Recovery of<i>Bazzania trilobata</i>following desiccation
Notice bibliographique
Résumé
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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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».