和動(dòng)物一樣,，植物也會(huì)受到各種脅迫,。當(dāng)遭受脅迫時(shí),，它們會(huì)釋放出一系列的化學(xué)物質(zhì),，其中包括溫室氣體甲烷。在空氣中,，甲烷吸收熱量的效率是二氧化碳的20倍,，并且這種氣體能在空氣中的存留時(shí)間多于10年。科學(xué)家已經(jīng)發(fā)現(xiàn)植物會(huì)在較強(qiáng)紫外線照射下釋放甲烷,，但還沒(méi)有研究其它環(huán)境因素以及全球氣候變化等對(duì)甲烷釋放情況的影響,。加拿Calgary大學(xué)的Mirwais Qaderi和David Reid考查了溫度，紫外線照射以及水脅迫對(duì)植物甲烷釋放的影響,。他們的工作發(fā)表在最新一期的Physiologia Plantarum,。
這些科學(xué)家發(fā)現(xiàn)高溫、水脅迫及紫外線照射能明顯的增加蠶豆,、向日葵,、豌豆、油菜,、大麥以及小麥等植物的甲烷釋放量,。其中豌豆的釋放量最高，大麥的釋放量最低,。Qaderi和Reid在文章中寫(xiě)道：“我們的結(jié)果揭示了熱帶森林地區(qū)高甲烷含量的成因,，結(jié)果表示高溫及相對(duì)干旱的季節(jié)可能會(huì)增加甲烷的釋放速度。”目前研究人員正考查二氧化碳含量增加以及其它一些環(huán)境因素對(duì)甲烷釋放的影響,。（生物谷Bioon.com）
生物谷推薦原始出處：
Physiologia Plantarum 14 Jul 2009
Methane emissions from six crop species exposed to three components of global climate change: temperature, ultraviolet-B radiation and water stress
Mirwais M. Qaderi 1,* and David M. Reid 1
1 Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4
We examined the effects of temperature, ultraviolet-B (UVB) radiation and watering regime on aerobic methane (CH4) emission from six crops–faba bean, sunflower, pea, canola, barley and wheat. Plants were grown in controlled-environment growth chambers under two temperature regimes (24/20 and 30/26°C), three levels of UVB radiation [0 (zero), 5 (ambient) and 10 (enhanced) kJ m−2 d−1] and two watering regimes (well watered and water stressed). A gas chromatograph with a flame ionization detector was used to measure CH4 emission rates [ng g−1 dry weight (DW) h−1] from detached fresh leaves of each species and attached leaves of pea plants. Plant growth [stem height, leaf area (LA) and aboveground dry matter (AG biomass)] and gas exchange [net CO2 assimilation (AN), transpiration (E) and water use efficiency (WUE)] were also determined. We found that higher temperature, water stress and UVB radiation at the zero and enhanced levels significantly enhanced CH4 emissions. Crop species varied in CH4 emission, which was highest for pea and lowest for barley. Higher temperature and water stress reduced all growth parameters, whereas ambient and enhanced UVB decreased stem height but increased LA and AG biomass. Higher temperature decreased AN and WUE but increased E, whereas water stress decreased AN but increased E and WUE. Zero and enhanced UVB reduced AN and E. Growth and gas exchange varied with species. Overall, CH4 emission was negatively correlated with stem height and AG biomass. We conclude that CH4 emissions may increase under climatic stress conditions and this extra source might contribute to the 'greenhouse effect'.
