Effects of potassium supply on limitations of photosynthesis by mesophyll diffusion conductance in Carya cathayensis
Effects of potassium supply on limitations of photosynthesis by mesophyll diffusion conductance in Carya cathayensis
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供钾对山核桃叶肉扩散导度光合作用限制的影响
DOI：
10.1093/treephys/tpr095
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发表时间：
2011-10-01
期刊：
影响因子：
4
通讯作者：
Chen, Miao
中科院分区：
文献类型：
--
作者：
Jin, Song Heng;Huang, Jian Qin;Chen, Miao
钾 (K) 通过多种方式影响光合作用过程；然而，光合作用对钾供应差异的反应机制尚不清楚。通过同时测量气体交换和叶绿素荧光，研究钾营养对温室山核桃幼苗（Carya cathayensis Sarg.）光合效率和叶肉导度（g（m））的影响。结果表明，叶片K浓度<0.7-0.8%似乎限制了叶片净CO2同化速率（A），并且g（m）和气孔导度（g（s））引起的光合作用相对限制随着K供应的增加而减小。然而，敏感性分析表明A对Rubisco最大羧化速率（V-c，V-max）和最大电子传输速率（J（max））最敏感。这些结果表明，缺钾植物的光合速率主要受光合作用生化过程（V-c、V-max 和 J(max)）的限制，而不是受 g(m) 和 g(s) 的限制。此外，山核桃幼苗中的 g(m) 与 g(s) 和单位面积叶片干质量 (M-A) 密切相关，这表明 g(m) 和 g(s) 的减少可能是叶片解剖适应的结果。
Potassium (K) influences the photosynthesis process in a number of ways; however, the mechanisms underlying the photosynthetic response to differences in K supply are not well understood. Concurrent measurements of gas exchange and chlorophyll fluorescence were made to investigate the effect of K nutrition on photosynthetic efficiency and mesophyll conductance (g(m)) in hickory seedlings (Carya cathayensis Sarg.) in a greenhouse. The results show that leaf K concentrations < 0.7-0.8% appeared to limit the leaf net CO2 assimilation rate (A), and that the relative limitation of photosynthesis due to g(m) and stomatal conductance (g(s)) decreased with increasing supplies of K. However, a sensitivity analysis indicated that A was most sensitive to the maximum carboxylation rate of Rubisco (V-c,V-max) and the maximum rate of electron transport (J(max)). These results indicate that the photosynthetic rate is primarily limited by the biochemical processes of photosynthesis (V-c,V-max and J(max)), rather than by g(m) and g(s) in K-deficient plants. Additionally, g(m) was closely correlated with g(s) and the leaf dry mass per unit area (M-A) in hickory seedlings, which indicates that decreased g(m) and g(s) may be a consequence of leaf anatomical adaptation.