Abscisic acid in the xylem: where does it come from, where does it go to?
| Autor: | Eleonore Hose, Wolfram Hartung, Angela Sauter |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Physiology
Water flow Plant Science Biology Models Biological Plant Roots Permeability Plant Epidermis Cell wall chemistry.chemical_compound Cell Wall Botany Abscisic acid Plant Stems organic chemicals fungi food and beverages Symplast Xylem Biological Transport biology.organism_classification Apoplast chemistry Shoot Plant hormone Abscisic Acid Signal Transduction |
| Zdroj: | Journal of Experimental Botany. 53:27-32 |
| ISSN: | 1460-2431 0022-0957 |
| Popis: | Abscisic acid is a hormonal stress signal that moves in the xylem from the root to the different parts of the shoot where it regulates transpirational water loss and leaf growth. The factors that modify the intensity of the ABA signal in the xylem are of particular interest because target cells recognize concentrations. ABA(xyl), will be decreased as radial water flow through the roots is increased, assuming that radial ABA transport occurs in the symplast only. Such dilutions of the plant hormone concentration can be compensated in different ways, which help to keep the ABA-concentrations in the xylem constant: (i) apoplastic bypass flows of ABA, (ii) ABA flows between the stem parenchyma and the xylem during transport and (iii) the action of beta-D-glucosidases that release free ABA from its conjugates to the root cortex and the leaf apoplast. The significance of reflection coefficients (sigma(ABA)), permeability coefficients of membranes (P(S)(ABA)) and apoplastic barriers for ABA is discussed. |
| Databáze: | OpenAIRE |
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