Baixas concentrações de macronutrientes beneficiam a propagação in vitro de Vriesea incurvata (Bromeliaceae), uma espécie endêmica da Floresta Atlântica, Brasil

Abstract

A cultura in vitro é uma ferramenta eficiente para a propagação de plantas de importância ecológica e econômica e permite o entendimento acerca de aspectos ecofisiológicos das espécies. Este estudo teve por objetivo avaliar a influência de diferentes concentrações de macronutrientes sobre o desenvolvimento in vitro e a sobrevivência ex vitro de plântulas de Vriesea incurvata, visando à conservação desta bromélia epifítica endêmica da Floresta Atlântica. A germinação in vitro foi avaliada aos 60 dias e as plântulas foram cultivadas por 180 dias em meio MS com 25 ou 50% dos macronutrientes, 25 ou 50% dos sais nitrogenados, bem como com 100% da formulação original do meio. As sementes apresentaram 95% de germinação. Em todos os tratamentos, houve 100% de sobrevivência das plântulas cultivadas in vitro. A redução de todos os macronutrientes ou dos sais nitrogenados mostrou-se benéfica, proporcionando maior comprimento da parte aérea e da raiz maior, maior número de folhas e de raízes, bem como maior massa fresca, além de ter propiciado 97% de sobrevivência das plântulas aclimatizadas ex vitro. Os dados obtidos permitem o estabelecimento de um protocolo de propagação in vitro de V. incurvata, com o objetivo de sua futura reintrodução no habitat natural. Palavras-chave: bromélias, conservação, micropropagação, nutrição mineral. AbstractIn vitro culture is an efficient tool for the propagation of plants of ecological and economic importance and allows the understanding about ecophysiological aspects of the species. The objective of this study was to assess the influence of different macronutrient concentrations on in vitro development and ex vitro survival of Vriesea incurvata plantlets, aiming the conservation of this endemic epiphytic bromeliad from the Atlantic Forest. The in vitro germination was assessed at 60 days and the plantlets were cultivated for 180 days on MS medium with 25 or 50% of the macronutrients, 25 or 50% of the nitrogen salts, or with 100% of the original formulation of the medium. The seeds showed 95% germination. In all treatments, there was 100% survival of in vitro cultivated plantlets. The reduction of all macronutrients or of the nitrogen salts was beneficial, and permitted a greater length of the aerial part and of the major root, a higher number of leaves and roots, and more fresh mass, as well as allowed 97% survival of ex vitro acclimatized plantlets. The obtained data allow the establishment of a protocol for in vitro propagation of V. incurvata, aiming its future reintroduction into the natural habitat.

Conservation of Vriesea flammea L.B.Sm., an endemic Brazilian bromeliad: effects of nutrients and carbon source on plant development

“…The methodologies used for sterilization of V. flammea seeds provided high rates of germination in vitro, comparable to the rates for other species of in vitro germinated bromeliads (Mekers, 1977;Mercier and Kerbauy, 1995;Bencke and Droste, 2008;Sasamori et al, 2016). Despite the success in germination rate, the use of sterile capsules to obtain plants from seeds germinated in vitro was not very feasible since it led to a high degree of contamination of seeds by fungi and bacteria.…”

“…Vriesea gigantea Gaudich., V. philippocoburgii Wawra and V. incurvata Gaudich. have been micropropagated only by means of sterilization of the capsules, optimizing the process for the cultivation of species with high germination rates (Droste et al, 2005;Sasamori et al, 2016). The presence of small holes in the capsule made by insects or the entrance of microorganisms according to the characteristic of the pericarp of the fruit of V. flammea during ripening may be contributing factors for the contamination of seed during micropropagation.…”

“…The results recorded for V. flammea corroborate the findings made for other species of bromeliads such as Aechmea blanchetiana (Baker) L.B.Sm., A. bromeliifolia (Rudge) Baker, Alcantarea imperialis (Carrière) Harms, Nidularium minutum Mez and Vriesea incurvata, which also showed higher development of morphometric parameters when grown with low concentrations of nutrients in the culture medium (Fráguas et al, 2002;Kanashiro et al, 2007;Sasamori et al, 2016). Because it contains higher amounts of mineral nutrients than other culture media, dilutions of the original formulation of MS medium (Murashige and Skoog, 1962) have been widely used for the propagation of various plant species (Fráguas et al, 2002;Endres Júnior et al, 2014;Sasamori et al, 2015Sasamori et al, , 2016.…”

Propagation of Dyckia vicentensis, an endemic bromeliad of the Pampa biome, Brazil

“…Several studies have shown the advantages of in vitro cultivation of other species of Dyckia (Pompelli & Guerra 2005;Silva et al 2008). Moreover, in a recent study carried out by Sasamori et al (2016) with Vriesea incurvata (Bromeliaceae), the in vitro germinated plantlets also showed high survival rate during acclimatization. In this study, it was also found that the reduction of all Due to the high degree of threat of extinction of the native bromeliads, studies related to their biology, propagation, and management together with the creation of areas of environmental protection for the in situ conservation should be priority actions.…”

“…1). In other bromeliads, such as Vriesea recurvata, the reduction of MS salt concentrations and the active charcoal (5 g L -1 ) were beneficial for in vitro germination, development, and acclimatization of the plants (Sasamori et al 2016). However, in other species of Dyckia, such as D. distachya (Pompelli & Guerra 2005) and D. maritima (Silva et al 2008), the MS medium with 100% salt concentration was used for in vitro germination.…”