土壤淹水条件下香附子光响应过程的模型比较

利用直角双曲线模型、非直角双曲线模型和直角双曲线修正模型对三峡库区消落带土壤淹水条件下香附子光响应过程的测量数据进行了重新拟合，分析了不同光响应模型对香附子的适用性及香附子主要光响应参数对土壤淹水的适应规律。结果表明，非直角双曲线模型对常规水分管理组（CK）香附子植株光响应过程的拟合效果要优于直角双曲线模型和直角双曲线修正模型，而直角双曲线修正模型对淹水组（T1）香附子植株光合响应过程的拟合效果要优于其他2种模型。光响应参数的拟合效果则表现为:非直角双曲线模型对LCP和R_d的拟合效果最佳，直角双曲线修正模型对LSP和P_nmax的拟合效果最佳，而直角双曲线模型对这些光响应参数的拟合效果最差。受水淹影响，香附子的光合能力以及光适应能力减弱，出现了不同程度的光抑制现象，水淹90 d后，T1处理香附子植株叶片LCP和R_d分别比对照增加了56.9%和43.1%，而叶片LSP和P_nmax分别比对照降低了52.3%和 47.4%。

Comparison of Light Response Models of Photosynthesis in Leaves of Cyperus routundus under Soil Flooding Conditions

We selected three light response models which were rectangular hyperbola model, non-rectangular hyperbola model and modified rectangular hyperbola model to fit the data of the photosynthesis of Cyperus routundus under different flooding conditions in hydro-fluctuation belt of the Three Gorges Reservoir Area, and analyzed the applicability of different light response models in C. routundus photosynthesis analysis under different flooding conditions and the adaption regulation of light response parameters to soil flooding. The results showed that non-rectangular hyperbola model for light response process of C. routundus in normal soil water condition（control） was better than that of rectangular hyperbola model and modified rectangular hyperbola model，while the modified rectangular hyperbola model for light response process of C. routundus in submersion condition（T1） was better than that of rectangular hyperbola model and non-rectangular hyperbola model. Among them, the non-rectangular hyperbola model best fit light compensation point （LCP） and dark respiration rate（R_d）, modified rectangular hyperbola model best fit light saturation point（LSP） and maximum net photosynthetic rate（P_nmax）, while rectangular hyperbola model worst fit these light response parameters. Photo-inhibition occurred significantly, and photosynthetic capacity was inhibited under soil flooding. Photo-inhibition occurred, light adaptation capacity weakened, and photosynthetic capacity was inhibited. After 90 days flooding，the LCP and R_d in the leaves of C. routundus increased by 56.9 % and 43.1% of control, respectively. While the LSP and P_nmax in the leaves decreased by 52.3% and 47.4% compared with the control.