Noah’s Ark for plants hits important milestone: 40,000 different plant species now banked at Kew’s Millennium Seed Bank at Wakehurst

Scientists record over 40,000 different species of wild plant seeds collected, dried and freeze-stored
Focused on increasing the genetic diversity of the collections and unlocking their potential to address global climate change and environmental issues
Endangered Perrier’s baobab and tiny orchid seeds among latest accessions to world’s biggest ex-situ conservation project
2.4 billion individual seeds stored in underground vaults at Wakehurst
Kew and international partners provide insurance policy for plants in face of climate change and biodiversity loss

A world-leading seed conservation programme led by the Royal Botanic Gardens, Kew is celebrating a major milestone today in its efforts to preserve rare, threatened, and important wild plants. As of 1st March, the Millennium Seed Bank (MSB) has banked more than 2.4 billion individual seeds representing a total of 40,020 different species of wild plants.

Described by scientists as ‘Noah’s Ark for plants’, the MSB is the world’s biggest wild seed storage facility, situated at the heart of Kew’s ‘living laboratory’ and wild botanic gardens, Wakehurst, in rural Sussex. Within the bomb- and flood-proof building are 98,567 seed collections sourced from 190 countries and territories, across all seven continents, nine biogeographic regions, and 36 biodiversity hotspots. In fact, the MSB holds the Guinness World Records title for world’s ‘largest seed bank’.

Dr Elinor Breman, Senior Research Leader at the Millennium Seed Bank, says: “Housed within the vaults of the Millennium Seed Bank is the world’s largest and most diverse collection of plants anywhere on the planet and that makes it an invaluable tool for scientists tackling the global biodiversity crisis. The path towards banking 40,000 individual species has been both challenging and rewarding and we are confident the coming years will prove just as fruitful. Conserving seeds at the MSB is not just about chasing numbers, it’s about increasing the genetic diversity of the collections and unlocking their potential to solve some of the biggest challenges we face today, from biodiversity loss to food security to climate change.”

Lord Benyon, the UK Government’s Minister for Biosecurity, says: “Kew’s world leading collection of diverse plants will be an important tool in tackling the challenges facing our nation today, including maintaining our food security, biosecurity loss and climate change. This landmark collection acts as a further example of Great Britain’s position as a global leader in plant biosecurity and sets an example for the world to follow.”

What species were added?

Among the most recent additions to the seed bank, pushing the number of collected species over 40,000, are wild plants from Madagascar, Pakistan, and the Caucasus. These include the critically endangered baobab Adansonia perrieri, or Perrier’s baobab, and the endangered Erythrophleum couminga, a leguminous tree endemic to the Bare de Ball National Park on the west coast of Madagascar. Although the stems and leaves of the latter are known to be used as a cardiac tonic, the plant is highly poisonous in high doses and its bark extract can cause shortness of breath, seizures, and even cardiac arrest.

Other recent highlights include a number of orchid species collected throughout the Caucasus region, such as Orchis coriophora, where the MSB is coordinating a dedicated seed conservation programme in Armenia. Orchid seeds are particularly tricky to collect and conserve as they are the smallest in the world, a single plant producing millions of dust-like seeds. Because of their minuscule size, they lack a food reserve and are generally unable to germinate on their own. Instead, many species rely on fungal partners - so-called mycorrhizal relationships - to germinate. Orchid seeds are also difficult to store but researchers at the MSB and in partner countries are developing new methods to maximise their longevity.

Why it matters

According to Kew’s State of the World’s Plants and Fungi report in 2020, two in five plants globally are threatened with extinction due to the degradation of natural ecosystems, land use change, and increasingly the uncertainties caused by climate change. Now, more than ever, scientists believe steps need to be taken to enact nature-positive change for the future. Ex-situ conservation, such as seed banking, has been identified as one way of protecting biodiversity and the genetic variety contained within.

Unlike partner gene banks focused on backing up the diversity of both domesticated and wild plants, such as the Svalbard Global Seed Vault for food crops, the MSB’s collections only represent threatened and wild useful plants. Wild plants, such as the crop wild relatives of the popular crops we consume, hold a much wider diversity of genes and traits that researchers are hoping can unlock the potential to target challenges including climate change, drought, disease, and pests.

In 2010, naturalist Sir David Attenborough dubbed the MSB “perhaps the most significant conservation initiative ever”, highlighting the importance of ex-situ conservation. He then reiterated this message in the Sky Atlantic documentary series Kingdom of Plants, when he said the MSB is not only “an insurance policy against the ultimate apocalypse” but a resource for saving plants “teetering on the edge of extinction”.

Dr Kate Hardwick, Conservation Partnership Coordinator at the MSB, says: “Scientists at Kew estimate that two-fifths of all plants are threatened with extinction in the wild and that shows us just how big of a crisis we are facing in terms of biodiversity loss, driven very much by habitat loss and climate change. In a bid to tackle these issues, Kew established the Millennium Seed Bank more than 20 years ago to provide a safety net that would safely store the seeds of wild plants from all over the globe. 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.”

