Theoretical Analysis of Systematic Errors Introduced by a Pedicel-Girdling Technique used to Estimate Separately the Xylem and Phloem Flows
✍ Scribed by SVETLANA FISHMAN; MICHEL GÉNARD; JEAN-GÉRARD HUGUET
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 298 KB
- Volume
- 213
- Category
- Article
- ISSN
- 0022-5193
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✦ Synopsis
The water budget of fruits was analysed by means of a biophysical model of fruit growth, built and calibrated recently for peaches [Prunus persica (L.) Batsch]. This analysis was applied to the evaluation of systematic errors introduced by a pedicel-girdling method (with the observations being treated by means of a subtractive technique) used to separate the contributions of xylem and phloem #ow to the total water in#ow to the fruit. The #ows were considered as solution transport through composite membranes and were calculated by means of equations drawn from non-equilibrium thermodynamics. The total in#ow of water was simulated as dependent on the water status in the tree. The hourly time step was used for the simulation. The #ows obtained by simulation of the pedicel-girdled fruit were compared with those found by simulation of the intact-pedicel fruit. The error introduced by the pedicel-girdling technique was evaluated theoretically and was shown to vary during the day, ranging from very small (relative error of 3}7%) at the period when the rate of fruit growth is maximal to 100% when the fruit volume does not change. The vascular #ows obtained from the &&girdling experiments'' are discussed in relation to the possible theoretically estimated errors.