Cadmium lets increase the glutathione pool in bryophytes

Glutathione (GSH) plays an important role in protecting plants from environ mental stresses like oxidative stress and xenobiotics. Glutathione-derived peptides are involved in heavy metal detoxification in plants and fungi. Te rrestrial and aquatic bryophytes were investigated for their biochemical re sponse to heavy metals. The GSH pool increased significantly in the first t wo days after supply of 100 mu mol/L Cd(II). PCs were not detected. Cd(II) also induced the enhancement of the GSH pool in the water moss Fontinalis a ntipyretica. Cysteine and gamma -glutamyl-cysteine also increased during Cd (II) treatment, but remained on a lower level. Uptake experiments with Cd(I I) showed a fast regulation of equilibrium between the Cd(II) content of th e medium and the plant surface, followed by a slow migration of Cd(II) to i ntracellular sites. The main storage compartment or heavy metals in Fontina lis ate the vacuoles, where they are precipitated as phosphates. In the cyt oplasm, the S-content increased during Cd(II) exposition. EEL-spectra indic ate that in the cytoplasm, Cd(II) is chelated by SH-groups. All findings su pport the idea that in the investigated moss species, GSH plays an essentia l role in heavy metal detoxification during the transport of the metals thr ough the cytoplasm.