caa a22 4500 477100856 CHVBK 20180405111541.0 cr unu---uuuuu 170330e19960901xx s 000 0 eng 10.1007/BF00620050 doi (NATIONALLICENCE)springer-10.1007/BF00620050 Water and solute transport along developing maize roots [Elektronische Daten] [Jürgen Frensch, Theodore Hsiao, Ernst Steudle] Hydraulic and osmotic properties were measured along developing maize (Zea mays L.) roots at distances between 15 and 465 mm from the root tip to quantify the effects of changes in root structure on the radial and longitudinal movement of water and solutes (ions). Root development generated regions of different hydraulic and osmotic properties. Close to the root tip, passive solute permeability (root permeability coefficient, Psr) was high and selectivity (root reflection coefficient, σsr) low, indicative of an imperfect semipermeable root structure. Within the apical 100-150 mm, Psr decreased by an order of magnitude and σsr increased significantly. Root hydraulic conductivity (Lpr) depended on the nature of the force (hydrostatic and osmotic). Osmotic Lpr was smaller by an order of magnitude than hydrostatic Lpr and decreased with increasing distance from the root tip. Throughout the root, responses in turgor of cortical cells and late metaxylem to step changes in xylem pressure applied to the base of excised roots were measured at high spatial resolution. The resulting profiles of radial and longitudinal propagation of pressure showed that the endodermis had become the major hydraulic barrier in older parts of the root, i.e. at distances from the apex ä 150 mm. Other than at the endodermis, no significant radial hydraulic resistance could be detected. The results permit a detailed analysis of the root's composite structure which is important for its function in collecting and translocating water and nutrients. Springer-Verlag, 1996 Hydraulic conductivity nationallicence Permeability coefficient nationallicence Reflection coefficient nationallicence Root development (solute transport, water transport) nationallicence Turgor nationallicence Zea nationallicence CPP : cell pressure probe nationallicence IT : root segments with intact tips nationallicence Lpr : root hydraulic conductivity nationallicence Lprh : hydrostatic hydraulic conductivity of root nationallicence Lpro : osmotic hydraulic conductivity of root nationallicence Papp : hydrostatic pressure applied to cut end of root nationallicence Pc : cell turgor nationallicence Pc, cor : turgor of cortical cell nationallicence Pc,xyl : turgor of late metaxylem vessel nationallicence Pro : stationary root pressure nationallicence Pr0,seal : stationary root pressure of sealed root segment nationallicence Psr : solute permeability coefficient of root nationallicence RPP : root pressure probe nationallicence TR : root segments with tip removed nationallicence σsr : reflection coefficient of root nationallicence Frensch Jürgen Lehrstuhl für Pflanzenökologie, Universität Bayreuth, D-95440, Bayreuth, Germany aut Hsiao Theodore Department of Land Air and Water Resources, Hydrologic Science, University of California, 95616, Davis, CA, USA aut Steudle Ernst Lehrstuhl für Pflanzenökologie, Universität Bayreuth, D-95440, Bayreuth, Germany aut Planta Springer-Verlag 198/3(1996-09-01), 348-355 0032-0935 198:3<348 1996 198 425 https://doi.org/10.1007/BF00620050 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00620050 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Frensch Jürgen Lehrstuhl für Pflanzenökologie, Universität Bayreuth, D-95440, Bayreuth, Germany aut NATIONALLICENCE 700 1- Hsiao Theodore Department of Land Air and Water Resources, Hydrologic Science, University of California, 95616, Davis, CA, USA aut NATIONALLICENCE 700 1- Steudle Ernst Lehrstuhl für Pflanzenökologie, Universität Bayreuth, D-95440, Bayreuth, Germany aut NATIONALLICENCE 773 0- Planta Springer-Verlag 198/3(1996-09-01), 348-355 0032-0935 198:3<348 1996 198 425 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer