中文摘要：

【目的】本研究采用7种模型对光响应曲线进行拟合,比较不同拟合模型的优劣,旨在优选出氮胁迫下最优的光合作用光响应模型,为研究玉米的氮素营养生理和栽培提供科学依据,为棕壤地区春玉米氮素高效管理提供理论依据。【方法】以郑单958玉米为研究对象,在棕壤长期定位肥料试验的基础上,采用LI-6400型便携式光合作用测定系统测定穗位叶在不同光强下的光合速率,从不同供氮水平研究灌浆期玉米穗位叶叶片的光合作用光响应特征,采用二次回归、直角双曲线、非直角双曲线以及直角双曲线修正等7种不同模型对光响应曲线进行拟合,通过拟合程度、拟合的表观量子效率(α)、最大净光合速率(Pnmax)、光饱和点(LSP)、光补偿点(LCP)和暗呼吸速率(Rday)6个参数的对比,比较7种模型的差异。【结果】1)随氮肥水平的提高,产量、氮素含量、叶绿素含量有所提高,而施氮处理的净光合速率则表现出降低的趋势。2)本研究中的7种模型均能较好地对施高量氮肥(N180处理)的玉米叶片Pn光响应进行拟合,决定系数除直角双曲线修正模型为0.992外,其余均为0.994。但是不同模型对光抑制现象明显的N0、N120处理的拟合效果差异较大,从决定系数比较来看,拟合效果优劣排序为直角双曲线修正模型、二次回归模型】非直角双曲线模型】指数模型】直角双曲线模型、动力学模型。3)直角双曲线修正模型和二次回归模型的Pnmax、LSP、LCP和Rday四个光合参数均与实测值较为接近,而其他模型除个别参数较为接近外,多数参数差别较大;另外由于直角双曲线模型、非直角双曲线模型和动力学模型的方程没有极值,不能直接得到光饱和点,使这三种模型损失了LSP这个重要的参数。4)随着施氮水平的提高,灌浆期玉米穗位叶α、Pnmax、LSP、LCP和Rday5个参数均逐渐升高。【结论】随着施氮水平的提?

英文摘要：

Objectives]In this PaPer,seven different 1ight resPonse mode1s were used to oPtimize the best mode1 under nitrogen stress through comParing the advantages and disadvantages of different fitting mode1s. This study cou1d Provide a scientific basis for the research of nitrogen nutrition Physio1ogy and cu1tivation of corn,and a theoretica1 basis for the N efficient management of sPring corn in brown soi1 region.[Methods]On basis of a 1ong-term exPeriment in brown soi1,the Photosynthesis of a maize(cu1tivar,Zhengdan958)ear 1eaves at the fi11ing stage was measured under different 1eve1s of nitrogen treatments,and seven different 1ight resPonse mode1s,inc1uding quadratic regression mode1,rectangu1ar hyPerbo1a mode1,non-rectangu1ar hyPerbo1a mode1,rectangu1ar hyPerbo1a modified mode1 etc. ,were used to se1ected the best mode1 by comParing the fitting degree and the five Parameters, aPParent quantum efficiency(α),maximum net Photosynthetic rate( Pnmax ),1ight saturation Point( LSP),1ight comPensation Point(LCP)and dark resPiration rate(Rday).[Results]1)With the increase of the nitrogen 1eve1, the yie1d,nitrogen content and ch1oroPhy11 content of corn are increased,whi1e the net Photosynthetic rate of the nitrogen treatments shows a reduced tendency. 2)In this study,the seven kinds of the mode1s can be we11 aPP1ied to fitting the corn 1eaf Pn 1ight resPonse of high amount nitrogen ferti1izer treatment N180 , the determination coefficient of the rectangu1ar hyPerbo1a correction mode1 is 0. 992 ,and the determination coefficients of the other mode1s are 0. 994. The fitted Photo inhibition Phenomena of the N0 and N120 treatments are different,so the different mode1s extend to hand1e different fitting effects,the decision coefficients are in order:The rectangu1ar hyPerbo1a modified mode1 and the quadratic regression mode1 > the non-rectangu1ar hyPerbo1a mode1 > the exPonentia1 mode1 > the rectangu1ar hyPerbo1a mode1 and the dynamic mode1. 3)The Photosynthetic Parameters of Pnmax,LSP,LCP and Rday of the right ang1e hyPerb