Background and Aims In hierarchically reticulate venation patterns, smaller orders of veins form areoles in which stomata are located. This study aimed to quantify the spatial relationship among stomata at the areole level. Methods For each of 12 leaves of M. cavaleriei var. platypetala, we assumed that stomatal characteristics were symmetrical on either side of the midrib, and divided the leaf surface on one side of the midrib into six layers equidistantly spaced along the apical–basal axis. We then further divided each layer into three positions equidistantly spaced from midrib to leaf margin, resulting in a total of 18 sampling locations. In addition, for 60 leaves, we sampled three positions from midrib to margin within only the widest layer of the leaf. Stomatal density and mean nearest neighbour distance (MNND) were calculated for each section. A replicated spatial point pattern approach quantified stomatal spatial relationships at different distances (0–300 μm). Key Results A tendency towards regular arrangement (inhibition as opposed to attraction or clustering) was observed between stomatal centres at distances <100 μm. Leaf layer (leaf length dimension) had no significant effect on local stomatal density, MNND or the spatial distribution characteristics of stomatal centres. In addition, we did not find greater inhibition at the centre of areoles, and in positions farther from the midrib. Conclusions Spatial inhibition might be caused by the one-cell-spacing rule, resulting in more regular arrangement of stomata, and it was found to exist at distances up to ~100 μm. This work implies that leaf hydraulic architecture, consisting of both vascular and mesophyll properties, is sufficient to prevent important spatial variability in water supply at the areole level.

中文翻译：

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骑士含笑气孔水平气孔空间分布特征platypetala（木兰科）


背景和目的在分层网状脉络模式中，较小顺序的静脉形成气孔所在的小孔。本研究旨在量化气孔水平上气孔之间的空间关系。方法 对于 M. cavaleriei var. 12 片叶子中的每一片。对于 platypetala，我们假设中脉两侧的气孔特征是对称的，并将中脉一侧的叶面沿顶基轴等距地分成六层。然后，我们将每层进一步分为从中脉到叶缘等距的三个位置，总共有 18 个采样位置。此外，对于 60 个叶子，我们仅在叶子最宽的一层内从中脉到边缘的三个位置进行了采样。计算每个部分的气孔密度和平均最近邻距离（MNND）。复制空间点模式方法量化了不同距离（0-300 μm）的气孔空间关系。主要结果 在距离 <100 μm 的气孔中心之间观察到规则排列的趋势（抑制，而不是吸引或聚集）。叶层（叶长尺寸）对局部气孔密度、MNND或气孔中心的空间分布特征没有显着影响。此外，我们没有发现在乳晕中心和远离中脉的位置有更大的抑制作用。结论 空间抑制可能是由单细胞间距规则引起的，导致气孔排列更加规则，并且发现空间抑制存在于距离达~100 μm的地方。这项工作意味着，由维管束和叶肉特性组成的叶片水力结构足以防止叶轮水平上供水的重要空间变化。