CryoConservation Centre for sub-Sahara Africa (CCESSA)

 

Biodiversity is under considerable threat, largely as a consequence of human activities, to the extent that some scientists consider us to be in the '6 th extinction'. In response, Target 8 of the Global Strategy for Plant Conservation of the Convention on Biodiversity (CBD) recommends that 60% of threatened plant species should be available in ex situ collections by 2010. The most cost-effective way of conserving plant genetic resources is as seed collections in seed banks, where the seeds are stored in the dry state, at low temperature and relative humidity (RH). Seeds that can be stored under these conditions are referred to as 'orthodox', and under the correct conditions can be stored for decades, possibly centuries. However, seeds of a significant number of species cannot be stored in this manner, and alternative storage methods need to be developed.

 In the interests of setting the scene for this, a little background is provided. We work with plant species producing non-orthodox seeds, and especially with those that are described as recalcitrant. Those that emerge as non-orthodox are more finely characterised and intensive research is undertaken to develop a cryostorage protocol for the embryonic axes. Currently, development of such protocols proceeds on an empirical basis; however, our analyses at every stage of the procedure will ultimately result in the understanding necessary to facilitate generalised guidelines for the various axis types.