Rumex acetosa L. is a dioecious flowering plant with well developed sex chromosome system: 2n = 12 + XX in the female plants and 2n = 12 + XY1Y2 in the male plants. To isolate sex-linked DNA, we carried out chromosome micromanipulation, followed by DOP-PCR, AFLP of the PCR products, reverse Southern hybridization and sequence analysis. From 500 AFLP specific clones, 13 X-chromosome and 5 Y-chromosome specific clones were obtained. Except one clone RADAX-239 ($underline{R}umex;underline{a}-underline{D}OP-PCR-underline{A}FLP-underline{Y}-chromosome;specific$), all clones appear to be R. acetosa plant-specific sequences and non-coding sequences. Southern blot analysis using these clones could not discriminate genomic DNAs either from male or female plants. Results of this study imply that both autosome-origin and degeneration of sex chromosomes are prevalent in plant systems.