The effects of priming on seed vigority and seedling growth of deteriorated seeds in three Astragalus species

 Seed priming is an effective method for enhancement of seed germination and seedling establishment in range plant species. In order to study of priming effects on seed germination of deteriorated seeds of Astragalus Spp., a factorial experiment was conducted based on completely randomized design with three replications in glasshouse condition in research institute of forests and rangeland, Tehran, Iran in 2016. The factor A was Astragalus species in three levels (Astragalus cyclophyllon, A. siliqusus andA. homosus), Factor B was seed deterioration in two levels (seed preserved in cold store (+4°C for 12 years), and accelerated aged seeds (by incubation in 100% relative humidity and temperature 40°C for 48 h). Factor C was priming treatments in four levels as: osmoprimings using PEG (-0.3Mpa and -0.6Mpa), hydropriming (soaking seeds in distilled water for 24 h) and control. Data were collected for seed germination, rate of germination, seed vigor, shoot, root and seedling length, root/shoot length ratio and seedling fresh weight. Result of analysis of variance showed significant effects of main factors and their interaction for most of traits. The A. siliqusus had higher mean values for all of traits except root length followed by A. cyclophyllon and A. homosus, respectively. The priming by deterioration interaction effect, showed that, for natural deteriorated seeds, both hydropriming and osmopriming -0.3Mpa had increased 25 to 96% means of traits except root length, whereas for artificial aged seed only hydropriming had improved 37% of seed vigor. It was concluded that for regeneration of aged seeds preserved for a long time in gene banks both hydropriming and osmopriming are effective methods to recover of deteriorated seeds of Astraglus spp.