EPR investigation of Mn(II), Fe(III) and free radical centers in green parts of living plants. Effects of environmental pollution

The needles of spruce and other conifers were investigated by using EPR spectroscopy. Contrary to previous studies, examples of weakened and diseased spruces exhibiting strong manganese(II) signals were found. This situation was found for trees damaged by acid rains in south-west Poland. For weakened spruces and pines from other regions the manganese(II) signal of decreased intensity and free radical signals were observed. Such trees also exhibited iron(III) signal, which appears to, be another indicator of reduced vitality. The influence of harmful agents on living plant parts was investigated on the basis of free radical EPR spectra.