當(dāng)前，生物入侵已成為嚴(yán)重的環(huán)境問(wèn)題,，是全球變化的重要組成部分,，入侵生態(tài)學(xué)尤其是與全球環(huán)境變化相結(jié)合，成為生態(tài)學(xué)研究的熱點(diǎn)問(wèn)題之一,。雜志Biological Invasions 刊登了中科院西雙版納熱帶植物園生物入侵生態(tài)學(xué)組最新研究論文"Innate and evolutionarily increased advantages of invasive Eupatorium adenophorum over native E. japonicum under ambient and doubled atmospheric CO2 concentrations ”,。
中科院西雙版納熱帶植物園生物入侵生態(tài)學(xué)組以紫莖澤蘭原產(chǎn)地（墨西哥）種群、入侵地（中國(guó)）種群,，以及本地近緣種白頭婆為材料,，利用哀牢山生態(tài)站的人工氣候室，研究了三類植物對(duì)二氧化碳濃度倍增的響應(yīng)差異,，分析了紫莖澤蘭生物入侵性的來(lái)源,，及其入侵性隨環(huán)境變化的演化。
研究結(jié)果表明,，對(duì)大多數(shù)的生長(zhǎng)性狀而言,，入侵地紫莖澤蘭種群表現(xiàn)優(yōu)于原產(chǎn)地種群，而原產(chǎn)地種群的紫莖澤蘭又優(yōu)于本地近緣種,，表明紫莖澤蘭既具有固有競(jìng)爭(zhēng)優(yōu)勢(shì),，又在入侵地發(fā)生快速進(jìn)化，從而成為一種“超級(jí)”入侵者,。研究同時(shí)測(cè)定了一類重要的含氮化防物質(zhì)生氰糖苷的含量,，發(fā)現(xiàn)在入侵種群內(nèi)，該物質(zhì)含量顯著低于原產(chǎn)地種群,，表明紫莖澤蘭在入侵過(guò)程中的確降低了化學(xué)防御的氮投入,。這進(jìn)一步驗(yàn)證了馮玉龍研究員提出的解釋植物入侵機(jī)理的“氮分配的進(jìn)化假說(shuō)”。
另外,，研究發(fā)現(xiàn),，二氧化碳濃度增加對(duì)三類植物的生長(zhǎng)都有促進(jìn)作用，且效果相當(dāng)，所以單獨(dú)的二氧化碳濃度增加可能并未加劇紫莖澤蘭的生物入侵性,。但是二氧化碳濃度增加的生態(tài)效應(yīng)與其他環(huán)境因子,，如氮水平等緊密耦合，因此后續(xù)研究正在進(jìn)行中,。（生物谷Bioon.com）
doi:10.1007/s10530-011-9940-y
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Innate and evolutionarily increased advantages of invasive Eupatorium adenophorum over native E. japonicum under ambient and doubled atmospheric CO2 concentrations
Yan Bao Lei, Yu Long Feng, Yu Long Zheng, Rui Fang Wang, He De Gong and Yi Ping Zhang
Both innate and evolutionarily increased ecophysiological advantages can contribute to vigorous growth, and eventually to invasiveness of alien plants. Little effort has been made to explore the roles of innate factors of alien plants in invasiveness and the effects of CO2 enrichment on alien plant invasions. To address these problems, we compared invasive Eupatorium adenophorum, its native conspecific, and a native congener (E. japonicum) under ambient and doubled atmospheric CO2 concentrations. Native E. adenophorum from Mexico grew slower than invasive E. adenophorum but faster than native E. japonicum under both CO2 concentrations. The faster growth rate of invasive E. adenophorum was associated with higher photosynthetic capacity and leaf area ratio. For invasive E. adenophorum, the higher photosynthetic capacity was associated with higher nitrogen (N) allocation to photosynthesis, which was related to lower leaf mass per area; the higher leaf area ratio was due to lower leaf mass per area and higher leaf mass fraction. Tradeoff between N allocations to photosynthesis versus defenses was found. CO2 enrichment significantly increased relative growth rate and biomass accumulation by increasing actual photosynthetic rate for all studied materials. However, the relative increase in growth was not significantly different among them. CO2 enrichment did not influence N allocation to photosynthesis, but increased N allocation to cell walls. The reduced leaf N content decreased N content in photosynthesis, explaining the down-regulation of photosynthetic capacity under prolonged elevated CO2 concentration. Our results indicate that both innate and evolutionary advantages in growth and related ecophysiological traits contribute to invasiveness of invasive E. adenophorum, and CO2 enrichment may not aggravate E. adenophroum’s invasion in the future.
