|Lindenmair, J; Matzner, E; Göttlein, A; Kuhn, AJ; Schröder, WH: Ion exchange and water uptake of coarse roots of mature Norway spruce trees (Picea abies L. Karst.) in Horst, WJ et al.: Plant Nutrition - Food Security and Sustainability of Agro-Ecosystems, Kluwer Academic Publishers, 568-569 (2001)|
Most rhizosphere studies about water and nutrient uptake of trees have only considered the fine root system. Our contribution is focused on the water and nutrient uptake characteristics of a widely ignored soil-plant interface - the coarse root system. To quantify water and ion uptake by older suberized roots, root chambers for field experiments were developed. These chambers were installed at more than 30 coarse root segments of mature Norway spruce and filled with a nutrient solution adapted to field conditions. Changes in nutrient concentration and water volume were recorded for several weeks. In order to trace ion uptake, experiments using stable isotopes were carried out. All coarse root segments took up a significant amount of water, with maximum rates of about 10 times lower than those for active fine roots. In some segments could be detected in the roots xylem, indicating actual uptake of ions into inner root parts.