光合作用光响应模型的比较

COMPARISON OF NEW AND SEVERAL CLASSICAL MODELS OF PHOTO-SYNTHESIS IN RESPONSE TO IRRADIANCE

用美国Li-Cor公司生产的Li-6400光合作用测定仪控制CO2浓度和温度,测量了华北平原冬小麦(Triticum aestivum)的光响应数据。分别用C3植物光响应新模型、直角双曲线模型、非直角双曲线模型和Prado-Moraes模型拟合这些实测数据,分析了由直角双曲线模型、非直角双曲线模型和Prado-Moraes模型拟合这些数据得到的最大净光合速率(The maximum net photosynthetic rate)远大于实测值,而光饱和点(Light saturation point)远小于实测值的原因。结果表明,由C3植物光响应新模型拟合的结果与实测数据符合程度最高(R2=0.9994和R2=0.9987);表观量子效率(Apparent quantum yield)不是一个理想的表示植物利用光能的指标,建议用植物光响应曲线在光补偿点处的量子效率作为表示植物光能利用的指标。

Aims Our objective is to compare a new photosynthetic light-response model with the non-rectangular hyperbola, rectangular hyperbola, and Prado-Moraes model in fitting data and obtaining the maximum net photosynthetic rate and the light saturation point. Methods We measured the light-response of photosynthetic rate of winter wheat （Triticum aestivum） under the same chamber CO2 concentration and different air temperatures in North China Plain using a gas analyzer Li-6400. The measured data were simulated by the new photosynthetic light-response model and the non-rectangular hyperbola, rectangular hyperbola and Prado-Moraes models, respec- tively. Important findings The new photosynthetic light-response model shows advantage over the non-rectangular hyperbola, rectangular hyperbola, and Prado-Moraes models in fitting data on the maximum net photosynthetic rate and the light saturation point. The main photosynthetic parameters calculated by the new one were very close to the measured data （R2=0.999 4 and R2=0.998 7）. Results showed that the apparent quantum was not an ideal indicator to assess the light use efficiency of plants. We suggest the apparent quantum yield be replaced by the quantum yield at the light compensation point due to the unity of the quantum yield for any C3 plant species under certain environmental conditions.