Developmental Changes of CuZn- and Mn-Superoxide Dismutase Isozymes in Seedlings and Needles of Norway Spruce (Picea abies L.)

Abstract

Changes in superoxide dismutase (SOD; EC 1.15.1.1) activity and isozymes were investigated in different developmental stages of Norway spruce (Picea abies L.). Spruce seeds, seedlings grown in a climate chamber and foliar buds from field-grown trees contained two CuZn-SODs comigrating with SODs I and II previously identified as the chloroplastic and cytosolic SODs in spruce needles [Kröniger et al. (1992) Plant Physiol. 100: 334]. In addition one Mn-SOD (SOD III) was identified by insensitivity to cyanide and H2O2. Highest total SOD activities were detected in buds before bud break and in germinating seeds. In seeds and foliar buds SOD II was the major isozyme, whereas SOD I was dominant in mature needles. SOD III was present in all developmental stages of the seedlings, but disappeared in field-grown trees during bud break and reappeared at the end of summer in mature needles. These results indicate that the activities of SODs I, II and III in Norway spruce are under independent developmental control.