The discreet and essential treasure of the Seed Bank Millennium, nestled in an underground in Wakehurst, south of London, is the largest world bank in wild seeds. It retains and protects more than 40,000 species, or almost a fifth of the plant heritage on the planet.
Today, the genetic diversity of plants becomes a strategic resource. In the absence of genetic variability, some cultures, among the most common, are exposed to diseases to which they cannot resist. For example, the popular Cavendish banana is threatened by the Fusarium oxyporum fungus.
In this context, wild species, often more resistant, can provide the genes necessary to develop varieties capable of better facing these threats. By keeping them, the Seed Bank Millennium preserves a reservoir of solutions to the agricultural crises of tomorrow.
More than a billion of these seeds are thus kept underground in a real fortress, in the heart of the Wakehurs gardens, in Sussex. “The seed bank was dug in a gigantic basin covered with concrete. It was designed to withstand bombs, radiation and even the impact of an airplane, because we are close enough to Gatwick airport,” explains Louise Colville, director of research at the Millennium Seed Bank, Monday in the whole world of RTS.
From forest to freezer, seed trip
For Louise Colville, this vegetable tank is much more than a simple stock of seeds: it is real life insurance for the planet: “Some 45% of species are threatened with disappearance, time is running out to save them from extinction.”
It is not always possible to conduct this work of conservation in their natural environment, which is no longer necessarily adapted or which has suffered from deforestation
Faced with this emergency, unfortunately, “it is not always possible to carry out this work of conservation in their natural environment, which is no longer necessarily adapted or which has suffered from deforestation”, explains the director of research at the Millennium Seed Bank.
The seeds therefore arrive from all over the world, because nearly 190 countries collaborate with the institution. Before being preserved, they go through a rigorous process. Once cleaned and dried for several weeks, the seeds are then frozen in order to guarantee their longevity. “This dry environment has another advantage: it makes it possible to kill the parasites that arrive with the seeds. This reduces the risk of infestation, which would be fatal for the seeds,” explains Louise Colville.
Seeds tested to survive the extreme
Finally, before being stored, the seeds passed in the X -ray to check their viability. Those passing the test are placed in glass jars, then kept at -20 degrees. But only the seeds called “Orthodox seeds” can be preserved.
About 50% of tropical trees produce seeds that cannot be dried and therefore we cannot store them in a cold room
“In tropical forests, especially humid, around 50% of trees produce seeds that cannot be dried and therefore we cannot store them in a cold room,” said Louise Colville. For these species, the Millennium Seed Bank uses and explores other techniques, such as cryocorenserers at -196 degrees, based on liquid nitrogen, a method still in development.
With nearly 2.5 billion seeds preserved, for 25 years, the institution has been a precious resource for scientific research. To better understand how seeds react to hostile environments, teams test their resistance to different types of stress, such as heat, radiation or the absence of gravity. This research makes it possible to anticipate their survival skills in extreme environments.
Radio subject: Catherine Ilic
Adaptation web: Miroslav Mares