Effect of elevated gibberellic acid application on growth and gene expression patterns in white spruce families from a tree improvement program in Alberta, Canada
Bibliographic record
Abstract
Nine open-pollinated families of Picea glauca (Moench) Voss from the Region D1 Controlled Parentage Program (Alberta, Canada) were systematically chosen from fast, medium and slow-growth rankings based on breeding values for height from field progeny tests at age 30 years. Seeds from these families were sown and grown to age 3 years to analyze the performance and correlations of growth, physiological traits and expression of gibberellin-related genes, with and without elevated gibberellic acid 3 (GA3) application, under greenhouse conditions. We observed a significant interaction effect between families and growth groups subjected to 50 μg μl-1 of GA3 treatment, causing a decrease in apical internode length, diameter, volume and absolute transcript level for fast-growing families but an increase for families in the slow-growth group for the same traits. We also observed that in the apical internode, the gene PgGA20ox1 had significantly more relative expression under the elevated GA3 treatment than the control trees. In the stem, PgGA3ox1 showed a significantly higher relative expression under elevated GA3 treatment compared with control trees. Also, the slow-growth group showed more relative expression of PgGA20ox1 (in the apical internode) and PgGA3ox1 (in the stem) than the fast-growth group. The apical internode length and diameter significantly increased by 24% and 16%, respectively, with the hormone treatment in the slow growing group. In general, the PgGID1 and PgDELLA1 genes were upregulated and downregulated respectively, in spruce shoots under the GA3 treatment, meaning a positive feedback regulation by those genes were influencing PgGA20ox1 and PgGA3ox1 expression in that tissue type. Moreover, there was a significant correlation between absolute transcript levels of PgGA20ox1 in the apical internode and apical internode length, and absolute transcript levels of PgGA3ox1 in the stem and the diameter, in the fast-growth group families. This study shows that expression of GA genes is a limiting factor for growth in certain white spruce families with a complex feedback mechanism. Finally, absolute transcript levels of endogenous GA relative to growth parameters in juvenile seedlings could potentially be used to accelerate the early selection of families with inherently rapid apical and radial growth expansion.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".