The smell of freshly cut grass: just another example of how plants communicate using volatile organic compounds, in this case to indicate that they are injured. It is known that other plants pick up and process these signals, but how they do so has been a mystery. Now, in Nature Communications, Japanese researchers show how this happens in real time.

When plants are damaged, volatile organic compounds such as terpenes and 6-carbon alcohols, aldehydes and esters are released. These trigger the plant’s defences, including sending Ca²⁺ signals to the rest of the plant. The volatiles released also cause plants in the immediate vicinity to switch on their defence systems. They are ready for what could be an imminent attack by voracious insects.

But how plants perceive these VOCs was unknown until now. To find out, researcher Masatsugu Toyota and his team at Saitama University in Japan built a custom system to detect fluorescent light in living plants. Before the research, however, Toyota was ’a little concerned about whether the plant could actually smell the volatiles’.