CREAF, E08193, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain.
ICREA, 08010, Barcelona, Spain.
New Phytol. 2019 Jul;223(2):632-646. doi: 10.1111/nph.15684. Epub 2019 Feb 8.
Trait variability in space and time allows plants to adjust to changing environmental conditions. However, we know little about how this variability is distributed and coordinated at different organizational levels. For six dominant tree species in northeastern Spain (three Fagaceae and three Pinaceae) we quantified the inter- and intraspecific variability of a set of traits along a water availability gradient. We measured leaf mass per area (LMA), leaf nitrogen (N) concentration, carbon isotope composition in leaves (δ C), stem wood density, the Huber value (Hv, the ratio of cross-sectional sapwood area to leaf area), sapwood-specific and leaf-specific stem hydraulic conductivity, vulnerability to xylem embolism (P ) and the turgor loss point (P ). Differences between families explained the largest amount of variability for most traits, although intraspecific variability was also relevant. Species occupying wetter sites showed higher N, P and P , and lower LMA, δ C and Hv. However, when trait relationships with water availability were assessed within species they held only for Hv and P . Overall, our results indicate that intraspecific adjustments along the water availability gradient relied primarily on changes in resource allocation between sapwood and leaf area and in leaf water relations.
性状在时空上的变异使植物能够适应环境条件的变化。然而，我们对这种变异性在不同组织水平上是如何分布和协调的知之甚少。我们对西班牙东北部的六种优势树种（三种壳斗科和三种松科）进行了研究，沿水分可利用性梯度量化了一组性状的种间和种内变异。我们测量了叶面积比（LMA）、叶片氮浓度（N）、叶片碳同位素组成（δC）、茎木材密度、Huber 值（Hv，边材横截面积与叶面积的比值）、比叶和比茎水力导度、木质部栓塞脆弱性（P ）和膨压损失点（P ）。大多数性状的变异主要由科间差异解释，但种内变异也很重要。占据更湿润生境的物种表现出更高的 N、P 和 P ，以及更低的 LMA、δC 和 Hv。然而，当在种内评估与水分可利用性的性状关系时，只有 Hv 和 P 具有相关性。总的来说，我们的结果表明，沿水分可利用性梯度的种内调整主要依赖于边材和叶面积之间的资源分配变化以及叶片水分关系的变化。
