Efeito de variedades e concentrações de polpa de banana no desenvolvimento in vitro de Cattleya walkeriana Gardner (Orchidaceae)

Abstract

The ornamental plants market is in current expansion, especially the orchids which are plants of remarkable beauty and have a promising market. In such context, the goal of this study was to establish an adequate culture med ium formula, based on banana pulp supplementation, for the in vitro growth of Cattleya walkeriana Gardner. The culture media were prepared, based on the nutritional formula "C" Knudson supplemented with 20, 40, 60, 80, 100, 120, 140 and 160 g L-1 banana pulps of the 'maçã , nanica and prata' varieties. After 6 months of in vitro cultivation, the analysis of the seedlings showed that the supplementation of the KC medium using any of the three banana pulp varieties, had stimulated root formation, having a more outstanding effect in the 80 and 100 g L-1 concentrations. The 120 and 140 g L-1 concentrations have stimulated significantly the number and length of leaves. In Higher concentrations of banana pulp it was shown a lesser variation of the medium initial pH. In order to promote the development of C. walkeriana seedlings in KC medium using banana pulp, the recommended strategy is that the seedlings should be initially inoculated in the 100 g L-1 supplemented medium using 'prata' or 'nanica' banana pulp varieties, and after the growth of new roots, these seedlings should be transferred to the 120 g L-1 KC medium of `prata` banana pulp variety.