Germinação de sementes de coroa-de-frade (Melocactus violaceus) visando a produção de mudas

Abstract

Melocactus violaceus (coroa-de-frade) is a native species of the family Cactaceae, and is cited as vulnerable on IUCN, LVFB and MMA The reproduction of Melocactus species in natural habitats occurs exclusively by seeds, each 10.000 germinating seeds naturally only one become plant. This presents slow growth and just come in the maturity after ten years. Occurrence areas of the which has been reduced due to habitat destruction and the over collection of this species for ornamental use. In the literature have many papers about cacti, however little is known about production systems. An ex situ propagation has been suggested as an alternative for conservation of these species become a low-cost alternative. The aim was to test the effect of different substrates and of gibberellin (GA3) action on the seed germination of the Melocactus violaceus. The experiment was conduct in greenhouse in Laboratory of the Conservation Biotechnology of Natives Species on University Federal of Rio Grande do Norte, Brazil. Were utilize two substrate conditions (vermiculite and sand+ organic materials) and three concentrations of the gibberellin (0 mg L-1, 500 mg L-1 e 1.000 mg L-1), in a completely randomized design with 4 replicates per treatment and 25 seeds. We avaliated germination percentage (PG), speed index (IVG) and mean germination time (TMG). The vermiculite substrate showed the biggest taxa of germination and greatest speed. There were significant differences between the substrates types in combination with gibberellin. In conclusion, the vermiculite is the most indicated for germination of the Melocactus violaceus.