Many plants used for traditional medicine in Africa are endangered because of over harvesting, so researchers are seeking ways to conserve the species in seed banks.
Conventional seed storage relies on drying or freezing to protect seeds from fungal infection and prevent them from germinating. But many African medicinal plants produce 'recalcitrant' seeds, which do not respond well to such methods.
In this essay in Science, Patricia Berjak of South Africa's University of KwaZulu-Natal relates some of her experiences during 30 years of research on seeds and seed storage.
One promising approach to the problem of recalcitrant seeds, says Berjak, is to remove the 'embryonic axis' — the portion of a seed that gives rise to the root and shoot of a new plant — and preserve it separately it from the rest of the seed. This method could, she believes, be used to create artificial seeds, in which the embryonic axis is stored in a gel.