Professor Kathy Willis, director of science at the Royal Botanic Gardens Kew, with the final episodes of her new history of our changing relationship with plants Kathy Willis examines how the technology that helped map whole genomes in plants and animals was to revolutionise the classification of flowering plants; the evolution of our rainforests as revealed by DNA fingerprinting; plants as essential regulators of our planet's atmospheric carbon and water cycles; how green spaces and ecosystems have a positive effect on our health and well being; the future role of plants as providers of food to feed the planet's growing population. Producer Adrian Washbourne.