Effect of different storage conditions in recalcitrant seeds of holm oak (Quercus ilex L.) during germination

The effect of three different storage treatments on holm oak (Quercus ilex L.) acorns was examined over a period of twelve months. Acorns from two seed lots were stored at 3°C with three different treatments: acorns mixed with peat inside a can with a pierced pipe through the middle, acorns mixed in moistened sand, or acorns inside polyethylene bags without medium. Samples were collected every two months and were analyzed for moisture content, germination and electrolyte leakage. Storage of acorns in polyethylene bags maintained the high seedling percentage usually observed after harvest in germination tests. The acorns stored mixed with peat or sand failed to maintain the germination vigour observed at harvest. Electrolyte leakage was significantly higher for acorns stored in peat rather than for the other two treatments. However, acorns stored in sand and in peat had a higher level of moisture content than those kept in polyethylene bags. These results suggest that storage of acorns from the recalcitrant holm oak in polyethylene bags could preserve the acorn germination over a longer period of time with respect to the usual methods.