温室黄瓜叶片光合速率的类卡方模型

Quasi-chi-square model for photosynthetic rate of cucumber leaf in greenhouse

为了精确模拟不同光照下温室黄瓜光合作用的变化规律,提出了一种类卡方模型(QCSM)进行建模。使用Li-6400便携式光合测定系统测定了温度分别为16℃、20℃、24℃、26℃、28℃、30℃和光量子流通量密度(PPFD)为0～2000μmol/(m2·s)动态条件下温室黄瓜叶片净光合速率(Pn),以Pn测定值为基础对QCSM参数进行了模拟。结果表明:QCSM拟合得到的黄瓜叶片净光合速率估计值Pn与实测值Pn相符。经过前一年的数据验证,模型精度较高,拟合优度达0.9908,残差标准误差(RSE)为0.4537。与负指数模型(ME)相比,QCSM净光合速率估计值与实测值较接近,同时,QCSM能得到包括光饱和点、补偿点、最大光合速率、暗呼吸、表观量子效率等在内的五个光合作用参数值。与非直角模型(NRH)相比,由QCSM估计的光饱和点、补偿点、暗呼吸与实际较接近。

In order to exactly simulate the rule of greenhouse cucumber Photosynthesis under different photosynthetic photo flux density （PPFD）, a model named quasi-chi-square model （QCSM）, was established. Net photosynthetic rate （Pn） data of cucumber leaf were measured by Li-6400 Portable Photosynthesis System under dynamic conditions of temperature being 16, 20, 24, 26, 28, 30℃, respectively, and PPFD being 0-2000μmol/（m^2·s）, and based on the measured values of Pn, parameters of QCSM were fitted. The results showed that the estimated net photosynthetic rate data of Pn by the model were coincided with the measured data of Pn. Validation by yesteryear data indicated that model precision was very high with goodness of simulation of 0.9908 and residual standard error （RSE） of 0.4447. The estimated values of Pn by QCSM were closer to measured values compared with that of minus exponential model （ME）, and five parameter values of photosynthesis, including light saturation point （LSP）, light compensation point （LCP）, maximum net photosynthetic rate （Pn max ）, dark respiration rate （DDR）, apparent quanta effect （AQE）, were obtained. Compared with those by non-rectangular model （NRH）, the estimated values of LSP, LCP and DDR by QCSM are closer to measured values.