长江中下游麦区不同年代小麦主推品种对土壤渍水的响应及其机理

Waterlogging is one of the important abiotic stress factors that restricting wheat production in middle and lower reaches of the Yangtse River. The effects of waterlogging on wheat growth and development have been extensive research. However, few studies focused on the responses and mechanisms of wheat cultivars in different eras to waterlogging during the evolution. In the study, using main wheat cultivars in different eras extending in middle and lower reaches of the Yangtse River as experiment materials, the changes of grain yield under different conditions of waterlogging (different phases and durations) are studied. The changes in population characteristic (tiller dynamic, LAI dynamic, dry matter accumulation and distribution and yield components), individual morphology (plant type characteristic, upper roots configuration and root aerenchyma morphology) and plant physiology (photosynthetic characteristic, antioxidative enzyme activity, root activity, nutrient elements absorption and distribution, ion balance and the key enzymes activities of sugar and nitrogen) are studied, and their relationships with yield were analyzed, to clarify waterlogging occurrence mechanism of wheat cultivars in different eras. For the modern main released wheat cultivars, the remedial approach after waterlogging is proposed by applying nitrogen fertilizer with compound fertilizer and plant growth regulator. The results provide theoretical basis and practical guidance for cultivars breeding and selecting, as well as anti-adversity and high-yield cultivation of wheat.

土壤渍水作为长江中下游麦区小麦生产的主要逆境之一，前人集中研究了不同渍水条件对小麦生长发育的影响，而品种演进过程中小麦对渍水响应特征及其机理尚缺乏研究。本项目以长江中下游麦区不同年代小麦主推品种为材料，研究其在渍水条件（渍水时期与持续时间）下的产量变化，明确渍水下群体特征（茎蘖动态、LAI动态、干物质积累与分配、产量构成）、个体形态（株型特征、上层根构型、根通气组织形态）和植株生理（光合特性、抗氧化酶活性、根系活力、营养元素的吸收与分配、离子平衡、糖氮代谢关键酶活性）的变化及其与产量的关系，阐明不同年代小麦主推品种对渍水响应机理；针对现代主推品种，通过渍后增施尿素和复合肥、喷施生长调节剂，研明实现渍害补救的调控途径，为该区小麦品种选育、品种应用和抗逆高产栽培提供理论依据与实践指导。

土壤渍水是长江中下游麦区小麦生产的主要逆境之一。项目针对长江中下游品种演进过程中小麦对渍水的响应特征及其机理开展研究。研究了不同渍水条件（拔节期、孕穗期、抽穗期和花后4个渍水时期以及拔节期和花后连续渍水5天、10天和15天）对小麦产量的影响，表明渍水均会不同程度地降低了小麦产量，以拔节期渍水减产幅度最高，产量降幅随渍水时间的延长呈扩大趋势，提出了长江中下游小麦渍害发生的特点。从幼苗形态和生长性状以及产量等方面比较了长江中下游不同年代小麦品种抗渍能力，认为苗期抗渍能力表现为当前品种由于早期品种，但随着小麦品种演进，产量水平虽不断提高，但拔节后渍水造成的产量减少量也在扩大，高产稳产性难度加大。研究了不同年代小麦品种在不同渍水条件下产量构成、干物质和氮素积累和转运、叶片光合特性、根和叶片抗氧化酶活性、株型特征、大量和微量元素吸收的变化及其与产量的关系，表明不同时期渍水造成减产的原因不尽相同，拔节期渍水对每穗粒数和干物质积累量影响较大，花后渍水后对千粒重和收获指数影响较大；随拔节期和花后渍水时间延长，渍水对产量构成、干物质和氮素积累和转运量的影响总体呈增大趋势；提出提高花后抗衰老和光合生产能力是实现渍后小麦高产稳产的关键，分析了拔节后渍水造成减产原因，初步阐明了长江中下游不同年代小麦品种对渍水的响应机理。项目还研究提出渍水后施用75kg hm-2尿素+225 kg hm-2复合肥或叶面喷施3.5g L-1尿素+0.1mmol L-16-BA具有较好的产量补救效果。相关结果可以为长江中下游小麦品种选育、品种应用和抗逆高产栽培提供理论依据与实践指导。