Exploring functional definitions of mycorrhizas: Are mycorrhizas always mutualisms?
Bibliographic record
Abstract
Mycorrhizas are considered to be classic mutualisms. Here, we define mutualism as a reciprocal increase in fitness of the symbionts, and we review the evidence for mycorrhizal mutualism at the community, whole-plant, and cellular scales. It is difficult to use results of most mycorrhizal studies because (i) fungal contribution to nutrient uptake is not accurately estimated, (ii) increased growth is not necessarily correlated with increased plant fecundity or survival, especially in communities, and (iii) benefits that occur only at certain times of year, or under specific extreme conditions, may not be detected. To produce the nonmycorrhizal controls required to study mutualism in the field, soil microflora and fauna must be severely perturbed; therefore, it is virtually impossible to evaluate effects of mycorrhizas on plant fitness under realistic conditions. Using the evidence available, we conclude that mycorrhizas can occupy various positions along the continuum from parasitism to mutualism, depending on the specific plant and fungal genotypes and their abiotic and biotic environments. Although we discuss the possibility of defining mycorrhizas by some physiological characteristic, we conclude that mycorrhizas should be defined on a structural or developmental basis and that any requirement to demonstrate mutualism be eliminated.Key words: mycorrhiza, mutualism, parasitism, physiology, fitness, community.
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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 | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 0.010 |
| Scholarly communication | 0.003 | 0.007 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 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".