Allelopathic Potential of Echinacea angustifolia's Ethanolic Root Extracts
Notice bibliographique
Résumé
The narrow-leafed purple coneflower (Echinacea angustifolia D.C.) is a perennial native to North America. Echinacea angustifolia is found on dry prairies from Texas to Saskatchewan, west to the Rocky Mountains and east to Minnesota. Echinacea angustifolia produces many biologically active compounds that have shown allelopathic effects on lettuce (Lactuca sativa), switchgrass (Panicum virgatum) and prairie dropseed (Sporobolus heterolopis). Natural allelopathic chemicals have the potential of being used for the production of herbicides that are environmentally safe. These allelopathic compounds possess components that could be used in the development of new herbicides. The objectives of this work are to identify the ethanol soluble compounds of E. angustifolia and to examine their potential for use as natural herbicides. The allelopathic potential of ethanol soluble compounds from E. angustifolia roots from five populations (South Dakota, North Dakota, Wyoming, Kansas, and Nebraska) were examined. A common allelopathy bioassay was performed using lettuce seeds germinated in the presence of the ethanol extracts pipetted on filter paper. The extracts were brought to dryness and were resuspended in deionized water. Analysis of the seed assay was completed by measuring percent germination and root elongation of 25 lettuce seeds per replication for extracts from each of 100 E. angustifolia plants (20 plants per population). Results from the lettuce seed bioassay experiment showed that germination in the presence of Echinacea extracts ranged from 100% to 0%. As collection sites moved southward, the allelopathic potential tends to decrease. Root extracts were concentrated by evaporation and analyzed by reverse phase high performance liquid chromatography (HPLC) using a C-18 column. Absorbancy was measured at 210-nm and 254-nm. HPLC analyses revealed eleven significant peaks in all populations. The parameters of germination, root elongation and peak area were used to conduct a multiple regression analyses. These results showed that compounds identified as peak numbers three and six contribute to 72 % of the allelopathic effects of E. angustifolia root extracts. Lettuce seed germination assays showed that peaks three and six caused significant reductions in both germination and root elongation. The combined peaks were found to have an additive effect on root elongation but a synergistic effect on germination. Since peaks three and six were of most interest they were further identified by comparison HPLC analyses performed by Bauer and Remiger (1989) and NMR (nuclear magnetic resonance) at the University of Illinois, Urbanna. Peak three was identified as undeca-2E-ene-8, 10-diynoic acid isobutylarnide and peak six was identified as dodeca-2E,4E,8, 10E-tetraenoic acid isobutylarnide.
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 | 0,000 | 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 | 0,000 |
| 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 ».