Utilização de macroalgas marinhas no cultivo in vitro de plantas

Abstract

In Brazil, activities connected to agricultural production have been intensified over the years. The increased search for plants with medical properties highly demanded for seedlings of Physalis peruviana L. due to its fruits nutraceutical potential. In parallel, the floristic sector is also rapidly growing, and among the main commercially explored dry flowers are the species of the genus Comanthera L. B. Sm. The extractive exploitation of the market led to a significant reduction of natural populations of Comanthera mucugensis (Giul.) L.R.Parra & Giul., the “sempre-viva of Mucugê”, placing it at risk of extinction. The development of pant tissue culture techniques has been one of the most significant contributions to the advance of the multiplication process of species with high commercial value and/or in the process of extinction. Besides the production of plants in large scale, it constitutes an option for ex situ conservation of vegetal genetic resources throughout in vitro conservation. Although it presents significant potential, in vitro cultivation of plants is associated to a high cost of production. As an alternative method, this work studied the effects of supplementation in nutritional medium with extracts of three marine seaweeds, Agardhiella subulata (C.Agardh) Kraft & M.J.Wynne, Hypnea pseudomusciformis Nauer, Cassano & M.C. Oliveira and Gracilaria sp. in the in vitro cultivation of C. mucugensis and P. peruviana. The use of A. subulata extract in high concentrations reduces the growth of P. peruviana, as well as the production and biomass of regenerated sprouts via direct organogenesis; however, supplementation in low concentration produces more vigorous sprouts. The extract also reduces the growth of C. mucugensis and induces the formation of sprouts by direct organogenesis, especially in higher concentrations. The supplementation with Gracilaria sp. extract promotes higher production of sprouts by plants, while H. pseudomusciformis extract increases the width of “sempre-viva” sprouts. This is the first report of studies using Brazilian seaweeds in plants tissue culture. The obtained results contribute to the establishment of new methods of spread and in vitro conservation of P. peruviana of C. mucugensis. Finally, we recommend studies of biochemical and molecular characterization of physiological responses induced by seaweeds extract in order to understand the mechanisms of action behind theses effects, still unknown.