Functional analysis of synchronous dichogamy in flowering rush, <i>Butomus umbellatus</i> (Butomaceae)
Bibliographic record
Abstract
Dichogamy is one of the most widespread floral mechanisms in flowering plants and is thought to have evolved to reduce interference between pollen import and export within flowers, especially self-pollination. Self-pollination between flowers may also be reduced if dichogamy is synchronous among flowers on an inflorescence. The analysis of dichogamy at both levels requires that the sexual phases of individual flowers be defined functionally in terms of pollen deposition and removal. We conducted morphological and functional analyses to investigate the degree of dichogamy within flowers and the synchronicity of dichogamy between flowers within inflorescences in an emergent, aquatic monocot, flowering rush (Butomus umbellatus). Based on daily observations of the development of marked flowers, data on the schedule of anther dehiscence within flowers, and repeat surveys of floral sex ratios in three populations, individual flowers appear to be strictly protandrous. On average, each flower spends ∼1 d in each of male and female phases with an intervening 1-d neuter phase during which there is no available pollen in anthers and stigmas are not yet exposed to receive pollen. Morphological criteria used to delimit the beginning and end of each of these three sex phases were validated by quantifying the temporal schedule of pollen removal from anthers and pollen deposition on stigmas. Experimental pollinations showed that the morphological changes marking the end of female phase are hastened by pollen deposition. At the umbel level, synchronous development within sequential cohorts of flowers reduced overlap of male and female sexual phases between flowers. On average (±1 SE), 72 ± 3% of flowers completed their female phase while no other flowers on the same umbel were in male phase. Computer simulations of umbel development showed that this value is significantly higher than expected if the timing of flower development within umbels was random (30 ± 1%). Surveys of floral sex ratios in three populations revealed that 87% of umbels were either unisexual male or female at any given time. Pollinators usually visited more than one flower in sequence when foraging on umbels, suggesting that synchronous dichogamy may be an adaptation to avoid geitonogamy. The adaptiveness of both flower- and umbel-level dichogamy is also suggested because both traits are expressed to a lesser extent in obligately clonal, triploid populations, where flowers do not make seeds and hence floral adaptations are not maintained by natural selection.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| 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".