Seed Storage Behaviour
In essence, seed storage behaviour refers to the capacity of seeds to survive desiccation. The classification used here largely follows that used in the hard copy Compendium of Information on Seed Storage Behaviour by T.D. Hong, S.H. Linington and R.H. Ellis, published in a limited run in 1998 by RBG Kew — ISBN 1 900347 49 0. A summary of the various storage categories used in SID is given below. More detailed information on the various storage categories, including the pitfalls and causes of misclassification, is available within the above reference.
Orthodox seeds can be dried, without damage, to low moisture contents, usually much lower than those they would normally achieve in nature. Over a wide range of storage environments their longevity increases with reductions in both moisture content and temperature, in a quantifiable and predictable way.
Recalcitrant seeds do not survive drying to any large degree, and are thus not amenable to long term storage, although the critical moisture level for survival varies among species. In this database this category includes those seeds, of some aquatic species in particular, described as viviparous.
Intermediate seeds are more tolerant of desiccation than recalcitrants, though that tolerance is much more limited than is the case with orthodox seeds, and they generally lose viability more rapidly at low temperature. They do not conform to all the criteria defining orthodox seeds, especially in respect of the quantification and predictability of the relations between longevity and both drying and cooling.
The database can be searched for any, or all of these categories. Where the compilers have judged from the evidence available that a species is likely (greater than evens chance), rather than certain, to display a particular storage behaviour, this is indicated by the addition of a question mark (e.g. 'recalcitrant ?'); and for the orthodox category only there is an additional subdivision of 'probable' ('orthodox p' — better than likely, but not absolutely certain). The database can also be searched using these sub-categories, or by combining them (e.g. 'any intermediate') — see the pick list for storage behaviour.
A large part of the storage behaviour dataset that is presently included within SID (approximately 7000 of the 9582 species entries), originates from the electronic version of the Compendium of Information on Seed Storage Behaviour. This dataset was the result of a collaboration between the International Plant Genetic Resources Institute (IPGRI), the University of Reading Department of Agriculture and RBG Kew, and was itself derived from an earlier hard copy version with very limited distribution, funded by IPGRI and compiled largely through Tran Dan Hong's herculean efforts. An electronic version of the Compendium database is also available for download.