This image shows microfilaments (in green) and cell nuclei (in red) of developing wood cells in poplar. Microfilaments are key components that make up the cytoskeleton in both plants and animals. In plants, the cytoskeleton is specialised for particular functions. Due to their lack of colour and small size, cytoskeletal components are usually studied after having been 'labelled' with antibodies containing fluorescence markers. Excitation of these markers using lasers in a confocal microscope allows them to be viewed.
This image shows the cells that will increase in length to run from the outside of the tree's trunk towards the inside (the ray cells, which are observed looking like the spokes of a wheel looking down at a cut tree stump) along with other cells that will increase in length parallel to trunk. In both cases the direction of cell extension is mirrored by the arrangement of the microfilaments. However, it is sill undetermined whether the microfilaments are actively involved in this cell extension.
