How They Work

http://www.xseeds.com/how-they-work/

To preserve plant life, seed banks keep seeds safe in a frozen state, ideally at a temperature between minus 10 and minus 20 degrees Celsius. Some seed banks may also employ alternative storage techniques, such as keeping living plants, also known as cryopreservation or in-vitro storage, in circumstances where storing the crop as a seed proves to be too difficult. This applies to plants like the potato, cassava, and banana, whose varieties don’t produce seeds. Instead, the plant’s living tissues are frozen to about minus 196 degrees Celsius with liquid nitrogen for improved long-term storage.