Abstract

Emergent aquatic plants mostly occur in shallow waters and root in bottom substrates, but their leaves emerge from the water surface and are thus exposed to air, similar to the leaves of terrestrial plants. Previous studies have found coordination between leaf water supply and demand in terrestrial plants; however, whether such a coordination exists in emergent aquatic plants remains unknown. In this study, we analysed leaf veins and stomatal characteristics of 14 emergent aquatic and 13 terrestrial monocotyledonous herb species (EMH and TMH), with 5 EMH and 8 TMH belonging to Poaceae. We found that EMH had significantly higher mean leaf area, leaf thickness, stomatal density, stomatal number per vein length and major vein diameter, but lower mean major vein length per area (VLA) and total VLA than TMH. There was no significant difference in stomatal length, minor VLA and minor vein diameter between the two groups. Stomatal density and total VLA were positively correlated among the EMH, TMH, as well as the 8 Poaceae TMH species, but this correlation became non-significant when data from both the groups were pooled. Our results showed that the differences in water supply between emergent aquatic and terrestrial plants modify the coordination of their leaf veins and stomatal traits.

中文翻译：

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水生与陆生单子叶草本植物叶片气孔与叶脉性状协调的差异

摘要

出水水生植物多发生在浅水区，根系在底层，但它们的叶子长出水面，因此暴露在空气中，类似于陆生植物的叶子。先前的研究发现陆生植物叶片水分供需之间存在协调关系；然而，这种协调是否存在于水生植物中尚不清楚。在这项研究中，我们分析了 14 种水生和 13 种陆生单子叶草本植物（EMH 和 TMH）的叶脉和气孔特征，其中 5 种 EMH 和 8 种 TMH 属于禾本科。我们发现 EMH 的平均叶面积、叶片厚度、气孔密度、每脉长的气孔数和主脉直径显着更高，但比 TMH 具有更低的平均每面积主脉长度 (VLA) 和总 VLA。两组间气孔长度、小VLA和小静脉直径无显着差异。EMH、TMH 以及 8 种禾本科 TMH 物种之间的气孔密度和总 VLA 呈正相关，但是当合并两组的数据时，这种相关性变得不显着。我们的研究结果表明，水生植物和陆生植物之间的供水差异改变了它们的叶脉和气孔特征的协调。