大气CO2/O3浓度升高条件下水稻倒伏的成因与调控研究

The rapid atmospheric changes including the increases in tropospheric CO2/O3 concentrations will significantly alter many elements of the future crop production environment that will have great impacts on crop yield and quality. Among these elements, the increase in lodging risk is one of the possible factors responsible for the fluctuation or reduction in crop production induced by the atmospheric changes. In order to preciely predict the impacts of atmospheric element changes on food security in near future, a systemic study is required for understanding the effects of elevated CO2/O3 concentrations on lodging resistance of crops. However, such study can only be conducted on the experimental platform with gas fumigation conditions that resemble natural field. The proposed research project will use growth chamber facilities with natural light and the free-air gas concentration enrichment (FACE) system for CO2 and O3 fumigation. The CO2/O3 concentrations projected in 2050 will be targeted as high gas concentration treatment, along with the current ambient CO2/O3 concentrations as the control. The objectives of this research are to elucidate physiological bases of rice lodging resistance as affected by CO2/O3, to understand the interactions of CO2/O3 by major biotic (genotypes) and abiotic factors (crop management techniques and environmental factors), and to explore adaptation strategies for minimizing lodging risk of rice in future high CO2/O3 conditions. Understanding the above questions and integrating the findings into the rice growth model will help us to confront the threats that the atmospheric changes imposed on rice production and to secure regional staple food supply.

迅速变化的大气环境（包括大气CO2/O3浓度升高）将极大地改变未来作物的生长环境进而对产量和品质产生显著影响。大气环境变化使作物生产力下降或波动的一个潜在因素是倒伏风险的增加。为了准确预测大气组份变化对未来粮食安全的影响，必需定量研究高浓度CO2/O3对作物倒伏抗性的影响及其作用机理。熏蒸环境接近于自然农田的试验平台为开展这一研究提供了重要契机。本项目依托独特的自由空气中微量气体浓度增高（FACE）系统和自然光气体熏蒸平台，动态模拟本世纪中叶大气CO2/O3浓度，研究高浓度CO2/O3环境下重要谷类作物水稻倒伏抗性的变化及其相关生理基础，评估CO2/O3与主要生物（品种）和非生物因子（主要栽培和环境因子）的互作效应，探明未来高浓度CO2/O3环境下最小化倒伏风险的技术途径。研明这些问题并将它们整合到基于过程的机理性生长模型，有利于稻作生产应对大气组分变化的技术选择和粮食安全战略的制定。

大气中二氧化碳（CO2）和臭氧（O3）浓度持续增加将显著改变作物的生长环境，进而对作物产量、品质及抗性产生深刻影响。稻作生产上倒伏问题日趋严重。相对产量和品质，人们对高CO2/O3浓度环境下水稻倒伏抗性的变化知之甚少，一个主要瓶颈因素是气体熏蒸手段的局限性。本项目利用具有空间优势的稻田FACE（Free-Air gas Concentration Enrichment）平台和自然光人工气候室，选用代表品种，系统研究了大气CO2/O3浓度升高对水稻生长和抗倒性的影响及其原因。结果表明，大气CO2浓度升高使稻米品质总体变劣，但使籽粒产量增加且倒伏风险减少。高CO2浓度环境下水稻倒伏风险减少主要与基部节间抗折力明显增强有关，而后者又与节间充实程度增加有关，表现在单位节间干重、节间碳水化合物浓度以及茎鞘占全株干重的比例增加。臭氧胁迫使水稻产量、品质和茎杆机械质量均呈下降趋势。臭氧胁迫导致水稻茎杆的抗折力显著下降，这与茎杆变细和充实程度减少有关，主要表现在节间横截面积、节间单位长度干重、茎鞘可溶性碳水化合物浓度以及光合产物向茎鞘和根系的转运比例减少。水稻结实期发生倒伏影响生长发育和抗倒性状对CO2或O3的响应，影响程度与供试品种和倒伏发生时期有关。大气CO2或O3浓度升高对水稻生长发育和抗倒性状的影响与气象因子、熏蒸方式、供试品种和施氮量等因素有关。上述结果整合到基于过程的机理性生长模型，将有利于稻作生产应对大气组分变化的技术选择和粮食安全战略的制定。项目实施期间研究小组发表标注基金资助的相关论文28篇，其中SCI收录5篇、CSCD收录论文22篇；另外，指导完成博士后出站报告1篇、博士毕业论文2篇和硕士毕业论文10篇。

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