INVESTIGATION ON THE GENETIC DIVERSITY OF PHRAGMITES STANDS USING GENOMIC FINGERPRINTING

The genetic diversity of stable and declining stands of Phragmites australis (Cav.) Trin. ex Steud. was investigated at various sites. DNA and polymerase chain reaction (PCR) fingerprinting were used to differentiate genotypes. Some sites are inhabited by homogeneous Phragmites stands, suggesting they consist of clones (genets, polycormones). Other sites are inhabited by several different clones. Reed stands at different lakes so far investigated exhibit different genotypes. The results support a new hypothesis about the causes of reed belt decline at many European lakes: it is supposed that the stability of reed stands is related to genetic diversity. Monoclonal stands should be limited in their adaptive response to changing site conditions. Recolonization of sites with changed conditions by well-adapted genotypes is difficult because of the preferentially vegetative propagation of littoral reed. The well-documented fact that reed belt decline is not restricted to eutrophic sites corresponds to the eutrophication hypothesis of reed belt decline if eutrophication is understood as a process of changing site conditions independent of the original status.