The differential bandings of the M-chromosome of Vicia faba, produced
in the period from prophase to metaphase of the mitotic cycle, has bee
n studied by means of pretreatment with low positive temperatures. Sta
ining was performed with the fluorochromes Hoechst 33258 and olivomyci
n and with acetocarmine. The result is a stable picture of differentia
l banding of euchromatic regions similar to the G- or R-type bandings
of animal chromosomes. About 15/17 bands, depending on staining, have
been identified and charted. There is an inversely proportional relati
on between the degree of condensation of the bands during prophase and
the fluorescence intensity of the dye Hoechst 33258.