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Steudle, Ernst ; Meshcheryakov, Anatoli B.:
Hydraulic and osmotic properties of oak roots.
In: Journal of Experimental Botany.
Bd. 47
(1996)
Heft 3
.
- S. 387-401.
ISSN 1460-2431
DOI: https://doi.org/10.1093/jxb/47.3.387
Abstract
Hydraulic and osmotic properties of root systems of 2.5-8-months-old oak seedlings (Quercus robur and Q. petraea) were measured using the root pressure probe. Root pressures of excised roots ranged between 0.05 and 0.15 MPa which was similar to values obtained for herbaceous species, Root hydraulic conductivity (Lp(r); per unit of root surface area) was much larger in the presence of hydrostatic than in the presence of osmotic pressure differences driving water flow across the roots, Differences were as large as a factor of 20 to 470. Roots of the young seedlings of Q. robur grew more rapidly than those of Q. petraea and had a hydraulic conductivity which was substantially higher, Nitrogen nutrition affected root growth of Q. robur more than that of Q. petraea, but did not affect root Lp(r) of either species. For Q. robur, Lp(r) decreased with root age (size) which is interpreted by an effect of suberization during the development of fine roots, Root hydraulic conductance remained constant for both species. For Q. robur, this was due to the fact that the overall decrease in Lp(r) was compensated for by an increase in root surface area. Root reflection coefficients (sigma(sr)) were low and ranged between sigma(sr)=0.1 and 0.5 for solutes for which cell membranes exhibit reflection coefficients of virtually unity (salts, sugars etc.). Solute permeability was small and was usually not measurable with the technique. When root systems were attached to the root pressure probe for longer periods of time (up to 10 d), solute permeability increased due to ageing effects which, however, did not cause a general leakiness of the roots as Lp(r) decreased. Hence, values were only used from measurements taken during the first day. Transport properties of oak roots are compared with those recently obtained for spruce (Rudinger et al., 1994). They are discussed in terms of a composite transport model of the root which explains low root sigma(sr) at low solute permeability and reasonable root Lp(r). The model predicts differences between osmotic and hydraulic water flow and differences in the transport properties of roots of herbs and trees as found.
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| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Zusätzliche Informationen: | BAYCEER33663 |
| Institutionen der Universität: | Forschungseinrichtungen > Forschungszentren > Bayreuther Zentrum für Ökologie und Umweltforschung - BayCEER Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Biologie > Lehrstuhl Pflanzenökologie Fakultäten Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Biologie Forschungseinrichtungen Forschungseinrichtungen > Forschungszentren |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik |
| Eingestellt am: | 11 Sep 2015 06:35 |
| Letzte Änderung: | 11 Sep 2015 06:35 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/19402 |