Protecting biodiversity goes beyond simply earmarking the most threatened and useful plants for conservation, it involves protecting the incredible genetic diversity contained within. This includes, for example, conserving the crop wild relatives of the foods we consume today by preserving their natural ecosystems (in-situ conservation) and storing their genetic material in seed banks (ex-situ conservation). By 2020, the MSB Partnership’s global seed banking efforts saw at least 350 partners in 74 countries store the seeds of more than 57,000 species in seed banks around the world. Target 8 of the Global Strategy for Plant Conservation 2011-2020, published by the United Nations Convention on Biological Diversity (CBD), called for at least 75% of threatened plant species to be held in ex-situ collections, including living plants in botanic gardens, as well as at least 75% of known threatened plants to be conserved in-situ.

Journey of a seed

Seeds arrive at the MSB in various forms and states, sometimes still attached to plants and fruit. Before they can be stored in the facility’s underground vaults, they are dried in a dry room at 15% relative humidity and 15˚C, prior to processing, when they are cleaned and x-rayed for signs of pests and poorly formed embryos. They are then re-dried to extend their storage life, with a seed’s lifespan doubled for every 1% reduction in its moisture content.

After drying, the seeds are typically at 3-6% moisture content – extracting all the water from the seeds can be damaging. Once ready, the seeds are placed in sealed glass containers and stored in a cold room at -20˚C to ensure their survival for up to hundreds of years. Every 10 years, seeds are withdrawn to test their germination viability.

In addition to being stored in the MSB’s vaults, at least half of the seeds collected abroad are stored in the country of origin. Doing so adds an additional level of security, makes seed collections more accessible to scientists and governments internationally, and helps foster relationships between Kew and its partners.

Interesting species

Among the most interesting specimens within the MSB’s collections are the seeds of plants deemed threatened or already extinct in the wild. These include the yellow fatu flower (Abutilon pitcairnense), the world’s smallest waterlily (Nymphaea thermarum), and a rare and threatened pea unique to eastern Australia that is known as clover glycine (Glycine latrobeana). In 2020, 250 seeds of clover glycine were withdrawn from the MSB and sent to the South Australian Seed Conservation Centre for propagation, to help the restoration of the Cudlee Creek fire scar.

Some of the latest accessions include seeds of Antarctic hair grass (Deschampsia antarctica) - one of the only two flowering plants native to Antarctica – collected during a field trip earlier in 2022. The seeds of this remarkable plant have been recently requested by a Ukrainian researcher exiled to Germany, who has been unable to carry out his research in Kyiv due to the ongoing war.

However, 8-20% of flowering plants are so-called recalcitrant species - they cannot be conventionally stored in the MSB as their seeds do not tolerate drying. Scientists are, consequently, investigating technologies such as cryo-preservation (rapidly freezing and storing seeds at low temperatures) to increase their preservation viability.

Using the seeds – from seed to seedling to plant

Germination specialists at the MSB test seeds every ten years for two reasons: to monitor the viability of individual collections, and to develop protocols for turning the seeds into full-grown plants. The seeds are germinated in petri dishes with agar – a jelly-like substance made from algae, which is a very convenient water supplying substrate – and in some cases are gently cut open or ‘chipped’ to allow water inside and overcome dormancy.

Rachael Davies, Germination Specialist, says: “Research into seed dormancy, germination, viability, and longevity is a valuable tool that helps us solve many collection-related problems. Developing germination protocols and overcoming these issues also enables both seeds and plants to be available for research and conservation, maximising their potential use for habitat repair or sustainable use projects.”

Some of the seeds that start to produce shoots are transferred to the MSB Nursery, where they are planted in a compost mix by horticulturists in Wakehurst’s Plant Propagation and Conservation Unit. If successful, the seedlings will take root in the compost and continue to grow under a horticulturist's watchful eye.

A globally connected partnership

The MSB’s collections are in a state of constant flux as seeds move in and out of its vaults, taxonomists revise species, or seeds are withdrawn for research purposes. Globally, the number of species conserved by the MSB Partnership (MSBP) is also higher than the individual collections stored at Wakehurst and represents nearly 57,500 species of wild plants. Seeds collected through the MSBP are duplicated to the seed bank under the Convention for Biological Diversity and Nagoya Protocol.

The MSBP is, consequently, as much an insurance policy for the future of global biodiversity, as it is a tool for fostering new relationships and seed storage capacity within partnered countries. Towards this goal, the MBSP Seed Conservation Standards provide a useful toolkit for countries and institutions to increase the quality and diversity of their seed collections under a common, internationally recognised conservation standard.

