'You wouldn't put a bag of frogs in the corner and expect them still to be happy and kicking at the end of a year. The same is true of seeds.'
As the wild areas of the world dwindle, plants are being destroyed before their usefulness can be known. But while saving whole forests may be impossible, saving their seeds is not. Colin Tudge visits Wakehurst Place in Sussex, where scientists of the Royal Botanical Gardens, Kew, are seeking surer and subtler ways both of storing seed and of quickening them into life. Producer ALISON RICHARDS
(Re-broadcast next Saturday)