Seed Banks and Plant Conservation
How the world's most important biological libraries are safeguarding plant diversity for future generations
A Seed banks -- facilities that preserve seeds from plant species in cold, dry storage conditions -- have become one of the most important tools in the effort to protect global plant diversity. By maintaining living collections of seeds outside their natural habitats, seed banks provide insurance against extinction of species whose wild populations are threatened by habitat destruction, climate change, invasive species, or disease. More than 1,750 seed banks currently operate worldwide, ranging from small national collections holding a few thousand samples to vast international facilities storing millions of seed lots.
B The principle behind seed banking is straightforward: seeds of most plant species can be dried to a low moisture content and stored at sub-zero temperatures -- typically around minus 20 degrees Celsius -- without losing their ability to germinate for decades or even centuries. This biological property, known as orthodox seed behaviour, applies to approximately 90 percent of flowering plant species. The remaining ten percent, including many tropical trees and aquatic plants, produce seeds that cannot survive drying and freezing. These so-called recalcitrant species must be conserved through living collections, tissue culture, or cryopreservation of embryonic material.
C The Svalbard Global Seed Vault, built inside a sandstone mountain on a Norwegian Arctic island in 2008, is the best-known seed bank in the world. Designed as a backup for existing national collections rather than a primary research facility, it holds duplicate samples donated by seed banks from around the globe. The vault's location -- deep within permafrost at 130 metres above sea level -- was chosen to ensure survival through power failures, coastal flooding, and a range of catastrophic scenarios. The vault currently holds more than 1.3 million distinct seed samples representing approximately 6,000 plant species.
D Beyond preserving existing diversity, seed banks support agricultural innovation by maintaining collections of crop wild relatives -- wild species closely related to domesticated food crops. These relatives often carry genetic traits, such as drought tolerance or disease resistance, that were lost from cultivated varieties through centuries of selective breeding focused on yield and appearance. Plant breeders working to develop varieties capable of withstanding conditions projected under future climate scenarios rely heavily on these collections. Several advances in wheat and rice breeding in recent decades have drawn directly on material held in seed banks.
E Significant gaps in coverage remain. Fewer than one third of the world's known plant species are currently represented in any seed bank, and coverage is especially poor for species native to tropical regions -- precisely where plant biodiversity is highest and habitat loss most severe. Wild species of commercial value, such as timber trees and medicinal plants, are better represented than less conspicuous groups such as native grasses and food plants used by indigenous communities. Addressing these gaps requires fieldwork to collect seeds from wild populations, which is resource- intensive and must be managed carefully to avoid damaging the communities that collectors aim to preserve.
F The long-term value of a seed collection depends not only on the number of species it holds but on the genetic diversity within each species. A bank holding a single sample from one population of a plant provides much weaker protection than one holding samples from multiple populations across the species' full range, since different populations carry distinct adaptations to local conditions. Best-practice guidelines recommend collecting seeds from a minimum of 50 unrelated individual plants per population and from several populations across the geographic range -- standards that are often difficult to meet given available fieldwork resources.
G Seed preservation technology continues to advance. New desiccation protocols that extend the viable storage life of seeds previously difficult to conserve are under development. Cryopreservation of pollen -- which can be used to cross-pollinate living plants after long periods in storage -- offers a complementary approach for species that produce large or moisture-sensitive seeds. Digital platforms are transforming database management, allowing collections at different institutions to be searched and cross-referenced. Some researchers have proposed a globally networked seed bank system with standardised protocols and freely shared data as the most efficient route to maximising conservation impact.