How concentration effects, osmotic stress, biomass penalties and metabolite responses are separated before any flavour claim.
Explanation
A treatment can increase the concentration of a compound per gram while reducing total plant growth. Both outcomes must be reported.
Response model
ExplanationConcentration alone can rise when a plant becomes smaller. Multiplying by dry mass reveals the total compound produced per plant.
Mint species show species-dependent essential-oil and antioxidant responses under salinity, accompanied by growth effects.
Arugula EC trials report simultaneous changes in growth, nutritional quality and flavour-related phytochemicals, demonstrating why yield and chemistry must be analysed together.
Measured water-stress sequence
Fevgas and colleagues published 145 hourly soil-moisture records with RGB, thermal and pseudo-colour lettuce images. The normally irrigated sequence starts at 75% and ends at 73%. The non-irrigated sequence starts at 75% and ends at 8%. A difference of at least 10 percentage points persists from 14 January 2024 at 09:24:45 (UTC+2).
Water availability and image-derived stress signals change on different scales
The upper panel contains every hourly moisture record. The lower panel measures a fixed colour rule on the authors’ pseudo-colour outputs.
Values
316 observations.
Note. Fevgas et al. (2025), CC BY 4.0. Sensor values and pseudo-colour images are reproduced from the published dataset. The two-plant sequence illustrates measurement alignment and is not used as a population estimate.
The lower panel applies one fixed pixel rule to the authors' pseudo-colour outputs: R > 180, G > 180, B < 130 and R + G > 420. Yellow overlay occupies 35.13–52.28% of the detected canopy in the 13 non-irrigated outputs and 0.02–4.11% in the irrigated outputs. This is a measurement of the published visualisation, not a newly trained disease or stress classifier.
Published pseudo-colour outputs for irrigated and non-irrigated lettuce
The authors’ images are shown at their original aspect ratio. No generated plant image or synthetic stress region is added.
Values
| Series | Value | Note |
|---|---|---|
| Irrigated · capture 1 | Published pseudo-colour output | Source file Normal_1.jpg. Full frame retained; no generated or edited plant content. |
| Irrigated · capture 7 | Published pseudo-colour output | Source file Normal_7.jpg. Full frame retained; no generated or edited plant content. |
| Irrigated · capture 13 | Published pseudo-colour output | Source file Normal_13.jpg. Full frame retained; no generated or edited plant content. |
| Non-irrigated · capture 1 | Published pseudo-colour output | Source file Stressed_1.jpg. Full frame retained; no generated or edited plant content. |
| Non-irrigated · capture 7 | Published pseudo-colour output | Source file Stressed_7.jpg. Full frame retained; no generated or edited plant content. |
| Non-irrigated · capture 13 | Published pseudo-colour output | Source file Stressed_13.jpg. Full frame retained; no generated or edited plant content. |
Note. Hybrid-framework pseudo-colour images from Fevgas et al. (2025), CC BY 4.0. The fixed yellow-pixel calculation is documented in summary.json.
Separating water, nutrient and disease signals
A colour change is not assigned a cause from RGB alone. Water stress is checked against reservoir level, root-zone contact, temperature and moisture or water-potential measurements. Nutrient state is checked against the delivered formulation, pH, EC and tissue analysis. Disease labels require symptom-specific expert or laboratory confirmation. The same image can contribute features to each analysis, but each endpoint has its own reference measurement.
Time to detection
For a new cultivation run, detection time is measured from the recorded treatment change to the first alert that remains above threshold for a declared number of consecutive captures. The report includes false-alert rate in control plants, sensitivity, median detection delay and an interval across biological replicates. This distinguishes early detection from a visually strong endpoint image.
FlavoRotor rule
No salinity or water-stress recipe is released without biomass, tissue water, visual quality, chemical endpoints and sensory confirmation. Severe stress is not used merely to create a larger analytical signal.