Effect of storage on Arbutus andrachne L. seed germination

Arbutus andrachne (Eastern, Greek or Cyprus strawberry tree) grows naturally in SE Europe and Asia Minor. It has the potential to be introduced for use in the urban and suburban landscape as well as for reforestation. In the present study the effect of seed storage on germination was studied. Arbutus andrachne seeds were harvested in three different years from a native adult tree (in mount Parnitha, Attiki, Greece), and maintained in the darkness, at 25°C for 3, 11 or 27 months. Seeds were placed in Petri dishes with half strength solid MS medium. Seeds of each harvest were placed for germination under 16 h light at 10, 15, 20 or 25°C (first treatment). In two additional treatments, seeds of each harvest were placed for cold stratification at 7°C, in darkness, for 40 or 60 days before transferred at 10, 15, 20 or 25°C (second and third treatment, respectively). Germination was affected by the duration of storage. Seeds stored for 27 months did not germinate. Seeds stored for 11 months germinated only at 10 and 15°C independently of cold stratification. Germination percentage was 75-85% at 10°C and 60-80% at 15°C depending on the treatment; increasing the period of cold stratification reduced gradually the germination percentage. Τ50 was 26-36 at 10°C and 20-24 at 15°C depending on the treatment; at 10°C, seeds that were treated with cold stratification germinated faster than those that were not treated with cold stratification, while at 15°C cold stratification did not affect the speed of germination. Seeds stored for three months germinated at 10 and 15°C. At 20°C they germinated to 38% and even germinated at 25°C if cold stratification was applied. At 10 and 15°C without cold stratification the germination percentage was similar to that of seeds stored for 11 months (78-80%), but the procedure was much faster (Τ50 was 13 days at 15°C and 21 days at 10°C). Cold stratification enhanced the germination of these seeds (Τ50 < 5) and induced high germination percentage (85-95%) at 20 and 25°C as well; at 60 day cold stratification germination was almost completed during the cold stratification period.