Feulgen, iron-propionocarmine and cupra-ammonium in preparing algal chromosomes for light microscopy

A method for obtaining algal chromosomal preparations is described employing the Feulgen 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 side provides cells stained with the Feulgen stain alone or with the Feulgen Fe-propionocarmine stain, thereby facilitating useful comparison. Where dilute the Fe-propionocarmine enhances nuclear staining without staining orthe organelles; where more concentration 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.