The FlavoRotor drum turns around a horizontal axis. Gravity remains vertical and close to 9.81 m·s⁻², while each plant module changes orientation relative to that vector. Rotation therefore produces a periodic directional stimulus, not reduced gravity. The encoder record links angle, angular speed and direction to every image and sensor sample.
\n\nGravity-sensing cells contain dense, starch-rich amyloplasts. After reorientation, the amyloplasts move towards the new lower side of the cell. That physical change alters gravity signalling and directional auxin transport. Unequal growth on opposite sides of the organ produces curvature: primary roots usually bend with gravity, while shoots usually bend against it.
\n| Stage | Root | Shoot | Measurement |
|---|---|---|---|
| Gravity sensing | columella cells in the root cap | endodermal cells | module angle and time after reorientation |
| Signal | asymmetric auxin transport towards the lower flank | directional auxin redistribution | organ angle and curvature over time |
| Growth response | positive gravitropic bending | negative gravitropic bending | root-tip angle, shoot angle and elongation rate |
The biological input depends on both orientation and exposure time. A slow cycle permits a longer dwell at each angle; a faster cycle changes direction more often. Drum speed is therefore reported together with acceleration ramps, stop duration and the complete angle-time series.
\n| Speed | Cycle period | Radius | Centripetal acceleration | Fraction of g |
|---|---|---|---|---|
| 0.5 rpm | 120 s | 0.15 m | 0.000411 m·s⁻² | 0.0000419 |
| 2.0 rpm | 30 s | 0.15 m | 0.00658 m·s⁻² | 0.000671 |
At these example settings, centripetal acceleration is less than 0.07% of g. The dominant physical input is the changing direction of the gravity vector in plant coordinates. Vibration, airflow, liquid movement and start-stop transients are measured separately because they can also change plant growth.
\nDrum angle also determines when each root module enters and leaves the nutrient solution. For every position, the run record stores immersion depth, immersed duration, drainage duration and retained liquid mass. A biological comparison must match average light and root-zone exposure between rotating and control plants; otherwise orientation, illumination and hydroponic contact change together.
\n| Group | Variable isolated |
|---|---|
| Static plant with matched mean light and root exposure | baseline |
| Rotating plant | combined periodic orientation treatment |
| Static plant with matched time-varying light | light distribution |
| Static plant with matched vibration | mechanical vibration |
| Rotating plant with slow acceleration ramps | start-stop transient |
Primary endpoints are chosen before cultivation: root-tip angle or shoot curvature for orientation response, plus one growth or chemistry endpoint. Encoder angle, three-axis acceleration, plant images, light exposure, immersion and air velocity are synchronised by timestamp. The analysis uses the plant or independent cultivation cycle as the experimental unit.
","text":"Rotation in the plant frame The FlavoRotor drum turns around a horizontal axis. Gravity remains vertical and close to 9.81 m·s⁻², while each plant module changes orientation relative to that vector. Rotation therefore produces a periodic directional stimulus, not reduced gravity. The encoder record links angle, angular speed and direction to every image and sensor sample. [I01] [I02] [R22] [R32] ROT-1 ω = 2πn / 60 Angular velocity ω in rad·s⁻¹ from drum speed n in rev·min⁻¹. ROT-3 θ(t) = θ₀ + ωt The plant-module angle follows the encoder angle θ₀ and measured angular velocity. ROT-4 T = 2π / ω = 60 / n One complete orientation cycle lasts 120 s at 0.5 rpm and 30 s at 2 rpm. How a plant detects reorientation Gravity-sensing cells contain dense, starch-rich amyloplasts. After reorientation, the amyloplasts move towards the new lower side of the cell. That physical change alters gravity signalling and directional auxin transport. Unequal growth on opposite sides of the organ produces curvature: primary roots usually bend with gravity, while shoots usually bend against it. [R63] Stage Root Shoot Measurement Gravity sensing columella cells in the root cap endodermal cells module angle and time after reorientation Signal asymmetric auxin transport towards the lower flank directional auxin redistribution organ angle and curvature over time Growth response positive gravitropic bending negative gravitropic bending root-tip angle, shoot