Department of Ecology, Evolution, and Natural Resources, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA,
Oecologia. 2013 Oct;173(2):363-74. doi: 10.1007/s00442-013-2639-2. Epub 2013 May 1.
The ability of some introduced plant species to outperform native species under altered resource conditions makes them highly productive in ecosystems with surplus resources. However, ruderal native species are also productive when resources are available. The differences in abundance among invasive and non-invasive ruderal plants may be related to differences in ability to maintain access to or store resources for continual use. For a group of ruderal species in the Pacific Northwest of North America (invasive Rubus armeniacus; non-invasive R. ursinus, R. parviflorus, R. spectabilis, and Rosa nutkana), we sought to determine whether differences in functional morphological traits, especially metrics of water access and storage, were consistent with differences in water conductance and growth rate. We also investigated the changes in these traits in response to abundant vs. limited water availability. Rubus armeniacus had among the largest root systems and cane cross-sectional areas, the lowest cane tissue densities, and the most plastic ratios of leaf area to plant mass and of xylem area to leaf area, often sharing its rank with R. ursinus or Rosa nutkana. These three species had the highest water conductance and relative growth rates, though Rubus armeniacus grew the most rapidly when water was not limited. Our results suggest that water access and storage abilities vary with morphology among the ruderal species investigated, and that these abilities, in combination, are greatest in the invasive. In turn, functional morphological traits allow R. armeniacus to maintain rapid gas exchange rates during the dry summers in its invaded range, conferring on it high productivity.
一些引入物种在资源改变的条件下能够胜过本地物种，这使得它们在资源过剩的生态系统中具有很高的生产力。然而，在有资源的情况下，原生的杂草物种也具有生产力。入侵和非入侵杂草植物之间丰度的差异可能与维持获取或储存资源以供持续使用的能力有关。对于北美的北美太平洋西北地区的一组杂草物种（入侵的覆盆子属 Armeniacus；非入侵的覆盆子属 Ursinus、Parviflorus、Spectabilis 和 Rosa nutkana），我们试图确定功能形态特征，特别是水分获取和储存的度量标准，是否与水分传导率和生长速率的差异一致。我们还研究了这些特征在丰富和有限的水分供应下的变化。覆盆子属 Armeniacus 具有最大的根系和藤茎横截面积、最低的藤茎组织密度，以及最大的叶面积与植物质量比和木质部面积与叶面积比，其在大多数情况下与覆盆子属 Ursinus 或 Rosa nutkana 的排名相同。这三个物种具有最高的水分传导率和相对生长速率，尽管在水分不受限制的情况下，覆盆子属 Armeniacus 的生长速度最快。我们的研究结果表明，在研究的杂草物种中，水分获取和储存能力随形态而变化，而且这些能力在入侵物种中最为强大。反过来，功能形态特征使覆盆子属 Armeniacus 能够在其入侵范围内的干燥夏季保持快速的气体交换率，从而赋予其高生产力。
