Simultaneous analyses of chromosomes in root meristems and of the biochemical status of needle tissues of three different clones of Norway spruce trees challenged with moderate ozone levels

Biochemical effects of both low and high ozone impact in long-term and shor t-term experiments are well investigated and documented; however, short-ter m treatments with moderate ozone levels have revealed divergent information concerning the biochemistry of needle tissues. Damage to the meristems of spruce trees have been found for several ozone treatments, in the form of a n enhanced number or chromosomal aberrations, which appeared to be persiste nt for up to 2 years after the ozone challenge. One of the main aims of the present study was to determine whether a moderate ozone concentration is a ble to induce damage in needle biochemistry and/or only in the genetic mate rial of root meristems. In the experiment three different clones of Norway spruce trees (Picea abies) were challenged with moderate ozone concentratio ns (up to SO nl/l) for 11 weeks in greenhouses. Simultaneous investigations of root rip meristematic cells and the biochemical status of needle tissue s regarding antioxidants and pigments were performed at two different sampl ing rimes: directly after the ozone treatment and 1 year later. Ozone effec ts in needles were absent both at the end of the fumigation and also after 1 year, but different clonal behaviour was found. Effect of ozone on chromo somal aberration rates in root tip meristems were observed and also the typ es of persisting chromosomal aberrations changed within the time course and within the different clones.