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Clarkson, David T. ; Carvajal, Micaela ; Henzler, Tobias ; Waterhouse, Rosemary N. ; Smyth, Audra J. ; Cooke, David T. ; Steudle, Ernst:
Root hydraulic conductance: diurnal aquaporin expression and the effects of nutrient stress.
In: Journal of Experimental Botany.
Bd. 51
(2000)
Heft 342
.
- S. 61-70.
ISSN 1460-2431
DOI: https://doi.org/10.1093/jexbot/51.342.61
Abstract
It has been shown that N-, P- and S-deficiencies result in major reductions of root hydraulic conductivity (Lp(r)) which may lead to lowered stomatal conductance. but the relationship between the two conductance changes is not understood. In a variety of species, Lp(r) decreases in the early stages of NO3-, H2PO42- and SO42- deprivation. These effects can be reversed in 4-24 h after the deficient nutrient is re-supplied. Diurnal fluctuations of root Lp(r) have also been found in some species, and an example of this is given for Lotus japonicus. In nutrient-sufficient wheat plants, root Lp(r) is extremely sensitive to brief treatments with HgCl2; these effects are completely reversible when Hg is removed. The low values of Lp, in N- or P-deprived roots of wheat are not affected by Hg treatments. The properties of plasma membrane (PM) vesicles from wheat roots are also affected by NO3--deprivation of the intact plants. The osmotic permeability of vesicles from N-deprived roots is much lower than that of roots adequately supplied with NO3- and is insensitive to Hg treatment. In roots of Lp(r) japonicus, gene transcripts are found which have a strong homology to those encoding the PIP1 and PIP2 aquaporins of Arabidopsis. There is a very marked diurnal cycle in the abundance of mRNAs of aquaporin gene homologues in roots of L. japonicus. The maxima and minima appear to anticipate the diurnal fluctuations in Lp(r) by 2-4 h. The temporal similarity between the cycles of the abundance of the mRNAs and root Lp(r) is most striking. The aquaporin encoded by AtPIP1 is known to have its water permeation blocked by Hg binding. The lack of Hg-sensitivity in roots and PMs from N-deprived roots provides circumstantial evidence that lowered root Lp(r) may be due to a decrease in either the activity of water channels or their density in the PM. It is concluded that roots are capable, by means completely unknown, of monitoring the nutrient content of the solution in the root apoplasm and of initiating responses that anticipate by hours or days any metabolic disturbances caused by nutrient deficiencies. It is the incoming nutrient supply that is registered as deficient, not the plant's nutrient status. At some point, close to the initiation of these responses, changes in water channel activity may be involved, but the manner in which monitoring of nutrient stress is transduced into an hydraulic response is also unknown.
Weitere Angaben
| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Zusätzliche Informationen: | BAYCEER33637 |
| 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 06:34 |
| Letzte Änderung: | 11 Sep 2015 06:34 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/19351 |