Native populations of endemic, rare and threatened Limonium species (L. meyeri, L. bulgaricum, L. latifolium, L. vulgare, L. asterotrichum and L. gmelinii) in Bulgaria were monitored and found seriously declined. To preserve these wild genotypes, an approach involving in vitro propagation of explants isolated from immature inflorescence stems was applied at the Institute of Ornamental Plants, Sofia. The rooted plantlets produced were acclimated and grown outdoors under an optimized cultivation regime, which resulted in the establishment of an ex situ plantation. Plant performance ex situ (determined by leaf rosette diameter, plant height and the number of flower stems) was substantially improved and the variation in the biometric indices was found remarkably lower than in natural environment. The developmental stages of ex situ plants appeared with a delay in relation to their onset in the native environment, but occurred synchronously within each species. Analysis of germination of seeds harvested from ex situ and in situ grown plants showed species-specific behaviour, but in general, seed vitality remained relatively low in laboratory conditions, in the soil and in vitro. In order to assess the potential for protecting the native Limonium species from uncontrolled harvesting, the possibility for the production of cut flowers in ex situ conditions was studied. High yield of cut flowers from ex situ plants in comparison with the potential yield from the wild plants and extended vase life in comparison with commercially produced Limonium sinuatum were obtained. The results demonstrated that the applied micropropagation and agrotechnique for protected cultivation are reliable tools for ex situ conservation of the endangered Limonium genotypes in the Bulgarian flora. In addition to its advantage as a rescue measure, the developed system was shown to be suitable for obtaining cut flowers of competitive market quality.
