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

Changes in superoxide dismutase (SOD; EC 1.15.1.1[EC]) activityand isozymes were investigated in different developmental stagesof Norway spruce (Picea abies L.). Spruce seeds, seedlings grownin a climate chamber and foliar buds from field-grown treescontained two CuZn-SODs comigrating with SODs I and II previouslyidentified as the chloroplastic and cytosolic SODs in spruceneedles [Krniger et al. (1992) Plant Physiol. 100: 334]. Inaddition one Mn-SOD (SOD III) was identified by insensitivityto cyanide and H₂O₂. Highest total SOD activities were detectedin buds before bud break and in germinating seeds. In seedsand foliar buds SOD II was the major isozyme, whereas SOD Iwas dominant in mature needles. SOD III was present in all developmentalstages of the seedlings, but disappeared in field-grown treesduring bud break and reappeared at the end of summer in matureneedles. These results indicate that the activities of SODsI, II and III in Norway spruce are under independent developmentalcontrol. (Received March 1, 1993; Accepted July 16, 1993)