Recovery of<i>Bazzania trilobata</i>following desiccation
Bibliographic record
Abstract
Colonies of Bazzania trilobata (L.) S. Gray, a common and abundant species on the floor of closed canopy mixed and coniferous forests in New Brunswick, were observed to be pale and dry within a 2-yr-old clear-cut area. This multi-part study used a combination of approaches to assess the species' tolerance of various drying regimes. 1) To determine viability of field-dried shoots, bundles of shoots from the clear-cut and from an adjacent closed canopy forest (controls) were compared in terms of color and net photosynthetic rate (using Infra Red Gas Analysis, IRGA) before and after two months of laboratory “recovery” conditions (light, temperature, and humidity similar to those documented in closed canopy forest). Shoot elongation during recovery was also quantified. Field-dried shoots were viable: following recovery period, they had increased in length, shifted in hue, and displayed positive net photosynthesis, however none of these measures of metabolic activity equaled those of the controls. 2) The moisture content at saturation, determined for reference, was 1296.4% by weight. 3) The drying effect of the IRGA process was evaluated by subjecting moist pre-weighed bundles of shoots to three successive sequences of IRGA, re-weighing, and 24 hr of recovery. IRGA resulted in slight (approximately 40%) moisture loss from shoots initially averaging 368.9% moisture (S.E. = 9.96%), but did not cause a significant decrease in net photosynthesis within this range. 4) Tolerance of drying was tested on freshly collected, forest-acclimated moist shoots. Initial net photosynthesis (by IRGA) and moisture content were determined for replicate bundles of shoots. These were then subjected to drying for 1, 2, 4, 7, and 12 d, while control groups were stored at recovery conditions. Net photosynthesis and moisture content were re-measured after drying, and again after 24 hr of recovery. Moisture content of controls declined by approximately 40% during IRGA, and gradually thereafter in recovery conditions; net carbon gain declined over the course of the study. Moisture content of dried shoots declined by an order of magnitude in all treatments, but returned to near control levels after recovery. However, net photosynthesis dropped to zero with drying, and did not resume after rehydration. In view of the sensitivity of B. trilobata to laboratory drying, and its viability on a 2-yr-old clear-cut, we suggest that a) field conditions are neither as severe nor as prolonged as those tested in the laboratory and b) the colonial form prevents inner shoots from uniform exposure to severe conditions.
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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".