外來(lái)植物的入侵機(jī)理是入侵生態(tài)學(xué)研究的重要課題之一,，也是研究最不清楚的問(wèn)題之一,。研究人員常常通過(guò)比較外來(lái)入侵植物和本地植物的差異來(lái)探討外來(lái)植物的入侵機(jī)理，然而,，如果本地植物被引種到其它地區(qū),，它們也可能成為入侵種，若真如此,，這種比較研究顯然不能揭示與外來(lái)植物成功入侵相關(guān)的植物性狀,。為探討外來(lái)植物的入侵機(jī)理，中科院西雙版納熱帶植物園的馮玉龍研究員等首次比較研究了兩種外來(lái)入侵植物和兩種同屬外來(lái)非入侵植物生理生態(tài)特性的差異,。結(jié)果表明與同屬外來(lái)非入侵植物相比,，入侵植物具有高的比葉面積（單位葉重的面積），這直接導(dǎo)致它們低的葉片建成成本,、高的葉氮向光合機(jī)構(gòu)分配比例和高的光合氮利用效率,。高的葉氮向光合機(jī)構(gòu)分配比例使入侵植物光合機(jī)構(gòu)中氮含量升高，這進(jìn)一步導(dǎo)致它們光合電子傳遞速率和羧化速率升高,、光合能力升高,。這些性狀可能與外來(lái)植物的入侵性有關(guān)，其中高的比葉面積起到關(guān)鍵作用,。該研究成果已于近日在國(guó)際重要植物學(xué)期刊《植物學(xué)》（Planta）上發(fā)表,。
與該研究結(jié)果相一致，西雙版納植物園生物入侵生態(tài)學(xué)研究組的另一項(xiàng)研究也表明兩種外來(lái)入侵植物的比葉面積高于它們的同屬本地種（Biological Invasions,，2008,，10：891—902），但在另外兩項(xiàng)研究中,，這種規(guī)律未得到證實(shí)（Physiologia Plantarum,，2008，132：350—358; 133: 318-326）,。高的比葉面積也在很多其它入侵植物上得到證明,。因此，這一易于測(cè)定的葉片性狀可能被用于預(yù)測(cè)外來(lái)植物的入侵潛力,。由于很多外來(lái)入侵植物源于有意引入的觀賞植物,，因此引種前分析比葉面積有利于減少引進(jìn)入侵植物的可能性，引種后避免培育高比葉面積的品種等也能降低引入物種成為入侵物種的風(fēng)險(xiǎn),。（生物谷Bioon.com）
生物谷推薦原始出處：
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.
