Stress-physiological response patterns in spruce needles relate to site factors in a mountain forest

Spruce trees are exposed to a complex of environmental factors at natural s tands. The patterns of physiological plant responses allow conclusions rega rding the stress combinations. At particular field sites small scale site f actors, e. g. edaphic conditions, contribute to the stress level of trees t ogether with large scale environmental factors such as altitudinal gradient s. In the present paper, physiological response patterns of spruce trees (Pice a abies [L.] Karst.) are related to large scale and small scale environment al factors. A principal component solution containing six accumulated components. Compo nent scores were calculated by a two-way analyis of variance (ANOVA) with t he large scale factor "altitude" and the small scale factor "water supply", in order to evaluate differences between sites and plant responses. Statis tical trends for an altitude effect on scores were observed for antioxidant s and pigment ratios (chlorophyll a/b and chlorophylls/carotenoids). For th e effect of the site type (good or deficient water supply) significant corr elations between water deficiency and antioxidant concentrations could be f ound. An independent support for this result was provided by measurements o f osmotic potentials in saturated needles, indicating that enhanced content s of ascorbate were correlated to more negative osmotic potentials. This st atistical approach showed that smale scale edaphic factors (e.g. deficient water supply) decisively contribute to the stress level of spruce trees.