In vitro regeneration of Senna alata (L.) Robx. (Fabaceae): An ancient medicinal plant

Abstract

Senna alata, a legume of medicinal importance, presents antifungal and antibacterial antioxidant activity. The main limitation is the presence of seeds with integument dormancy within natural populations. This study aimed to establish an efficient protocol for the in vitro propagation and acclimatization of seedlings. The seeds were disinfected with different concentrations of NaOCl; for the regeneration of the shoots, cotyledon segments were inoculated in MS and WPM medium, supplemented with plant growth regulators, auxins (1-NAA and 2,4-D), interaction with cytokinins (TDZ and BAP), and activated carbon. The seedlings were acclimated in nursery conditions using vermiculite, sand, and soil substrates. Using NaOCl (0.5%) for 30 min resulted in 98.0% disinfected seeds while 95.4% of scarified seeds germinated. High node and shoots numbers (8.3 ± 0.4; 12.6 ± 0.8, respectively) were obtained when using the MS medium containing 1-NAA + TDZ (0.1 + 1.0 mg L-1), while the use of MS medium supplemented with 2,4-D + TDZ (0.1 + 1.0 mg L-1) resulted in longer shoots (6.0 ± 0.5 cm). Using WPM medium with IBA + BAP (1.0 + 0.1 mg L-1) improved rooting (14.0 cm ± 1.3) and the number of roots (5.0 ± 0.0) in the treated plants. The vermiculite substrate with sand promoted 81.5% of acclimatized plants. This study allowed obtaining high levels of germination, regeneration in vitro and acclimatization of S. alata.