Two distinct fungi colonize roots and rhizomes of the myco-heterotrophic <i>Afrothismia gesnerioides</i> (Burmanniaceae)
Bibliographic record
Abstract
The subterranean organs of Afrothismia gesnerioides H. Maas consist of short rhizomes densely covered with ovoid root tubercles, each of which may extend into a short filiform root extension. Serial sections revealed the presence of two distinct fungi occupying different niches within the plant tissues. Rhizomes and roots are divided into separate compartments hosting different morphotypes of the aseptate, exclusively intracellular hyphae of fungus A: (i) straight and persistent hyphae in the root epidermis, root extension, and outer rhizome cortex, (ii) coiled but still persistent hyphae in the third root layer, (iii) coiled hyphae undergoing degeneration in the root cortical parenchyma, (iv) starch depositions in the inner rhizome cortex and no colonization by fungus A, and (v) a partly collapsed root hypodermis serving as compartment barrier. The colonization by fungus A is interpreted as an aberrant arbuscular mycorrhiza of the Paris type. The compartmentation allows the separation of tissues where the hyphae stay functional from those in which the fungal material is digested. This pattern may represent a complex but efficient strategy for a sustained benefit from the few fungal penetrations that occur. Comparison with earlier work on Afrothismia winkleri (Engl.) Schltr. revealed considerable differences between the mycorrhizae that are interpreted as evolutionary steps. There are signs that these changes even may have improved the mycorrhizal benefit for the plant. The monomorphic hyphae of fungus B are smaller in diameter, septate, grow inter- as well as intra-cellularly, but are always characteristically appressed to the inner cell walls. It does not change its appearance within the root/rhizome compartments as does fungus A. Neither hyphal degeneration nor interferences with fungus A, starch depositions, or alterations in the development of A. gesnerioides could be noticed. Fungus B possibly is a commensal, but relevance to the symbiosis cannot be ruled out.
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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 | 0.001 | 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".