Lychnophora pinaster, known as arnica, is a medicinal plant of the Cerrado ecosystem in Brazil. It is widely used in the form of alcoholic extract for its anti-inflammatory and anesthetic and healing effects on sprains, bruises, and inflammation. Owing to the great difficulty of propagation, it is listed by the Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis in the category of plants vulnerable to extinction. Micropropagation offers a solution to this problem by allowing the preservation and expansion of germplasm. The objective of this research was to establish a protocol for in vitro propagation of arnica. The best medium for germination of arnica embryos and plantlet growth was a quarter strength semisolid Murashige and Skoog medium (MS/4) containing 0.75% (w/v) sucrose. For shoot induction, the best results were obtained on MS/4 with 2.76 μm of benzylaminopurine. Maximum shoot elongation before rooting occurred in the presence of 8.67 μm of gibberellic acid for 19 d. Microshoots were successfully rooted in the presence of 10.7 μm of naphthalene acetic acid for 15 d. After rooted plantlets were acclimatized in a greenhouse for 20 d, the survival rate was 100% when planted in a soil from the area of occurrence of the species, whereas 0% survived when planted in Plantmax.
Ana V. de Souza, José E.B.P. Pinto, Suzan K.V. Bertolucci, Ricardo M. Corrêa, Larissa C. do B. Costa and William E. Dyer
Flávia D. Pereira, José Eduardo B.P. Pinto, Luciana D.S. Rosado, Helen C.A. Rodrigues, Suzan K.V. Bertolucci and Osmar A. Lameira
The aim of the study was to develop a method for the in vitro propagation of Ananas erectifolius (Bromeliaceae), a fiber-rich Amazonian species. In vitro cultures were established from axillary buds of field-grown plants cultured on medium without plant growth regulators (PGRs). Stumps were excised from in vitro plantlets and incubated under dark conditions on medium supplemented with different combinations of 1-naphthaleneacetic acid (NAA), kinetin, and gibberellic acid (GA3). The most efficient induction of etiolated shoots occurred on explants cultured in the presence of NAA at 10.74 μm (T1 medium) or NAA at 5.37 μm + GA3 at 3 μm (T2 medium). Apical tips and nodal segments of the etiolated shoots were recultured under a 16-h photoperiod in medium without PGRs, and the effects of residual PGRs were evaluated by determining the numbers and lengths of plantlets that regenerated within 30 days. Residual PGRs exhibited no effect on the length of the regenerated plantlets but significantly affected the number of plantlets regenerated from nodal segments but not from apical tips. Nodal segments and apical tips derived from etiolated shoots produced, respectively, on T2 and T1 medium were most appropriate for plantlet regeneration. Nearly all (98%) regenerated plantlets formed roots when cultured in liquid medium without PGRs, and all plantlets survived acclimatization under greenhouse conditions. The stumps originating from etiolated shoots regenerated new etiolated shoots when recultured in the dark on medium without PGRs, thus providing a supply of new explants for plant regeneration.