和动物一样，植物也会受到各种胁迫。当遭受胁迫时，它们会释放出一系列的化学物质，其中包括温室气体甲烷。在空气中，甲烷吸收热量的效率是二氧化碳的20倍，并且这种气体能在空气中的存留时间多于10年。科学家已经发现植物会在较强紫外线照射下释放甲烷，但还没有研究其它环境因素以及全球气候变化等对甲烷释放情况的影响。加拿Calgary大学的Mirwais Qaderi和David Reid考查了温度，紫外线照射以及水胁迫对植物甲烷释放的影响。他们的工作发表在最新一期的Physiologia Plantarum。
这些科学家发现高温、水胁迫及紫外线照射能明显的增加蚕豆、向日葵、豌豆、油菜、大麦以及小麦等植物的甲烷释放量。其中豌豆的释放量最高，大麦的释放量最低。Qaderi和Reid在文章中写道：“我们的结果揭示了热带森林地区高甲烷含量的成因，结果表示高温及相对干旱的季节可能会增加甲烷的释放速度。”目前研究人员正考查二氧化碳含量增加以及其它一些环境因素对甲烷释放的影响。（生物谷Bioon.com）
生物谷推荐原始出处：
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'.
