Hoechst 33258 as a vital stain for plant cell protoplasts.

A method for staining nuclei in unfixed protoplasts using Hoechst 33258 is described. It was found that the dye was not taken up by all protoplasts except in the presence of a detergent and that the staining of the nuclei was pH- and concentration-dependent. The use of vital fluorescent probes with plant protoplasts may be helpful for the identification, selection and subsequent culture of hybrid fusion products in automatic cell sorting systems.