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（leaf economics and hydraulic traits）显著影响光合作用过程。尽管不同物种类群间这些性状的协同水平存在差异，但物种内部的叶片功能性状协同模式仍有待深入解析。此外，大气CO₂浓度升高通常会以差异化方式调控叶片光合、经济及水力性状的表达，然而大气CO₂浓度波动对物种内部性状协同模式的影响，目前仍尚未得到充分验证。本研究以生长于环境CO₂浓度（ambient CO₂, aCO₂）与升高CO₂浓度（elevated CO₂, eCO₂）条件下的14份赤桉（Eucalyptus camaldulensis）基因型为材料，分析了核心叶片光合性状（如净光合速率（net photosynthesis）与光合生物化学过程（photosynthetic biochemistry））、经济与水分利用性状（如比叶重（leaf mass per unit area）与气孔导度（stomatal conductance））及水力性状（如叶脉密度（vein density））之间的关联。我们首先解析了aCO₂条件下叶片性状的协同水平，随后评估了eCO₂生长环境是否会改变这种协同模式。研究结果显示，在aCO₂条件下生长的基因型中，与光合能力、经济及水分利用、水力相关的叶片性状间呈现解耦关系，但各功能群内部的性状组间均存在显著相关关系。多数叶片光合、经济及水分利用性状对eCO₂生长环境存在显著响应，且不同性状的响应方向与幅度存在差异；与之相反，叶片水力性状不受生长环境CO₂浓度波动的影响。尽管如此，eCO₂生长环境并未显著改变aCO₂条件下观测到的叶片性状协同模式。上述结果表明，分别与光合能力、经济及水分利用、水力相关的叶片性状组，可在单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eCO₂生长环境并未显著改变性状协同模式，但基因型间叶片功能性状的解耦现象，可能使遗传分化的种群产生新颖的性状组合，从而适应其本地环境的变化。