Evaluation of different methods for breaking cypsela dormancy in two local populations of Scotch thistle (<i>Onopordum acanthium</i> L.) collected from the west and northwest of Iran
Bibliographic record
Abstract
Scotch thistle ( Onopordum acanthium L.) is a weed species on farmlands and pastures in parts of the west and northwest of Iran. Cypselas can remain in the soil seedbank over a prolonged period due to varying degrees of dormancy. This study examined different methods for breaking cypsela dormancy in two local populations of Scotch thistle at the research laboratory of the Faculty of Agriculture of Azarbaijan Shahid Madani University in 2020. In these experiments, the effects of sulfuric acid, wet and dry prechilling, potassium nitrate, and gibberellic acid were evaluated on the breaking of dormancy. All the experiments were conducted as a completely randomized design with four replications and two runs. The response of two local populations of Scotch thistle were similar, and no significant difference was observed. The experiment treatments significantly increased cypsela germination compared with the control. The maximum germination percentages were observed in cypselas soaked in 98% sulfuric acid for 10 min (60.60%), KNO3 for 96 h (69.36%), GA3 for 48 h (88.43%), and wet prechilling for 72 h (34.61%). Although prechilling increased germination, it was suggested that germination could be more than the recorded values if the duration of wet prechilling was increased. The best cypsela germination rate, mean germination time, T50, and radicle and plumule length were observed after soaking in GA3 for 48 h and KNO3 for 96 h. It seems that water-soluble inhibitors in the embryo and probably the cypsela coat cause seed dormancy in this weed species. These findings could help develop effective management strategies associated with the dormancy of cypselas for this species.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| 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) | 0.000 | 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".