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RESEARCH PRODUCT

Comparative Investigations on the Photosynthetic Electron Transport Chain of Spruce (Picea Abies) with Different Degrees of Damage in the Open Air

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Several components of the photosynthetic electron transport chain (P-700, cytochrome f, QB-protein) as well as the rate of electron transport and the chlorophyll content of the needles of spruce trees with different degrees of damage were investigated. The investigations were carried out in pair comparison at a location in the Hunsruck (West Germany). The rate of electron transport was determined as photoreduction of 2,6-dichlorophenolindophenol. Significant damage to the electron transport system is shown in the thylakoids of the damaged trees compared to the less severely damaged trees. In the spruce trees with more damage, the rates of electron transport are significantly lower. The investigation of the water-splitting enzyme system by feeding in electrons by means of diphenylcarbazide indicates that the electron transport on the oxidizing side of photosystem II is impaired. In the more damaged trees the content of QB-protein, cytochrome f as well as P-700 referred to dry weight is markedly lowered. On the other hand, in relation to chlorophyll only the content of P-700 and QB-protein is significantly decreased. These investigations imply that the thylakoid membranes are sites of early damage from air pollution.