Effects of temperature and water deficit on cambial activity and woody ring features in Picea mariana saplings
Bibliographic record
Abstract
Increase in temperature under the projected future climate change would affect tree growth, including the physiological mechanisms related to sapling responses, which has been examined recently. The study investigated the plant water relations, cambial activity and wood formation in black spruce saplings [Picea mariana (Mill.) B.S.P.] subjected to water deficit and warming. Four-year-old saplings growing in three greenhouses were submitted to different thermal conditions: T0, with a temperature equal to the external air temperature; and T + 2 and T + 5, with temperatures set at 2 and 5 K higher than T0, respectively. We also submitted saplings to two irrigation regimes and studied the effects of a water deficit of 32 days in May-June. We evaluated plant water relations, cambial activity, wood formation and anatomical characteristics from May to October 2010. Lower needle physiology rates were observed during water deficit, with 20-day suspension of irrigation, but after re-watering, non-irrigated saplings attained the same values as irrigated ones in all thermal conditions. Significant differences between irrigation regimes were detected in cambial activity at the end of the water deficit and after resumption of irrigation. Under warmer conditions, the recovery of non-irrigated saplings was slower than T0 and they needed from 2 to 4 weeks to completely restore cambial activity. No significant differences in wood anatomy were observed between irrigation regimes, but there was a sporadic effect on wood density under warming. During wood formation, the warmer conditions combined with water deficit increased sapling mortality by 5 and 12.2% for T + 2 and T + 5, respectively. The black spruce saplings that survived were more sensitive to water availability, and the restoration of cambial activity was slower at temperatures higher than T0. Our results suggest that black spruce showed a plastic response to intense water deficit under warming, but this would compromise their survival.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".