Efeito de diferentes suplementos adicionados no cultivo in vitro do híbrido de Laeliacattleya

Abstract

The effects caused by the addition of different combinations and concentrations of growth regulators and of different supplements added to the nutrition medium for in vitro growth and development of plants of the orchid hybrid, Laeliacattleya, from species crossing of Hadrolaelia purpurata Lindl. (Chiron; Castro) Cattleya intermedia Grah. are provided. Research aims at discovering effects which are equivalent to added supplements with combinations of growth regulators. Six-month-old plants were inoculated in KC culture medium and supplemented with coconut water (100 ml.L-1), banana pulp (90 g.L-1) and diallelic combinations (0,0; 0,5; 1,0; 1,5 mg.L-1) of growth regulators (ANA, IBA, KIN and 6-BA). After 8 months of culture, the addition of banana pulp reproduced the effects of auxins (IBA or NAA) in KC culture medium for the plants' development and the addition of coconut water simulated the effects of cytokinines addition (6BA and KIN). IBA or NAA combinations with KIN were more adequate to enhance in vitro plant development in KC medium than the combinations of auxins with 6-BA. On the other hand, composition made up of banana pulp or coconut water demonstrated an additional effect which potentializes the effects of growth regulators and thus triggers a higher number of roots, leaves and buds and enhances a greater growth in roots and leaves. Addition of coconut water stimulated the production of buds and a greater number of leaves and warranted a low pH in the culture medium. Results show that the most adequate form in stimulating the complete in vitro growth and development of Laeliacattleya hybrid plant by reproducible procedures is the addition of different auxins and cytokinines and, in the case of commercial outputs, the supplementation of KC medium with banana pulp and coconut water, together or in separate.