【作者】 韩慧敏； 田中伟； 蔡剑； 姜东； 曹卫星； 戴廷波；

【Author】 HAN Huimin~1 TIAN Zhongwei~1 CAI Jian~1 JANG Dong~1 CAO Weixing~(1,2) DAI Tingbo~(1*) 1.Key Laboratory of Crop Physiology,Ecology and Production Management,Ministry of Agriculture, Nanjing Agricultural University,Nanjing 210095,China 2.National Engineering and Technology Center for Information Agriculture,Nanjing Agricultural University, Nanjing 210095,China

【机构】 南京农业大学农业部作物生理生态与生产管理重点实验室； 南京农业大学国家信息农业工程技术中心；

【摘要】 冬小麦在苗期经常遭遇降水贫乏,使幼苗的光合作用和生长受到抑制,最终影响物质和能量的积累。本文通过15%（m/v）PEG-6000（-0.24 Mpa）模拟干旱的水培试验研究了硝态氮（NO₃^-）、铵态氮（NH₄⁺）和铵硝混合态氮对冬小麦‘望水白’的光合作用的影响,以期为耐旱品种选育和改良提供理论依据。试验于温室进行,幼苗分别用3种不同氮素形态的营养液培养,五叶期进行干旱处理5 d。研究结果表明,与正常水分处理相比,水分胁迫下所有氮素形态营养的幼苗叶面积和相对含水量显著降低,而且在NH₄⁺营养下降低幅度最大。水分胁迫下NH₄⁺和铵硝混合态氮营养条件下叶绿素含量显著降低,但是在NO₃^-营养下却有所升高。水分胁迫对NO₃^-营养下的光合速率没有影响,但显著降低了其他两种营养条件下的光合速率。气孔导度在水分胁迫下显著降低,而NO₃^-的降低程度小于其他两种氮素营养。但是,水分胁迫对最大光化学速率和PsⅡ实际光化学效率没有影响,表明光系统Ⅱ未遭水分胁迫破坏。水分胁迫下,NO_<sup>-营养的幼苗叶片Rubisco含量增加了10.6%,但是与对照相比,水分胁迫降低了其他两种氮素形态营养条件下幼苗叶片的Rubisc0含量。综上,水分胁迫下硝态氮营养可能通过调节Rubisco活性提高苗期冬小麦的光合速率。更多还原

【Abstract】 To investigate the effects of nitrate（NO₃^-）,ammonium（NH₄⁺） and the mixture of NO₃^- and NH₄⁺ on photosynthesis of wheat seedlings（Triticum aestivum L.） under water stress, hydroponic experiments with a simulated water stress induced by 15%（m/v） PEG-6000（- 0.24 Mpa） were conducted in a greenhouse.Winter wheat cultivars,Wangshuibai was used. Seedlings were supplied with the 3 diferent nitrgen nutrient solutions and were treated with PEG 6000 for 5 days at the five-leaf stage.The results showed that the leaf area and relative water content were significantly reduced in all N treatments under water stress compared with the well water treatments and both parameters were reduced most in NH₄⁺ nutrition.The chlorophyll content were significantly reduced in NH₄⁺ and the mixture of NO₃⁺ and NH₄⁺ nutrition,but increased in NO₃^- nutrition.Water stress,when only nitrate nitogen present,did not affect the photosynthesis rate.However,it was reduced significantly in the other two containing solutions.The stomatal conductence was reduced significantly under water stress,and when in the nitrate nitrogen nutrition,it was reduced less than the other two nitrgen nutrient solutions. However,there were no significant differences on maximal quantum yield and effective quantum yield of PSⅡphotochemistry compared with control,indicating that PSⅡwas not damaged by water stress.Under water stress,Rubisco content in newly expanded leaves increased 10.6%in the sole NO₃^- treatment Wangshuibai;but decreased in the other two N treatments.We concluded that maybe nitrate nutrition increased photosynthesis rate by regulating the Rubisco activity under water stress at early development stage of winter wheat.更多还原