Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, Goettingen, 37073, Germany.
Centre for Biodiversity and Sustainable Land Use (CBL), University of Goettingen, Goettingen, 37075, Germany.
New Phytol. 2021 Aug;231(4):1387-1400. doi: 10.1111/nph.17448. Epub 2021 Jun 6.
Plant hydraulic traits are key for understanding and predicting tree drought responses. Information about the degree of the traits' intra-specific variability may guide the selection of drought-resistant genotypes and is crucial for trait-based modelling approaches. For the three temperate minor broadleaf tree species Acer platanoides, Carpinus betulus and Tilia cordata, we measured xylem embolism resistance (P ), leaf turgor loss point (P ), specific hydraulic conductivity (K ), Huber values (HVs), and hydraulic safety margins in adult trees across a precipitation gradient. We further quantified trait variability on different organizational levels (inter-specific to within-canopy variation), and analysed its relationship to climatic and soil water availability. Although we observed a certain intra-specific trait variability (ITV) in safety-related traits (P , P ) with higher within-tree and between-tree than between populations variability, the magnitude was small compared to inter-specific differences, which explained 78.4% and 58.3% of the variance in P and P , respectively. In contrast, efficiency-related traits (K , HV) showed a high ITV both within populations and within the crowns of single trees. Surprisingly, the observed ITV of all traits was neither driven by climatic nor soil water availability. In conclusion, the high degree of conservatism in safety-related traits highlights their potential for trait-based modelling approaches.
植物水力特性是理解和预测树木干旱响应的关键。有关这些特性在种内变异程度的信息可能指导抗旱基因型的选择，对于基于特性的建模方法至关重要。对于三种温带小阔叶树种，欧洲槭、欧洲山毛榉和欧洲椴，我们在一个降水梯度上测量了成年树木的木质部栓塞阻力 (P )、叶片膨压损失点 (P )、比水力导率 (K )、胡伯值 (HVs) 和水力安全裕度。我们进一步量化了不同组织水平（种间到冠层内变异）上的特性变异性，并分析了其与气候和土壤水分可用性的关系。尽管我们观察到与安全相关的特性（P 、P ）在种内存在一定的变异性（ITV），但其在树木内和树木间的变异性高于种群间的变异性，但与种间差异相比，其幅度较小，分别解释了 P 和 P 变异的 78.4%和 58.3%。相比之下，与效率相关的特性（K 、HV）在种群内和单株树冠内均表现出较高的 ITV。令人惊讶的是，所有特性的观察到的 ITV 既不受气候也不受土壤水分可用性的驱动。总之，安全相关特性的高度保守性突出了它们在基于特性的建模方法中的潜力。
