Abstract
Xylem pressure potentials and stomatal diffusion resistances were measured in the field in Ilex opaca Ait. during days which differed in temperature and vapor pressure deficit. Water flux into leaves was calculated by combining the field data with laboratory determinations of the relation between tissue water deficit and water potential. Estimates of apparent plant resistance were then calculated from fluxes and differences between soil water potential and xylem tension. The resistance depended strongly on water flux, dropping by a factor of over 7 from low to high water flow rates. This extends the generality of variable plant resistances measured in controlled environment studies to I. opaca as it occurs naturally in the field. The relation of apparent plant resistance to water flux as estimated in this study can be useful in simulation models which calculate water uptake to leaves as a flux driven by a difference in soil and leaf water potentials across a resistance between the bulk soil and the leaf.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Huck M. G., Klepper B., Taylor H. M. Diurnal variations in root diameter. Plant Physiol. 1970 Apr;45(4):529–530. doi: 10.1104/pp.45.4.529. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lopushinsky W. Effect of Water Movement on Ion Movement into the Xylem of Tomato Roots. Plant Physiol. 1964 May;39(3):494–501. doi: 10.1104/pp.39.3.494. [DOI] [PMC free article] [PubMed] [Google Scholar]