Conserving the world's endangered plants at Kew Gardens

Conserving the world's endangered plants at Kew Gardens
Alok Jha visits Kew Gardens to see how scientists are tackling the environmental crisis that has seen a fifth of all plant species under threat. Prof Stephen Hopper, Kew's chief scientist, outlines the importance of conservation, while members of the Kew horticulturalist team show the complicated techniques they use to help save plants