Andrew Goldsworthy, a botanist, believes plants developed their weather forecasting ability to gear up their metabolism for an expected downpour. It could explain what every gardener knows - that plants look particularly healthy after thundery weather.
According to Goldsworthy this is an effect that cannot simply achieved with a sprinkler. The theory is that if plants are watered unexpectedly they cannot react quickly enough to gain the maximum benefit. But if they could tell in advance when it was likely to rain, they could prepare for growth by switching on the necessary biochemical machinery.
Goldsworthy has carried out experiments at Imperial College, London, which show that plant cells react to electric current. In thundery weather, even before the storm breaks, very high voltage gradients build up. Goldsworthy believes plants have evolved a way of exploiting these conditions. He told New Scientist magazine: "Plants are very clever at sensing the environment and if there's any signal they could possibly use, my guess is they'll use it."