Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Factors modulating superoxide dismutase activity in needles of spruce trees (Picea abies L.). | 807s Ann. Sci. For. 1989 46 suppl. 807S-81ŨS Forest Tree Physiology E. Dreyer etal. eds. Elsevier INRA Factors modulating superoxide dismutase activity in needles of spruce trees Picea abies L. A. Polle1 B. Krings2 and H. Rennenberg1 1 Fraunhofer Institut fiir Atm. Umweltforschung Kreuzeckbahnstr. 19 D-8100 Garmisch-Partenkir-chen and 2 Botanisches Institutder Universităt ZU Kôln Gyrhofstr. 15 D-5000 Kôln 41 . Introduction Superoxide dismutases SOD are considered to be a major enzymic defense against oxygen toxicity in cells Fridovich 1986 . These enzymes contain either Cu Zn Mn or Fe in their catalytic center Fridovich 1986 . Most abundant in plants are Cu Zn-SODs which are characterized by a broad pH-optimum between pH 7 and pH 10 and an inhibition by cyanide and H2O2 Fridovich 1986 SODs detoxify superoxide radicals originating from physiological functions such as photosynthesis under excess light energy Robinson 1988 as well as different environmental stress factors such as herbicides and air pollutants O3 so2 NO2 Rabinowitch and Fridovich 1983 Fridovich 1986 . Since it is generally assumed that air pollution is one of the major reasons for forest decline in Central Europe we compared SOD activity in needles of healthy and injured spruce trees growing in the field. Materials and Methods Experiments were performed with needles from Norway spruce trees Picea abies L. growing in the field. Extracts of spruce needles were prepared as described elsewhere Polle et al. 1989 . After dialysis the activity of superoxide dismutase was determined according to the method of Misra and Fridovich 1972 . This assay is based on the autooxidation of epinephrine to adrenochrome at pH . 0 2 serves as the chain-propagating species in this reaction. SOD competes for Oj- thus inhibiting adrenochrome formation. By definition 1 unit of SOD is the amount of extract that inhibits the maximal rate of adrenochrome formation by 50 . Results To determine SOD activity we adapted .
