Nutritional requirements for germination and in vitro development of three Orchidaceceae species in the southern Brazilian Amazon

Abstract

Tissue culture is an alternative form of producing healthy, vigorous and regular plants on a large scale. The purpose of this study was to evaluate the most efficient culture medium for in vitro plantlet germination and development of three Orchidaceae species. Seeds disinfested of three species were dispersed in distilled water and dripped into basic Murashige and Skoog (MS) medium. The experimental design was completely randomized in a factorial 3 x 4 (three species x four culture media), with 5 replications. Four treatments were established: (1) full-strength MS medium, with the full nutrient concentration (MSØ), (2) full-strength MS medium plus 0.3% activated charcoal (MSØ ACh), (3) half- strength MS medium (½ MS) and (4) half- strength MS medium with 0.3 % activated charcoal (½ MS ACh). Germination was evaluated after 15, 20, 25, 30, and 60 days. The shoot height, leaf number and length, root number and length of plantlets of the three studied species were assessed. In A. variegata, 73% germinated after 60 days in ½ MS ACh medium. In the same period, 100% of E. viparum and S. gloriosa seeds germinated in MSØ ACh medium. The plant height, leaf number and length, root number and length were significantly higher for the species A. variegata and E. viviparum in MSØ ACh medium. The culture media ½ MS and MSØ with addition of activated charcoal favored in vitro germination for the three orchid species of this study.