EN
There are many unsolved taxonomic problems at the intraspecific level in the genus Thalictrum (Ranunculaceae), which may be clarified using molecular systematics methods. No molecular systematics methods have been applied yet to the genus Thalictrum; this study analyzes different leaf tissue preservation and DNA isolation techniques, and the applicability of RAPD. A modified DNA isolation procedure using solution of laundry detergent as a detergent buffer system was the most suitable, especially for dealing with large samples. Since the use of differently preserved leaf tissues simultaneously with fresh leaf tissue may improve sampling in taxonomic research, and because the RAPD technique is sensitive to different factors, the possible drawbacks of using such tissues in RAPD analyses were checked. Of the four preserved leaf tissues, only DNA from silica gel-preserved leaf tissue gave suitably reliable RAPD results to be used with fresh leaf tissue in more extensive taxonomic research. Differently preserved leaf tissues are very problematic starting materials for simultaneous use with fresh leaf tissue in the same RAPD analysis. If differently preserved leaf tissues are to be used and reliable results are to be obtained, research techniques similar to those used in this paper should be applied.