Abstract
A shortage of seedlings of Peucedanum japonicum Thunb. var. latifolium M.Hotta et Shiuchi in Minamisatsuma city of Kagoshima prefecture has become a serious problem recently because P. japonicum plants are popular as a healthy vegetable in islands of Kagoshima and Okinawa prefecture. In our interview with farmers and research, the reason for it was a low germination percentage of P. japonicum var. latifolium. The objective of our research was to clarify the temperature which increased germination percentages. One hundred seeds were put in 9 cm-diameter petri dishes with 10 mL distilled water, dishes were tested in 24hrs dark conditions in incubators. We also compared the germination of seeds with decortication and control treatments. In 24hrs constant temperature treatments (20, 25, and 30℃), about 40% of germination percentages were observed at 25℃ with decortication, and lower germination percentages were at 20℃. No germination was observed at 30℃. In 12/12hrs alternative temperature treatments(10/25℃, 20/25℃, 20/30℃, and 25/30℃), seeds could not germinate at 10/25℃, 20/30℃ and 25/30℃, and control at 20/25℃ treatments showed about 10% germination percentages, while decortication treatments at 15/20℃, 15/25℃ showed more than 20%, and more than 40% at 20/25℃, especially. Therefore, it was estimated that daily changes of temperature could affect germination severely, and for the increase of germination percentages, the temperature has to be adjusted 20/25℃ and it will be better with decortication.
