In Vitro Establishment and Acclimatization of Two Threatened Species of the Genus Eugenia (Myrtaceae)

Eugenia squarrosa Ekman & Urban and Eugenia subdisticha Urban (Myrtaceae) are two threatened endemic species from Santa Clara province, Cuba. These species are considered as potential producers of important secondary metabolites. Their natural populations are damaged by human activities which has infringed their natural habitats. Due to the low percentage of seed germination, traditional propagation is very difficult. Therefore, in order to increase the seedling numbers, tissue culture techniques are a very attractive alternative. The aim of this work was to achieve the establishment in vitro cultivation and acclimatization of these species. Seeds from plants in their natural habitat (and also young branches of E. squarrosa) were collected. For disinfection of E. squarrosa seeds, the effect of three concentrations (2.0, 2.5 and 3.0%) of sodium hypochlorite (NaOCl) for 20 minutes was studied. Previous to the disinfection of buds with NaOCl (1, 2 and 3% for ten minutes) a treatment with alcohol (70%) during two minutes was carried out. For the disinfection of E. subdisticha seeds, the best treatment obtained with E. squarrosa (2% NaOCl during 20 minutes) was used. A culture medium with 50% Murashige - Skoog salts was employed. For both species 100% disinfection of seeds with all treatments studied was achieved. With E. squarrosa the highest percentage (88.6%) of explants free of contaminants was obtained by treatment with 3% NaOCl. However, the highest survivor rate (47.5%) was obtained with a lower concentration of NaOCl (2%). The germination percentage was 45% and 89.5% for E. squarrosa and E. subdisticha, respectively. For the acclimatization of both species, a substrate mixture of organic material and xeolite (80: 20) was used. During the acclimatization process, 38% of E. squarrosa and 75.6% of E. subdisticha plantlets survived.