Water released from wood during transpiration (capacitance) can meaningfully affect daily water use and drought response. To provide context for better understanding of capacitance mechanisms, we investigated links between capacitance and wood anatomy. On twigs of 30 temperate angiosperm tree species, we measured day capacitance (between predawn and midday), water content, wood density, and anatomical traits, that is, vessel dimensions, tissue fractions, and vessel–tissue contact fractions (fraction of vessel circumference in contact with other tissues). Across all species, wood density (WD) and predawn lumen volumetric water content (VWC_L‐pd) together were the strongest predictors of day capacitance (r²_adj = .44). Vessel–tissue contact fractions explained an additional ~10% of the variation in day capacitance. Regression models were not improved by including tissue lumen fractions. Among diffuse‐porous species, VWC_L‐pd and vessel–ray contact fraction together were the best predictors of day capacitance, whereas among semi/ring‐porous species, VWC_L‐pd, WD and vessel–fibre contact fraction were the best predictors. At predawn, wood was less than fully saturated for all species (lumen relative water content = 0.52 ± 0.17). Our findings imply that day capacitance depends on the amount of stored water, tissue connectivity and the bulk wood properties arising from WD (e.g., elasticity), rather than the fraction of any particular tissue.

中文翻译：

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木材日电容与30种温带树种的水分含量，木材密度和解剖结构有关。

蒸腾过程中木材释放的水（电容）会显着影响日常用水和干旱响应。为了提供背景以更好地理解电容机制，我们研究了电容与木材解剖结构之间的联系。在30种温带被子植物树的树枝上，我们测量了日电容（黎明前和中午之间），水含量，木材密度和解剖学特征，即血管尺寸，组织分数和血管-组织接触分数（血管周长的分数）与其他组织接触）。在所有物种中，木材密度（WD）和黎明前腔容积水含量（VWC _L-pd）一起是日电容的最强预测因子（r ² _adj= .44）。血管与组织的接触分数解释了日电容变化的约10％。通过包括组织管腔分数不能改善回归模型。在弥散多孔物种中，VWC _L-pd和血管-射线接触分数一起是日电容的最佳预测指标，而在半/环状多孔物种中，VWC _L-pd，WD和血管-纤维接触分数是最好的预测指标。黎明前，所有物种的木材都未完全饱和（管腔相对水含量= 0.52±0.17）。我们的发现表明，日电容取决于储存的水量，组织的连通性以及WD产生的大块木材特性（例如，弹性），而不是任何特定组织的分数。