The Millennium Seed Bank (MSB) celebrates a milestone after banking more than 40,000 different plant species in an effort to preserve rare, endangered and important wild plants.
Dubbed Noah’s Ark for plants, MSB holds the Guinness World Record for the largest seed bank on Earth.
It stores 98,567 seed collections from 190 countries and territories on all seven continents, nine biogeographic regions and 36 biodiversity hotspots.
Sir David Attenborough said the MSB is “perhaps the most important conservation initiative of all time”, as it not only helps protect plant species in the event of an apocalyptic event, but acts as a resource for save plants on the verge of extinction.
Dr Kate Hardwick, Conservation Partnership Coordinator at MSB, said: “Kew scientists estimate that two-fifths of all plants are at risk of extinction in the wild and this shows us how far the crisis has we face in terms of biodiversity loss, driven largely by habitat loss and climate change.
“In an effort to address these issues, Kew established the Millennium Seed Bank over 20 years ago to provide a safety net that would safely store the seeds of wild plants from around the world.
“Working with over 260 partners in at least 97 different countries, Kew has effectively created a Noah’s Ark for plants, ensuring their survival in the race against extinction.”
Some notable plant species in the MSB’s collection are the world’s smallest water lily, a rare and endangered pea unique to eastern Australia, and Antarctic grass – one of only two flowering plants native to the continent frozen.
In addition to storing seeds in the vault (in situ conservation), scientists also preserve wild relatives of the crops we eat in their natural ecosystems (ex situ conservation).
The United Nations Convention on Biological Diversity has called for at least 75% of threatened plant species to be conserved ex-situ as well as at least 75% of known threatened plants to be conserved in-situ.
Biosecurity Minister Lord Benyon said: “Kew’s diverse global plant collection will be an important tool in addressing the challenges facing our nation today, including maintaining our food security, loss of biosecurity and climate change.
“This historic collection acts as a further example of Britain’s position as a world leader in plant biosecurity and sets an example for the world to follow.”
When the seeds arrive, they are dried, cleaned and X-rayed for signs of parasites and malformed embryos. Every 1% reduction in their moisture content doubles their lifespan.
Seeds usually retain about 3-6% of their moisture, as drying them out completely could be damaging. Then they are stored at minus 20°C where they can survive for centuries.
Every 10 years they are removed and placed in Petri dishes to see if they germinate, which tests the health of seed collections and helps scientists develop methods to grow them into adult plants.
However, 8-20% of flowering plants cannot be stored in this way because their seeds cannot tolerate drying. Scientists are therefore studying technologies such as cryopreservation that could help extend their lifespan.
Germination specialist Rachael Davies said: “Research on seed dormancy, germination, viability and longevity is a valuable tool that helps us solve many collection issues.
“Developing germination protocols and addressing these issues also allows seeds and plants to be available for research and conservation, maximizing their potential use for habitat repair or sustainable use projects. “