Orchids - secret of their success
28 February 2011
The secret behind the phenomenal success of the orchid family, among the largest flowering plant groups in the world at over 22,000 species, may have been revealed as a ten-year study by an international group of scientists discovered different species appear to work in partnership to make the most of available resources.
The team, including botanists from Imperial College, London and the Royal Botanic Gardens, Kew, studied 52 orchid species in a small region of South Africa, using DNA technology to investigate the relationships between the plants and their pollinators. They also looked into how orchids use the mycorrhizal fungi which live among their roots.
In one example, they found that when two closely-related orchids, Pterygodium pentherianum and P. schelpei, live in the same location, instead of trying to out-compete each other they adapted. P. pentherianum puts its pollen on a bee's front legs, while P. shelpei applies it to the bee's abdomen – so the same bee can carry pollen from two distinct species at once.
'It's given us a fundamental insight into how so many new species can originate, and once they originate how they are able to coexist without exchanging genes,' said Professor Tim Barraclough of Imperial College, who led the team.
The researchers also looked into the mutually beneficial relationship between orchids and microscopic fungi living on their roots, helping the plant take up nutrients. Using DNA barcoding they found different orchid species in the same location also adapt to use different fungal partners, accessing different pools of nutrients and so enabling them to live side by side without competition.