Floral nectar production in <i>Helleborus foetidus</i>: an ultrastructural study
Bibliographic record
Abstract
The floral nectaries of Helleborus foetidus L. were studied using scanning and transmission electron microscopy, as well as light microscopy. Nectaries are tubular and consist of an external epidermis, a photosynthesizing parenchyma, large branches of vascular tissue, a nectar-producing parenchyma, and an internal epidermis. The external epidermis is characterized by thick outer walls and a thin cuticle. Cells of the photosynthesizing parenchyma are characterized by chloroamyloplasts. The nectar-producing parenchyma consists of small cells with lobed nucleus, several small vacuoles, and numerous undifferentiated elongated plastids. These cells contain lipid bodies, Golgi membranes, and rough endoplasmic reticulum and are connected by numerous plasmodesmata. Parenchyma cells around sieve elements contain some amyloplasts. The outer cell wall of the internal epidermis displays a central thinned area containing a depression. The cuticle is very thick with amorphous structure, especially evident in its proximal part. Secretion takes place only in the inner basal region of the nectary cup. The surface of the internal epidermis is devoid of secreting structures. Nectar is released by fracture of the cuticle and underlying cell wall; however, epidermal cell death is not apoptotic. This holocrine secretion is coupled with a more common merocrine secretion through which nectar accumulates in subcuticular spaces. This combined secretion mode produces an enriched “nectar soup” crucial for interactions with pollinators and yeasts during winter flowering.
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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".