Effect of photoperiod on apical growth cessation in tamarack (Larix laricina) and balsam poplar (Populus balsamifera) provenances from northern Ontario / by Paul D. Charrette
Bibliographic record
Abstract
The effects of four photoperiods (i.e. 6, 10, 14, and 18 hours) on the rate of apical \ngrowth cessation and apical bud primordia production were studied in controlled \nenvironment experiments using tamarack {Larix laricina (Du Roi) K. Koch) seedlings and \nrooted cuttings, and balsam poplar {Populus balsamifera L.) rooted cuttings from \nprovenances in northern Ontario. The objectives of this study were to investigate 1) the \neffect of photoperiod on shoot growth and the rate of growth cessation among provenances \nof tamarack and balsam poplar, 2) the variation in the rate of growth cessation between \nspecies from northern Ontario, and 3) the effect of different photoperiods on apical bud \nprimordia production among tamarack provenances. First-year tamarack seedlings from \nfour provenances in northern Ontario, balsam poplar rooted cuttings from five provenances \nranging from Rhinelander, Wisconsin to Hudson Bay, and two-year old tamarack rooted \ncuttings from five provenances in northern Ontario were tested. Tamarack provenances \ndisplayed significant variation in the critical daylength for inducing growth cessation, but \ndid not vary in the rate of growth cessation. Tamarack seedlings produced twice as many \naxial needle primordia in apical buds under a 10 hour photoperiod than a six hour \nphotoperiod. Balsam poplar displayed clinal variation in the critical daylength for inducing \ngrowth cessation and in the rate of growth cessation. The variation in the rate of growth \ncessation during short photoperiods was seen as an adaptation to an increasing rate of \nchange in daily photoperiod with increasing latitude.
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 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".