Feng Yu-Long, Auge Harald, Ebeling Susan K
Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, 88 Xuefu Road, Kunming 650223, China.
Oecologia. 2007 Sep;153(3):501-10. doi: 10.1007/s00442-007-0759-2. Epub 2007 May 30.
The general-purpose genotype hypothesis and the hypothesis of the evolution of invasiveness predict that invasive species are characterized by particular traits that confer invasiveness. However, these traits are still not well-defined. In this study, ecophysiological traits of eight populations of the invasive shrub Buddleja davidii from a wide range of European locations and five co-occurring native woody species in Germany were compared in a common garden experiment. We hypothesized that the invader has higher resource capture ability and utilization efficiency than the natives. No differences were detected among the eight populations of B. davidii in any of the traits evaluated, indicating that the invader did not evolve during range expansion, thus providing support to the general-purpose genotype hypothesis. The invader showed significantly higher maximum electron transport rate, maximum carboxylation rate, carboxylation efficiency, light-saturated photosynthetic rate (P(max)) and photosynthetic nitrogen utilization efficiency (PNUE) than the five natives. Leaf nitrogen content was not significantly different between the invader and the natives, but the invader allocated more nitrogen to the photosynthetic machinery than the natives. The increased nitrogen content in the photosynthetic machinery resulted in a higher resource capture ability and utilization efficiency in the invader. At the same intercellular CO(2) concentration, P (max) was significantly higher in the invader than in the natives, again confirming the importance of the higher nitrogen allocation to photosynthesis. The invader reduced metabolic cost by increasing the ratio of P (max) to dark respiration rate (R (d)), but it did not reduce carbon cost by increasing the specific leaf area and decreasing leaf construction cost. The higher nitrogen allocation to the photosynthetic machinery, P(max), PNUE and P(max)/R(d) may facilitate B. davidii invasion, although studies involving a wide range of invasive species are needed to understand the generality of this pattern and to fully assess the ecological advantages afforded by these features.
通用基因型假说和入侵性进化假说预测，入侵物种具有赋予其入侵性的特定性状。然而，这些性状仍未得到很好的界定。在本研究中，通过一项共同园实验，比较了来自欧洲各地的8个入侵灌木醉鱼草种群以及德国5种共生本土木本植物的生态生理性状。我们假设入侵者比本土植物具有更高的资源捕获能力和利用效率。在评估的任何性状中，8个醉鱼草种群之间均未检测到差异，这表明入侵者在范围扩张过程中并未进化，从而为通用基因型假说提供了支持。入侵者的最大电子传递速率、最大羧化速率、羧化效率、光饱和光合速率（P(max)）和光合氮利用效率（PNUE）均显著高于5种本土植物。入侵者和本土植物的叶片氮含量没有显著差异，但入侵者比本土植物将更多的氮分配到光合机构中。光合机构中氮含量的增加导致入侵者具有更高的资源捕获能力和利用效率。在相同的细胞间CO(2)浓度下，入侵者的P(max)显著高于本土植物，再次证实了较高的氮分配对光合作用的重要性。入侵者通过提高P(max)与暗呼吸速率（R(d)）的比值降低了代谢成本，但它没有通过增加比叶面积和降低叶片构建成本来降低碳成本。尽管需要开展涉及广泛入侵物种的研究来了解这种模式的普遍性并全面评估这些特征所带来的生态优势，但较高的氮分配到光合机构、P(max)、PNUE和P(max)/R(d)可能有助于醉鱼草的入侵。
