Two cytoplasmic features of prophase in wheat root cells

Summary A study has been made of prophase in cells of wheat root. An advanced stage in the preparation of the mitotic spindle structure prior to nuclear membrane breakdown is described. The pre-prophase band of microtubules is found to be present in cells containing such cytoplasmic features of late prophase. Also at this time a vesicle-filled area is seen within the nucleus. This area is outside the nuclear membrane but isolated from the cytoplasm by conducting channels. It is proposed that this structure represents a mechanism for the transport of material from the nucleus into the cytoplasm.