【作者】 陈永山；

【导师】 罗卫红；

【作者基本信息】 南京农业大学 ， 作物栽培学与耕作学， 2007， 硕士

【摘要】 光合作用是作物产量和品质形成的基础，直接受叶片氮素含量的影响，叶片光合作用速率是判断和分析作物氮素营养状况的重要指。叶绿素荧光技术是以光合作用理论为背景反映光合作用内在机理的新兴技术，它以测量简便、反应灵敏、获得结果快速和对作物无破坏性等特点被广泛应用于作物对逆境响应机理的分析，在作物氮素营养诊断上具有较大的潜力。因此利用叶片光合速率的测定和叶绿素荧光技术进行温室黄瓜叶片氮素营养状况的定量分析具有重要的理论和实践意义。本研究以温室水果型黄瓜戴多星（Cucumis Sativus cv．Deltastar）和申绿72（Cucumis sativus cv.Shenlv72）为试验材料，于2003年11月-2005年11月分别在上海Venlo型玻璃温室、PVC连栋温室以及连栋塑料大棚内进行了不同定植期和不同氮素处理水平的栽培试验，通过黄瓜功能叶片的光合作用速率测定、叶绿素荧光参数测定、植株养分化学分析以及温室内小气候数据采集，建立了适合不同光温条件下温室黄瓜叶片氮浓度与叶片最大总光合速率的定量关系，建立了适合不同温度条件的叶片氮浓度与叶绿素荧光参数定量关系以及叶绿素荧光参数与叶片最大总光合速率定量关系。并用与建立模型相独立的数据对模型进行了检验，结果表明模型能较好预测温室黄瓜叶片光合作用速率、叶绿素荧光参数和叶片氮素含量。主要结果如下：首次系统分析了不同定植期的光温条件差异对黄瓜叶片氮素含量的影响，利用定植后生理发育时间和定植到初果期以及初果期到盛果期的日平均辐热积定量描述了光温条件和生育期对温室黄瓜叶片氮素含量的影响。结果表明，黄瓜叶片氮素含量随定植后生理发育时间的变化在定植到初果期表现为负指数递增，而在初果期到生育末期表现为负指数递减，而且指数方程参数与相应的日平均辐热积表现出正弦函数关系。因此可以根据温室内温度和太阳辐射来计算定植后的生理发育时间和相应的日平均辐热积，进而求算不同光温条件下温室黄瓜叶片适宜氮浓度及其随生育期的变化(N％_opt（t）)。通过实测的叶片氮浓度与相应定植期的叶片适宜氮浓度之比值求算，消除了不同定植期的光温条件差异对叶片氮素含量的影响，建立了适合不同光温条件下温室黄瓜叶片氮素含量与叶片光合作用速率关系的模拟模型。用与建模相独立的试验数据对模型进行检验，结果表明该模型对温室黄瓜叶片最大总光合速率的预测结果与实测结果之间基于1：1直线的决定系数R²和回归估计标准误差RMSE分别为0．83和1．56μmol CO₂·m^-2·s^-1。首次利用光合作用温度三基点定量分析温室内1．5m高空气温度对黄瓜叶片叶绿素荧光参数的影响，结果表明，无氮胁迫处理的黄瓜叶片光适应下PSII的实际量子效率（ΦPSⅡ）随温室内1．5 m高空气温度的变化表现为三段函数关系。用试验数据拟合得到温度大于22℃时的方程参数，由此计算不同温度条件下（大于22℃）温室黄瓜叶片ΦPSⅡ的适宜值。在此基础上，定量分析了不同施氮水平的黄瓜叶片氮素含量与叶片叶绿素荧光参数的关系。结果表明，消除光温条件差异影响的黄瓜叶片氮素含量与消除温度差异影响的叶片ΦPSⅡ表现出负指数递增关系，用与建模相独立的试验数据对模型进行检验，结果表明模型对黄瓜叶片光适应下PSⅡ的实际量子效率（ΦPSⅡ）的模拟结果与1：1直线间的R²为0．86，预测的回归估计标准误（RMSE）为0．05。黄瓜叶片氮素含量与叶片叶绿素荧光参数的定量关系是实现叶绿素荧光技术作为温室黄瓜叶片氮素胁迫诊断手段的前提。首次利用黄瓜叶片ΦPSⅡ随温室内1．5 m高空气温度变化的函数关系，定量分析了温室黄瓜叶片叶绿素荧光参数与叶片光合作用速率的关系。结果表明，黄瓜叶片ΦPSⅡ与叶片最大总光舍速率表现出负指数递增关系。在此基础上，初步建立了基于叶绿素荧光参数与叶片光合作用速率定量关系的温室黄瓜叶片氮素胁迫诊断模型。用模型估算黄瓜叶片最大总光合速率，再由叶片最大总光合速率估算叶片氮浓度的方法，并与建模相独立的试验数据相比较，结果表明，该模型可以较好预测温室黄瓜叶片氮浓度，预测结果与实测结果之间基于1：1直线的决定系数R²和回归估计标准误差RMSE分别为0．66和0．175％。与直接由叶片光合作用速率测定来估算叶片氮素含量的胁迫诊断方法相比，本模型克服了叶片光合速率数据的测定因仪器价格昂贵，且操作程序复杂而不能在生产上进行实际运用的缺点，为温室黄瓜氮素胁迫诊断提供简便、快速和准确的监测手段。本研究建立的模型可以根据温室内温度和太阳辐射以及温室黄瓜叶片叶绿素荧光参数估算叶片光合作用速率或叶片氮素含量，与已有的温室黄瓜作物生长模型相结合，可以定量预测不同光温条件下氮素对温室黄瓜生长速率的影响，从而为不同定植期种植的温室黄瓜作物的氮肥优化管理提供理论依据和决策支持。更多还原

【Abstract】 Photosynthesis and chlorophyll fluorescence parameters analyzed have been important tools for estimating crop biochemical contents （nitrogen, chlorophyll）, and is becoming increasingly popular in recent years. In this study, a series of field experiments with greenhouse cucumber including different nitrogen treatments were carried out in a Venlo-type greenhouse, a multi-span PVC greenhouse, and a multi-span plastic greenhouse in Shanghai （E121.5°, N31.2°） from 2003 to 2005 to collect data for model development and validation. Leaf photosynthesis rate and leaf chlorophyll fluorescence parameters were measured with Li-6400 portable photosynthesis system and a modulated fluorometer （FMS-2 Hansatech, Norfolk, UK） using the saturation pulse method after the nitrogen treatments started, respectively. The objectives of this research were to quantify the effects of leaf nitrogen concentration on leaf photosynthesis rate of greenhouse cucumber under different radiation and temperature conditions, to determine the relationship between leaf nitrogen concentration and leaf chlorophyll fluorescence parameters, and