.3%, −15.1%, −3.0%, and that of head rice percentage was +2.1%, +6.4%, +3.6%, −7.0%. Crown root-promoting genetic materials exacerbated the negative impact of elevated [CO2] on the appearance and processing quality of Zhonghua 11, with the chalky grain percentage increased by 17.7% and 11.5% under elevated [CO2], and the chalkiness degree increased by 34.4% and 19.1%, head rice percentage decreased by 10.1% and 0.8%, respectively. The chalky grain percentage and chalkiness degree of nitrate absorption-promoting material (NIL) did not change significantly at elevated [CO2], and the head rice percentage decreased by 4.2%. The appearance quality of NIL was significantly improved as compared with that of Nipponbare, with the chalky grain percentage and chalkiness degree decreased by 16.5% and 17.9% under elevated [CO2], and 26.3% and 28.9% under ambient [CO2]. 【Conclusion】The promotion of transpiration and nitrate absorption through genetic regulation could be one of the effective ways to improve the appearance and processing quality of rice under elevated [CO2] in the future.