Weithmann G, Schuldt B, Link R M, Heil D, Hoeber S, John H, Müller-Haubold H, Schüller L-M, Schumann K, Leuschner C
Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Göttingen, Göttingen, Germany.
Centre for Biodiversity and Sustainable Land Use (CBL), University of Göttingen, Göttingen, Germany.
Plant Biol (Stuttg). 2022 Dec;24(7):1272-1286. doi: 10.1111/plb.13366. Epub 2021 Dec 1.
Leaf morphological and physiological traits control the carbon and water relations of mature trees and are determinants of drought tolerance, but it is not well understood how they are modified in response to water deficits. We analysed five sun-canopy leaf traits (mean leaf size (LS), specific leaf area (SLA), Huber value (HV), water potential at turgor loss point (Ψ ) and foliar carbon isotope signature (δ C)) in European beech (Fagus sylvatica L.) across three precipitation gradients sampled in moist (2010), dry (2019) and very dry (2018) summers, and tested their response to short-term water deficits (climatic water balance (CWB) preceding sample collection) and long-term water availability (mean annual precipitation (MAP), plant-available soil water capacity (AWC) and neighbourhood competition). Across the 34 sites, LS varied seven-fold (3.9-27.0 cm ), SLA four-fold (77.1-306.9 cm²·g ) and HV six-fold (1.0-6.65 cm ·m ). In the 2018 dataset, LS showed a negative and HV a positive relationship to MAP, which contradicts relations found in multi-species samples. Average Ψ ranged from -1.90 to -2.62 MPa and decreased across the sites with decreasing CWB in the month prior to measurement, as well as with decreasing MAP and AWC in 2019. Studied leaf traits varied considerably between years, suggesting that mast fruiting and the severe 2018 drought caused the formation of smaller leaves. We conclude that sun-canopy leaf traits of European beech exhibit considerable plasticity in response to climatic and edaphic aridity, and that osmotic adjustment may be an important element in the drought response strategy of this anisohydric tree species.
叶片形态和生理特征控制着成熟树木的碳和水分关系，是耐旱性的决定因素，但人们对它们如何响应水分亏缺而发生改变却了解甚少。我们分析了欧洲山毛榉（Fagus sylvatica L.）在湿润（2010年）、干旱（2019年）和极干旱（2018年）夏季所采集的三个降水梯度样本中的五个阳生冠层叶片特征（平均叶面积（LS）、比叶面积（SLA）、胡伯值（HV）、膨压丧失点水势（Ψ）和叶片碳同位素特征（δC）），并测试了它们对短期水分亏缺（采样前的气候水分平衡（CWB））和长期水分可利用性（年均降水量（MAP）、植物可利用土壤水分容量（AWC）和邻体竞争）的响应。在这34个样地中，LS变化了7倍（3.9 - 27.0平方厘米），SLA变化了4倍（77.1 - 306.9平方厘米·克），HV变化了6倍（1.0 - 6.65厘米·米）。在2018年的数据集中，LS与MAP呈负相关，HV与MAP呈正相关，这与在多物种样本中发现的关系相矛盾。平均Ψ范围为-1.90至-2.62兆帕，在测量前一个月随CWB降低以及2019年随MAP和AWC降低而在各采样点下降。所研究的叶片特征在不同年份间差异很大，表明大年结果和2018年的严重干旱导致了更小叶片的形成。我们得出结论，欧洲山毛榉的阳生冠层叶片特征对气候和土壤干旱表现出相当大的可塑性，并且渗透调节可能是这种非等水植物物种干旱响应策略中的一个重要因素。
