A new study by researcher Ellen Nisbet and his team has dismissed an earlier finding which claimed that plans produce methane, a potent greenhouse gas, as part of their normal operations.
The study by researchers at Cambridge University and Royal Holloway, University of London, has shown that although plants can take up methane dissolved in water through their roots and emit it through their leaves, they do not make it themselves under normal conditions.
The study, to be published in the `Proceedings of the Royal Society B', says plants do not produce tens of millions of tonnes of the potent greenhouse gas in the course of their daily operations as an earlier study suggested.
The controversial study, published three years ago, stated that plants produce methane, as part of their normal operations – meaning that more trees would do more harm than good and that forests only help to add to global warming.
While a new group of researchers says it has refuted the 2006 study, the scientist who did the original work sticks to his claims that went against the standard idea that forests absorb and store carbon dioxide.
The earlier study that found plants giving out methane gas was conducted using a glass chamber covering plants growing in the wild and then measuring how the mix of gases within the chamber changed.
According to researcher Nisbet, the methane gas present in the glass chamber would have come from the earth below rather than from the plants.
To eliminate the chances of methane being formed through decaying of matter in the soil the research team led by Nisbet grew several different varieties of plant, including maize and rice, in media that contained no organic material, so eliminating the chances of methane. The experiments conducted on plants in closed chambers produced no methane at all, the y said.