Autochthonous Streptomyces regulate the metabolism of seedlings of Araucaria angustifolia (Coniferales) during root colonisation
Bibliographic record
Abstract
Araucaria angustifolia (Bertol.) Kuntze, known as Brazilian pine, is an endangered species of great ecological and economic importance. This species grows slowly and unevenly, with high mortality in commercial plantations. Streptomyces is a genus of soil microorganisms that may have a beneficial effect on plant growth. This study evaluated the effect of three autochthonous Streptomyces spp. isolates (PM1, PM4 and PM9) on the initial metabolism and development of A. angustifolia seedlings. The enzymatic activity of phenylalanine ammonia-lyase, polyphenol oxidase and peroxidase, and the levels of phenolic compounds, flavonoids and chlorophyll were determined in extracts from roots and leaves of the seedlings. Assays were carried out 1, 3 and 9 days after the roots were inoculated with each isolate. Length and fresh mass of shoots and roots as well as the volume and density of roots were evaluated at 100 days after seedling inoculation. All the Streptomyces spp. showed rhizospheric competence and produced auxin. The activities of polyphenol oxidase and peroxidase exhibited a tissue-temporal regulation in the presence of the isolates. Levels of phenolics, flavonoids and chlorophylls did not change in the period analysed. The root system of seedlings inoculated with all isolates was shorter and denser, with a small volume. The PM9 isolate promoted shoot growth and affected plant metabolism, proving to be a promising rhizobacterium with a plant growth-promoting rhizobacteria role.
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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".