叶肉细胞导度研究进展

The research progress of mesophyll conductance

叶肉细胞导度指叶片叶肉细胞内部的CO2扩散能力,在植物生理生态及全球气候变化和陆地生态系统相互关系的研究中具有重要作用。系统介绍了叶肉细胞导度的发现、发展过程及其研究进展、几种目前国际上常用的叶肉细胞导度测度方法的原理、计算过程;强调了叶肉细胞导度作为光合作用扩散过程一部分的重要意义,明确了叶肉细胞导度的定义及分布范围。并探讨了不同方法的优缺点及注意事项。总结分析了叶肉细胞导度对不同环境因子(温度、水分及环境中CO2和O3浓度等)的响应,从不同角度对叶肉细胞导度的生态学意义进行了简单的概括。对叶肉细胞导度的未来研究进行了展望。

Mesophyll conductance（gm） is the diffusional capacity of CO2 inside mesophyll cells.It was regarded as an infinite constant in research on photosynthetic process in the past.But results of relevant research in the past 20 years show that mesophyll conductance is not only a finite value but also changes with many environmental factors（temperature,water content,leaf nutrient content）.Comparing to stomatal conductance（gs）,mesophyll conductance is a more important limited factors to photosynthetic rate.More and more attentions have been paid on its role in studying plant eco-physiology and the relationship between global climate change and terrestrial ecosystem.Processes of discovery and development of mesophyll conductance and relevant research progress were reviewed systematically.The role of mesophyll conductance in CO2 diffusion process during photosynthesis was stressed.Tentative definition and value span of mesophyll conductance were summarized.This paper introduced theories and mathematical processes of methods frequently used for measuring mesophyll conductance,including instant carbon isotope discrimination method,electronic transport rate（J） variable method,electronic transport rate constant method,method of difference between intercellular CO2 and inside chloroplast CO2,and method of initial slope different between A-Ci and A-Cc curve.Advantage and disadvantage,as well as attention points,of the methods were deeply discussed.Responses of mesophyll conductance to environmental factors（temperature,water content,concentration of ambient CO2 and O3） were summarized.Relationship between mesophyll conductance and indicator of long term plant water use efficiency（WUE）,δ13C of leaves,was analyzed and discussed.In addition,application of mesophyll conductance in interpreting ecological strategy of plants was also discussed.Perspectives for the future research on mesophyll conductance were suggested finally.