Diffusional limitations explain the lower photosynthetic capacity of ferns as compared with angiosperms in a common garden study
Diffusional limitations explain the lower photosynthetic capacity of ferns as compared with angiosperms in a common garden study
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DOI：
10.1111/pce.12402
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发表时间：
2015-03-01
影响因子：
7.3
通讯作者：
Flexas, J.
中科院分区：
文献类型：
--
作者：
Carriqui, M.;Cabrera, H. M.;Flexas, J.
蕨类植物被认为具有较低的光合速率比被子植物，他们缺乏良好的气孔调节。然而，没有研究直接比较在共同环境中在最佳条件下生长的两组植物的光合作用。我们提出了一个共同的花园比较7被子植物和7蕨类植物配对的栖息地偏好，目的是（1）确认蕨类植物确实有较低的光合作用能力比被子植物和量化这些差异;（2）确定扩散与生化限制的重要性;和（3）分析叶片解剖特征的潜在意义，在设置两组的光合作用能力。蕨类植物的平均光合速率约为被子植物的一半，气孔和叶肉对CO2的导度（g（m））、最大羧化速率和电子传递速率均较低。定量限制分析表明，气孔导度和叶肉导度是导致蕨类植物光合作用低于被子植物的共同原因。然而，单独的g（m）是蕨类植物光合作用的最大限制因子。被子植物和蕨类植物的叶片解剖结构存在显著差异，尤其是细胞壁厚度和叶绿体表面暴露于胞间空气空间的差异，但没有文献同时比较同一个园林中蕨类植物和被子植物的光合功能。蕨类植物的光合速率约为被子植物的一半，气孔导度和叶肉导度是导致其光合速率较低的共同原因。蕨类植物的光合作用主要受g（m）的制约，g（m）是细胞壁厚度和叶绿体表面暴露于细胞间隙的最相关的解剖特征。
Ferns are thought to have lower photosynthetic rates than angiosperms and they lack fine stomatal regulation. However, no study has directly compared photosynthesis in plants of both groups grown under optimal conditions in a common environment. We present a common garden comparison of seven angiosperms and seven ferns paired by habitat preference, with the aims of (1) confirming that ferns do have lower photosynthesis capacity than angiosperms and quantifying these differences; (2) determining the importance of diffusional versus biochemical limitations; and (3) analysing the potential implication of leaf anatomical traits in setting the photosynthesis capacity in both groups. On average, the photosynthetic rate of ferns was about half that of angiosperms, and they exhibited lower stomatal and mesophyll conductance to CO2 (g(m)), maximum velocity of carboxylation and electron transport rate. A quantitative limitation analysis revealed that stomatal and mesophyll conductances were co-responsible for the lower photosynthesis of ferns as compared with angiosperms. However, g(m) alone was the most constraining factor for photosynthesis in ferns. Consistently, leaf anatomy showed important differences between angiosperms and ferns, especially in cell wall thickness and the surface of chloroplasts exposed to intercellular air spaces.No previous studies simultaneously compared the photosynthetic functioning of ferns and angiosperms in a common garden. The photosynthetic rate of ferns was about half that of angiosperms, being stomatal and mesophyll conductances co-responsible for the lower photosynthesis. The photosynthesis in ferns was mainly constrained by g(m,) being cell wall thickness and the surface of chloroplasts exposed to intercellular air spaces the most related anatomical traits.