title: Boron accumulation and toxicity in hybrid poplar (Populus nigra × euramericana).
abstract: Poplars accumulate high B concentrations and are thus used for the phytomanagement of B contaminated soils. Here, we performed pot experiments in which Populus nigra × euramericana were grown on a substrate with B concentrations ranging from 13 to 280 mg kg(-1) as H(3)BO(3). Salix viminalis, Brassica juncea, and Lupinus albus were grown under some growing conditions for comparison. Poplar growth was unaffected at soil B treatment levels up to 93 mg kg(-1). Growth was progressively reduced at levels of 168 and 280 mg kg(-1). None of the other species survived at these substrate B levels. At leaf B concentrations <900 mg kg(-1) only <10% of the poplar leaf area showed signs of toxicity. Neutron radiography revealed that chlorotic leaf tissues had B concentrations of 1000-2000 mg kg(-1), while necrotic tissues had >2000 mg kg(-1). Average B concentrations of up to 3500 mg kg(-1) were found in leaves, while spots within leaves had concentrations >7000 mg kg(-1), showing that B accumulation in leaf tissue continued even after the onset of necrosis. The B accumulation ability of P. nigra × euramericana is associated with B hypertolerance in the living tissue and storage of B in dead leaf tissue.
authors: Institute of Terrestrial Ecosystems, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland. rainer.rees@env.ethz.ch
authors: Rainer
authors: R
authors: Rees
authors: Brett H
authors: BH
authors: Robinson
authors: Manoj
authors: M
authors: Menon
authors: Eberhard
authors: E
authors: Lehmann
authors: Madeleine S
authors: MS
authors: Günthardt-Goerg
authors: Rainer
authors: R
authors: Schulin
mesh_terms: D001673:Biodegradation, Environmental; D001895:Boron / Q000378:metabolism* / Q000633:toxicity; D002678:Chimera; D018515:Plant Leaves / Q000378:metabolism; D032107:Populus / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D012989:Soil Pollutants / Q000378:metabolism* / Q000633:toxicity
chemical_list: D012989:Soil Pollutants; D001895:Boron