the relationship between leaf photosynthesis rate and leaf chlorophyll fluorescence parameters, and to develop models for monitoring nitrogen status in greenhouse cucumber. This word would provide theoretical basis and key techniques for non-destructive monitoring of nitrogen fertilization management in greenhouse cucumber.The effects of leaf nitrogen concentration on leaf photosynthesis rate of greenhouse cucumber were investigated under different radiation and temperature conditions. The results showed that the optimal leaf nitrogen concentration for photosynthesis was found to be an exponential function of the physiological development time （PDT） and the product of thermal effectiveness and PAR （TEP）. The leaf optimal nitrogen concentration was calculated by formula as follows: N%_opt（t） is leaf optimal nitrogen concentration of anytime in whole growing season; a is initial leaf nitrogen concentration of seedings when transplanting, determined as 2.5% from the result of our experiment data; N%_max is the maximum leaf nitrogen concentration of the whole growing season; b is the increasing rate of leaf nitrogen concentration from planting date to the time when leaf nitrogen concentration reaches N%_max; Tpdt is physiological development time for the duration from transplanting to the date when the N%_max obtained, determined as 20 days from the result of our experiments data; N%_min is the minimum leaf nitrogen concentration from the time when leaf nitrogen concentration reaches N%_max to the end of the growing season; TC is the time coefficient for the leaf nitrogen concentration changing N%_max to N%_min.y=y_max*sin (0.5π*ATEP/ATEP_opt)y is referred to parameters of N%_max, b, N%_min, TC; y_max is defined as the maximum of these parameters, which appeared in the experiments （from August to November 2005） as our experiments, and determined as 4.8%、0.155、3.8%和9.5, respectively; ATEP is the average daily value of TEP over the period from planting date to fruit setting (for N%_max and b) and from fruit setting to fruit harvest (for N%_min and TC), MJ·m^-2; ATEP_opt is the average daily value of TEP over the period from planting date to fruit setting and from fruit setting to fruit harvest when the maximum values of N%_max, b, N%_min, TC attained, determined as 4.01和2.89 MJ·m^-2 according to the data from the experiments （from August to November 2005）, respectively.The relationship between the ratio of the actual maximum leaf gross photosynthesis rate （Pgmax_i） to that under conditions without nitrogen deficiency （Pgmax₀） （PR= Pgmax_i / Pgmax₀） and the ratio of the actual leaf nitrogen concentration （N%） to the optimal leaf nitrogen concentration (N%_opt) (NR= N%/ N%_opt) was also found to be an exponential function.Based on these quantitative relationships, a general model was developed to estimate the effects of leaf nitrogen concentration on the maximum leaf gross photosynthesis rate of greenhouse cucumber under different PAR and temperature conditions.PR=1.05*（1-exp（-5.6*（NR-0.42）/1.05）） R²=0.80 SE=0.10PR is the ratio of the actual maximum leaf gross photosynthesis rate to that under conditions without nitrogen