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Plant Physiology 99:1084-1089 (1992) © 1992 American Society of Plant Biologists Antioxidants and Manganese Deficiency in Needles of Norway Spruce (Picea abies L.) Trees 1Fraunhofer Institut für Atmosphärische Umweltforschung, Kreuzeckbahnstr. 19, W-8100 Garmisch-Partenkirchen, Federal Republic of Germany, GSF-Forschungszentrum für Umwelt und Gesundheit, Institut für Ökologische Chemie, Ingolstädter Landstr. 1, W-8042 Neuherberg, Federal Republic of Germany
Chlorotic and green needles from Norway spruce (Picea abies L.) trees were sampled in the Calcareous Bavarian Alps in winter. The needles were used for analysis of the mineral and pigment contents, the levels of antioxidants (ascorbate, glutathione), and the activities of protective enzymes (superoxide dismutase, catalase, ascorbate peroxidase, monodehydroascorbate radical reductase, dehydroascorbate reductase, glutathione reductase). In addition, the activities of two respiratory enzymes (glucose-6-phosphate dehydrogenase, NAD-malate dehydrogenase), which might provide the NADPH necessary for functioning of the antioxidative system, were determined. We found that chlorotic needles were severely manganese deficient (3 to 6 micrograms Mn per gram dry weight as compared with up to 190 micrograms Mn per gram dry weight in green needles) but had a similar dry weight to fresh weight ratio, had a similar protein content, and showed no evidence for enhanced lipid peroxidation as compared with green needles. In chlorotic needles, the level of total ascorbate and the activities of superoxide dismutase, monodehydroascorbate radical reductase, NAD-malate dehydrogenase, and glucose-6-phosphate dehydrogenase were significantly increased, whereas the levels of ascorbate peroxidase, dehydroascorbate reductase, glutathione reductase, and glutathione were not affected. The ratio of ascorbate to dehydroascorbate was similar in both green and chlorotic needles. These results suggest that in spruce needles monodehydroascorbate radical reductase is the key enzyme involved in maintaining ascorbate in its reduced state. The reductant necessary for this process may have been supplied at the expense of photosynthate.
2 Present address: University College of Science, Department of Biochemistry, 35 Ballygunge Circular Road, Calcutta 700 109 India. 1 Parts of this study were funded by the Bayerisches Staatsministerium für Landesentwicklung und Umweltfragen. This article has been cited by other articles:
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