Department of Biosciences, College of Humanities and Sciences, Nihon University, Setagaya-ku, Tokyo, Japan.
Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori, Japan.
PLoS One. 2022 Sep 22;17(9):e0275024. doi: 10.1371/journal.pone.0275024. eCollection 2022.
Plants respond to environmental stressors, such as an oligotrophic environments, by altering the morphological and physiological functions of their leaves. Sex affects these functions because of the asymmetric cost of reproduction in dioecious plants. We compared the leaf mass per leaf area (LMA), ratio of intercellular air space in leaf mesophyll tissue (mesophyll porosity), palisade thickness, and carbon isotope ratio (δ13C) of leaves of the dioecious shrub Myrica gale based on sex and gradients of soil water chemistry across habitats in the field. The PCA showed that the first three principal components accounted for 84.5% of the variation. PC1 to PC3 were associated with the origin of soil water, nitrogen status of habitats, and sea-salt contributions, respectively. LMA varied from 5.22 to 7.13 μg/cm2, and it was positively related to PC2 and negatively related to PC3, but not to PC1 or sex, suggesting that LMA was low under poor nitrogen conditions and varied with salinity. Mesophyll porosity values were over 50% for all habitats. Mesophyll porosity was positively affected by PC3 and smaller in females than in males. This suggests that M. gale exhibits differences in mesophyll anatomy according to sex. Palisade thickness ranged from 0.466 to 0.559 mm/mm. The leaves of females had thinner palisade layers per mesophyll layer than those of males; however, the habitat did not affect the thickness of the palisade layer per mesophyll layer. The δ13C values of leaves varied from -32.14 to -30.51 ‰. We found that δ13C values were positively related to PC2 but not to PC1, PC3, and sex. Under poor nitrogen conditions, the δ13C of M. gale leaves decreased, suggesting that nutrient deficiency would decrease more under the long-term averaged ratio of photosynthesis than stomatal conductance, leading to low water use efficiency.
植物会通过改变叶片的形态和生理功能来应对环境胁迫，例如贫营养环境。性别会影响这些功能，因为在雌雄异株植物中，繁殖的不对称成本。我们比较了基于性别的和土壤化学梯度的田野栖息地中雌雄异株灌木杨梅的叶面积质量与叶面积比（LMA）、叶片间质组织中细胞间空气空间的比例（叶肉孔隙度）、栅栏厚度和叶片的碳同位素比（δ13C）。PCA 表明，前三个主成分占变异的 84.5%。PC1 到 PC3 分别与土壤水的起源、栖息地的氮状况和海盐水的贡献有关。LMA 从 5.22 到 7.13 μg/cm2 不等，它与 PC2 呈正相关，与 PC3 呈负相关，但与 PC1 或性别无关，表明在氮条件差的情况下 LMA 较低，并随盐度变化。所有栖息地的叶肉孔隙度均超过 50%。叶肉孔隙度受 PC3 的正向影响，且雌性小于雄性。这表明杨梅根据性别表现出不同的叶肉解剖结构。栅栏厚度范围为 0.466 至 0.559 mm/mm。与雄性相比，雌性叶片每叶肉层的栅栏层较薄；然而，栖息地不会影响每叶肉层的栅栏层厚度。叶片的 δ13C 值从-32.14 到-30.51 ‰不等。我们发现 δ13C 值与 PC2 呈正相关，但与 PC1、PC3 和性别无关。在氮素缺乏的情况下，杨梅叶片的 δ13C 值降低，这表明在长期平均光合作用与气孔导度的比值下，养分缺乏会减少，导致水分利用效率降低。
