基于植物光响应修正模型的水稻Kok效应研究

Kok效应是植物在其光补偿点附近光合作用对光强的响应有一个较大的改变.应用植物光响应修正模型研究温度为30℃、CO_2浓度分别为300和400μmol·mol~(-1)时水稻在光补偿点附近量子效率的改变情况以及Kok效应.结果表明:水稻叶片的量子效率在光补偿点附近不是常数,且与暗呼吸速率无关,但与光呼吸有关.认为水稻叶片在光补偿点附近量子效率的改变来自其净光合速率对光强的非线性响应和它的光呼吸作用.

Study on Kok effect of rice based on the modified model of light-response of photosynthesis

The linear response of photosynthesis to light at low photon flux densities is known to change largely in the vicinity of the light compensation point so that the quantum yield seems to decrease as radiation increases.This change was termed Kok effect.The relationship between the quantum yield and light intensity was discussed in detail in this paper based on a modified model of light-response curve of photosynthesis for rice at 300 and 400μmol·mol~(-1).The change of quantum yield in the vicinity of the light compensation point and Kok effect were studied.The quantum yield in the vicinity of the light compensation point at two different CO_2 concentrations was not kept stable.and the change value of quantum yield in the vicinity of the light compensation point was affected by the photorespiration rather than dark respiration rate.The fitted results showed that the response of photosynthesis to irradiance in the vicinity of the light compensation point was nonlinear.The reasons that quantum yield changed in the vicinity of the light compensation point seemed to be nonlinear response between the photosynthetic rate and light intensity,and photorespiration of rice.