Zhao Wanli, Fu Peili, Mao Qinggong, Liu Guolan, Li Yuanqiu, Xia Jiangbao, Zhao Ping
Shandong Key Laboratory of Eco-Environmental Science for Yellow River Delta, Binzhou University, Binzhou, Shandong, China.
Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, China.
Front Plant Sci. 2023 Jul 26;14:1051692. doi: 10.3389/fpls.2023.1051692. eCollection 2023.
Leaf phenology (evergreen vs. deciduous) and morphology (simple vs. compound) are known to be related to water use strategies in tree species and critical adaptation to certain climatic conditions. However, the effect of these two traits and their interactions on the coordination between minor vein density (MVD) and stomatal density (SD) remains unclear. In this study, we examined the leaves of 108 tree species from plots in a primary subtropical forest in southern China, including tree species with different leaf morphologies and phenologies. We assessed nine leaf water-related functional traits for all species, including MVD, SD, leaf area (LA), minor vein thickness (MVT), and stomatal length (SL). The results showed no significant differences in mean LA and SD between either functional group (simple vs. compound and evergreen vs. deciduous). However, deciduous trees displayed a significantly higher mean MVD compared to evergreen trees. Similarly, compound-leaved trees have a higher (marginally significant) MVD than simple-leaved trees. Furthermore, we found that leaf morphology and phenology have significantly interactive effects on SL, and the compound-leafed deciduous trees exhibited the largest average SL among the four groups. There were significant correlations between the MVD and SD in all different tree groups; however, the slopes and interceptions differed within both morphology and phenology. Our results indicate that MVD, rather than SD, may be the more flexible structure for supporting the coordination between leaf water supply and demand in different leaf morphologies and phenologies. The results of the present study provide mechanistic understandings of the functional advantages of different leaf types, which may involve species fitness in community assembly and divergent responses to climate changes.
叶片物候（常绿与落叶）和形态（单叶与复叶）已知与树种的水分利用策略以及对特定气候条件的关键适应性有关。然而，这两个特征及其相互作用对小叶脉密度（MVD）和气孔密度（SD）之间协调的影响仍不清楚。在本研究中，我们检查了来自中国南方亚热带原始森林样地的108种树种的叶片，包括具有不同叶片形态和物候的树种。我们评估了所有物种的九个与叶片水分相关的功能性状，包括MVD、SD、叶面积（LA）、小叶脉厚度（MVT）和气孔长度（SL）。结果表明，在任何一个功能组（单叶与复叶、常绿与落叶）之间，平均LA和SD均无显著差异。然而，与常绿树相比，落叶树的平均MVD显著更高。同样，复叶树的MVD高于单叶树（边缘显著）。此外，我们发现叶片形态和物候对SL有显著的交互作用，复叶落叶树在四组中表现出最大的平均SL。在所有不同的树种组中，MVD和SD之间都存在显著相关性；然而，在形态和物候方面，斜率和截距有所不同。我们的结果表明，MVD而非SD可能是支持不同叶片形态和物候中叶片水分供需协调的更灵活结构。本研究结果为不同叶片类型的功能优势提供了机制性理解，这可能涉及群落组装中的物种适应性以及对气候变化的不同响应。
