Effect of physical and chemical seed treatments on germination and vigour index in aonla (emblica officinalis)

Emblica officinalis is an important medicinal plant and used as a constituent of ayurvedic and unani medicine. The seed showed dormancy and causes a big challenge in seed germination. Exogenous dormancy is observed due to non imbibitions of water by intact hard seed coat. Enhanced water imbibition rate (0.364-0.395gm/gm dry seeds/day) was observed in mechanically chipped treated seeds on 1st day soaking. The seeds taken under study were subjected to quick seed viability test (TZ) which showed 91-94% seed viability. The low value of electrical conductivity (0.2190.230μmho/cm) of the seeds leachates, also indicated the high intactness of the seeds. The hot water treatment for 10 minutes recorded better germination (65-75%) as compared to the mechanical (chipping) treatment (35-40%). The chipped seeds treated with 0.5% KNO3 was found most effective in enhancing germination percentage (95-100), vigour index and speed of germination over the GA3 and Thiourea treatments. Thus the mechanically chipped seeds followed by imbibition of chemical (GA3, KNO3 and Thiourea) solution recorded synergistic action in terms of the better germination and the seedling vigour.