Caracterização botânica, avaliação da germinação de sementes e regeneração de plantas de Brugmansia suaveolens (Willd.). Bercht. & J. Presl

Abstract

The knowledge of morphological and ecophysiological features ofBrugmansia suaveolens (Willd.).Bercht.& J. Presl is the first step towards the use of this species with biotechnological purpose. This study aimed to: 1) the morphological characteristics of specimens of B. suaveolens, 2) evaluation of in vitro germination rates under different conditions of seed´s treatment. 3) the establishment of an efficient regeneration protocol in B. suaveolens. We evaluated the rates of regeneration, the percentages of calli induction and calli size, germination of embryos, the number of embriogenic spots and the number of regenerated plantlets. As results, 22 individuals were collected and grouped into three different groups, differing only by flowers colors. The fruits showed mean values of: 975 mm long, 189 mm wide and 6.99 g of weight Seeds presented mean values of7 mm long, 6.00 mm width, 3.04 mm thicknessand mass of 0.39 g.The estimated period for initiation of the germination process without the presence of the tegument was 14 days. In all treatments there was an increased cumulative germination. Regarding the effect of pre-treatments can be observed that temperatures of 4 ºC and 50 ºC did not promote differences between treatments. Exposure to sulfuric acid and soaking the seeds in water for longer periods of reduced germination. The presence of gibberellic acid caused inhibition of embryo development in vitro. In the development of regeneration protocols, the establishment of plants from mature embryos of this species, the percentage of calli induction ranged from 26 to 100%, the ratio seedling / callus induced ranged from 0 to 0.84 and the efficiency of regeneration ranged from 0 to 32%. The dosages of 0.5 mg L-1 2.4 D and 1.0 mg L-1 KIN were more efficient regarding to calli induction, calli size, number of green spots points and regenerated plantlets. High concentrations of growth regulators (1 mg L-1 2-4 D and 1.0 mg L-1 KIN) were inhibitory to calli formation and regeneration, the absence of these regulators promoted the formation of calli but any plantlets of B.suaveolens were gotten