Abstract

The aim of this study was to investigate the methods that increase the germination of the native species Cercis siliquastrum and Carpinus orientalis, whose seeds exhibit dormancy. Seeds of C. siliquastrum were collected from a natural habitat and an urban environment, and seeds from both origins were given 6 different dormancy-breaking treatments. Seeds of C. orientalis were collected from an urban environment and were given 5 different dormancy-breaking treatments. For C. siliquastrum seeds, the treatment that gave the best final germination was the combination of acid scarification for 30 min and immersion in 500 ppm gibberellin (GA₃) (52% for the seeds from the urban environment and 62.5% for the seeds from the natural habitat germinated). For C. orientalisseeds, the results showed that, the most effective treatment was moist-cold stratification for 12 weeks which resulted in 84% germination.

Key words: Carpinus orientalis, Cercis siliquastrum, dormancy, gibberellin, scarification, stratification.