Pretreatments to overcome seed coat dormancy in Dimorphandra mollis.

Abstract

Dimorphandra mollis Benth. is a multipurpose tree species providing important subsistence and economic benefits to rural communities of the Brazilian cerrado. Seeds of D. mollis were collected to test for germination following one of 24 pretreatments intended to overcome seed coat impermeability. The tests were conducted for 21 days at 28°C under a 24-hour constant light regime. Seeds without a pretreatment resulted in only 4% germination while immersion in sulfuric acid for 45 min to 1 hours and mechanically scarifying the seeds with a file improved germination to over 90%. A sulfuric acid treatment for 1 hours followed by a 2 hour water soak was the most efficient method of accelerating germination rate. Seeds exposed to sulfuric acid for longer than 1 hours showed marked decreases in viability. Though several heat pretreatments with boiling water provided germination responses of over 50%, fire was not successful in eliciting germination significantly higher than the control. These results provide viable pretreatment options for both large and small-scale reforestation efforts.