By Marta Zaraska
IN THE classic post-apocalyptic novel The Day of the Triffids, giant carnivorous plants terrorise humanity. Triffids can walk and are equipped with venomous stingers, but their real power lies in their ability to communicate and so plot against us.
It sounds far-fetched, but since John Wyndham’s book was published in 1951, one aspect of this fiction has proved to be science fact: plants do talk to one another. If you stroll through a forest and take a deep breath, you can smell the “words” – complex volatile chemicals such as beta-pinene, which smells fresh and piney. Plants produce thousands of these, combining them to create “sentences”.
However, this fragrant language is under threat. Air pollution is disrupting floral scents, turning their messages into gibberish. Not only is this having an impact on plants’ abilities to survive, it is also bad news for pollinating insects – and for us, because it affects everything from crop yields to the smell of our favourite flowers. Luckily, there is a way we can help our botanical friends fight back.
It has long been known that insects such as pollinators and pests can distinguish between plants by the unique bouquet of chemicals they release. What’s new is the idea that plants use their emissions to talk among themselves. “Plants release volatile chemicals into the atmosphere – these can be viewed as a language in the sense that a plant releasing the chemicals can be viewed as ‘speaking’ and the plant receiving them as ‘listening’ and then responding,” says chemical ecologist James Blande at the University of Eastern Finland.