caa a22 4500 397522150 CHVBK 20180308164635.0 cr unu---uuuuu 161202e199508 xx s 000 0 eng 10.1093/jxb/46.8.895 doi (NATIONALLICENCE)oxford-10.1093/jxb/46.8.895 Mineral nutrition and transport in xylem and phloem of Banksia prionotes (Proteaceae), a tree with dimorphic root morphology [Elektronische Daten] [W. Dieter Jeschke, John S. Pate] Xylem sap of proteoid roots, lateral roots, sinker root and age classes of trunk segments, and phloem sap of mid-trunks were collected from trees of Banksia prionotes (Proteaceae) in native habitat on highly impoverished sands in south-western Australia. Proteoid roots were major exporters of phosphate, K+ and amino acids during the wet winter season and showed in vitro nitrate reductase activity during periods of soil nitrification. Other parts of the root served as general sources of Na +, Cl−, Mg2+, Ca2+, and SO2−4. Lateral root xylem sap was more concentrated in virtually all solutes than that of sinker roots, even during the dry summer following senescence of proteoid roots. Gradients in xylem sap concentration up the main trunks suggested lateral abstraction and storage of incoming phosphate in basal stem parts during winter and a subsequent release to the xylem in summer. Phloem sap was many times more concentrated in nutrient ions than xylem sap, and, like xylem sap, showed unusually low K+ and H2PO4− relative to Na+, Cl− and SO2−4, suggesting a sparing role of the latter three ions in meeting ionic requirements of transport. Amino acid analyses showed higher overall concentrations in phloem than xylem sap, but much lower proportions of total amino N as glutamine and asparagine in the former sap. This suggested utilization of xylem-derived amide N by leaves for growth and synthesis of phloem-mobile amino acids. © Oxford University Press Research Papers nationallicence Banksia prionotes nationallicence mineral transport nationallicence proteoid roots nationallicence xylem sap nationallicence phloem sap nationallicence Jeschke W. Dieter Julius-von-Sachs-lnstitut fur Biowissenschaften, Lehrstuhl für Botanik 1, Universität Würzburg D-97082 Würtzburg, Germany aut Pate John S. Botany Department, University of Western Australia Nedlands, WA 6009, Australia aut Journal of Experimental Botany Oxford University Press 46/8(1995-08), 895-905 0022-0957 46:8<895 1995 46 exbotj https://doi.org/10.1093/jxb/46.8.895 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/jxb/46.8.895 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Jeschke W. Dieter Julius-von-Sachs-lnstitut fur Biowissenschaften, Lehrstuhl für Botanik 1, Universität Würzburg D-97082 Würtzburg, Germany aut NATIONALLICENCE 700 1- Pate John S. Botany Department, University of Western Australia Nedlands, WA 6009, Australia aut NATIONALLICENCE 773 0- Journal of Experimental Botany Oxford University Press 46/8(1995-08), 895-905 0022-0957 46:8<895 1995 46 exbotj Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford