Role of Seed Priming in Enhancing Germination, Growth and Seedling Quality of Terminalia arjuna under Nursery Conditions

Abstract

Terminalia arjuna (Roxb. exDC.) Wight & Arn. is an ecologically and economically important tree species valued for its roles in agroforestry, afforestation, riverine ecosystems, timber use, tannin production, and traditional medicinal applications. However, nursery propagation of T. arjuna and related Terminalia species is often constrained by slow, irregular, and poor seed germination, mainly because of hard seed coats, dormancy, and variation in seed quality. This review synthesises available information on seed priming and pre-sowing treatments used to improve germination, seedling vigour, and nursery performance in T. arjuna and selected related species, including T. bellirica, T. chebula, T. tomentosa, T. catappa, T. sericea, and T. laxiflora. The reviewed studies indicate that hydropriming, osmopriming, halopriming, hormonal priming, biopriming, scarification, solid matrix priming, and nanopriming may enhance germination and early seedling growth when applied under suitable species-specific conditions. Among these methods, water soaking, hot-water treatment, mechanical or chemical scarification, and gibberellic acid treatments are frequently reported as effective approaches for improving germination percentage, germination speed, seedling height, root growth, collar diameter, and seedling vigour. Biopriming and substrate-based approaches also show potential for improving nursery establishment and reducing seedling losses. However, responses vary with species, seed provenance, seed size, storage period, treatment concentration, and soaking duration. The review highlights the need for standardised, experimentally validated nursery protocols for T. arjuna and related Terminalia species. Further work is required to evaluate treatment safety, long-term field performance, and practical applicability under different nursery and agroforestry conditions.