低温冻害对冬小麦生育及产量影响机理模块研究

Wheat is one of the major staple food crops in the world. Frozen injury is one of the familiar agro-meteorological disasters in winter wheat production. Frozen injury of winter wheat tended to be more complicated with the increasing of winter temperature and changing of wheat cultivars. Wheat models, as the useful tools in agricultural research and profession work, are short of simulating the effects of frozen injury on growth and yield. The combination methods of indoor low-temperature chambers and outdoor field frozen injury experiments are applied to study the climatic conditions that frozen injury occurred against different winter wheat varieties with winterness, semi-winterness, and weak-winterness, and to establish and improve indicator evaluation system that represented the quantitative relation between frozen injury and wheat growth. To explore the influence mechanism of frozen injury on winter wheat development process (spike differentiation, photosynthesis and respiration, drymatter distribution and final yield) and their quantitative relations, in order to build the cold stress factor index and quantitative simulation method and to provide a generic simulation module. The measured and historic crop and the meteorological data are used to evaluate the module. This research has great scientific and practical importance. It can provide theoretical foundation and technical support for developing current wheat models, and also provide important instrument for the related researches and profession work.

小麦是世界上最重要的粮食作物,低温冻害是冬小麦生产中常见农业气象灾害，随着冬季气温升高和小麦种植品种改变，冬小麦冻害风险呈现复杂变化趋势；小麦模型是现代农业科研和业务重要工具，但现有模型中低温冻害影响模拟功能严重不足。小麦模型发展及科研与农业气象业务迫切需求能够定量描述冻害胁迫过程的机理模型。项目拟采用室内低温箱和室外田间冻害试验相结合的方法，研究冬性、半冬性和弱春性小麦品种冻害发生的气象条件，完善冻害指标体系，确立适于冻害影响量化关系及影响因子构建的指标；探讨冻害对冬小麦生育过程（幼穗分化、光合呼吸作用、物质生产及产量）影响机理及定量关系；构建冻害胁迫影响因子及冻害胁迫过程数值模型，研制冬小麦冻害影响通用模拟模块；利用实测与历史资料对所建模块进行验证与应用分析。研究可为发展现有作物模型提供理论基础与技术支持，为相关科研、业务应用提供重要手段，具重要科学意义与应用价值。

本研究系统搜集了北方冬麦区多年多站点气象数据资料与作物灾损资料。完成了大田试验、低温控制箱冻害试验、地里转移试验，取得了不同品种类型（冬性、半冬性和弱冬性）冬小麦不同低温指标的作物生长发育特性与产量数据，研究了不同低温冻害对冬小麦发育进程的影响和冻害对冬小麦光合作用、干物质生产的影响；量化了冻害与冬小麦产量构成因素以及最终产量的关系；确定了冬性、半冬性和弱春性冬小麦品种不同冻害等级的气象指标，包括气温、土壤温度和土壤负积温；根据冻害条件下冬小麦的生理生化反应确定3个能够反应冬小麦冻害的生理生化指标，包括叶绿素荧光指标，超氧化物歧化酶SOD和过氧化物酶POD指标，完善了冬小麦冻害指标体系；基于不同低温程度越冬死亡率数据，建立的小麦越冬LT50动态变化曲线；基于不同低温程度和低温日数控制试验资料，建立了冬小麦越冬死亡率模拟方程。.研究结果表明：冬性、半冬性和弱春性小麦品种分蘖节50%致死温度（LT50）气象指标为-20℃，-15℃和-11℃；土壤有效负积温指标为-200℃·h，-90℃·h和-90℃·h；冻害造成小麦叶片叶绿素荧光指标（fv/fm）下降，冻后5天fv/fm指标下降最明显；冻害对拔节后旗叶单叶水平的光合作用无显著影响；越冬冻害造成小麦返青期推迟，越冬耗损率增大，冬性品种小麦返青期推迟速率为1.6d/℃，越冬耗损率为5.5%/℃；冻害造成冬小麦产量显著下降，对成穗数的影响最大，千粒重和穗粒数在极端低温下显著降低。基于冬前叶龄，抗寒锻炼天数，日平均温度和日照时数影响因子，建立冬小麦LT50动态模拟方程，利用低温箱和大田试验资料对所建方程进行验证，模拟效果较好。