Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears (UIB), INAGEA, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
Department of Molecular and Cell Biology, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa.
J Exp Bot. 2021 Mar 29;72(7):2600-2610. doi: 10.1093/jxb/erab022.
Resurrection plants are vascular species able to sustain extreme desiccation in their vegetative tissues. Despite its potential interest, the role of leaf anatomy in CO2 diffusion and photosynthesis under non-stressed conditions has not been explored in these species. Net CO2 assimilation (An) and its underlying diffusive, biochemical, and anatomical determinants were assessed in 10 resurrection species from diverse locations, including ferns, and homoiochlorophyllous and poikilochlorophyllous angiosperms. Data obtained were compared with previously published results in desiccation-sensitive ferns and angiosperms. An in resurrection plants was mostly driven by mesophyll conductance to CO2 (gm) and limited by CO2 diffusion. Resurrection species had a greater cell wall thickness (Tcw) than desiccation-sensitive plants, a feature associated with limited CO2 diffusion in the mesophyll, but also greater chloroplast exposure to intercellular spaces (Sc), which usually leads to higher gm. This combination enabled a higher An per Tcw compared with desiccation-sensitive species. Resurrection species possess unusual anatomical features that could confer stress tolerance (thick cell walls) without compromising the photosynthetic capacity (high chloroplast exposure). This mechanism is particularly successful in resurrection ferns, which display higher photosynthesis than their desiccation-sensitive counterparts.
复苏植物是具有维管束的物种，能够在其营养组织中维持极端的干燥。尽管它具有潜在的意义，但在非胁迫条件下，叶片解剖结构在 CO2 扩散和光合作用中的作用在这些物种中尚未得到探索。在来自不同地点的 10 种复苏物种中，评估了净 CO2 同化（An）及其潜在的扩散、生化和解剖决定因素，包括蕨类植物、同形叶绿素和异形叶绿素的被子植物。获得的数据与以前在脱水敏感的蕨类植物和被子植物中发表的结果进行了比较。复苏植物中的 An 主要由 CO2 通过叶肉的导度（gm）驱动，并受到 CO2 扩散的限制。复苏物种的细胞壁厚度（Tcw）大于脱水敏感植物，这一特征与叶肉中 CO2 扩散受限有关，但也有更多的叶绿体暴露于细胞间隙（Sc），这通常导致更高的 gm。这种组合使每 Tcw 的 An 比脱水敏感物种更高。复苏物种具有不寻常的解剖特征，这可能赋予它们对胁迫的耐受性（厚细胞壁）而不影响其光合作用能力（高叶绿体暴露）。这种机制在复苏蕨类植物中特别成功，它们比脱水敏感的蕨类植物表现出更高的光合作用。
