持续增高的大气CO2浓度使主要粮食作物食用部位锌浓度及其有效性普遍下降，这将使更多人口置于“隐性饥饿”的风险之中，给人类营养造成严重威胁。因此，破解高CO2浓度环境中籽粒特别是胚乳锌营养的变劣机理及其调控途径成为急需解决的重要课题。利用开放式CO2熏蒸平台结合人工气候室，首先研明高CO2浓度对水稻籽粒锌浓度及有效性影响的基因型差异；然后选用代表品种，通过离体穗培养、锌稳定同位素与激光剥蚀电感耦合等离子体质谱仪联用技术，动态追踪灌浆期锌进入籽粒胚乳的路径，结合植株蒸腾、锌在木质部的转运等关键生理过程的变化，揭示水稻胚乳锌浓度对高CO2浓度的响应机制；最后设置多因子互作试验，研究改变栽培措施对水稻胚乳锌浓度和有效性的调节效应，探索高CO2浓度环境下胚乳锌生物强化的农艺途径。这一研究有望在高CO2浓度引发主食锌营养变劣的机制及其对策方面取得新认识，从而为有效解决人类锌营养缺乏问题提供科学依据。

Rising atmospheric CO2 concentration reduces zinc (Zn) concentration and its bioavailability in edible parts of staple food crops, this will put more people under the risk of “hidden hunger”, and poses a serious threat to human nutrition. Thus, understanding the mechanism of high CO2-induced decline of Zn level in grain, especially endosperm, in response to high CO2 concentration and its manipulation becomes an urgent issue. The growth chamber facilities with natural light and the free-air gas concentration enrichment (FACE) system for CO2 fumigation will be used. Firstly, the genotypic variation in rice grain Zn concentration and bioavailability in response to elevated CO2 concentration will be investigated, the contrasting genotypes will be selected for the following studies. Secondly, the physiological mechanisms responsible for Zn concentration decline under elevated CO2 concentration will be studied through examining the key physiological processes determining Zn transport efficiency in xylem, including plant transpiration, xylem sap flow rate and components change. The dynamics of Zn translocate into and distribute in rice endosperm during grain development will be traced by the LA-ICP-MS, facilitated by using stable Zn isotope and ear culture technique. Thirdly，the multi-factor design will be applied to study the influence of changing cultivation measures on Zn concentration and bioavailability in endosperm of rice grain, and find effective agronomical approaches for rice biofortification under elevated CO2 environment. The results of this research will provide new information for understanding physiological mechanism and its regulation for CO2-induced deterioration in rice zinc nutrition, and provide a scientific basis for effectively resolving the problem of human Zn deficiency.