Experimental branch cooling increases foliar sugar and anthocyanin concentrations in sugar maple at the end of the growing season
Bibliographic record
Abstract
Autumnal leaf anthocyanin expression is enhanced following exposure to a variety of environmental stresses and may represent an adaptive benefit of protecting leaves from those stresses, thereby allowing for prolonged sugar and nutrient resorption. Past work has shown that experimentally induced sugar accumulations following branch girdling triggers anthocyanin biosynthesis. We hypothesized that reduced phloem transport at low autumnal temperatures may increase leaf sugar concentrations that stimulate anthocyanin production, resulting in enhanced tree- and landscape-scale color change. We used refrigerant-filled tubing to cool individual branches in a mature sugar maple (Acer saccharum Marsh.) tree to test whether phloem cooling would trigger foliar sugar accumulations and enhance anthocyanin biosynthesis. Cooling increased foliar sucrose, glucose, and fructose concentrations 2- to nearly 10-fold (depending on the specific sugar and sampling date) relative to controls and increased anthocyanin concentrations by approximately the same amount. Correlation analyses indicated a strong and steady positive relationship between anthocyanin and sugar concentrations, which was consistent with a mechanistic link between cooling-induced changes in these constituents. Tested here at the branch level, we propose that low temperature induced reductions in phloem transport may be responsible for increases in foliar sugars that trigger anthocyanin displays at grander scales.
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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 | 0.001 | 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 | 0.002 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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".