Purification and Properties of Manganese Superoxide Dismutase from Norway Spruce (Picea abies L. Karst)

A manganese-containing superoxide dismutase (SOD; EC 1.15.1.1 [EC] )was purified to electrophoretic homogeneity from seeds of Norwayspruce (Picea abies L.). The apparent molecular mass of thepurified enzyme was 86 kDa, as determined by gel filtration.The subunit molecular mass, estimated by SDS-polyacrylamidegel electrophoresis, was 22 kDa both in the presence and inthe absence of 2-mercaptoethanol. Thus, the native enzyme isa homotetramer with subunits that were not linked by disulfidebonds. The isoelectric point of this Mn-SOD was 5.5. The specificactivity of the Mn-SOD was strongly pH-dependent and was 400units per nmol SOD at pH 7.8 and 30 units per nmol SOD at pH10.4. The first 25 amino acid residues in the amino terminalregion of spruce Mn-SOD exhibited a high degree of sequencehomology to those of Mn-SODs from other organisms. In Mn-deficientneedles the activity of Mn-SOD was only half of that in non-deficientneedles, whereas the activity of CuZn-SOD was doubled. (Received May 20, 1994; Accepted October 31, 1994)     

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)     

Seasonal Fluctuations of Ascorbate-Related Enzymes: Acute and Delayed Effects of Late Frost in Spring on Antioxidative Systems in Needles of Norway Spruce (Picea abies L.)

Seasonal changes of ascorbate peroxidase and monodehydroascorbateradical reductase activities were studied in foliar tissuesof Norway spruce (Picea abies L.). In mature needles, APX activitiesdid not show seasonal fluctuations and were similar to thosefound in resting buds. Monodehydroascorbate radical reductaseactivity was higher in needles than in buds and higher in winterthan in summer. Maximum activities of both enzymes were foundbefore bud break and minimum activities in newly formed needles.When spruce seedlings were exposed to an artifical frost eventof –5°C for one night in spring, ascorbate peroxidaseactivity declined in young needles before the onset of visibleinjury but corresponding to a sudden upsurge in lipid peroxidation.After one week, some shoots showed severe symptoms of injury,some were slightly injured and others did not show any visibleinjury. In lethally injured needles, antioxidative protection(ascorbate peroxidase, monodehydroascorbate radical reductase,glutathione reductase, glutathione, ascorbate, superoxide dismutase)had collapsed. Surviving needles showed a coordinated increasein all components of the antioxidative system suggesting anefficient induction of defense systems. However, enhanced protectionwas observed only transiently. In fall, needles that had beenexposed to frost in spring contained significantly less antioxidantsthan unstressed needles indicating that unseasonal frost causedmemory effects. (Received September 16, 1995; Accepted May 28, 1996)