Improving Germination of Hawthorn (Crataegus pseudoheterophylla Pojark.) Seed by Potassium Nitrate, Sulfuric Acid and Stratification

The genus of Hawthorn (Crataegus L.), belonged to Rosaceae family has medicinal and ornamental applications. Its seed germination is poor, due to stony endocarp and embryo dormancy. This study was carried out to determine methods to break dormancy in Crataegus pseudoheterophylla seeds. For this purpose, seeds were sown in plastic pots as a factorial experiment in randomized completely block design (RCBD) with 3 replications. Treatments including chemical scarification in KNO3 for 0, 2500, 5000, 7500 and 10000 mg l-1 and concentrate sulfuric acid (H2SO4 96 %) for 0, 30, 45, 60, 90, 120, 150, 180 and 210 minutes followed by continues regime (1 month at 23 °C, then 3 months at 4 °C) and alternate regime (1 month at 4 °C and, 2 weeks at 23 °C, then 1 month at 4 °C and 2 weeks at 23 °C, finally 1 month at 4 °C) were applied. Results showed that in KNO3, the highest germination percentage (19.33 %) and germination speed (4.18 number/day) was determined at 10000 mg l-1 alternate stratification and in sulphuric acid, the highest percentage germination (55 %) and speed germination (8.63 n/d) was determined for 120 minutes alternate stratification. The highest mean time germination in both scarification treatments was observed in continues regime.