IN VITRO PROPAGATION OF <i>Casearia sylvestris </i>SWARTZ (SALICACEAE)

Abstract

In order to do an in vitro propagation of Casearia sylvestris, a tree native to Brazilian forests, studies of in vitro seed germination were performed and aseptic seedlings obtained were used as explant donors for micropropagation. Mature and immature seeds, stored for 10 days at 10 or 25°C were inoculated in medium containing 10% of MS salts and kept in the light (a 16-hour photoperiod) or continuous dark, at 25°C. For immature seeds, gibberellic acid (GA₃) was or was not tested at a concentration of 1.5 mg l^-1. From the seedlings obtained, the cotyledon and apical segments were removed and cultured in complete MS medium with five combinations of 6-benzylaminopurine (BAP) and naphthalene acetic acid (NAA): 0.0; 0.25; 0.5; 1.0; 2.0 and 0.0; 0025; 0.05; 0.1; 0.2 mg L-1, respectively. The aerial shoots formed in vitro were cultured in MS medium containing 0.0 or 1.5 mg L^-1 indole-3-butyric acid (IBA) for rooting. The highest percentage of germination (60%) occurred in mature seeds exposed to light, regardless of other treatments, and may be considered positive photoblastic. The highest percentage of germination of immature seeds (27%) occurred when previously stored at 10 ° C with or without GA₃. The induction of aerial shoots was more efficient in apical segments in a medium containing the lowest combination of BAP and NAA or free of these growth regulators. The higher number of roots occurred in aerial shoots obtained from cotyledon segments, with or without IBA. After acclimatization, 83% of the plants survived.