Simple generalisation of a mesophyll resistance model for various intracellular arrangements of chloroplasts and mitochondria in C(3) leaves.
Simple generalisation of a mesophyll resistance model for various intracellular arrangements of chloroplasts and mitochondria in C(3) leaves.
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DOI：
10.1007/s11120-017-0340-8
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发表时间：
2017-05
影响因子：
3.7
通讯作者：
Struik PC
中科院分区：
文献类型：
--
作者：
Yin X;Struik PC
叶肉电导（g m）的经典定义代表了一个表观参数（g m，app），因为它的地方（照片）呼吸的CO2在同一个隔间，其中羧化Rubisco发生。最近，托伦和同事开发了一个框架，其中g m更好地描述了物理扩散参数（g m，dif）。它们将叶肉抵抗力（rm，dif = 1/gm，dif）分解为细胞壁和质膜阻力（rwp）和叶绿体阻力（rch），表明gm，app对光呼吸（F）和呼吸（Rd）CO2释放与净CO2吸收（A）的比值敏感：gm，app = gm，dif/[1 + ω（F + Rd）/A]，其中ω是rch在rm，dif中的分数.我们在此扩展框架进一步考虑各种情况下的细胞内安排的叶绿体和线粒体。我们表明，托伦等人的公式。意味着要么线粒体，（光）呼吸CO2的释放，位于质膜和叶绿体连续体之间，或CO2在胞质溶胶中是完全混合的。然而，托伦等人的模型仍然是有效的，如果ω被ω（1-σ）代替，其中σ是经历r ch（除了r wp和气孔阻力）的（光）呼吸CO2的分数，如果这种CO2要逃离被重新固定。因此，g m，app对（F + Rd）/A的响应介于经典方法中的无灵敏度（σ =1）和托伦等人模型中的高灵敏度（σ =0）之间。
The classical definition of mesophyll conductance (g m) represents an apparent parameter (g m,app) as it places (photo)respired CO2 at the same compartment where the carboxylation by Rubisco takes place. Recently, Tholen and co-workers developed a framework, in which g m better describes a physical diffusional parameter (g m,dif). They partitioned mesophyll resistance (r m,dif = 1/g m,dif) into two components, cell wall and plasmalemma resistance (r wp) and chloroplast resistance (r ch), and showed that g m,app is sensitive to the ratio of photorespiratory (F) and respiratory (R d) CO2 release to net CO2 uptake (A): g m,app = g m,dif/[1 + ω(F + R d)/A], where ω is the fraction of r ch in r m,dif. We herein extend the framework further by considering various scenarios for the intracellular arrangement of chloroplasts and mitochondria. We show that the formula of Tholen et al. implies either that mitochondria, where (photo)respired CO2 is released, locate between the plasmalemma and the chloroplast continuum or that CO2 in the cytosol is completely mixed. However, the model of Tholen et al. is still valid if ω is replaced by ω(1−σ), where σ is the fraction of (photo)respired CO2 that experiences r ch (in addition to r wp and stomatal resistance) if this CO2 is to escape from being refixed. Therefore, responses of g m,app to (F + R d)/A lie somewhere between no sensitivity in the classical method (σ =1) and high sensitivity in the model of Tholen et al. (σ =0).