Plants Under Stress Release More Methane than Previously Thought

Like animals, plants get stressed too. And when they do, they release an array of chemical compounds, including the potent greenhouse gas methane. Methane (CH₄) is 20 times more effective than carbon dioxide in trapping heat in the atmosphere, where it stays for more than ten years. Scientists have shown that plants under high ultraviolet (UV) stress conditions release methane but little study has been done to establish the effects of multiple environmental factors, as components of global climate change, on plant methane emissions. Mirwais Qaderi and David Reid from the University of Calgary in Canada explored the combined effects of temperature, UVB radiation and water stress, on methane emissions in plants. Their work appears in the current issue of Physiologia Plantarum.

The scientists found that higher temperature, water stress and UVB radiation significantly enhanced CH₄ emissions of faba bean, sunflower, pea, canola, barley and wheat. The highest methane emission was recorded in pea and the lowest recorded in barley. "Our results may shed some light on the large CH₄ plumes that have recently been observed over some tropical forests, suggesting that higher temperature and relatively drier seasons might have enhanced the rates of CH₄ emission from plants in this region," wrote Qaderi and Reid. The researchers are now examining the effects of elevated carbon dioxide, in combination with other environmental factors, on CH₄ production in plants.

The paper is available at http://dx.doi.org/10.1111/j.1399-3054.2009.01268.x