Changes in elemental uptake and arbuscular mycorrhizal colonisation during the life cycle of Thlaspi praecox Wulfen

Elemental uptake and arbuscular mycorrhizal (AM) colonisation were studied during the life cycle of field collected Cd/Zn hyperaccumulating Thlaspi praecox (Brassicaceae). Plant biomass and tissue concentrations of Cd, Pb, Zn, Fe and Ni were found to vary during development, while no variation in P, K, Ca, Mn and Cu tissue concentrations were observed. The lowest Cd bioaccumulation in rosette leaves (BAFRL) observed during seeding was partially attributed to lower translocation from roots to rosette leaves and partially to high translocation to stalks, indicating a high Cd mobility to reproductive tissues, in line with our previous studies. The highest intensity of AM colonisation (M%) was observed in the flowering phase and was accompanied by increased root Cd, Zn, Pb and Fe contents. In addition, a positive correlation between AM colonisation and Fe contents in rosette leaves was found. The results indicate developmental dependence of AM formation, accompanied by selective changes in nutrient acquisition in T. praecox that are related to increased plant needs, and the protective role of AM colonisation on metal polluted sites during the reproductive period.