The plant vigor hypothesis applies to a holoparasitic plant on a drought-stressed host
Bibliographic record
Abstract
Parasitic plants extract resources from host vascular tissues but their responses to environmental fluctuation experienced by the host are poorly studied. Three frequently-cited hypotheses for effects of environmental stress on plant resistance to herbivores predict decreased, increased, or fluctuation in herbivore performance in response to drought stress. We tested which hypothesis best accounts for how drought stress applied to a perennial herb affects growth of the holoparasite, Cuscuta gronovii Willd. ex Roem. & Schult. (common dodder), an obligate shoot parasite. Verbesina alternifolia (L.) Britton ex Kearney (wingstem) supporting single, young C. gronovii were exposed to continuous, pulsed, or no water stress for 32 days and then dry mass of each parasite was determined. Consistent with the plant vigor hypothesis, C. gronovii grew significantly better on well-watered hosts. Continuous and pulsed drought stress of the host resulted in similar growth reduction relative to no drought stress. In addition to reducing absolute growth of the holoparasite, continuous and pulsed drought stress reduced the growth of the holoparasite relative to host growth. Although functionally similar to insect phloem feeders, growth of holoparasites such as C. gronovii is constrained by source–sink relations. Our results suggest drought stress experienced by a host weakens source strength and reduces uptake by the holoparasite acting as a sink.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".