Localized increases of polyphenol concentration and antioxidant capacity in relation to the differential accumulations of copper and cadmium in roots and in shoots of sunflower
Bibliographic record
Abstract
In this study, we examined the relevance of polyphenols in the response of sunflower plants to acute Cu and Cd stresses. More specifically, we aimed to correlate spatially and temporally the accumulation of polyphenols with the occurrence of oxidative stress, and to estimate their contribution to the antioxidant capacities. Under our experimental conditions, the presence of Cu and Cd (75 µmol·L–1) in the nutrient solution caused oxidative damage, as detected by the accumulation of malondialdehyde, in roots of Cu-treated plants and in leaves of Cd-treated plants; in the latter, significant inhibition of photosynthesis also occurred. These effects were in agreement with the preferential accumulation of Cu in the roots and the greater translocation of Cd to the shoots. This oxidative damage was associated with a concerted plant response, characterized by stimulation of phenylalanine ammonia-lyase, ascorbate peroxidase, and guaiacol peroxidase activities, and by the accumulation of polyphenols whose concentrations were closely correlated (R2 = 0.95) to the total antioxidant capacity of plants extracts. Globally, the co-occurrence of oxidative damages and polyphenol accumulation, and the correlations among polyphenol concentrations, total antioxidant capacities, and stimulations of the peroxidases support the involvement of polyphenols in protection against oxidative damage generated by Cu and Cd in plants.
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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".