Effect of various dormancy breaking treatments on seed germination, seedling growth and seed vigour of medicinal plants

Study was conducted during 2013-14 to examine the role of various dormancy breaking treatments, viz.hot water treatment, scarification, stratification, concentrated acids (H 2 SO 4 , HNO 3 and HCl), gibberellic acid, potassium nitrate, alcohol, and acetone and gamma-rays irradiation on the percentage germination, seedling growth and seed vigour.Dried seeds were incubated in the plant growth chambers for 20-28 days at constant temperature of 25±2 °C under continuous light (16 hrs) photoperiod after its treatments.Maximum percent germination 97.2% was obtained in Innula racemosa followed by Rheum webbianum (95.1%),Carum carvi (93.4%),Saussurea lappa (90.01%) and Bunium persicum (81.4%) when seeds were pretreated with acid (H 2 SO 4 for 5 minutes).According to results obtained in present study, all studied species found best germination with H 2 SO 4 for 5 minutes in duration of 30 days.The seedlings derived from seeds exposed to the various treatments performed well when grown in a green house.Maximum length of seedlings were found in 24.3 cm in S. lappa followed by R. webbianum (23.8 cm) and C. carvi (22.2 cm) when seeds were pretreated with H 2 SO 4 for 5 minutes, on the other side B. persicum (19.4cm) in hot water treatment at 80°C for 20 minutes and I. racemosa (17.4 cm) in 0.2 KNO 3 for 10 minutes.Highest value of seed vigour index (2263) and lowest seed vigour index (390) was found in R. webbianum and B. persicum.The well developed seedlings were observed in 90 days and transplanted it for further developments.The data have implications for conservation and cultivation of the species studied.