A simple and rapid technique for the immunofluorescence confocal microscopy of intact Arabidopsis root tips.

Visualisation of immunofluorescence labelling of Arabidopsis roots has previously been limited to single cell layers. A simple, rapid method has been devised in which the whole root can be processed to allow antibody penetration into several cell layers. When optically sectioned using confocal microscopy, cellular arrangements of microtubules, callose, calmodulin and a phosphoprotein epitope have been visualised using this technique. As the root is not physically sectioned, information regarding the three-dimensional position of individual cells in relation to each other and the tissue as a whole is retained. Using this technique, we have assessed the effect of brefeldin A on the frequency of mitotic arrays in root tip cortical and epidermal cells, and found that the occurrence of phragmoplasts increases significantly with brefeldin A treatment. This study demonstrates the possible future use of the whole root technique to assess rapidly the developmental, mutational and inhibitor-induced changes in the organisation of cellular components in Arabidopsis.