Cytoplasmic streaming. Coloured light micrograph (LM) of a section through some onion cells, Allium cepa, showing cytoplasmic streaming. Strands of cytoplasm can be seen in the cell at centre. Cytoplasmic streaming, or cyclosis, is the mechanism by which general transport and solute movement takes place within the cell. This two-way process is aided by protein microtubules of the cell's cytoskeleton. Cellular transport also occurs by diffusion. The cytoplasm is a viscous fluid inside the cell wall that surrounds the nucleus and other cell contents. Differential interference contrast. Magnification: x330 at 35mm size.