Leaf stomatal density is known to co‐vary with leaf vein density. However, the functional underpinning of this relation, and how it scales to whole‐plant water transport anatomy, is still unresolved. We hypothesized that the balance of water exchange between the vapour phase (in stomata) and liquid phase (in vessels) depends on the consistent scaling between the summed stomatal areas and xylem cross‐sectional areas, both at the whole‐plant and single‐leaf level. This predicted size co‐variation should be driven by the co‐variation of numbers of stomata and terminal vessels. We examined the relationships of stomatal traits and xylem anatomical traits from the entire plant to individual leaves across seedlings of 53 European woody angiosperm species. There was strong and convergent scaling between total stomatal area and stem xylem area per plant and between leaf total stomatal area and midvein xylem area per leaf across all the species, irrespective of variation in leaf habit, growth‐form or relative growth rate. Moreover, strong scaling was found between stomatal number and terminal vessel number, whereas not in their respective average areas. Our findings have broad implications for integrating xylem architecture and stomatal distribution and deepen our understanding of the design rules of plants' water transport network.

中文翻译：

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不同木本植物幼苗中木质部和气孔的异速变化。

叶片气孔密度与叶片静脉密度共同变化。但是，这种关系的功能基础以及如何扩展到整个植物的水运输解剖学仍未解决。我们假设汽相（气孔）和液相（容器）之间的水交换平衡取决于整个植物和单叶的总气孔面积和木质部横截面积之间的一致比例。水平。这种预计的大小协变量应由气孔和末梢血管​​数量的协变量驱动。我们研究了从整个植物到跨越53种欧洲木质被子植物种的幼苗的单个叶片的气孔性状和木质部解剖性状的关系。在所有物种中，无论叶片习性，生长形式或相对生长率的变化如何，每一种植物的总气孔面积与茎木质部面积之间以及叶片的总气孔面积与中叶木质部木质部面积之间都存在强且收敛的缩放比例。此外，在气孔数和末端血管数之间发现了强比例，而在它们各自的平均面积中却没有。我们的发现对整合木质部建筑和气孔分布具有广泛的意义，并加深了我们对植物水输送网络设计规则的理解。而不在各自的平均面积内。我们的发现对整合木质部建筑和气孔分布具有广泛的意义，并加深了我们对植物水输送网络设计规则的理解。而不在各自的平均面积内。我们的发现对整合木质部建筑和气孔分布具有广泛的意义，并加深了我们对植物水输送网络设计规则的理解。