Data from: Leaf photosynthetic, economics and hydraulic traits are decoupled among genotypes of a widespread species of eucalypt grown under ambient and elevated CO2

Leaf economics and hydraulic traits strongly influence photosynthesis. While the level of coordination among these traits can differ between sets of species, leaf functional trait coordination within species remains poorly understood. Furthermore, elevated concentrations of atmospheric CO2 commonly influence the expression of leaf photosynthetic, economics and hydraulic traits in contrasting ways, yet the effect of variable concentrations of atmospheric CO2 on patterns of trait coordination within species remains largely untested. We examined the relationships among key leaf photosynthetic (e.g. net photosynthesis and photosynthetic biochemistry), economics and water-use (e.g. leaf mass per unit area and stomatal conductance) and hydraulic traits (e.g. vein density) in 14 genotypes of Eucalyptus camaldulensis grown in ambient (aCO2) and elevated (eCO2) [CO2]. We examined the level of coordination among leaf traits in aCO2 and then assessed whether growth in eCO2 altered that coordination. We found that leaf traits related to photosynthetic capacity, economics and water-use, and hydraulics were decoupled among genotypes grown in aCO2, yet strong relationships were generally observed among suites of traits within each ‘functional group’. Significant responses to growth in eCO2 were observed for most leaf photosynthetic and economics and water-use traits, with the magnitude and direction of the response varying among traits. In contrast, leaf hydraulics traits were unaffected by variable growth CO2. Despite this, growth in eCO2 did not substantially alter patterns of leaf trait coordination observed in aCO2. These results suggest suites of leaf traits associated with photosynthetic capacity, economics and water-use and hydraulics, respectively, can form independent axes of variation among genotypes of a single species, regardless of growth CO2. Although growth in eCO2 did not substantially alter patterns of trait coordination, decoupling of leaf functional traits among genotypes may allow genetically distinct populations to produce novel combinations of traits that may be adaptive in response to changes in their local environment.

叶片经济性状与水力性状对光合作用具有显著调控作用。尽管不同物种类群间的性状协调水平存在差异，但同一物种内部的叶片功能性状协调机制仍未得到充分阐释。此外，大气CO₂浓度升高通常会以迥异的方式影响叶片光合、经济与水力性状的表达，然而大气CO₂浓度波动对物种内性状协调模式的影响，在很大程度上仍未得到实证检验。本研究以生长于环境CO₂（ambient CO₂, aCO₂）与升高CO₂（elevated CO₂, eCO₂）条件下的14份赤桉（Eucalyptus camaldulensis）基因型为材料，分析了关键叶片光合性状[如净光合速率与光合生物化学特性]、经济与水分利用性状[如单位面积叶质量与气孔导度]以及水力性状（hydraulic traits）之间的关联。我们首先分析了环境CO₂条件下叶片性状间的协调程度，随后评估了升高CO₂生长条件是否会改变这一协调模式。研究结果显示，在环境CO₂条件下生长的基因型中，与光合能力、经济及水分利用相关的叶片性状与水力性状彼此解耦，但在每个功能类群内部，各性状组间通常存在显著关联。多数叶片光合、经济与水分利用性状对升高CO₂生长条件表现出显著响应，且响应的幅度与方向因性状而异。与之形成鲜明对比的是，叶片水力性状不受生长环境CO₂浓度变化的影响。尽管如此，升高CO₂生长条件并未显著改变环境CO₂条件下观测到的叶片性状协调模式。上述结果表明，分别与光合能力、经济与水分利用以及水力相关的叶片性状组，可在同一物种的基因型间形成独立的变异轴，且不受生长CO₂浓度的影响。虽然升高CO₂生长条件并未显著改变性状协调模式，但基因型间叶片功能性状的解耦现象，或可使遗传分化的种群产生全新的性状组合，从而可能使其适应局部环境的变化。