Influence of air pollutants and nutrient deficiency on D-1 protein content and photosynthesis in young spruce trees

Long-term fumigation with different mixtures of air pollutants, such as O sub(3), NO sub(2) and SO sub(2), in combination with potassium deficiency in 4-year-old spruce trees shows clearly that the photosynthetic apparatus reacts very sensitively to environmental stress. Even when no change in photosynthetic oxygen evolution of the leaves was measurable, the content of D-1 protein in the reaction center of photosystem II already increased significantly at low stress conditions. With increasing concentrations of pollutants, the content of D-1 protein decreased considerably. This pattern was observed with all combinations of gases, although they differed in effectiveness. The most potent effect on the content of D-1 protein was found with a combined fumigation of SO sub(2) plus NO sub(2).