Effect of Soaking Treatment on Germination of Hard Coated Tropical Forest Tree Seeds

Abstract

Seed germination and seedling growth performance of Maesopsis eminii and Terminalia catappa under different water soaking treatments were evaluated for 120 days under nursery conditions. A total of 1400 seeds were pre-treated with hot (95oC) and cold water (ambient temperature) by soaking for 12, 24 and 48 hours with a control of no soaking. The seeds were sown directly into polythene pots filled with uniform growth medium (top forest soil, sand and clay soil mixed in a ratio of 5:3:2) to avoid disturbance of the root system after germination. The seeds were sown in a randomized block design with seven treatments and three replicates. Data were analysed using ANOVA in GenStat v18. Results indicated that soaking enhanced seed germination. Soaking of seeds in cold water for 12 hours resulted into higher germination (90% for Terminalia catappa and 85% for Maesopsis eminii) than the control (48%). Soaking period and water temperature significantly influenced seedling vigour (F value = 0.962; p = 0.038). Soaking seeds in cold water for 24 hours enhanced Maesopsis eminii seedling growth by 8.0 cm Terminalia catappa seedlings by 7.4 cm. Seed dormancy, germination percentage and growth performance in hard coated seeds such as Maesopsis eminii and Terminalia catappa can be broken by soaking in cold water for 12-24 hours. Pre-germination treatments significantly influences the germination and seedling growth.