Thiol content of spruce needles at forest limits.

We determined the water-soluble thiol (SH) content and the osmolality of the cell sap in spruce trees of both low- and high-altitude origin that were transplanted to two test areas at different altitudes (400 m and 1700 m). There was little or no significant difference in SH content and osmotic value between trees of low- or high-altitude origin at the same altitude, but the sulfhydryl (SH) content varied with the altitude of cultivation, being higher at 1700 m than at 400 m. SH content and osmotic value were higher in winter, independent of altitude and provenance. The annual pattern of water-soluble and protein-bound SH content and glutathione reductase activity was measured in spruce trees at 1700 m; these values also peaked in winter and were lowest in summer.