NO GENERAL OZONE-SPECIFIC INDICATOR AMONG THE HEXANE-SOLUBLE AND DICHLOROMETHANE-SOLUBLE COMPONENTS OF PICEA-ABIES NEEDLES EXPOSED TO OZONEIN OPEN-TOP CHAMBERS

The effect of ozone (<10, 200 or 400 mug m-3) on hexane- and dichlorom ethane-soluble components of Picea abies needles was determined by fum igating potted grafts from mature frees. The trees (>55 and 125 years, 2.5 m high), representing six clones of Norway spruce, were fumigated in open-top chambers at two locations in Norway for one growth season . The needles were extracted with hexane and dichloromethane; 142 comp ounds from the hexane extract and 164 silylated compounds from the dic hloromethane extract were analysed by gas chromatography although no i dentifications were made. The concentration of four of the compounds f rom the hexane extract changed with ozone dose in a way that made them promising as indicators, but the present analytical method could not verify this possibility. None of the other 302 compounds qualified as a general indicator of ozone stress in Norway spruce, as none changed its concentration with ozone dose consistently in all ramets of all cl ones. Most of the variation in the experiment is mainly attributable t o genetic variation and to climate.