Recalcitrant seed

[4] The two main mechanisms causing damage to recalcitrant seeds are desiccation effects on the intracellular structures and metabolic damage from the formation of toxic chemicals such as free radicals.

[5] An example of the first type of damage would be found in some recalcitrant nontropical hardwood seeds, specifically the acorns of recalcitrant oaks, which can be stored in a non-frozen state for up to two years provided that precautions are taken against drying.

These seeds show deterioration of cell membrane lipids and proteins after as few as 3–4 days of drying.

[6] Other recalcitrant seeds, such as those of the sweet chestnut (Castanea sativa), show oxidative damage resulting from uncontrolled metabolism occurring during the drying process.

The storage guideline is to put them in refrigeration at 45–65% RH, for a maximum of five years.