Effect of phosphorus treatment on growth and yield in the medicinal herb <i>Calendula officinalis</i> L. (Standard Pacific) under hydroponic cultivation
Bibliographic record
Abstract
The North American market for herbal medicine has been rapidly growing over the past 20 yr. This has effectively created a stro ng public and regulatory demand for high quality, uniformity and safety of medicinal plant products. Greenhouse hydroponic cultivation under controlled environmental conditions allows the grower to provide pesticide-free conditions, lacking environmental contaminants, resulting in superior product quality and consistency. Calendula officinalis is evaluated here as an alternative greenhouse crop. Growing conditions (P concentrations) were manipulated in order to maximize flower-head (capitulum) yield, as the se are the most valuable marketable structures. It was found that high P concentrations did not increase flower production, but instead produced significantly more leaf biomass.Plants receiving the lowest P concentration, with an intermittent watering reg ime, had the greatest absolute reproductive output, and greatest mass of all tissues assessed, except for leaf tissue. They also had the greatest proportion of biomass allocated to reproductive structures. Calendula officinalis shows promise as a medicinal greenhouse crop that requires low P levels for optimal capitulum (inflorescence) production (target tissue). Its xerophytic characteristics are best supported through modification of standard hydroponic systems; these modifications may be widely applicab le to medicinal plants since many share Calendula’s xerophytic characteristics. We conclude that discontinuous nutrient supply and relatively low ratios of P relative to N and K may enhance production of target medicinal tissues of Calendula officinalis. Key words:
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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 | 0.000 | 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 | 0.001 |
| 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".