Studies on Redoxcomponents of the Thylakoid Membrane and on the Activities of Phosphoenolpyruvate Caroxylase and Glutamate Dehydrogenase of Spruce Trees in an Open-top Chamber Experiment

1997

S. 103-132

6 Tab., 9 Abb., zahlr. Lit. Ang.

Unselbständiges Werk

200104676

In order to study primary effects of anthropogeneous air pollutants on phenotypically healthy spruce trees (Picea abies (L.) Karst.), investigations were carried out as an open-top chamber experiment over a period of four years. Spruce trees growing in open-top chambers with unfiltered ambient air were compared to spruce trees standing in chambers with purified air. Trees standing outside in the vicinity of the chambers served as an open-air control. Our studies comprise the biochemical characterization of early changes in the composition of the thylakoid membranes and in the acitivities of phosphoenolpyruvate carboxylase and glutamate dehydrogenase. Under all conditions the content of chlorophyll a+b shows a typical annual course with a maximum in late summer. Appart from chamber-effects due to reduced light intensities, the following pollutant-induced changes can be observed: The annual mean of the chlorophyll a+b concentration decreases continuously in chamber trees with ambient air and in open-air trees from year to year. The chamber trees treated with filtered air, however, show a constant but lower content of chlorophyll a+b. An increased oxidation speed of antennae chlorophylls can be observed on isolated thylakoid membranes of spruce trees growing in chambers with ambient-air conditions. A positive correlation between the oxidation speed and the ozone concentration of the ambient air can be observed. The concentrations of the cytochromes f and b-563 are distinctly lower in thylokoids of chamber trees with ambient air. The acitivity of phosphoenolpyruvate carboxylase is significantly higher in spruce trees kept in chambers with ambient air than in those trees treated with purified air. The importance of anthropogeneous air pollutants, especially ozone, as a damage factor in the low mountain range of Germany is discussed.