title: Mineral nutrient deficiency increases the sensitivity of photosynthesis to sulphur dioxide in needles of a coniferous tree, Abies nordmanniana.
abstract: Abies nordmanniana (Stev.) Spach was cultivated in rooting media either rich in nutrients (control) or low in magnesium (low Mg) or low in magnesium and nitrogen (low Mg-N), respectively. Intact, attached needles were exposed, in the light (460 μmol photons m-2s-1), to an atmosphere containing 1 ppm SO2for 5 h. Measurements of light- and CO2-saturated rates of photosynthetic O2evolution, Amax, were performed before and after SO2treatments. In needles from well fertilized plants, Amaxwas high (about 50 μmol m-2s-1) and was not affected by SO2. Needles from low-Mg and low-Mg-N plants had lower photosynthetic rates and showed a marked decline in Amaxin response to the SO2treatment. Stomatal conductance was similar in the three groups of plants during SO2treatments.
authors.affiliation: Lehrstuhl für Botanik II der Universität, Mittlerer Dallenbergweg 64, W-8700, Würzburg, Federal Republic of Germany.
authors.forename: Iris
authors.initials: I
authors.lastname: Jung
authors.affiliation: Lehrstuhl für Botanik II der Universität, Mittlerer Dallenbergweg 64, W-8700, Würzburg, Federal Republic of Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Winter
keywords: Abies; Mineral deficiency; Photosynthesis; Sulphur dioxide