0000000000184326
AUTHOR
Bernhard Dietz
Vom Nutzen der Sozialwissenschaften für die Zeitgeschichte
Vorspann Die Historiker Rüdiger Graf und Kim Christan Priemel haben in der Oktobernummer 2011 der Vierteljahrshefte eine wichtige Diskussion über das Verhältnis von Zeitgeschichte und Sozialwissenschaften angestoßen und ihrer Zunft die mitunter allzu unbekümmerte Entlehnung sozialwissenschaftlicher Theorien angekreidet. Bernhard Dietz und Christopher Neumaier führen diese Diskussion fort und stellen dabei ihr Projekt einer Historischen Wertewandelsforschung vor, das von einer reflektierten Nutzung der Sozialwissenschaften zeugt.
Investigation on the Photosynthetic Membranes of Spruce Needles in Relation to the Occurrence of Novel Forest Decline I. The Photosynthetic Electron Transport
The investigations described here were carried out in the context of our research project on the physiological, biochemical, and cytomorphological characterization of spruce trees growing in natural habitats and showing damage of varying intensity. Here we report on specific aspects of the photosynthetic apparatus. The aim of the measurements was to analyze whether or not the activity of the photosynthetic electron transport pathway is affected in damaged trees. The investigations were carried out on a 20 to 25-year-old spruce plantation in the Hunsrück mountains and on an 80-year-old spruce plantation in the Westerwald mountains. The photosynthetic electron transport rate was determined by…
Investigation on the Photosynthetic Membranes of Spruce Needles in Relation to the Occurrence of Novel Forest Decline II. The Content of QB-Protein, Cytochrome f, and P-700
In order to obtain an insight into the damage of thylakoid membranes of spruce (Picea abies) trees with damage of varying intensity, investigations were performed on the content of Qв-protein, cytochrome f, and P-700 in chloroplasts of spruce needles from apparently healthy and from damaged trees. Needles from the second and third needle year and the seventh whorl were chosen. The investigations were carried out in 1986 on a 20 to 25-year-old spruce plantation in the Hunsriick mountains and on an 80-year-old spruce plantation in the Westerwald mountains. In damaged trees an unequivocal decrease in the content of Qв-protein, cytochrome f, and P-700 was found, even in needle groups that appea…
Comparative Investigations on the Photosynthetic Electron Transport Chain of Spruce (Picea Abies) with Different Degrees of Damage in the Open Air
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 inve…