Activities and survival of endophytic bacteria in white clover (<i>Trifolium repens</i>L.)
Bibliographic record
Abstract
In this study, the genera, abundance, and activities of endophytic bacteria in field-grown white clover (Trifolium repens) and the fate of introduced antibiotic-tolerant bacteria in white clover tissues were investigated. Pseudomonas, Pantoea, and Corynebacterium were the most frequently isolated endophytic bacteria genera, whereas Xanthomonas, Microbacterium, and Cellulomonas occurred less frequently. The average bacterial populations in stolons and roots were approximately 100,000 colony-forming units (CFU) (g wet mass)-1. Of the 28 strains tested for activity, none were chitinolytic or able to inhibit the root pathogen Codinaea fertilis in vitro. However, Fusarium oxysporum and Cylindrocladium scoparium were inhibited by one and five strains, respectively. Four of seven strains tested depressed clover seedling growth. In pot experiments, colonization and recovery of spontaneous rifampicin-tolerant mutants (Rif+) of bacteria were studied in clover plants for periods up to 20 weeks. The strains used, sourced from white clover (endophytic and rhizoplane) and organic compost, had previously shown growth promotion potential of white clover seedlings by increasing plant mass and decreasing nematode numbers. In one experiment in this present study, five Rif+ strains were individually inoculated onto white clover seedlings, all five were re-isolated from shoots after 6 weeks and four strains were re-isolated after 20 weeks (numbers of Rif+ bacteria ranged from 51 to 200 CFU (g wet mass)-1). No Rif+ bacteria were isolated from root tissue at either time. In the second experiment, conducted with two strains of Rif+ bacteria, the population was highest in the shoots (range>500 CFU of Rif+ bacteria (g shoot fresh mass)-1) in weeks 2 and 3, declining to <200 CFU in week 5. Again, no Rif+ bacteria could be detected in roots. No Rif+ bacteria were recovered after 14 weeks for one of the strains. It appears that the main route of bacterial entry into seedlings was through stomata and that bacteria remained in the aerial parts of plants rather than migrating to the roots.
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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) | 0.000 | 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 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".