2008-7-23 15:05:14

Planta：探究外来植物入侵性状的新方法

佚名

外来植物的入侵机理是入侵生态学研究的重要课题之一，也是研究最不清楚的问题之一。研究人员常常通过比较外来入侵植物和本地植物的差异来探讨外来植物的入侵机理，然而，如果本地植物被引种到其它地区，它们也可能成为入侵种，若真如此，这种比较研究显然不能揭示与外来植物成功入侵相关的植物性状。为探讨外来植物的入侵机理，中科院西双版纳热带植物园的冯玉龙研究员等首次比较研究了两种外来入侵植物和两种同属外来非入侵植物生理生态特性的差异。结果表明与同属外来非入侵植物相比，入侵植物具有高的比叶面积（单位叶重的面积），这直接导致它们低的叶片建成成本、高的叶氮向光合机构分配比例和高的光合氮利用效率。高的叶氮向光合机构分配比例使入侵植物光合机构中氮含量升高，这进一步导致它们光合电子传递速率和羧化速率升高、光合能力升高。这些性状可能与外来植物的入侵性有关，其中高的比叶面积起到关键作用。该研究成果已于近日在国际重要植物学期刊《植物学》（Planta）上发表。

与该研究结果相一致，西双版纳植物园生物入侵生态学研究组的另一项研究也表明两种外来入侵植物的比叶面积高于它们的同属本地种（Biological Invasions，2008，10：891—902），但在另外两项研究中，这种规律未得到证实（Physiologia Plantarum，2008，132：350—358; 133: 318-326）。高的比叶面积也在很多其它入侵植物上得到证明。因此，这一易于测定的叶片性状可能被用于预测外来植物的入侵潜力。由于很多外来入侵植物源于有意引入的观赏植物，因此引种前分析比叶面积有利于减少引进入侵植物的可能性，引种后避免培育高比叶面积的品种等也能降低引入物种成为入侵物种的风险。（生物谷Bioon.com）

生物谷推荐原始出处：

Planta，Volume 228，383-390， Yu-Long Feng，Yu-Long Zheng

Specific leaf area relates to the differences in leaf construction cost, photosynthesis, nitrogen allocation, and use efficiencies between invasive and noninvasive alien congeners

Yu-Long Feng¹, Gai-Lan Fu¹ and Yu-Long Zheng¹

(1)	Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, 88 Xuefu Road, Kunming, 650223, China

Received: 21 January 2008 Revised: 20 March 2008 Accepted: 25 March 2008 Published online: 6 April 2008

Abstract Comparisons between invasive and native species may not characterize the traits of invasive species, as native species might be invasive elsewhere if they were introduced. In this study, invasive Oxalis corymbosa and Peperomia pellucida were compared with their respective noninvasive alien congeners. We hypothesized that the invasive species have higher specific leaf (SLA) than their respective noninvasive alien congeners, and analyzed the physiological and ecological consequences of the higher SLA. Higher SLA was indeed the most important trait for the two invaders, which was associated with their lower leaf construction cost, higher nitrogen (N) allocation to photosynthesis and photosynthetic N use efficiency (PNUE). The higher N allocation to photosynthesis of the invaders in turn increased their PNUE, N content in photosynthesis, biochemical capacity for photosynthesis, and therefore light-saturated photosynthetic rate. The above resource capture-, use- and growth-related traits may facilitate the two invaders’ invasion, while further comparative studies on a wider range of invasive and noninvasive congeners are needed to understand the generality of this pattern and to fully assess the competitive advantages afforded by these traits.