DIFFERENTIAL STAINING OF THE CELL ORGANELLES OF ALLIUM CEPA USING A NEW FIXATIVE AND A NEW STAIN

Abstract

The reactions of the root-tip cells of Allium cepa, fixed in Iodine-Formaldehyde-acetic(I.F.A.), Acetic alcohol and Navashin's fluid to Giemsa stain are compared with those obtained after staining with Methyl green-Pyronin I.F. A.gives optimal preservation of the cell organelles but differs from Acetic alcohol In that it accentuates the blue colour of Giemsa and the red of Methyl green - Pyronin.The red colour of Gremsa is transient in material fixed in navashin for one hour
and absent in those fixed for twenty - four hours.The differential staining with Methyl green-Pyronin, was observed only when the time of fixation in navashin was limited to one hour.

The nucleus and the chromosomes in prophase and late telophases are stained purple red by Giemsa and bluish green by Methyl green-pyronin. The chromosomes at other phases of division have a slightly darker shade. The nuclear membrane, the nucleoli, the cytoplasm, the achromatic figure and especially the phragmoplast are blue in Giemsa and red in Methyl green - Pyronin. The cell plate which is unstained in early stages of formation stains in late telophase.