The sensitivity of photosynthesis to O2 and CO2 concentration identifies strong Rubisco control above the thermal optimum
The sensitivity of photosynthesis to O2 and CO2 concentration identifies strong Rubisco control above the thermal optimum
复制标题
DOI：
10.1111/nph.14258
复制
发表时间：
2017-02-01
期刊：
影响因子：
9.4
通讯作者：
Sage, Rowan F.
中科院分区：
文献类型：
--
作者：
Busch, Florian A.;Sage, Rowan F.
Farquhar、von Caemmerer和Berry （FvCB）提出的C-3光合作用的生化模型假设，光合作用中的二氧化碳同化受到三个生化过程之一的限制，而这三个过程并不总是容易被识别出来。这导致对生化限制的不恰当评估，从而限制了模型预测的准确性。我们利用CO2同化速率和光合电子传递对叶绿体中O-2和CO2浓度变化的敏感性来评估光合作用的局限性。评估对O-2和CO2浓度的敏感性将固定参数的不确定性的影响降到最低，同时完全消除了确定模型可变参数的需要，如V-cmax、J或T-P。我们的分析表明，Rubisco在高温下限制碳同化，而在较低温度和较高CO2浓度下则受到磷酸三糖利用的限制。可以将测量值先验地分配给FvCB模型的三个功能之一，从而允许测试模型选定的固定参数的适用性。这种方法可以提高光合作用模型在从叶片水平到估算全球碳收支的尺度上的可靠性。
The biochemical model of C-3 photosynthesis by Farquhar, von Caemmerer and Berry (FvCB) assumes that photosynthetic CO2 assimilation is limited by one of three biochemical processes that are not always easily discerned. This leads to improper assessments of biochemical limitations that limit the accuracy of the model predictions. We use the sensitivity of rates of CO2 assimilation and photosynthetic electron transport to changes in O-2 and CO2 concentration in the chloroplast to evaluate photosynthetic limitations. Assessing the sensitivities to O-2 and CO2 concentrations reduces the impact of uncertainties in the fixed parameters to a minimum and simultaneously entirely eliminates the need to determine the variable parameters of the model, such as V-cmax, J, or T-P. Our analyses demonstrate that Rubisco limits carbon assimilation at high temperatures, while it is limited by triose phosphate utilization at lower temperatures and at higher CO2 concentrations. Measurements can be assigned a priori to one of the three functions of the FvCB model, allowing testing for the suitability of the selected fixed parameters of the model. This approach can improve the reliability of photosynthesis models on scales from the leaf level to estimating the global carbon budget.