Induction of tetraploidy in Juncus effusus by colchicine

Tetraploidy was induced in vitro in mat rush (Juncus effusus L.) cultivar Nonglin-4 by exposure to colchicine (0, 50, 100 and 500 mg dm^?3) for 6, 12 and 24 h. Flow cytometric analysis was used to confirm the ploidy level. Anatomical and ultrastructural analyses at cellular and subcellular levels in tetraploid and diploid control plants revealed differences between diploid and tetraploid plants. The leaf epidermis had larger stomata but lower stomatal density in tetraploid plants. In addition, mesophyll cells in tetraploid plants appeared more compact and showed less intercellular spaces along with increased size of vascular bundles. However, a significant reduction of chlorophyll content was observed in tetraploid plants that might be the result of structural modification in the lamellar membranes of chloroplasts.