Uptake, Assimilation and Translocation of Mineral Elements in Monoxenic Cultivation Systems

This chapter synthesize available information on the in vitro studies on element uptake and translocation by AM fungi. Compartmented monoxenic cultures using root-organ culture system were shown to be useful in studies involving essential elements such as P and N, and nonessential ones such as radionuclides U and Cs. Results published showed that AM fungi are able to take up and to translocate these elements. However, the relative extent of this process depend on the nature of the element and on other factors such as the chemical composition of the growth medium. The uptake of radionuclide by the extraradical mycelium has an ecological significance as AM fungi are part of the rhizospheric biomass. This indicates that mycorrhizal fungi can play an important role in the interception of radionuclides with an influence on their migration in the soil profile and on their accumulation by growing plants. The root-organ culture system could be also used to characterise different fungi with respect to transport efficiency, to study the capacity of fungi to exploit certain forms of a nutrient (precipitated P, organic forms of N or P) and to verify transport of elements for which mycorrhizal transport is less well or not yet documented. The latter may also relate to minimum concentrations necessary to induce/activate specific membrane transporters.