The shoot regeneration capacity of excised Arabidopsis cotyledons is established during the initial hours after injury and is modulated by a complex genetic network of light signalling
Bibliographic record
Abstract
Excised plant tissues (explants) can regenerate new shoot apical meristems in vitro, but regeneration rates can be inexplicably variable. Light affects rates of shoot regeneration, but the underlying mechanisms are poorly understood. Here, excised Arabidopsis cotyledons were dark-light shifted to define the timing of explant light sensitivity. Mutants and pharmacological agents were employed to uncover underlying physiological and genetic mechanisms. Unexpectedly, explants were most light sensitive during the initial hours post-excision with respect to shoot regeneration. Only ∼100 µmol m(-2 ) s(-1) of fluorescent light was sufficient to induce reactive oxygen species (ROS) accumulation in new explants. By 48 h post-excision, induction of ROS, or quenching of ROS by xanthophylls, increased or decreased shoot regeneration, respectively. Phytochrome A-mediated signalling suppressed light inhibition of regeneration. Early exposure to blue/UV-A wavelengths inhibited regeneration, involving photoreceptor CRY1. Downstream transcription factor HY5 mediated explant photoprotection, perhaps by promoting anthocyanin accumulation, a pigment also induced by cytokinin. Surprisingly, early light inhibition of shoot regeneration was dependent on polar auxin transport. Early exposure to ethylene stimulated dark-treated explants to regenerate, but inhibited light-treated explants. We propose that variability in long-term shoot regeneration may arise within the initial hours post-excision, from inadvertent, variable exposure of explants to light, modulated by hormones.
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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 | 0.000 |
| 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".