Successful partnerships include a long-standing collaboration with the South Africa National Biodiversity Institute (SANBI) to help develop and fund a national seed collection for South Africa - home to more than 21,000 species of plants. Working with partners across more than 100 countries since the year 2000, has allowed the MSB to become the largest and most genetically diverse resource of plant knowledge on the planet.

ENDS

For high-res images, please download from the following link and credit as named: https://we.tl/t-0b39oHtfDK

For interview requests or other press enquiries please contact Sebastian Kettley, Media Officer (s.kettley@kew.org), Charlotte Newell, PR Manager (c.newell@kew.org); or the Press Office (pr@kew.org)

Notes to Editors

Targets and priorities

Increase the MSB’s focus on collection quality to ensure all banked seeds are fit for purpose
Improve the genetic diversity of the collections, with increased focus on sub-specific taxa
Prioritise plants threatened with extinction, endemic plants, and plants most useful for human adaptation and innovation
Prioritise ecosystems at risk of climate change, such as montane, maritime, and island
Support tree conservation in the UK through the UK National Tree Seed Project and globally through the Global Tree Seed Bank Programme
Bank the crop wild relatives of major cultivated crops to unlock their potential and strengthen food security

Timeline of MSB milestones

1995: Millennium Seed Bank Project is awarded the Millennium Commission grant
1996: Work on the project kicks off on the grounds of Wakehurst Place, Sussex
2000: The MSB building is officially opened by HRH The Prince of Wales, who at the time called the initiative a “gold reserve...a place where this reserve currency, in this case life itself, is stored.”
2005: Yellow fatu flower (Abutilon pitcairnense) grown in Kew Gardens from MSB seed after going extinct in the wild
2007: A seed of Oxytenanthera abyssinica is the billionth seed banked by the MSB
2009: 10% of the world’s known flora is successfully banked with the addition of the wild banana Musa itinerans
2010: Sir David Attenborough describes MSB as "perhaps the most ambitious conservation initiative ever" on 10^th anniversary
2020: ‘Flower of Kent’ apple tree seeds processed by the MSB and flown aboard the International Space Station are planted by astronaut Tim Peake at Woolsthorpe Manor
2020: MSB celebrates its 20^th anniversary

Key MSB facts and figures

The MSB has banked 2,456,432,314 seeds as of March 1
Seeds stored at the MSB are kept in sealed containers inside vaults at –20°C
Seeds are held in dry rooms at 15C and 15% relative humidity ahead of being packed and stored in the vaults
The smallest seeds banked in the MSB are of the orchid Aerides odorata, measuring no more than 0.2mm across
75% of the MSB’s requested seeds have gone on to be used in scientific research and 13% in conservation
The MSB’s glass building took two-and-a-half years to complete with solar power, laboratory equipment, as well as flood and radiation-proof chambers
The MSB vaults cover an area of 900m2
The majority of the UK’s bankable native species are represented in the MSB’s collections

About Kew Science

Kew Science is the driving force behind RBG Kew’s mission to understand and protect plants and fungi, for the well-being of people and the future of all life on Earth. Over 300 Kew scientists work with partners in more than 100 countries worldwide to halt biodiversity loss, uncover secrets of the natural world, and to conserve and restore the extraordinary diversity of plants and fungi. Kew’s Science Strategy 2021–2025 lays out five scientific priorities to aid these goals: research into the protection of biodiversity through Ecosystem Stewardship, understanding the variety and evolution of traits in plants and fungi through Trait Diversity and Function; digitising and sharing tools to analyse Kew’s scientific collections through Digital Revolution; using new technologies to speed up the naming and characterisation of plants through Accelerated Taxonomy; and cultivating new scientific and commercial partnerships in the UK and globally through Enhanced Partnerships. One of Kew’s greatest international collaborations is the Millennium Seed Bank Partnership, which has to date stored more than 2.4 billion seeds of over 40,000 wild species of plants across the globe. In 2020, Kew scientists estimated in the State of the World’s Plants and Fungi report that 2 in 5 plants globally are threatened with extinction.

About Wakehurst

Please note that Wakehurst is referred to just as Wakehurst, not Wakehurst Place. It is not a National Trust property. The National Trust bequeathed the Mansion and grounds of Wakehurst in 1963. It was then entrusted to us here at Kew in 1965, and we now work in partnership with the National Trust to care for our collections and heritage areas. Wakehurst is Kew’s wild botanic garden in the Sussex High Weald. Its ancient and beautiful landscapes span 535 acres and are a place for escape, exploration, tranquillity, and wonder. Its diverse collection of plants from Britain and around the globe thrive within a tapestry of innovative gardens, temperate woodlands, meadows, and wetlands. Wakehurst is a centre for UK biodiversity and global conservation, seed research and ecosystem science. At its heart is Kew’s Millennium Seed Bank, the world’s largest store of seeds from wild plant species.