In vitro REGENERATION OF Agave wocomahi GENTRY (ASPARAGACEAE)

Abstract

Agave wocomahi is a species with the potential to be exploited for various purposes; however, the low efficiency of their natural propagation systems means that there are no specimens available, and the harvesting of wild plants would threaten natural populations. Protocols for in vitro culture and propagation of this species were developed. Budding of lateral meristems was induced by culturing stem segments in basal medium with 1 mg L^-1 of 6-benzyl amino purine (BA); subsequently, the stem, leaf, and root morphogenic responses explants were determined. Treatments were established with naphthaleneacetic acid (NAA), indoleacetic acid (IAA), 4-amino-3,5,6-trichloropicolinic acid (PIC) and 2,4-dichlorophenoxyacetic acid (2,4-D), in concentrations of 1.5 and 4.0 mg L^-1, alone or combined with 1.5 and 3.0 mg L^-1 of BA. The formation of five types of callous tissue (TC) was observed, of which the nodular tissue was generated mainly in stem and leaf explants and the TC with roots in root explants. Treatments with PIC, alone or combined with BA, caused higher callus induction (99.16 %) in stem explants, with nodular TC prevailing. Adventitious shoots were generated by direct and indirect organogenesis in the IAA treatments; furthermore, indirect somatic embryogenesis was observed in callus generated with 1.5 mg L^-1 IAA with 1.5 and 3.0 mg L^-1 BA, with BA alone and in combination with 2,4-D. The development of the presumed embryos into seedlings was favored by removing the plant growth regulators and adding 1 g L^-1 of activated charcoal to the medium. The plants generated adapted to ex vitro conditions with a survival greater than 90 %. These in vitro multiplication protocols could become a tool for the sustainable use of the species.