Many aspects of studying roots and root-associated microorganisms require knowledge on the concentrations and distribution of elements, to understand the uptake and transport of ions and their roles in metabolic processes and water relationships. This chapter deals with classical and modern analytical methods to quantify elements in the roots, to localize and visualise the distribution of elements (e.g. heavy metals) in the roots and mycorrhizas. The following methods are covered in this chapter:
• plant digests
• elemental and ionic analysis of digests
• histochemical methods
• X-ray microanalytical methods

Specific contribution to rhizosphere research
None of these methods have been developed specifically for rhizosphere related question. However, elemental contents in roots and mycorrhizal fungi are often determined with the aid of these methods.