title: The simultaneous effect of soil-borne NaF and air pollutant SO2on CO2-uptake and pollutant accumulation.
abstract: Spruce cuttings were potted in quartz sand. One half was watered with tap water, the other with deionized water containing 100 ppm F-as NaF, during winter till bud break. After flushing the plants were exposed continuously for five weeks (June/July) either to normal air or to air with 0.025 and 0.075 ppm SO2, respectively. CO2-uptake was measured in the laboratory (40,000 lux) with an IRGA.Even in the absence of visible symptoms of injury to last year's needles, root-applied fluoride did suppress CO2-uptake significantly. Also the fumigation with 0.075 ppm SO2caused a depression of CO2-uptake, whereas 0.025 ppm SO2remained without significant reaction within five weeks. Fluorides infiltrating through roots and airborne SO2acting together may depress CO2-uptake synergistically.Soil applied fluoride accumulated particularly in roots and twigs, whereas very little was found in the stem. The F--accumulation even increased with increasing SO2-concentrations but was without effect on S-accumulation.
authors.affiliation: Swiss Federal Institute of Forestry Research, CH-8903, Brimensdorf, Switzerland.
authors.forename: Th
authors.initials: T
authors.lastname: Keller