Effects of NO2 on assimilatory nitrate- and sulfate reduction in needles from spruce trees (Picea abies L.) : Air Pollution and Forest Decline. 14th International Meeting for Specialists in Air Pollution Effects on Forest Ecosystems

1989

S. 401-403

3 Abb., 1 Tab., 10 Lit. Ang.

Unselbständiges Werk

200034736

This poster presents a choice of results from experiments done in the years 1985 to 1987 about the influence of NO2 on the extraktable activitis of nitrate reductase (NR), nitrite reductase (NiR), adenosine 5'- phosphosulphate sulfotransferase (APSSTasse) and the content of free amino acids in needles from spruce trees. Three or five years old pottet clones were exposed in open-top chambers or narby a highway with a control in a rural region with low air pollution. During the aeration experiments the NO2 concentrations were 100 and 150 .g/m3 respectively. The NO2 concentration near the highway was about 89 .g/m3 and at the control site about 12 .g/m3. The open-top chamber experiments showed that NO2 in the concentrations used caused a significantly increased extractable NR- and NiR-activitly in the needles. The activity of the APSSTase measured was not significantly influenced. Similar effects were observed in the trees near the highway. The differences were detected during the first 24 or 48 hours of exposure and were always reversible. The amino acid contents were not significantly affected after the exposure. In an experiment with a longer exposure we got some indications that in presence of higher NO2 concentrations the total amino acid content slightly increased. Further experiments will show, whether and in what quantity the NO2-nitrogen is incorprated by spruce needles.