Time Travelers on Ice

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If Britain's plant life were to be suddenly wiped out by some catastrophe--the dinosaurs were, after all--there is now the means of bringing much of it back. Two room-sized freezers in a concrete vault carved out of a Sussex field will soon become a repository for the seeds of all the nation's wild flowering plants. At a cost of $130 million, the Royal Botanic Gardens, better known as Kew Gardens, are completing a building at their southern England offshoot, Wakehurst Place, as a seed bank for Britain's flora and for plants of the world's driest regions. There, in suspended animation, tens of millions of potential new plants will be able to survive for centuries. Natural history broadcaster David Attenborough calls them "time travelers" in a project he describes as "perhaps the most significant conservation initiative ever undertaken."

Seed banks have been around since the 1940s, but almost always for conserving and research of commercial crops. Kew's Millennium Seed Bank, built with the help of National Lottery funds, will instead be dedicated to the seeds of everything from trees to brambles, grasses, shrubs and meadow flowers. First dried, cleaned and tested for viability--there is no point in keeping seeds that will not germinate--the seeds are then packed in glass jars for storage at -20C. The collection will not include the non-flowering plants such as ferns and fungi, which have spores that cannot be preserved this way, rather than seeds.

Noah's fridge, as the bank has been called, is a grand gesture to future generations who will see the increasing destruction of their environment. Plants are essential to life on earth and the repercussions from the extinction of even individual species are usually little understood. For a start, 25% of Western medicines are plant-derived but less than 20% of the world's plants have been studied for possible benefits to man.

Once Britain's botanical heritage is on ice--the seed bank still lacks 32 elusive species out of a total 1,442 flowering species in Britain--Kew will begin gathering seeds in the arid tropics, home to 20% of the world's human population. Although dryland wild plants often provide people with essential food, fodder, fuel and medicines, encroaching deserts are destroying these resources. With a target of 24,000 species by 2010, Kew will start collecting in Africa, South America, Asia and even in the U.S.

The seed gathering in Britain was done with the help of a network of knowledgeable amateurs. "There is hardly a square mile in the country that is not visited by a mad-keen amateur botanist--they are the very best," says project coordinator Steve Alton. Over the three years of collecting for the project, he regularly sent an updated "seeds wanted" list to 250 volunteers, then waited for the mail to bring in small cotton sacks filled with dry clumps of seeding plants. Meanwhile, Alton and other professionals were out tracking down the elusive and inaccessible. They abseiled down cliffs to collect the rock whitebeam's berries, plunged wet-suited into lakes for aquatic species and trekked up mountains for alpines.

Probably the most elusive of the 32 still ungathered is the ghost orchid. Growing in deep, dark woods at only three sites in Britain, it has no leaves or true roots, lives underground until it flowers, and has not been seen since 1986. "The trick is to go out at night and lie on the ground with a torch," says Alton. "That way you'll light up the brownish flowers if they're there." The wall germander, a tiny plant with a pink flower, is also rare. Though common in France, it has traveled just a few meters into Britain: cold weather, rabbits, and wind and sea spray confine it to a single clifftop in Sussex. "It is tenacious of life, bless it, but so hard to collect," says Alton.

There have been plenty of more commonplace problems: trying to find a plant that was tall and green in summer but has turned invisible in the brown, crunchy, dried field of autumn, when its seeds are mature; or discovering that a farmer has cut his hay before the rare snake's head fritillary orchid seeds could be collected. Another difficulty was defining what is truly a native: the wall germander which made it into Britain by itself was counted indigenous, but not the sweet chestnut, which was brought over by the Romans, even if that was 1,000 years ago.

A major stumbling block was also posed by so-called recalcitrant seeds. They die when dried--but drying is essential before freezing because the water in plant tissues expands and ruptures cell walls when it turns to ice. Unfortunately, the acorns of two native oaks, that most symbolic of English trees, are recalcitrant.

The vast array of seeds that can be conserved, however, will become an insurance policy against that bleak and barren field that stretches forever: extinction.