Determining the role of N remobilization for growth of apple (Malus domestica Borkh.) trees by measuring xylem‐sap N flux
Bibliographic record
Abstract
The contribution of N remobilization to the seasonal growth of field-grown Malus domestica (apple) trees was measured using two different techniques. 'Fuji' trees grafted on M.9 apple rootstocks were planted in the field and fertilized and irrigated for two growing seasons. During the second year, the trees received 15N-labelled fertilizer and destructive harvests were taken during the spring and summer to determine the pattern of N remobilization and uptake. At the same time, patterns of N translocation in the xylem were measured by sampling saps at each harvest and analysing them for their constituent amino acids and amides. Total water flux through the trunk xylem was also measured throughout the sampling period using the heat balance technique. The flux of amino compounds in the xylem was then calculated to see if this approach could quantify remobilization. Most of the N for leaf growth was provided by remobilization, which lasted for some 40 d following bud-burst. The labelled N was not taken up until 14 d after remobilization had started. The predominant amino compounds recovered in the xylem were Asn, Asp, Arg, and Gln, whose concentration peaked during remobilization, except for Arg whose concentration was highest at bud-break and declined thereafter. The amount of N translocated in the xylem as Asn, Asp and Gln correlated well with the amount of N remobilized (as measured by the recovery of unlabelled N in the new above-ground growth). The data suggest that Arg is translocated predominantly as a consequence of root uptake and they are discussed in relation to measuring N remobilization in field-grown trees.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| 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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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 teacher head, 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".