Feulgen iron propiono carmine and cupra ammonium in preparing algal chromosomes for light microscopy

A method for obtaining algal chromosomal preparations is described employing the Fuelgen method for DNA staining, Fe-propionocarmine as an enhancing stain, and cupra-ammonium to remove cell wall material. Fe-propionocarmine applied as a gradient to the slide provides cells stained with the Feulgen stain alone or with the Fuelgen Fe-propionocarmine stain, thereby facilitating useful comparison. Where dilute, the Fe-propionocarmine enhances nuclear staining without staining other organelles; where more concentrated, it also stains the nucleolus, spindle, spindle polar bodies, pyrenoid and protoplast. Treatment with cupra-ammonium, to remove polysaccharide wall material, followed by neutralization with propionocarmine, enables thinner squashes and better chromosome spreads without loss of differential staining. Preparations mounted in euparal are long-lasting.