THE EFFECT OF DROUGHT ON CELL WALL THICKNESS AND RADIAL DIMENSION OF TRACHEIDS OF PICEA ABIES (L.) KARST.

The presented paper deals with morphological parameters of tracheids of Norway spruce (Picea abies (L.) Karst.) exposed to long-term drought stress. Microcores were sampled in Hoxmark, Norway, in 2-week intervals during the growing season of 2010. The microcores were used to analyse morphological parameters of tracheids - their radial diameter and the cell wall thickness. These morphological parameters were then correlated with meteorological data. We used two families of Norway spruce for the experiment. One tree from each family was located in the control plot, the other one in experimental conditions - drought stress was induced artificially for the entire growing season. The hypothesis about the negative effect of drought on morphological parameters of tracheids was not confirmed in this case - no statistically significant differences were found between the stressed and the control plot trees. The experiment results indicate that drought affects the resulting tree-ring width but not morphological parameters of tracheids.