Effects of mycorrhizal fungi on tree seedling growth: quantifying the parasitism–mutualism transition along a light gradient
Bibliographic record
Abstract
Mycorrhizal fungi colonize tree seedlings shortly after germination, and the nature of this relationship (mutualistic to parasitic) has been reported to vary as a function of resources; however, this transition has rarely been quantified. Using a light gradient, we grew seedlings of eight tree species in soils that were cultivated by several co-existing species of trees. We used data on root mycorrhizal fungi to quantify colonization along the gradient of light. We then analyzed plant growth as a function of both the light gradient and the extent of mycorrhizal colonization. Mycorrhizal fungi colonization varied among species but was not correlated with the species’ seed sizes or shade tolerances. Within a species, colonization varied among soil sources, but those differences followed neither the conspecific–heterospecific dichotomy, nor the soil host’s arbuscular–ectomycorrhizal associations commonly reported. At high light levels, seedlings growth increased with increasing levels of colonization for seven species, and at low light levels, the effect of colonization was negative for five species. We also quantified the light threshold at which the plant – mycorrhizal fungi relationship shifted from neutral to positive (four species), from negative to neutral (one species), and from neutral to negative (one species), documenting differences among species that could exacerbate competitive interactions during recruitment.
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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 | 0.001 |
| 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".