A. Wulff et al., OZONE-SENSITIVITY OF SCOTS PINE AND NORWAY SPRUCE FROM NORTHERN AND LOCAL ORIGIN TO LONG-TERM OPEN-FIELD FUMIGATION IN CENTRAL FINLAND, Environmental and experimental botany, 36(2), 1996, pp. 209
Long-term experiments are needed to study the effects of realistically
low ozone concentrations. In our three-season-long experiment, seedli
ngs of Scots pine and Norway spruce were exposed to slightly elevated
levels of ozone in an open-field system in central Finland. Two proven
ances (one local and one from northern Finland) were used. The respons
es included increased needle chlorosis and changes in chlorophyll a an
d b, fatty acid ratios, secondary metabolites and ultrastructure. Howe
ver, responses were rather mild and often had a slightly different pat
tern in different provenances, species and year needle classes. The fa
ct that the ozone-induced effects were rare in the present study sugge
sts that (i) Scots pine and Norway spruce are not very sensitive to sl
ightly elevated levels of ozone or (ii) the observed nitrogen deficien
cy masked any ozone-induced effects. However, a differential behaviour
of the seedlings from the two provenances was observed. It is conclud
ed that the northern provenance specimens might be more ozone sensitiv
e when transplanted to a more southern location with a warmer climate
than those of the local provenance.