大气CO_(2)浓度上升与增温对双季稻籽粒铁、锌和植酸含量及累积量的影响

Effects of elevated atmospheric CO_(2) concentration and warming on the content of iron,zinc,and phytic acid in double cropping rice grains

为揭示未来气候变化趋势对稻谷Fe、Zn含量和积累量的影响,本研究利用开顶式气室(Open Top Chamber,OTC)系统模拟大气CO_(2)浓度上升(EC处理,+100μL·L^(-1))和增温(ET处理,+1.5℃)以及二者相互作用(ETEC处理,+1.5℃,+100μL·L^(-1))的气候变化情景,对江汉平原2017—2019年双季稻籽粒Fe、Zn以及植酸含量进行持续3 a的大田试验观测。结果表明:双季稻籽粒Fe和Zn含量对大气CO_(2)浓度上升与增温的响应存在较大的年际间差异,其中对大气CO_(2)浓度上升的响应较增温更为敏感。与对照(CK)相比,EC处理显著降低2018年晚稻籽粒Fe含量(-13.41%,P<0.05),显著增加2019年早稻和晚稻籽粒Fe含量(+29.70%和+27.95%,P<0.05);ET处理显著降低2018年早稻籽粒Zn含量(-13.49%,P<0.05)。就3 a观测平均值而言,EC处理显著降低早稻籽粒Zn含量(-8.28%,P<0.05),而ETEC处理显著降低晚稻籽粒Zn含量(-10.91%,P<0.05)。本研究发现CO_(2)浓度上升与增温叠加作用效果有别于各单因子影响,尤其对高温干旱年份晚稻籽粒Zn含量的降低具有显著的正协同效应。本研究预测未来气候变化可能增加稻米食用人口出现“隐性饥饿”的风险。

Global climate change,which is characterized by increasing atmospheric CO_(2) concentrations and warming,significantly affects agro-ecosystem productivity and food security.To reveal the impact of future climate trends on the content and accumulation of iron(Fe)and zinc(Zn)in rice,this study used Open Top Chamber(OTC)systems to simulate climate change scenarios with increasing atmospheric CO_(2) concentration(EC treatment,+100μL·L^(-1))and warming(ET treatment,+1.5℃),as well as their interactions(ETEC treatment,+1.5℃,+100μL·L^(-1)).The study involved field experiments and observations on Fe,Zn,and phytic acid content in double cropping rice grains on the Jianghan Plain from 2017 to 2019.The results showed significant interannual variations in the response of Fe and Zn contents in rice grains to greater atmospheric CO_(2) concentration and warming,and the contents were more sensitive to the atmospheric CO_(2) concentrations than to warming.Compared with the control(CK),Fe content in late rice grains decreased with the EC treatment in 2018(-13.41%,P<0.05),but increased significantly in early and late rice grains in 2019(27.95%-29.70%,P<0.05).With the ET treatment,Zn content in early rice grains significantly decreased in 2018(-13.49%,P<0.05).In terms of the three-year observed average,the Zn content in the EC treatment was significantly reduced in early rice grains(-8.28%,P<0.05),while the Zn content in the ETEC treatment was significantly reduced in late rice grains(-10.91%,P<0.05).This study found that the positive synergistic effects of greater CO_(2) concentrations and warming are different for each factor.A significant reduction of Zn content in late rice grains in high temperature and drought years was observed.Accordingly,we predict an increasing risk of a"hidden hunger"for the rice-eating population under future climate change scenarios.