Panicked plants studied
Scientists say plants appear to ‘panic’ in reaction to rain.
New research has revealed complex chemical signals are triggered when water lands on a plant, to help it prepare for the dangers posed by rain.
After spraying plants with water and observing the effect, researchers observed a chain reaction in the plant caused by a protein called Myc2.
“When Myc2 is activated, thousands of genes spring into action preparing the plant’s defences,” says Professor Harvey Millar from the University of Western Australia.
“These warning signals travel from leaf to leaf and induce a range of protective effects.”
While they rely on water to live, Dr Millar says there is actually good reason for plants to panic about rain.
“As to why plants would need to panic when it rains, strange as it sounds, rain is actually the leading cause of disease spreading between plants,” he said.
“When a raindrop splashes across a leaf, tiny droplets of water ricochet in all directions. These droplets can contain bacteria, viruses, or fungal spores. A single droplet can spread these up to 10 metres to surrounding plants.”
Evidence also suggests that when it rains, the same signals spreading across leaves are transmitted to nearby plants through the air.
“One of the chemicals produced is a hormone called jasmonic acid that is used to send signals between plants,” Dr Millar said.
“If a plant’s neighbours have their defence mechanisms turned on, they are less likely to spread disease, so it’s in their best interest for plants to spread the warning to nearby plants.
“When danger occurs, plants are not able to move out of the way so instead they rely on complex signalling systems to protect themselves.”
Professor Millar says it is clear that plants have an intriguing relationship with water, as rain is both a major carrier of disease but also vital for a plant’s survival.