植物光响应修正模型中系数的生物学意义研究

Study on biological significance of coefficients in modified model of photosynthesis-irradiance

植物光合作用对光响应修正模型被广泛应用于植物光合特性的研究,但该模型中系数的生物学意义不清楚。通过分析,认为植物光响应修正模型中系数分别为光抑制项和光饱和项。通过量纲分析,植物光响应修正模型中光抑制项和光饱和项的生物学意义是光系统II天线色素分子光量子吸收截面与其处于激发态平均寿命的乘积。光系统II天线色素分子处于激发态的平均寿命较长且光量子吸收截面较小,则不利于光量子的吸收;如果光系统II天线色素分子的光量子吸收截面较大且其激发态的平均寿命较短,则有利于光量子的吸收。研究结果表明:如果光饱和项系数大且光抑制项系数也大,则植物越容易受抑制;如果光饱和项系数小且光抑制项系数也小,则植物越不容易发生光抑制。

A modified model of photosynthesis-irradiance was used widely in investigating photosynthetic characteristics of plants.However,the biological significances of two coefficients in the modified model were unclear.It showed that two coefficients were considered as photo-inhibition and photo-saturation term,respectively.Through dimension analysis,their biological significances were the product of cross section of photosynthetic pigment in PSII for quantum absorption and average life of photosynthetic pigment in the excited state for photo-inhition and photo-saturation term in the modified model of photosynthesis-irradiance.That light absorption cross sections was less and the average lifetimes of photosynthetic pigment in the excited state were longer would not be useful to light energy absorption.On the contrary,that light absorption cross sections was greater and the average lifetimes of photosynthetic pigment in the excited state were shorter would be useful to light energy absorption.Investigations showed that plants were easily photo-inhibited if photo-inhibition and photo-saturation term are large.