Anatomical and diffusional determinants inside leaves explain the difference in photosynthetic capacity between Cypripedium and Paphiopedilum, Orchidaceae
Anatomical and diffusional determinants inside leaves explain the difference in photosynthetic capacity between Cypripedium and Paphiopedilum, Orchidaceae
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叶子内部的解剖和扩散决定因素解释了兰科杓兰和兜兰之间光合作用能力的差异
DOI：
10.1007/s11120-017-0466-8
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发表时间：
2018
影响因子：
3.7
通讯作者：
Shi-Bao Zhang
中科院分区：
文献类型：
--
作者：
Zhong-Hui Yang;Wei Huang;Qiu-Yun Yang;Wei Chang;Shi-Bao Zhang
与其他被子植物相比，兰科植物的大多数成员具有较低的光合作用能力。然而，潜在的机制仍不清楚。塞浦路斯属和兜兰属在兰科植物中亲缘关系很近，但它们的光合作用表现不同。本文探讨了3种绞股蓝和3种兜兰的内部解剖和扩散电导在决定光合作用中的作用，并定量分析了它们对光合作用的扩散和生化限制。兜兰的光饱和光合作用速率(An)、气孔导度(GS)和叶肉导度(Gm)均低于绞股蓝。AN值与G、Gm呈正相关。然而，在这两个物种中，And受到转基因比生化因素或GS更强烈的限制。较大的Gs值主要受较大的气孔器面积和较小的气孔深度影响，而较小的Gm值则取决于单位叶面积的叶肉细胞和叶绿体暴露在细胞间隙中的表面积减小和细胞壁厚得多。这些结果表明，叶片解剖结构是影响转基因的关键因素，这在很大程度上是造成这两个属之间光合作用能力差异的原因。我们的发现为兰花的光合作用生理和功能多样性提供了新的见解。
Comparing with other angiosperms, most members within the family Orchidaceae have lower photosynthetic capacities. However, the underlying mechanisms remain unclear. Cypripedium and Paphiopedilum are closely related phylogenetically in Orchidaceae, but their photosynthetic performances are different. We explored the roles of internal anatomy and diffusional conductance in determining photosynthesis in three Cypripedium and three Paphiopedilum species, and quantitatively analyzed their diffusional and biochemical limitations to photosynthesis. Paphiopedilum species showed lower light-saturated photosynthetic rate (AN), stomatal conductance (gs), and mesophyll conductance (gm) than Cypripedium species. ANwas positively correlated with gsand gm. And yet, in both species ANwas more strongly limited by gmthan by biochemical factors or gs. The greater gsof Cypripedium was mainly affected by larger stomatal apparatus area and smaller pore depth, while the less gmof Paphiopedilum was determined by the reduced surface area of mesophyll cells and chloroplasts exposed to intercellular airspace per unit of leaf area, and much thicker cell wall thickness. These results suggest that leaf anatomical structure is the key factor affecting gm, which is largely responsible for the difference in photosynthetic capacity between those two genera. Our findings provide new insight into the photosynthetic physiology and functional diversification of orchids.