Water entry into detached root systems saturates with increasing externally applied pressure; a result inconsistent with models of simple passive diffusion
Bibliographic record
Abstract
The most widely accepted model of radial water entry from the soil into the xylem of roots is based on principles of ordinary passive diffusion. However, long-standing problems with this model remain unresolved, which concern variable intrinsic properties of conductivity, Lp, changing reflection coefficients, sigma, and inaccurate resolution of osmotic differentials between the soil and xylem. Our study re-examined pressure flow relationships in isolated roots of tomato (Lycopersicon esculentum Mill. cv. Montfavet), pea (Pisum sativum cv. Baccara) and soybean (Glycine max L. Merryl cv. Essor) manipulated in a pressure chamber. In addition to problems previously recognized with the simple passive diffusion model, a new conflict, flow saturation, was observed at high pressures. Experiments revealed that the plateau in flow, Jmax seen at high pressures followed natural rhythms diurnally and developmentally, and was not due to root damage or unnatural flow restriction. Near the end of the photoperiod, Jmax closely correlated with root dry mass. The above inconsistencies between observations in pressure-flow kinetics and ordinary passive diffusion indicate that either the current model should be adjusted or a new model should be proposed.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".