Effect of Osmopriming, Hormonal priming and Hydropriming on the enhancement of aged seed germination and seedling growth of Tansey (Tanacetum polycephalum)

In order to study of Salsalic acid and Ascorbic acid pretreatments on the enhancement of aged seed germination and seedling growth of Tanacetum polycephalum in laboratory condition, a factorial experiment based on completely randomized design with three replications was conducted in seed technology laboratory in research institute of forests and rangeland, Tehran, Iran in 2015. The factors A were seed deterioration in four levels as: seed preservation in basic cold room (-18°C), active cold room (+4°C), aged seeds (by Incubation in saturated humidity and temperature 41°C for 48h), and control. Factor B were seven levels of seed priming as: osmopriming (PEG -0.3Mpa), hormone priming (250 and 500 ppm of Ascorbic acid and Salsilic acid), hydro priming (distilled water) and control. Data were collected for germination traits as percentage and speed of germination, primary root, shoot seedling length, vigor index and seedling fresh weight. Result of analysis of variance showed significant differences between seed deteriorations and seed priming levels for all of traits expect seedling fresh weight (P<0.01) and their interaction effects were significant for all traits except root length and vigor index (P<0.01). Result of seed deterioration treatments showed that the higher root length with average values of 21.31 and 19.73 cm and higher vigor index with average values of 32.01 and 20.81 were obtained in basic and active cold room, respectively, indicating the positive effects of cold temperature on increasing 8 and 52% of latter traits in base store than that for active store. The mean comparisons of priming technique showed that both osmo-(PEG) and hydro priming (distilled water) had significant effects on increasing root length and vigor index. The result of priming by seed deteriorations interactions for aged seed showed that the higher mean values for seed germination and speed of germination were obtained by hydropriming and higher mean values of shoot and seedling length were obtained by hormonal-priming (Ascorbic acid 500 ppm).