Synthetic seeds of Acmella oleracea (Asteraceae) from micropropagated plants in different concentrations of 6-benzylaminopurine

Abstract Acmella oleracea, a leafy vegetable native to the Amazon region, has potential for the cosmetic, pharmaceutical and gastronomic industries. Hot environments and or low relative humidity accelerate losses of vigor and quality, making unfeasible to storage seeds of this plant. This makes necessary to develop new propagation and conservation techniques for A. oleracea. The objective was to evaluate the biometric characteristics, describe the stomata and to verify the presence or absence of epicuticular wax on the abaxial leaf epidermis of A. oleracea plantlet obtained from the conversion of synthetic seeds (SS) in vitro. The nodal segments of micropropagated plantlets, at different concentrations of 6-benzylaminopurine (BAP) (0.000; 0.025; 0.050; 0.100 and 0.200 mg l-1), were sectioned into explants of approximately 0.3 cm, encapsulated in alginate matrix to produce SS, inoculated in test tubes with Murashige & Skoog culture medium and kept in a growth room at a temperature of 25 ± 2 ºC and a photoperiod of 16 hours. The percentage of SS conversion, number of leaves and shoots, height and root dry mass were higher in the treatments with BAP. Shoot dry mass was 54.5% higher on plants originated from SS obtained with 0.100 mg l-1 of BAP than in the control. Anomocytic and ellipsoid-shaped stomata were well defined and epicuticular wax deposition was not observed on the abaxial epidermis of A. oleracea plantlets leaves. The stomata of A. oleracea and the absence of epicuticular wax on the leaf epidermis of this plant were similar between treatments.