Accumulation of phenolic compounds in plants and nutrient solution of hydroponically grown peppers inoculated with<i>Pythium aphanidermatum</i>
Bibliographic record
Abstract
Root browning is a principal symptom of pythium root rot of pepper (Capsicum annuum) caused by Pythium aphanidermatum, but its biochemistry and physiological importance are poorly understood. Phenolic compounds were quantified over time in hydroponically grown pepper plants that were inoculated with zoospores of P. aphanidermatum or not inoculated (controls). The data were examined in relation to biotrophic colonization of the roots by the pathogen (roots remained white), necrotrophic colonization (roots turned brown), and plant growth. Colonization remained biotrophic in a temperature regime of 22:19 °C (temperature reduced at 2 days after inoculation) but became necrotrophic when the temperature was raised from 22 °C to 28 °C and when plants were kept continuously at 28 °C. Concentrations of free and cell-wall-bound phenolics, respectively, increased two- to three-fold and up to six-fold in inoculated roots compared with noninoculated roots maintained at 28 °C, and after the temperature was raised in the 22:28 °C regime; no differences were found in the 22:19 °C regime. Phenolic accumulation in inoculated roots coincided with, and paralleled, root browning. Pearson correlations of free and bound phenolics in relation to browning of the roots were moderate to high (r p = 0.40–0.90) and high (r p = 0.80–0.93), respectively. Observations of roots stained with p-nitroaniline indicated that phenolic compounds accumulated mainly in the brown as opposed to white roots. Increases in free and bound phenolics in the shoots coincided with phenolic accumulation and browning in the roots, but the leaves remained green. Phenolic compounds accumulated in nutrient solutions of all treatments, but levels were higher for inoculated plants with brown roots compared with those with only white roots and compared with the controls. Pythium aphanidermatum did not significantly affect dry mass of roots and shoots under conditions conducive to biotrophy (22:19 °C), but growth ceased and dry mass often declined when inoculated roots turned brown (28 °C). It is concluded that marked increases in concentrations of phenolics in roots, shoots, and nutrient solutions, and abrupt cessation of growth in hydroponically grown pepper plants inoculated with P. aphanidermatum were associated with the development of root browning.
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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 | 0.000 |
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".