宁夏引黄灌区滴灌玉米4种光响应曲线模型比较

为探讨宁夏引黄灌区滴灌玉米光合响应机制,采用Li-6400XT气体交换测量系统测定2年玉米大喇叭口期的光响应曲线,选取4种通用的光响应曲线模型分别对玉米光响应过程进行分析、拟合与比较,筛选出6个不同氮素处理下最优光响应模型,并利用最优模型计算分析玉米光合生理特征参数。结果表明,滴灌玉米功能叶片光合能力随着施氮量的增加呈递增趋势。通过模型误差计算与分析,4种光响应曲线模型拟合精度存在差异,且直角双曲线、非直角双曲线和指数模型对于高氮处理的光响应曲线拟合度均高于低氮处理。相对其他3种模型,直角双曲线修正模型拟合精度最高,可作为最优光响应曲线模型模拟引黄灌区水肥一体化玉米光响应动态。由最优模型对各氮素处理光响应生理参数计算分析表明,360 kg/hm^2氮处理玉米叶片的光响应参数均高于其他氮处理,有利于提高玉米对强光的适应范围和光能利用效率,增强光合作用。

Comparison of Four Light Response Curve Models of Drip Irrigation Maize in Ningxia Yellow River Irrigation District

The main objective of the study was to explore the photosynthesis response mechanism of drip irrigation water and fertilizer integrated maize in Ningxia Yellow River Irrigation District. The portable gas exchange measurement system(Li-6400 XT) was used to measure the light response curves of two years maize at the big flare stage under six different nitrogen rates. The most frequently used four models were used to analyze, compare and fit light response curves of maize to screen the best of them all under different nitrogen application rates, which was used to calculate the photosynthetic physiological characteristics parameters. It showed that the photosynthetic capacity of functional leaves increased with nitrogen application rates increasing in drip irrigation maize. Model error analysis showed that there were differences in fitting accuracy of four light response curve models. And the fitting accuracy of high nitrogen treatments was better than those of low to rectangular hyperbolae model, non-rectangular hyperbolae model, and exponential model. However, compared with the three models, the fitting accuracy of modified rectangular hyperbola model was the best highest in four models, which could be the best one to fit light-response curves of maize in the integration of water and fertilizer in irrigation Area of Yellow River Diversion. Using Optimum model was used to calculate and analyze the photosynthetic physiological parameters. It showed that apparent quantum efficiency(α), dark respiration rate(Rd), light compensation point(LCP), light saturation point(LSP) and maximum net photosynthesis rate(Pnmax) of 360 kg/ha were higher than those of others. Reasonable nitrogen application can improve the adaptation range to strong-light, light use efficiency and photosynthesis of maize.