How are seeds stored in banks?
Seed collection, organization and storage will vary by seed bank facility. Let's take a look at how one facility manages its library of seeds to get a taste of how it's done. The following steps display how the Department of Environment and Conservation, a local organization in Australia, banks its seeds:
- First, researchers decide what seeds to collect. Generally, they give priority to threatened plants.
- After plants are located, seed collection begins. Seeds are most viable for collection and storage when ripe. In the case of fruits, most release their seeds when ripe. However, some plants will retain their seeds for extended periods, which allows a longer collection time. Other plants might seed irregularly, and thus require repeat visits.
- Researchers collect the seeds manually with tweezers, pole cutters, seed traps or nets and buckets, depending on the type of plant.
- For each collection, they record details like location, plant description, habitat, soil type and other information. This information provides data about the local plant population and ensures optimal replanting conditions.
- Collectors then assign each sample a unique number.
- Collectors clean each sample to ensure high quality. Seeds can be cleaned by shaking them through a sieve or with a machine that blows air on them.
- To reduce the moisture content of the seeds, collectors dry them in a temperature- and humidity-controlled room. Afterwards, they place the seeds in sealed, airtight containers.
- The final storage step is to freeze the seeds at minus 4 degrees Fahrenheit (minus 20 degrees Celsius).
[source: Nature Base]
Difficult-to-store seeds may respond better to cryopreservation, or in-vitro storage. For example, the banana plant doesn't produce seeds, so alternative storage methods are necessary. In-vitro storage means that living plant tissues are stored, rather than seeds. Scientists then place these living tissues in liquid nitrogen -- around minus 320 degrees Fahrenheit (minus 196 degrees Celsius) -- to ensure better long-term storage [source: Bioversity International].
Although shelf life varies from crop to crop, most seeds can survive in cold storage for decades and some even longer. Eventually, though, all seeds will die. Before this happens, scientists remove seeds from storage and plant them to harvest and re-bank fresh seeds.
With all these seeds in storage, who gets ownership of the seeds? Usually the owners of the seed banks control their own seeds. But in the case of the Svalbard Vault in Norway, depositors retain possession rights of the seeds they place in the bank [source: Svalbard FAQ]. Of course, these ownership rights don't preclude one country lending seeds to another country in need.
Next, we will take a closer look at the "Doomsday Vault," along with other seed bank facilities around the world.