How plants warn each other of danger

For the first time, scientists at Exeter University have captured on film the process by which plants alert each other to possible dangers.

When a plant is under attack it releases a gas which warns neighbouring plants to protect themselves.

In a new BBC Two series, Professor Iain Stewart explains how the Earth's development was driven by plants and how they have adapted for survival.

How To Grow A Planet is broadcast on BBC Two at 21:00 GMT on Tuesdays 7,14 and 21 February or catch up via BBC iPlayer.