Thursday, October 22, 2009

Not all Banks are Bad Banks

In the last week, the Royal Botanic Gardens at Kew in London celebrated collecting and storing its 24,200th plant species. The plant seeds are banked at Kew's Millennium Seed Bank in Sussex. The Sussex site is part of a 180 acre estate centred around a magnificant mansion.

Kew's Millennium Seed Bank was set up in the year 2000 upon the realisation that 60-100,000 of the world's 300,000 plant species are threatened with extinction. The bank aims to conserve seed (and thus the genetic information) of plants around the world - with particular emphasis put on plants either most at risk or those which are potentially most useful to humans.

The bank has international partners and together, they aim to have stored seed from 25% of the world's plants by 2020. Of course there is a conservation reason to protect these plant species from extinction, but Kew are eager to emphasise the current and future uses of plants as a reason for their work.The most obvious use of plants is in food, something that is becoming more and more important in developing countries where food insecurity has led to civil unrest in recent years.

In fact, just last week the UN Secretary-General Ban Ki-moon said that "for the first time in history, more than one billion people are hungry". Speaking at the launch of World Food Day (October 16th) the Secretary-General remarked, "Over the past two years, volatile food prices, the economic crisis, climate change and conflict have led to a dramatic and unacceptable rise in the number of people who cannot rely on getting the food they need to live, work and thrive."

The medicinal uses of plants is also important. For example, the rose periwinkle of Madagascar is a source for not one, but two anti-cancer drugs used to treat leukaemia and Hodgkin's disease. The substances, vinblastine and vincristine were first discovered when the dried plant was crushed to form a tea. Drinking the tea was found to decrease the number of white blood cells in the body.

Plants are also a useful source of fuels (charcoal, biofuels), fibres (cotton), building materials (mahogany) as well as having an intrinsic benefit to the environment and our appreciation of that environment. In short, there is every reason to conserve the plants that we have.

The poet Walt Whitman puts it very well in his poem Song of Myself:

I believe a leaf of grass is no less than the journey work of the stars,
And the pismire is equally perfect, and a grain of sand, and the egg of the wren,
And the tree-toad is a chef-d'oeuvre for the highest,
And the running blackberry would adorn the parlors of heaven..

That plant which brought Kew over that magic 10% level was a species of pink banana which is a particular favourite of the Asian elephant. Musa itinerans, or the yunnan banana as it is known is also an important wild relative of the cultivated banana. This valuable genetic resource will allow breeding of new varieties of banana with disease resistance. This is crucial if we are to continue to eat banana.

In the next 10-20 years the most popular variety 'Cavendish' will almost certainly become unviable due to the pressures of disease. A new variety, which the consumer will accept and have the disease resistant qualities will need to be produced during that time. The genetic information in the yunnan banana may well contribute to the breeding programme.

Professor Stephen Hopper, director of the Royal Botanic Gardens, Kew, told BBC News: "the seed bank, as an insurance strategy, is a good sensible way of keeping your options open for the future."


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