Seed ecophysiology and plant population ecology of Cynoglossum officinale L. and Tragopogon spp.
Notice bibliographique
Résumé
In order to understand persistence strategies of Cynoglossum officinale L., Tragopogon pratensis L., and T. dubius Scop. in the rangelands of British Columbia, ecophysiological characteristics of seed germination in C. officinale and Tragopogon spp. and dynamics of seed and plant populations in T.pratensis were investigated. A deep innate (primary) dormancy was found in C. officinale seeds, and the seed coat of this species played an important role in the regulation of seed germination by controlling 02availability to the embryo. Removal of the seed coat stimulated02 uptake which was due to both an increase in seed respiration and phenolic oxidation; seeds of C. officinale contained high levels of phenolic substances and seed extracts showed high polyphenol oxidase activity. The seed coat also prevented leaching of phenolic substances, which however, were not necessary for seed germination. Rosmarinic acid, the mostprominent phenolic substance present in the seeds of C.officinale, did not inhibit germination of decoated seeds at concentrations up to 3 mM. Analysis of the pattern of methanol-extractable phenolic substances showed no significant quantitative or qualitative correlation between changes inspecific phenolic compounds and seed germination induced by stratification or seed coat removal. These results suggest that phenolic substances in C. officinale seeds do not inhibit germination of this weed, but seed coat regulates germination by controlling 02 availability to the embryo. Ecophysiological characteristics of T. pratensis and T.dubius seed germination were studied under controlled conditions. Existence of secondary dormancy in these species was demonstrated by inducing dormancy by anaerobiosis treatment. This dormancy may play an important role in the persistence of Tragopogon spp. Secondary dormancy could be released by stratification and after-ripening in T. pratensis, but not by light. Seeds germinated over a range of temperatures with 15 C as the optimumin both weeds. A seed burial study showed that increased seeding depth had no effect on seed germination, but reduced seedling emergence. These results suggest that seeds in Tragopogon spp.can germinate in darkness and the reservoir of non-dormant seeds will become completely depleted under conditions conducive to germination regardless of burial depth. Patterns of plant mortality and reproduction in populations of T. pratensis and dynamics of its seed banks were investigated. Seedlings were marked in 1990 and 1991 and their fates monitored. High density-independent seedling mortality was observed in both cohorts. None of the plants flowered in the first or second growing season in the 1990 cohort. These results indicate that T.pratensis is not a biennial species. Size of age-specific plants varied significantly suggesting variations in growth rate among individuals. Flowering and seed production in non-age-specific populations were correlated with the root crown diameter (RCD).The variation of minimum RCD for plants that flowered in two years (0.2 and 0.6 cm) suggested that T. pratensis does not have a critical size requirement for flowering. The dynamics of seed banks were studied in space and time. Seed burial depth had a significant effect on seed dormancy after 2 to 3 months of burial. The seed populations were almost completely depleted after 9 to 10 months of burial. Since T. pratensis only has a transient seed bank, high seed production and long vegetative survival may play important roles in the persistence of this weed.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
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 | 0,001 | 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 | 0,000 |
| 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 ».