Immunogold localization of intra- and extra-cellular proteins and polysaccharides of plant cells

This paper illustrates post-embedding immunogold labelling of protein and polysaccharide molecules of plant cells. For EM studies, one is restricted (for most plant cells) to the post-embedding approach because the surrounding cell wall prevents access of antibodies (and secondary gold-tagged markers) to internal sites. The large size of many plant cells also does not lend itself to diffusional entry of antibodies. The molecules localized include seed storage proteins that are large and present in major quantities, a smaller less abundant, water soluble albumin, an oxygen-binding protein, components of the photosynthetic electron transport chain, and complex sugars from the cell wall. A range of preparative procedures and embedding plastics are used.