Comparative molecular studies on the genetic diversity of an ex situ garden collection and its source population of the critically endangered polish endemic plant Cochlearia polonica E. Fröhlich

Abstract

Cochlearia polonica (Brassicaceae) is a narrow endemic plant extinct in the wild, known only from one transplanted population in southern Poland. The suitable habitats for this species are confined to shallow water courses and springs on sandy ground. During the second half of twentieth century the natural populations of C. polonica declined due to anthropogenic effects (primarily due to a major change of ground water levels). Consequently, 14 individuals were transplanted in the 1970 s into a secondary locality of similar habitat conditions of Centuria river. In the late 1980s five individuals from the transplanted population were used to establish an artificial ex situ site in the Botanical Garden of the Polish Academy of Sciences in Warsaw. In order to investigate the effect of 18 years of ex situ conservation, the level of genetic diversity and genetic structure of the ex situ conserved botanical garden population and its source population were sampled and analyzed using inter simple sequence repeat markers. The percentage values of polymorphic bands and Nei’s gene diversity indicated average genetic variation at species level, whereas at the population level it was relatively low, especially for the garden population. The results suggested differences in genetic composition of the analyzed populations and implied homogenization of the genetic structure of the ex situ conserved population. Ex situ conservation resulted in a decrease of the species’ genetic diversity, implying that the artificial population only partly represents the primary genetic variability found in the source population.