Nutrient disturbance through manganese accumulation in Douglas fir

The disturbance of the nutrient balance induced by a surplus of manganese is discussed as the main cause of the disease striking Douglas fir. In this context a close examination of the iron balance is of great interest. Despite high total iron content, damaged Douglas fir show symptoms similar to that of an iron deficiency chlorosis in which the redox state of iron seems to be affected (physiological iron-deficiency). The first results of the project strengthen this assumption. During this research project iron dependent systems (e.g. activities of iron dependent enzymes, structure of chloroplasts etc.) are being scrutinised by the use of various microtechnical and chemical methods. It is the aim to elucidate the interrelation between cause and effect of the disturbance of the nutrient balance.