Improvement of germination of Vitex agnus castus L. seeds with seed pre-treatments

To investigate the germination ability of Vitex agnus castus L. seeds, pre-treatments with sulfuric acid (for 60-120 min), chilling (for 2 weeks at 5 degrees C) and soaking in water or 400 ppm GA(3) (for 6-10 hrs) were applied, followed by incubation at 20 degrees C (for 2 weeks) and transfer to 30 degrees C (for 1 week), 90% RH and natural light cycling. Seeds incubated at 20 degrees C or 30 degrees C without any pretreatment failed to germinate. Seeds scarified with sulfuric acid for 30 to 60 min followed by incubation at 20 degrees C showed little germination. However, upon transfer to 30 degrees C, germination increased to 90-100%. Seeds pre-treated for 8-10 hrs with 400 ppm GA(3) showed about 20% germination during incubation at 20 degrees C. Upon transfer to 30 degrees C, germination of chilled seeds increased to 60%, and of water and GA(3)-soaked seeds to about 80-90%. These results indicate that V. agnus castus L. seeds show seed coat and endosperm dormancy.