Nonstructural carbohydrate-balance response to long-term elevated CO<sub>2</sub> exposure in European beech and Norway spruce mixed cultures: biochemical and ultrastructural responses
Bibliographic record
Abstract
Two dominant central European tree species (Fagus sylvatica L. and Picea abies (L.) Karst.), in a mixed culture in semi-open glass domes, were used to simulate the reaction of forests to long-term elevated CO2 (EC) in a mountainous area (Beskydy Mountains, the Czech Republic). We investigated the effects of EC on soluble carbohydrate levels and composition. Starch content was evaluated using two methods: biochemical (glucose content after enzymatic hydrolysis) and stereological (starch grain proportion, size, and number in chloroplasts). In beech and spruce foliage, no significant changes in total soluble carbohydrate levels were observed. In spruce, starch content determined biochemically increased under EC, whereas no changes were detected in beech. The starch content determined stereologically increased only in beech. In spruce, EC exposure caused comparable starch increases in current-year and previous-year needles, although the former had a higher starch content and numerous larger starch grains regardless of CO2 concentration. In both species, the biochemical determination of carbohydrates exhibited greater individual tree uniformity, in contrast to large intraspecies variability. No changes in leaf soluble carbohydrates under long-term elevated CO2 demonstrate the ability of the studied tree species to efficiently allocate the photosynthates among the sinks. Thus, no photosynthetic downregulation via carbohydrate-level signalling can be expected.
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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 | 0.000 |
| 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 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".