Meios de cultivo e sistemas de micropropagação no crescimento in vitro e estabelecimento ex vitro de orquídeas nativas do Cerrado

Abstract

The Orchidaceae family has great representation in the Brazilian Cerrado, however, the beauty and diversity of its flowers makes some species suffer predatory collection. One way to reduce the vulnerability of these orchids due to extractivism is commercial production. Thus, the objective was to evaluate the production and conservation of three native species from the Cerrado, through in vitro cultivation techniques. Two experiments were carried out at the Laboratory of In vitro Cultivation of Flowers and Ornamental Plants, one of them in partnership with the Laboratory of Biotechnology and Genetic Improvement of Sugarcane, both from the Faculty of Agricultural Sciences (FCA) of the Universidade Federal da Grande Dourados (UFGD). The first experiment aimed to evaluate the in vitro growth of Cattleya nobilior Rchb.f., Cattleya walkeriana Gardner and Schomburgkia crispa Lindl., cultivated by different systems of myxotrophic in vitro culture system that allows gas exchange, using culture media supplemented with different organic materials without addition sucrose (1) MS; 2) MS + banana pulp (PB); 3) MS + coconut water (AC); 4) MS + banana flour (FB); 5) MS + PB + AC; 6) MS + FB + AC), as well as ex vitro establishment. For C. nobilior, the MS medium combined with banana pulp and coconut water provided the greatest in vitro growth and ex vitro establishment of the plants. For C. walkeriana, the cultivation in MS medium supplemented only with coconut water was favorable for the in vitro growth and acclimatization of the seedlings. For S. crispa, the culture medium that favored both in vitro growth and acclimatization of plants was MS supplemented with banana pulp. The second experiment aimed to evaluate the in vitro growth of C. nobilior cultivated in different micropropagation systems (1) conventional system (SC); 2) temporary immersion bioreactor (BIT)) and culture media (1) MS; 2) MS + banana pulp (PB); 3) MS + coconut water (AC); 4) MS + PB + AC), in addition to the ex vitro establishment of plants from in vitro cultivation. Cultivation in a temporary immersion bioreactor using MS medium supplemented with banana pulp promoted growth, both in in vitro cultivation and in the acclimatization of seedlings. In this way, cultivation in a bioreactor using MS + PB medium is recommended both for in vitro growth and for the ex vitro establishment of C. nobilior.