Physiological behaviour of cork-oak acorns (Quercus suber L.) during storage and variation between trees.

The mature acorns were harvested on twelve selected trees from a cork oak p opulation in Southern Portugal (Herdade da Palma). After drying, the seed l ots were stored on three types bags (polyethylene with 30 mum and 50 mum th ick and plastic mesh), for six months at 0 degreesC. At the time of natural dissemination, the acorns from the majority of the trees from the same pop ulation were under the same state of morphological and physiological maturi ty. The moisture content was about 44-47% and a germination rate above 92%. At this time, the germination was very slow because of the existent embryo nic dormancy that seems to be dependent on the individual trees. During the storage, germination rate is improved. This might be explained by the brea king dormancy during storage. The mean germination time was on an average 1 0 days for fresh seeds and decreased to about 4 days after 6 months storage . A relationship between viability and seed moisture content was observed. The Mean Germination Time of dried seed and stored seed for 4 months in pla stic mesh bag increased to about 13 days. The germination capacity was stro ngly decreased when the seed moisture content was below 30%.