Impact of Leaf Morphological and Anatomical Traits on Mesophyll Conductance and Leaf Hydraulic Conductance in Mangrove Plants

Mesophyll conductance (g_m) and leaf hydraulic conductance (K_leaf) are two important physiological processes that control photosynthesis. However, few studies have investigated the correlations between them. We measured the morphological and anatomical traits of the leaves and the maximum photosynthetic rate (A_max), g_m and K_leaf in nine mangrove forest species to explore the correlation between the structural and functional traits of the leaves in these species. Our results showed that there were large variations in K_leaf (0.78-5.50 mmol·m^-2·s^-1·MPa^-1), g_m (0.06-0.36 mol·m^-2·s^-1) and A_max (7.23-23.71 μmol·m^-2·s^-1) across the nine species. Mesophyll conductance was significantly correlated with A_max, but not with leaf mass per area. Among the nine species, stomatal density was correlated with vein density, indicating a balance between leaf-level water transpiration and supply. There was no significant relationship between K_leaf and vein density, nor between A_max and g_m. Decoupled coordination between leaf economic and hydraulic traits for plants growing in mangrove forests indicates additional leaf trait such as water storage tissues assisting their leaf carbon assimilation, This study showed the special leaf structural and physiological adaptation of mangrove plants to the stressful habitats.