Enterolobium cyclocarpum (Jacq.) Griseb. seed analysis, pre-germination treatments and initial growth

Abstract

Enterolobium cyclocarpum is used in the recovery of deforested areas of subtropical dry forests. However, seeds are hard-coated and impermeable to water, so that germination is slow and uneven. Therefore, before starting the production of seedlings of this species for reforestation and plantations, appropriate pre-germination treatments to encourage germination should be determined. In this study, seed weight, moisture content and viability were estimated, and pre-germination treatments applied, including: controls, sanding the seeds, and soaking the seeds in water at room temperature (20 °C) for 96 h, in hot water (75 °C) for 4 h, and in concentrated sulfuric acid for 30 minutes. The seeds were sown in Styrofoam trays, using as substrate mixture of 75 % sand and 25 % forest soil. A completely randomized design was used with four replications of 100 seeds for treatment. The germination capacity, mean daily germination, peak and germination value, height and basal diameter of seedlings at six months of age were evaluated. There were significant differences (P < 0.0001) among treatments for all germination and growth parameters. The best pre-germination treatments for prompt seeds germination of E. cyclocarpum were soaking in sulfuric acid and sanding the seed, while sanding and soaking in water at room temperature during 96 h proved best for basal diameter growth and seedling height.