Tracing uptake and translocation of phosphorus in wheat using oxygen isotopes and mathematical modelling
Bibliographic record
Abstract
Summary Understanding P uptake in soil–plant systems requires suitable P tracers. The stable oxygen isotope ratio in phosphate (expressed as δ18OP) is an alternative to radioactive labelling, but the degree to which plants preserve the δ18OP value of the P source is unclear. We hypothesised that the source signal will be preserved in roots rather than shoots. In soil and hydroponic experiments with spring wheat (Triticum aestivum), we replaced irrigation water by 18O‐labelled water for up to 10 d. We extracted plant inorganic phosphates with trichloroacetic acid (TCA), assessed temporal dynamics of δ18OTCA‐P values after changing to 18O‐labelled water and combined the results with a mathematical model. Within 1 wk, full equilibration of δ18OTCA‐P values with the isotope value of the water in the growth medium occurred in shoots but not in roots. Model results further indicated that root δ18OTCA‐P values were affected by back transport of phosphate from shoots to roots, with a greater contribution of source P at higher temperatures when back transport was reduced. Root δ18OTCA‐P partially preserved the source signal, providing an indicator of P uptake sources. This now needs to be tested extensively for different species, soil and climate conditions to enable application in future ecosystem studies.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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".