不同水分条件下水稻光合作用的光响应模型的比较

Evaluation of Photosynthesis Light Response Model for Rice Leaf under Different Water Conditions

采用非直角双曲线模型、直角双曲线模型和直角双曲线修正模型,研究了不同水分条件对水稻叶片光响应特征的影响。结果表明:随土壤水分的降低,水稻功能叶片的光响应曲线下降,且在光强高于400μmol/(m2.s)时,不同土壤水分状况的光响应曲线差距变大。三种模型模拟结果总体上都能较好地反映光合作用的光响应特征。光响应特征参数方面,三种模型都能反映水分亏缺对水稻叶片LCP的影响,但仅直角双曲线修正模型拟合的Pmax与实测最为接近,且非直角双曲线模型不能反映水分变化对AQY的影响。采用传统的线性回归方法得到的LSP值大幅度偏低,其所对应的光合速率仅为同模型中最大净光合速率的39%～55%,而直角双曲线修正模型通过模型参数直接计算确定的LSP与实测值最接近。因此,总体上直角双曲线修正模型在反映水稻叶片的光响应特征及对水分亏缺的响应方面具有优越性。

Non-rectangular hyperbola model, rectangular hyperbola model and modified rectangular hyperbola model are used to reveal the impact of different water conditions on the rice leaf photosynthesis light response characteristics. The results show that with the reduction of soil moisture, light response curves for rice functional leaves fells, and in the light intensity higher than 400μmol/ （m2 · s）, the gap of the light response curve between different soil moisture conditions is larger. All the three models perform over ally well in reflecting the photosynthetic light response characteristics, according to the statistics analysis. They can reflect the influ- ence of water deficit on the light response parameters of LCP. The Pmax for modified rectangular hyperbola model is the closest to measured, but the non-rectangular hyperbola model can not reflect the impact of the water change on AQY. The LSP determined by the traditional linear regression method is significantly low, the corresponding photosynthetic rate is only 39%-55% of the maximum net photosynthetic rate. The LSP for the modified rectangular hyperbolic model can be calculated directly based on the model parameters, which are closest to the LSP with the measured values. Therefore, the modified rectangular hyperbolic model is the most suitable one to reflect the influence on light response characteristics of rice leaves by water deficit.