Influence of Cd(II), Cr(VI) and Fe(III) on early steps of deetiolation process in wheat: fluorescence spectral changes of protochlorophyllide and newly formed chlorophyllide

Destruction of the phototransformable Pchlide655 leading to the lower efficiency of Pchlide to Chlide phototransformation was observed. This effect was more pronounced in the case of Cd(II) than for Cr(VI) and it was the lowest for Fe(III). The maximum of the fluorescence band of the newly formed Chlide in metal-treated samples was blue-shifted with respect to the untreated sample. The shift depended on the concentration of metal ions as well as on the time of incubation, and it was the largest for Cd(II), smaller for Fe(III), and the lowest for Cr(VI). This, in consequence, decreases the time needed to complete the blue Shibata-shift like spectral changes of Chlide. Different mechanisms of action of the investigated metal ions are discussed.