Effects of achene dimorphism on dormancy and progeny traits in the two ephemerals <i>Hedypnois cretica</i> and <i>Crepis aspera</i> (Asteraceae)
Bibliographic record
Abstract
Hedypnois cretica (L.) Dum.-Cours. and Crepis aspera L. are ephemeral composites native to the Mediterranean coastal desert of Sinai, Egypt, with marked achene dimorphism. This study examined the relationship between achene morphology and both some progeny traits and germination behaviour in terms of final germination percentage and germination speed. The effects of length of achene storage and temperature of storage on germination behaviour were particularly examined. Fresh harvested seeds showed little germination. After 6 months of storage, central achenes attained higher germination percentages in the two species and germinated faster in C. aspera than the peripheral achenes. The dormancy loss was faster in achenes of H. cretica than in those of C. aspera. Greater germination dimorphism was associated with greater dimorphism in size and morphology and consequently in the dispersal ability of the two morphs of C. aspera than in H. cretica. Warm storage significantly enhanced the germination level and speed of the heavier peripheral achenes compared with those of the central achenes of both species, so this was dependent on storage period. Plants produced by peripheral achenes had a significantly greater size than those from central achenes. This difference was more pronounced in H. cretica and persisted until 70 days postemergence but disappeared after 40 days in C. aspera. Results are discussed in light of possible adaptive significance and selective forces, such as the differential dispersal, dormancy, and growth of the two morphs, that maintain the dimorphism in the unpredictable heterogeneous deserts.Key words: achene dimorphism, Asteraceae, dormancy, germination, storage temperature.
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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 | 0.000 |
| 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".