Differences in tissue concentrations of hydrogen peroxide in the roots and cotyledons of annual and perennial species of flax (<i>Linum</i>)
Bibliographic record
Abstract
Short-lived annuals should allocate more resources towards reproduction, whereas long-lived perennials should allocate more resources towards tissue maintenance. Although ecological data support this hypothesis, no studies have examined the physiological basis for lifespan differences between annuals and perennials. Based on the oxidative theory of aging, hydrogen peroxide (H2O2) levels should be lower in perennating tissues (e.g., basal roots) — but not nonperennating tissues (e.g., cotyledons) — from perennials compared with annuals. We tested this prediction using two annual and two perennial species of flax ( Linum ). As predicted, H2O2concentrations were lower in roots from perennials than from annuals, reflecting higher catalase activity in roots from perennials. In cotyledons, contrary to our predictions, H2O2concentrations were actually higher in perennials than in annuals, despite higher catalase activity in perennials as well, likely reflecting higher H2O2production via peroxisomes and chloroplasts. Therefore, we propose that, consistent with the oxidative theory of aging, perennial flax species have a lower oxidative burden in their roots, but this comes at the cost of a greater oxidative burden in their shoots. As we demonstrate, perenniality is ancestral in Linum, and so derivation of the annual condition likely involved a physiological shift towards a more equitable oxidative burden between roots and shoots.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".