Use of CE to Analyze Solutes in Pico- and Nano-Liter Samples from Plant Cells and Rhizosphere

This chapter describes the use of capillary electrophoresis (CE) in the accurate quantitative mapping of small molecules and ions in intact function tissues between individual cells at single cell resolution. It can also be used for the analysis of the heterogeneity of soil surrounding roots at similar spatial resolution, providing a link between plant and environment. No pretreatment or genetic manipulation of the plant is required. The application is an extension of the Single Cell Sampling and Analysis technique (SiCSA), in which glass micromanipulation of microcapillaries allows samples in the pl and nl volume range to be obtained and manipulated under paraffin oil (to prevent evaporation) before being introduced to the CE column. An advantage of this approach is that the entire sample can be brought to the detector (without the loading losses associated with other techniques). The power of SiCSA-CE is that the results can be directly related to a range of other single-cell resolution parameters ranging from mechanical and hydraulic properties to gene expression. Several protocols and (contrasting) applications are provided.