A seed's-eye view of the Millennium Seed Bank

Through our partnership with Kew Gardens on the UK National Tree Seed Project (generously funded by the players of the People's Postcode Lottery), we manage over 80 amazing volunteers who collect the seed from woodland trees across the UK and send it to the Millenium Seed Bank (MSB).

The seeds themselves are stored in the vaults at Wakehurst Place in West sussex and although our volunteers work hard to collect the seeds, they don't necessarily get to see what happens to them after they send them in. Preparing and storing the seeds is not as simple a task as it may seem on the surface. So we asked the scientists at the MSB, which is owned and run by Kew, to answer some common questions that intrigue people involved with the project. Discover the surprising answers below. 

Seeds preparation. (Louise Taylor)
Seeds preparation. (Louise Taylor)

What happens in a typical day at the MSB?

"I’m not sure there is a typical day! Across the whole MSB research projects, seed processing (including banking) and the monitoring of conservation projects are going on all year round. From a seed banking perspective, seeds are constantly arriving so cleaning, drying, banking and germination testing are ongoing."

Madagascan orchid species which are polyembryonic. (Jonathon Kendon)
Madagascan orchid species which are polyembryonic. (Jonathon Kendon)

What is the most unusual seed stored at the MSB and what makes it unusual?

"We have some seeds from a rare Madagascan orchid species which are polyembryonic. This means that each seed has multiple embryos inside so a single seed will produce multiple seedlings. There are only eight individuals of this species left in the wild."

Seeds in the MSB vaults. (Clare Trivedi)
Seeds in the MSB vaults. (Clare Trivedi)

Is there a holy grail of seeds that the MSB want to see in its collection?

"The MSB currently has a target to conserve 25% of the worlds orthodox seeded flora - that's plants which produce seeds able to tolerate drying - by 2020 in order to bank a rich variety of species from the global flora. Priority is given to species which are known to be useful, e.g. trees and crop wild relatives, and to species which are endemic, rare or known to be threatened."

What types of research have the seeds in your bank been used in and have they been involved in any major discoveries?

"There are four main research themes ongoing at the MSB. For example, some of the research ongoing at the MSB relates to the optimal storage conditions for seeds, how to maximise the length of time the seeds remain viable for in storage - that's their ability to germinate given the right set of conditions and an absence of dormancy - and the requirements seeds need to germinate. This ensures that we are able to grow the seeds we have stored in the bank and that the collections remain viable for a long time."

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MSB Vaults (Louise Taylor)
MSB Vaults (Louise Taylor)

What is the largest seed you have in the MSB?

"One of the largest seeds we have banked belongs to a species of Pandanus from Australia with a single seed weighing almost 50g."

What is the smallest seed in your collection?

"Some of the smallest seeds we have banked at the MSB belong to species in the orchid family. A thousand seeds of some species in the orchid family can weigh less than 0.0005g."

How long does the process take from collecting a seed right through to storing the seed?

"This depends on the species and what states the seeds arrive at the MSB in, but generally several months. All seeds have to be dried down to 3-7% moisture content prior to banking which can take several months."

Seeds ready for storage. (Louise Taylor)
Seeds ready for storage. (Louise Taylor)

Can all seeds be stored?

"No. Seeds can be grouped into two main categories, orthodox and recalcitrant. The majority of seeds are orthodox, meaning they can tolerate drying and are able to be stored under the standard -20C conditions. Recalcitrant seeds on the other hand do not tolerate drying so cannot be stored under the standard conditions. This recalcitrant group includes seeds of oaks and chestnuts. One option being researched for these seeds is the use of liquid nitrogen through cryopreservation for storage."

What treatment do seeds need before they can be stored?

"Before storage, the main treatment seeds receive is being dried down to 3-7% seed moisture content. This increases the longevity of the seeds in the bank. For every 1% drop in seed moisture content the seed longevity in the bank doubles."

The Millennium Seed Bank Facility. (Kew)
The Millennium Seed Bank Facility. (Kew)

Want to support conservation work as a volunteer?

Get involved