Effects of air pollutants on plants. Open-top experiments

The open-top facility is located on the ground of the Fraunhofer-Institut Grafschaft. Open-tops were installed on 8 test areas. Four chambers each were streamed through by filtered or enfiltered air respectively. On the remaining four sites, the clone spruces graw under local conditions. The construction and operation of an Open-top facility especially the open-top chambers, the filter and the aerationsystem are described. The data registration for ozone sulphur dioxide, nitrogen oxides and microclimate, as well as their processing are presented. First results prove that there exist different concentrations of gases in filtered and unfiltered air. In addition deviations of microclimate in the chambers in relation to the open field are demonstrated. Investigated parameter of the exposed cloned Norway spruces are: pigment composition, nutrient-contents, stomatal resistance and morphology of epicuticular waxes. (IUCT)