基于根系无氧呼吸途径差异的小麦耐渍机理及其氮素调控机制解析

In the middle and lower reaches of the Yangtze River, waterlogging was supposed to be the major climatic disaster, which may produce a severe effect on wheat production. Wheat could survive by accessing energy through anaerobic respiration under waterlogging condition. There were two different ways for pyruvic acid from glycolysis metabolism to provide energy. One way was to improve the pyruvate decarboxylase and alcohol dehydrogenase activity, which could produce ethanol and energy. The other way was to improve the lactate dehydrogenase activity, which could produce lactic acid and energy. The accumulation of lactic acid would result in the reduction of the PH value, which was the main reason for the death of wheat under the waterlogging condition. Researches on other plants indicated that waterlogging tolerant varieties showed a significantly higher alcohol dehydrogenase and antioxidant enzyme activities. However, there was a lack of necessary research on wheat and little research had been done on effects of nitrogen application on the morphological and metabolic adaptation of wheat root to waterlogging. With 4 wheat varieties which showed significantly differences on waterlogging tolerance, we carried out the field experiment, by using four waterlogging duration after anthesis designed as 0, 3, 6 and 9d, respectively. Root morphology parameter, anaerobic respiration enzyme, antioxidant enzyme, nitrogen metabolism enzyme and photosynthetic characteristics were measured to determine waterlogging tolerances of different wheat. Meanwhile, field experiment was conducted under different period of nitrogen application to study its regulation mechanism on root development. The objective of this study was to provide theoretical basis for waterlogging resistance and stable-yielding cultivation of wheat in rice stubble land in this area.

淹渍是长江中下游稻茬麦区重要的气候灾害。小麦渍水后根系主要通过无氧呼吸方式获得能量。无氧呼吸条件下，糖酵解代谢产物丙酮酸通过两条途径代谢产生能量：在丙酮酸脱羧酶作用下生成乙醛，乙醛在乙醇脱氢酶作用下生成乙醇；丙酮酸在乳酸脱氢酶作用下直接生成乳酸。乳酸积累，造成细胞质酸化，pH值降低是渍害条件下植物死亡的主要原因。在其他作物中的研究发现，耐渍性强的品种主要通过乙醇代谢产能，并且抗氧化酶活性和光合性能较高。但是，关于耐渍性不同的小麦根系无氧呼吸途径的差异未见报道，并且关于追肥时期调控受渍小麦根系代谢，缓解小麦渍害的生理机制研究较少。本研究选用耐渍性不同的4个小麦品种，在小麦开花后设置0、3、6和9天四个渍水时长，研究渍水下不同小麦根系形态、无氧呼吸酶、抗氧化酶和氮代谢酶活性与叶片光合性能。同时利用设置不同的追氮时期，研究氮肥对受渍小麦的调控机制，为该区域稻茬小麦抗渍稳产栽培提供理论依据。

本项目针对长江中下游稻茬麦区生长发育后期的渍水逆境造成小麦减产的生产现状，在安徽农业大学郭河现代农业示范园区开展不同小麦品种的耐渍性差异及其调控试验，在小麦开花后设置0、3、6和9天四个渍水时长，利用田间水分控制以及实验室生理生化分析等手段，研究了耐渍性不同的小麦品种根系无氧呼吸途径及抗氧化能力差异的生理机制及其氮肥调控机理。主要通过研究渍水条件下不同小麦根系形态、无氧呼吸酶和抗氧化酶活性与叶片光合性能。明确了基于根系形态、无氧呼吸途径和抗氧化能力等指标的小麦耐渍生理机制以及氮肥提高小麦根系耐渍能力的调控机理，提出了小麦耐渍稳产的氮肥运筹模式，为该区域稻茬小麦抗渍稳产栽培提供理论依据。依托本项目资助发表论文5篇，其中被SCI收录1篇，中文核心期刊4篇。申请国家发明专利1项，授权实用新型专利2项。培养在读研究生2人。