Propagação e conservação in vitro de Vriesea sucrei (L.B. Smith & R.W. Read): Bromeliaceae em perigo de extinção da Mata Atlântica

• Autor(a) principal: Pessotti, Kamila Vilas
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/9977
• topic: Conservation; Propagation; Conservação; Vriesea sucrei; In vitro; Agronomia; Bromeliacea; Plantas - Propagação in vitro; 57

The in vitro propagation techniques allow the production of large numbers of uniform plantlets, with high physiological and phytosanitarian quality. Thus, it enables a rapid and genetically reliable multiplication, as well as the preservation of species threatened of extinction. The objective of the present study was to establish a protocol for the in vitro and ex situ propagation and conservation of Vriesea sucrei, in order to implant a germoplasm bank for this Bromeliaceae threatened of extinction. Seeds of V. sucrei were inoculated in vitro on culture mediums and substrates. Seven different germination treatments were tested: MS liquid, MS gelled, K liquid, K gelled, washed sand, coconut fiber and control (distilled water). Germination and survival percentages, as well as the germination speed index (GSI), were calculated. Initial growth measurements, such as height and number of leaves, were registered. Plantlets deriving from in vitro germination were submitted to conservation treatments, consisting of a factorial combination (2x3x2x2) of the following physiological variables: culture medium formulation (MS and K), concentration of macro and micronutrients of the culture medium (1, ½ and ¼), physical state of the culture medium (gelled and liquid) and incubation temperature (15°C and 25°C). The surviva l rate, increment in height, number of leaves, number of roots, length of the longest root, chlorophyll content and anatomical leaf structure were evaluated after 120 days in culture. V.sucrei plantlets with six months of age, obtained from in vitro germination, were used as explants to induce lateral buds. Lateral bud induction treatments consisted of a factorial combination (2x2x4) of two culture mediums (MS and K), two physical states of the culture medium (gelled and liquid) and four combinations of auxins (IAA and NAA), cytokinins (cinetin and BAP) and one amine (adenine) in different proportions. Multiplication efficiency was calculated as the percentage of seedlings that gave rise to adventitious shoots as well as the mean number of shoots/seedling. The in vitro germination of V. sucrei seeds on MS liquid medium, K liquid medium, sand and control were equally efficient, presenting high GSI, germination and survival rates. Treatments containing nutritive media (MS liquid and K liquid) would be the most indicated to obtain plants with a more vigorous initial growth in height and number of leaves. The natural slow growth of the species V. sucrei favored its conservation in in vitro germplasm banks. The low temperature of 15°C was t he main factor that determined the reduction of the in vitro growth, without, however, compromising the survival rates. The ½ MS liquid medium at 15°C presented high survival rate, plants with diminished growth, high chlorophyll content and anatomical leaf structure with no abnormalities. These results suggest that this treatment would be the most indicated to implant an in vitro germplasm bank for V. sucrei. As for the lateral bud induction experiment, MS liquid media supplemented with 0,5 mg/L ANA and 2 mg/L BAP gave rise to a higher percentage of plants with lateral buds and also a higher number of lateral buds/plant. However, all treatments tested generated a low number of lateral buds/plant.