长江中下游地区花生生长对旱涝胁迫的响应机理及模拟

The alternative stress of “pre-waterlogging and post-drought” caused by weather “Meiyu” and “lasting severe drought in the summer and fall” is the main meteorological factor restricting the high yield of peanut in the middle and lower reaches of Yangtze River. However, the research on the response mechanism of peanut growth to stress of both drought and waterlogging is still unclear. Therefore, this project is to carry out a soil column experiment in rain proof greenhouse to simulate drought alternative stress after waterlogging at peanut’s middle-late growing stages (flowering, pod setting and mature phase). The changes of above-ground and below-ground biomass and yield of peanut under the stress of waterlogging/drought and alternative stress of waterlogging and drought will be analyzed, so as to preliminary reveal the effects of drought and flood stress on peanut growth and yield. The changes of peanut root morphology and main physiological indices at the middle-late growing stages will be studied, so as to further reveal the adaptive regulation of root morphology and physiological characteristics to different degrees of drought and flood stress. In addition, a macroscopic root water uptake model was established by the determination of three main controlling factors, i.e. soil water stress correction coefficient, root density distribution function and plant water stress, used to simulate the peanut root water uptake under the stress of drought-waterlogging and its hysteresis effects in the middle and lower reaches of the Yangtze River. The results could provide theoretical guidance to explore the mechanism of water uptake, morphology and physiological adaptation of peanut roots and deeply understand the fluctuation of peanut yield in this region under the background of global climate change.

“梅雨”和“伏秋旱”天气导致的“前涝后旱”双重胁迫模式，是限制长江中下游地区花生高产的主要气象因素，然而旱涝双重胁迫模式下花生生长的响应机理研究还不清楚。本项目拟开展防雨温室土柱试验模拟花生生育中后期（花针期、结荚期和饱果期）遭受的前涝后旱双重胁迫过程，分析涝/旱单胁迫和旱涝双重胁迫条件下花生地上/地下部生物量及产量的变化特征，初步揭示旱涝胁迫对花生生长发育及产量的影响规律；通过研究花生生育中后期根系形态和主要生理指标的变化特征，进一步揭示花生根系形态发育和生理特性对不同程度旱涝胁迫的适应性调节机理；确定土壤水分胁迫修正系数、根系密度分布函数和植物水分胁迫指数3个主控因子，建立适用于模拟长江中下游地区旱涝胁迫及其滞后效应条件下花生根系吸水规律的宏观根系吸水模型。研究结果可为探明花生根系吸水、形态和生理适应机制和深入理解全球气候变化背景下该地区花生产量波动提供理论指导。

在全球气候变暖背景下，极端降水事件频繁发生，导致我国花生产区的旱涝灾害呈现频度增高、危害加重、复杂多变的特点；“梅雨”和“伏秋旱”天气导致的“前涝后旱”双重胁迫模式，是限制长江中下游地区花生高产的主要气象因素，然而旱涝双重胁迫对花生生长和产量的影响机制尚不清楚。本项目通过在防雨棚自制土柱中开展水分控制试验，研究涝/旱单胁迫和前涝后旱双重水分胁迫对花生生长和产量的影响。旱涝胁迫对花生生长的影响研究表明，轻度旱胁迫有利于根系生长，胁迫程度增加会抑制花生地上地下部生长、但会促进根系变粗和抗氧化酶(SOD、POD、CAT)活性的升高；轻度涝胁迫抑制、中重度涝胁迫促进花针期根系生长和抗氧化酶活性升高，但重度胁迫会显著抑制地上部生长；而单涝胁迫对结荚期花生根系生长和根酶活性均起抑制作用，受胁迫程度越高地上地下部生长越慢。与结荚期旱胁迫相关的旱涝胁迫会增加根系的长度和体积，尤其是叠加花针期涝胁迫会显著提高POD活性、降低CAT活性和单株叶面积，而结涝结旱会导致MDA活性值、单株地上部叶鲜重和叶面积的显著下降；相反地，与饱果期旱胁迫相关的旱涝胁迫会减小花生根系长度和体积，花涝饱旱会显著降低SOD和POD活性、叶片鲜重。旱涝胁迫对花生产量的影响研究表明，涝旱单胁迫都会降低花生产量，饱果期受旱的减产量大于结荚期受旱，重度旱胁迫对饱果期的减产影响最大，最高可达19.7%；轻度涝胁迫对花针期和结荚期的最高减产均为38.4%，单涝胁迫对结荚期产量的影响大于花针期，淹水时间越长减产越严重，远杂9102在结荚期淹水15天减产98.3%；花涝结旱、结涝结旱、花涝饱旱和结涝饱旱等双重胁迫中，花涝结旱对花生的减产较少，结涝结旱的减产为28%，花涝饱旱和结涝饱旱的减产则高达43.6%和41.4%。综上所述，平原区花生花针期和结荚期需避免长时间的淹涝，饱果期根据受旱程度进行适当补水，均可有效降低产量损失。本研究结果可为长江中下游地区花生旱涝防灾减灾和耐性品种选育提供理论指导。