Biochemical indicators for novel forest decline in spruce

The impact of air pollution on 24 stands of spruce trees in several regions in Germany was investigated. We looked for evidence of biochemical and physiological change at the level of the photosynthetic thylakoid membranes as well as for changes in the antioxidative system in two year old needles. We observed that, as the chlorophyll content decreases in the needles, the amoung of D1 protein declines far more rapidly in relation to the redox components P700 and cytochrome f. Consequently, the PSII/PSI stoichiometry keeps dropping to pregressively lower, meaning unfavorable, values at the chlorophyll content diminishes. This is particularly the case in the higher elevation characteristically increases while the D1 protein content falls. The higher α-tocopherol values, however, are obviously neither able to protect the D1 protein from degradation nor to compensate for the higher oxidative stress. Apart from that the ascorbate/tocopherol ratios remained in the majority of cases in the unfavorable range of far below 10, where an effective protection of the membranes from free radicals is not guranteed. This then is mirrored in the increased degradation of D1 and the lower PSII/PSI ratio.