Conservação in vitro de bromélias em condições de crescimento lento

Abstract

The Bromeliaceae concentrates species of plants typically tropical and subtropical of the Americas. Most of these specimens occur naturally in Brazil, where one of the family centers of diversity remains. Most of the individuals of this family display high ornamental potential, due to the great variability of colors and forms, making them responsible for a significant commercial volume in the floriculture branch. In addition, several species of the family are on different red lists of threat. The objective of the present work is to establish an in vitro germplasm bank of bromeliads for the purpose of conservation of these species under conditions of slow growth. Seeds of 57 species of bromeliads from different subfamilies were established in MS culture medium. Evaluations were carried out daily to verify the onset of germination. After 60 days of establishment, the percentage of germination and percentage of contamination were evaluated considering fungi and bacteria. For the conservation trials, 48 species were established at two growing temperatures (conservation room = 19 ± 1 ° C and growth room = 26 ± 1 ° C) and two concentrations of MS salts. Six months after planting, the following variables were evaluated: plant height in cm, number of green leaves, number of senescent leaves and number of roots. In general, the concentration of MS salts did not directly influence the development of the conserved plants. The plants incubated in a conservation room at a temperature of 19 ± 1 oC showed reduction of the cellular metabolism and consequently lower plant height and number of roots. It was possible to conserve 48 species of bromeliads for a period of six months without the need of subculture. Genotypic plasticity should be taken into account when considering the conservation of bromeliad germplasm.