ABSTRACT
The species Bombax malabaricum, popularly known as red-cotton tree, presents secondary metabolites of medicinal interest. Like other species of the Malvaceae, their seeds have tegumentary dormancy, which hinders their sexual propagation. Thus, this study aimed to break the dormancy of B. malabaricum through physical and chemical strategies. For mechanical scarification of the seeds it were employed: abrasion of the tegument with sandpaper and cut with scissors in the region opposite to the hilum. For chemical scarification: hydrochloric acid (HCl), nitric acid (HNO3), sulphuric acid (H2SO4), sodium hydroxide (NaOH) and potassium hydroxide (KOH) for a period of 30 minutes. The seeds were also subjected to immersion in 40 mg L-1 of GA3 for the same period. Four replicates of 25 seeds were used for each treatment and then they were conducted for calculation in a B.O.D. germination Chamber. The results obtained were applied in order to calculate: Germination, Germination Speed Index, Average Time of Germination and Percentage of Damaged Seeds. The HNO3proved to be the best treatment in the Germination trials (83.5%), followed by the HCl (71.5%) and the mechanical scarification techniques with sandpaper (71.5%) and scissors (67.5%). The HNO3 also showed the lowest percentage of damaged seeds (3.5%); The H2SO4 was the treatment that caused more damage to the seeds (36.5%).
Keywords
Red-cotton tree; Germination; Scarification; Nitric acid