Colchicine-induced heritable variation in cell size and chloroplast numbers in leaf mesophyll cells of diploid ryegrass (Lolium perenne L.)

Summary

A 3 hr treatment period with a 0.2% aqueous solution of colchicine was given to one week old seedlings of imbred lines of perennial ryegrass (Lolium perenne L.). The surviving plants developed as mixoploids and were subsequently split down into single tillers and then classified as either diploid or tetraploid. The undoubled diploids of the treated material (C2x) were then self-pollinated and the seeds grown in the following generation (CT1) without any further treatment. In the CT1 generation comparisons were made between the C2x and the control 2x treatments within the same inbred lines, and heritable differences were found for leaf mesophyll cell plan areas and chloroplast numbers. The cell areas were significantly less in the C2x compared with the 2x treatment in four out of the five lines studied, and the chloroplasts numbers were likewise lower in two out of the five lines. In one line there was a significantly higher mean number of chloroplasts per cell in the C2x material compared with that of the 2x.