Influence of arbuscular mycorrhiza and cadmium on the polyamine contents of Ri T-DNA transformed Daucus carota L. root cultures

Abstract

Influence of arbuscular mycorrhizal (AM) colonisation on free polyamine (PA) contents and ratios was investigated in vitro by Ri T-DNA transformed root cultures (Daucus carota L. and Glomus intraradices Schenck & Smith) under Cd-treatment. Roots were soaked in Cd(NO3)2 solutions of 3x10-6 M and 5x10-5 M concentrations for 6 hours. Roots were strongly colonised and their Cd-content increased in case of the higher Cd-treatment only. In contrast to earlier results, Cd treatment reduced putrescine and spermidine contents of the non-mycorrhizal (NM) Daucus carota roots, whereas that of mycorrhizal (M) roots did not change. Spermine content showed a slight increase in all cases. NM roots always had higher PA ratios. AM symbiosis may have established a more equalised environment for the roots and so decreased the volume of physiological responses induced by stress conditions, which are normally reflected by strong changes in polyamine contents.