deficiency; NR is the ratio of the actual leaf nitrogen concentration to the optimal leaf nitrogen concentration.Independent experimental data were used to validate the model. The coefficient of determination （R²） and the root mean squared error （RMSE） between the estimated and the measured maximum leaf gross photosynthesis rate based on the 1:1 line are 0.83 and 1.56umol CO₂·m^-2-s^-1, respectively.The actual photochemical efficiency of PSII reaction （ΦP5II） under conditions without nitrogen deficiency was found to be an exponential function of air temperature at 1.5m above the ground inside the greenhouse. The optimal leafΦPSII under different temperature was calculated as follow:ΦPSII（T） is the optimal leafΦPSII under conditions without nitrogen deficiency when the temperature is T;ΦPSII_max is the maximumΦPSII of the whole growing season; a is the increasing rate ofΦPSII from the base temperature to the base optimum temperature whenΦPSII_max obtained; b is the decreasing rate ofΦPSII from the upper optimum temperature to the maximum temperature after theΦPSII_max obtained; T’_b, T’_ob, T’_ou, T’_m are the base temperature, the base optimum temperature, the upper optimum temperature and the maximum temperature, determined as 5, 22, 28,45℃, respectively, for greenhouse cucumber photosynthesis. The parameters ofΦPSII_max and b are determined as 0.65 and 0.13 from experiments data, respectively. Farther experiments of low temperature growing seasons are needed to determine the parameters of a.Based on this quantitative relationship, a general equation was developed to estimate the relationship between leaf nitrogen concentration and leafΦPSII under different temperature conditions.ΦPSII R =0.95*（1-exp（-6*（NR-0.4）/0.95）） R²=0.680, SE=0.103NR is the ratio of the actual to the optimal leaf nitrogen concentration;ΦPSII R is the ratio of the actual to the optimal leafΦPSII.Independent experimental data were used to validate the model. The coefficient of determination （R²） and the root mean squared error （RMSE） between the predicted and the measured leafΦPSII based on the 1:1 line are 0.86 and 0.05, respectively.The relationship between leafΦPSII and the maximum leaf gross photosynthesis rate of greenhouse cucumber under different temperature conditions was estimated as follow, based on the relationship between leafΦPSII and air temperature at 1.5m above the ground inside the greenhouse.PR =1.05*（1-exp （-4.5*（ΦPSIIR -0.3）/ 1.05）） R²= 0.68, SE = 0.10PR is is the ratio of the actual maximum leaf gross photosynthesis rate to that under conditions without nitrogen deficiency;ΦPSII R is the ratio of the actual to the optimal leafΦPSII.A nitrogen monitored model based on quantified relationship between chlorophyll fluorescence parameters and leaf photosynthesis rate was developed. Independent experimental data were used to validate the model. The coefficient of determination （R²） and the root mean squared error （RMSE） between the predicted and the measured leaf nitrogen concentration based on the 1:1 line are 0.66 and 0.175%, respectively, showing that the model is good for nitrogen fertilization management in greenhouse cucumber.更多还原