The effect of osmotic stress on the germination of european hop-hornbeam (Ostrya carpinifolia scop.) seeds

European Hophornbeam (Ostrya carpinifolia Scop.) is a type of deciduous tree that can be seen in bush, shrub and tree forms. In the studies conducted for the germination of the European Hophornbeam, it has been determined that there is a germination barrier caused by embryos, need stratification and better germinated at low temperatures. During the germination process of European Hophornbeam seeds the water level in the soil is an important environmental factor that affects germination. If water potential decreases, germination is delayed and stops after a certain level. One of the methods for the determination of the effect of water stress on the germination is osmotic potential created with the help of solutions to determine the effects of water stress on the germination. Although there are several studies on the elimination of the germination barrier of the European Hophornbeam, there are not enough studies on the effect of osmotic stress on germination. In this study; it is aimed to determine the effect of the different osmotic stress levels on the germination of seeds belonging to European Hophornbeam. Seeds were collected from 8 different populations in different regions of Turkey (Kastamonu-Sendag, Düzce-Yığılca, Antalya-Finike, Antalya-Akseki Erzurum Ispir, Artvin-Hatilla, Sinop-Ayancık, Adana-Saimbeyli). Polyethylene glycol (PEG 6000) was used to produce osmotic stress levels. Six levels of osmotic stress (0, -0.5, -1, -2, -3, -4 bar) were established, 0 bar pressure level was determined as a control group. Michel and Kaufmann formula were used in the calculations. In the experiments, 11 cm petri dishes and two layers of filter papers were used. Two different germination temperatures (15/5 °C and 15/10 °C 8/16 hours) were determined by taking into consideration the previous germination studies. The differences between the populations in terms of germination percentages were tested by variance analysis and grouped according to Duncan test. According to the results of the analysis, it was determined that there was a significant difference between the populations in terms of germination percentage with 99 % confidence interval.