Architecture: Stowing the seeds of life

If the Earth dries out, how will we be able to make the desert bloom once more? The answer lies five metres below the Sussex Weald.

Boffins at Kew have plans to save the world in the next century when the world turns into one big desert. Deep underground, beneath their new laboratories at Wakehurst in Sussex opening next year, a seed bank stores 25,000 species from arid regions. By the year 2010, if the worst happens, they can forest the Sahara with prickly juniper, bring frankincense back to Somalia, and set baobab trees all around the Limpopo river in Africa.

Forget the rainforest - the scientists at Kew have, because they realise that only the politicians can save it. Logging is a political agenda, not a botanical one. But in the dried out, desolate areas of Australia, Africa, India, Mexico and Brazil - where the rainfall is less than 600ml a year - people eke out a living on dusty soil so eroded that it blows away in the wind. One fifth of the world population lives in these parched regions.

Botanists estimate that one in eight plants every year are becoming extinct, leaving our planet forever. Scientists at the Royal Botanical Gardens of Kew got the Millennium Commission to give them a pounds 30m Lottery handout, matched by donor-funding to a total project cost of pounds 50m, to make a seed collection and a cluster of laboratories to house it. "It's costing as much as Chelsea FC would pay for a decent forward line, but will last a lot longer," says Roger Smith, project director at Kew.

Seeds are immediately X-rayed for insects that could destroy the whole collection. Once dried, the seeds are stored in an icy chamber at minus 20C. Every 10 years, some of them are germinated to check the batch hasn't passed its sell-by date.

Designated a site of outstanding natural beauty and special scientific interest, the sloping spur of the Weald at Wakehurst was tricky. Any new building had to be "at once imperceptible but when perceived, of peerless quality", according to the the planners. So Stanton Williams, the architects, placed the seed storage vaults five metres underground with the laboratories, greenhouses and a visitor centre on top.

To explain their elevations, the architects hand out a photograph of a long seed-pod. Pragmatic as well as poetic, the architects took their inspiration from a bean pod, swelling protectively around 10 hard-shelled seeds, creating 12 barrel-vaulted buildings, each measuring 14.4m by 7.2m. Above the deep freeze, these single-storey vaulted labs cluster around the gardens in which pink drifts of sea-thrift thrive. Glazed at both ends, and facing east-west, they get maximum sunlight.

To get Lottery money from the Millennium Commission, Kew had to make their new outstation at Wakehurst accessible to the public. In a winter garden which doesn't really live up to its name, since nothing much will grow there, an educational display introduces plants in their natural habitat.

When the new laboratories open in 2001, you will be able to come right into the core and, through the windows, watch the scientists at work ("which is about as exciting as watching paint dry," Roger Smith says disarmingly). The aim is to demystify the men in white coats, as well as let them work in a controlled environment.

"It simply says, here we are, this is what we do, and explains it to the visitor who can interpret it as they will. Wakehurst estate is all about private discovery, and the new building is in the same spirit," Smith says.

The most powerful reason to bank seeds, he believes, is their potential use in medicine. Members of the Women's Institute collect yew clippings because it is used clinically in a cancer drug called Taxol. The chemotherapy for childhood leukaemia, Vinblastin, is made from periwinkle plants.

Paul Williams of Stanton Williams believes that this is the first Lottery- funded project that is really meaningful. It's not just an excuse for a new building which everyone then wonders how to fill. "We've produced an environment which holds on to the DNA of plants and grafts it back again," he says.

Rooms for research and contemplation cloistered rhythmically about a courtyard planted with clipped Dutch elms are reminiscent of Le Corbusier's La Tourette monastery, where natural light streaming though coloured light wells, into the dim chapel, make one doubt Le Corbusier's avowed agnosticism.

Stanton and Williams took their practice to La Tourette in France for a week's retreat. "Did you know that Le Corbusier designed every space to mirror the proportions of those 100 cell-like rooms? So the chapel is exactly 100 times bigger in volume than the 100 rooms. As you move about, you carry with you that imperceptible sense of personal space. It's an incredible experience," Paul Williams says.

At Chelsea Physic Gardens last Wednesday, Paul Williams and Roger Smith gave a joint lecture entitled "Architecture, Science and Spirituality". Not on religious grounds - although, it has to be said, there is something proselytising about the plight of our planet - but to capture the new age.

Few establishments have the credibility to embark upon such a mammoth global quest.

"We draw upon our links, not in the old spirit of the Empire when Victorians took away cuttings in their sponge bags, but with the co-operation of many countries responsible for their own actions.

"First we ask, `Do you want to play?' then: `Are you mandated?' With their informed consent, we begin seed-collection."

So what happens if global warming makes Waterworld the reality, rather than seas of sand? What use desert palms and thorn scrub then?

Roger Smith is sanguine. "I'm not Nostradamus and we can't solve all the world' s problems.

"But I know that when I'm an old man sitting on Hove seafront, tucked up beneath a warm tartan blanket, I'll be glad we did something to shore up our heritage. Otherwise we have nothing to leave our children's children."

Sir David Attenborough, who is a trustee of the Royal Botanical Gardens at Kew in west London, writes a fitting epitaph for the project: "Without plants, there would be no animals, no human beings - no life on this earth."