A Comparison of the Methods of X-ray Microanalysis, Compartmental Analysis and Longitudional Ion Profiles to Estimate Cytoplasmic Ion Concentrations in Two Maize Varieties

The ion content of compartments within plant root cells has been studied by three different methods; flux analysis using radioactive isotopes, longitudinal ion profiles and X-ray microanalysis. The data provide estimates of the concentrations of K+ and CI- in the cytoplasm of roots of culture solution and salt grown maize by three independent methods. In the cultivar LG11 grown in 50 mol m-3 NaCl X-ray microanalysis, compartmental analysis and longitudinal profiles yielded approximately agreeing values for cytoplasmic K+ of 90, 70 and 62 mol m-33 of tissue volume respectively. However, the methods disagreed on cytoplasmic Cl- where the value obtained by compartmental analysis was about four times that from X-ray microanalysis and longitudinal profiles. Possible reasons for this are discussed.