Application of stable isotopes in plant iron research

Abstract

Stable isotopes offer an excellent and safe tool to study uptake and metabolic processes in Fe plant research. Iron stable isotopes (54Fe, 56Fe, 57Fe and 58Fe) can be used either in fractionation or in tracer studies. Although fractionation studies based on Fe isotopic distribution in natural materials have been scarce, valuable information has been already obtained. Iron isotopic fractionation could document Fe transport by organic molecules, microorganisms and possibly plants in the geologic past. Iron tracer studies have been carried out so far in plant research using radioisotopes (especially 59Fe and 55Fe). These studies have been focused on the uptake and breakdown of synthetic or natural chelates, as well as on the shoot translocation rates of the Fe supplied by those compounds. The trend in the coming years for plant Fe nutrition research will be to shift away from high-risk Fe radioisotopes, and use instead enriched Fe stable isotopes, since the analytical techniques used for their quantification are improving progressively. Also, Fe isotope costs are becoming more affordable. Different possibilities to use stable isotopes in Fe plant studies are proposed, in an attempt to suggest new ways to study Fe deficiency in plants. Furthermore, the possible use of other stable isotopes, such as 13C, 15N and others, in plant Fe studies is discussed. © 2006 Springer.