植物叶肉导度的测定方法及其研究进展

叶肉导度(g_m)表征CO₂从植物气孔下腔到叶绿体内光合作用羧化位点的传输导度,是光合作用的重要限制因子,也是改良作物光合作用和资源利用效率的关键参数。¹³C分馏在线联测法是研究植物光合生理的重要手段,也是目前测定C3植物g_m的主流方法之一。但该方法对实验设备要求较高、难度较大,因此尚未被广泛采用。本文综述了当前测定g_m的主流方法的适用性和特点;介绍了¹³C分馏在线联测法的理论基础——光合¹³C分馏模型,¹³C分馏在线联测法的实测方法、计算公式和测定系统的搭建,以及C3植物叶肉导度的调控因素。最后对¹³C分馏在线联测法的改进、操作要点和未来应用场景进行了展望。

Mesophyll conductance to CO2: Methods and current knowledge

Mesophyll conductance (g_m), the total conductance of CO₂ diffusion from substomatal cavity to the site of carboxylation within chloroplast, is a major limiting factor for photosynthesis and a key parameter for improving photosynthetic resource use efficiency of crops. Online ¹³C discrimination method is an important method for plant eco-physiological studies and a well-established method for measuring g_m of C3 plants, although it has not been widely used due to challenges in methodology and high demands on experimental facilities. In this review, we summarized the characteristics of commonly used methods for g_m, introduced the basic theory of the online ¹³C discrimination method, namely Farquhar’s photosynthetic ¹³C discrimination model; systematically introduced the practical measurements, equations and the components of facilities; and reviewed the drivers for variation in g_m of C3 plants. At the last part, we discussed the outlook of the development of methodology, new experimental protocols, and applications in measurement scenarios.