Germination study on Arbutus unedo L. (Ericaceae) and Podocytisus caramanicus Boiss. & Heldr. (Fabaceae) PAVLOS SMIRIS1*, ELIAS PIPINIS1, MARIA ASLANIDOU1, OLGA MAVROKORDOPOULOU1, ELIAS MILIOS2 and ANTONIOS KOURIDAKIS1 1 Laboratory of Silviculture, School of Forestry and Natural Environment, Aristotle University, Thessaloniki 541 24, Greece 2 Department of Forestry, Enviromental Management & Natural Resources, Democritus University of Thrace, Orestiada, Greece Abstract Both species Arbutus unedo and Podocytisus caramanicus that were studied show some difficulty in seed germination. The main factor for the inhibition of germination in Arbutus unedo is embryo dormancy and seed coat imposed dormancy in Podocytisus caramanicus. These species are commercially valuable for their uses (they are being cultivated as ornamental shrubs and have small requirements in water and nutrients) but they also have a scientific value since few surveys have been conducted concerning dormancy breaking and seed germination. The objective of the present work is to study the effect of various treatments in seed dormancy breaking. After the treatment, the seeds of both species were subjected to germination test under controlled conditions (20oC/16 h dark period and 25oC/8 h light period). The maximum percentage of germination for Arbutus unedo (85.75%) was observed when the seeds were soaked for 24 h in 500 ppm GA3 and then stratified (chilled) for a period of 3 months. The maximum percentage of germination for Podocytisus caramanicus (63%) was observed when the seeds were immersed in concentrated sulphuric acid (98%) for 20 min.   < back .