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- Title
Root System Water Uptake and Respiration for Agave deserti: Observations and Predictions Using a Model Based on Individual Roots.
- Authors
ALM, DAVID M.; NOBEL, PARK S.
- Abstract
Water uptake and root respiration for the desert succulent Engelm. were predicted in the laboratory and in the field using a model based on root hydraulic conductivity (L) and the rate of maintenance respiration previously determined in the laboratory for individual roots as non-linear functions of root age, soil temperature (T), and soil water potential (). Root carbon dioxide loss and shoot transpiration were measured in the laboratory for plants with root systems in solution and in water-saturated soil, where T was varied from 10°C to 40°C. In the field, was also varied (from 11°C to 28°C) while was maintained at —0.01 or ≤—5 MPa, or r was allowed to oscillate naturally while declined from —0.05 to —0.89 MPa over a 4-d period. After each experimental treatment, roots were divided into 15 age classes (1 week to 3 years), and the root xylem water potential was measured. Averaging over all experiments for the entire root systems, the predicted total daily water uptake was 102% ±4% of the observed transpiration, and the predicted total daily root respiration was 96%±5% of that observed (mean ± s.e. mean, for n = 11 d). Thus, the respiratory maintenance cost of root system water acquisition can be accurately predicted based on the behaviour integrated for individual roots.
- Publication
Annals of Botany, 1991, Vol 67, Issue 1, p59
- ISSN
0305-7364
- Publication type
Article