Combining leaf gas-exchange and stable carbon isotopes to assess mycoheterotrophy in three species of Pyroleae
Bibliographic record
Abstract
Determining the extent of mycoheterotrophy (MH) in plants, primarily through the use of stable isotope methods, has gained considerable attention in the last decade. The aim of this study was to characterize the rates of photosynthesis (PS) and several gas-exchange parameters, as well as stable carbon isotope composition (δ13C) of partially mycoheterotrophic (PMH) Pyroleae compared with autotrophic reference species of Ericaceae. An end-member mixing model was applied to δ13C, deriving estimates of % C gained via fungi (CDF). The δ13C was significantly enriched for Orthilia secunda and Pyrola chlorantha (relative to autotrophs) resulting in estimates of CDF ranging from 13.8% to 20.8%. Despite significantly lower PS rates for O. secunda and P. chlorantha, as well as lower conductance and transpiration, there were no significant differences in the Ci:Ca ratios across all of the species, suggesting that the C isotope inferences for these two species were reflective of fungal C gains. By contrast, results for all of the variables indicated primarily autotrophic C nutrition for Chimaphila umbellata. Further studies, such as isotope labelling experiments or assessments of biochemical constraints to autotrophy, may resolve the uncertainties in these species, allowing more accurate understanding of the complex nutritional mode of these plants.
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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 | 0.001 | 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 | 0.001 | 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".