angle and elongation rate The biological input depends on both orientation and exposure time. A slow cycle permits a longer dwell at each angle; a faster cycle changes direction more often. Drum speed is therefore reported together with acceleration ramps, stop duration and the complete angle-time series. Mechanical acceleration ROT-2 a c = ω²r Centripetal acceleration at radial distance r. ROT-5 a eff (t) = g + a c (t) + a vibration (t) The measured acceleration at a plant module combines gravity, rotation and vibration as vectors. Speed Cycle period Radius Centripetal acceleration Fraction of g 0.5 rpm 120 s 0.15 m 0.000411 m·s⁻² 0.0000419 2.0 rpm 30 s 0.15 m 0.00658 m·s⁻² 0.000671 At these example settings, centripetal acceleration is less than 0.07% of g. The dominant physical input is the changing direction of the gravity vector in plant coordinates. Vibration, airflow, liquid movement and start-stop transients are measured separately because they can also change plant growth. [R21] Rotation and root-zone exposure Drum angle also determines when each root module enters and leaves the nutrient solution. For every position, the run record stores immersion depth, immersed duration, drainage duration and retained liquid mass. A biological comparison must match average light and root-zone exposure between rotating and control plants; otherwise orientation, illumination and hydroponic contact change together. Controlled rotation experiment Group Variable isolated Static plant with matched mean light and root exposure baseline Rotating plant combined periodic orientation treatment Static plant with matched time-varying light light distribution Static plant with matched vibration mechanical vibration Rotating plant with slow acceleration ramps start-stop transient Primary endpoints are chosen before cultivation: root-tip angle or shoot curvature for orientation response, plus one growth or chemistry endpoint. Encoder angle, three-axis acceleration, plant images, light exposure, immersion and air velocity are synchronised by timestamp. The analysis uses the plant or independent cultivation cycle as the experimental unit. [R02] [R21] [R63]","source_ids":["I01","I02","R02","R21","R22","R32","R63"],"visuals":[{"id":"rotation-gravity-cycle","type":"interactive rotation and gravity-vector diagram","title":"Gravity direction during one drum revolution","article":"rotation-gravity","source_ids":["I01","I02","R63"]}],"sources":[{"id":"I01","authors":"FlavoRotor project team","year":2026,"title":"FlavoRotor prototype implementation record","publication":"Internal engineering report","doi":null,"url":"/research/platform","source_type":"internal primary record","relevance":"Documents the built rotating prototype, sensing electronics, dashboard and current validation limitations.","verification":"Derived from the original FlavoRotor project document","verified_on":"2026-07-26","verification_status":"INTERNAL PRIMARY RECORD","verified_against":"Original internal project file and extracted media"},{"id":"I02","authors":"FlavoRotor project team","year":2026,"title":"FlavoRotor v2.0 system architecture","publication":"Internal engineering design report","doi":null,"url":"/research/platform","source_type":"internal primary record","relevance":"Documents the proposed magnetic drive, axial lighting, four-channel peristaltic dosing and imaging architecture.","verification":"Derived from the original FlavoRotor v2.0 engineering document","verified_on":"2026-07-26","verification_status":"INTERNAL PRIMARY RECORD","verified_against":"Original internal project file and extracted media"},{"id":"R02","authors":"Seeburger, P.; Herdenstam, A.; Kurtser, P.; Arunachalam, A.; Castro-Alves, V. C.; Hyötyläinen, T.; Andreasson, H.","year":2023,"title":"Controlled mechanical stimuli reveal novel associations between basil metabolism and sensory quality","publication":"Food Chemistry","doi":"10.1016/j.foodchem.2022.134545","source_type":"peer-reviewed research","relevance":"Supports testing controlled mechanical stimulation as a contributor to basil metabolic and sensory response.","verification":"Publisher, PubMed, ISO or official proceedings metadata checked 2026-07-26","url":"https://doi.org/10.1016/j.foodchem.2022.134545","verified_on":"2026-07-26","verification_status":"DOI METADATA CHECKED","verified_against":"Publisher, DOI landing page, PubMed or official repository where available"},{"id":"R21","authors":"Chehab, E. Wassim; Eich, Elizabeth; Braam, Janet","year":2009,"title":"Thigmomorphogenesis: a complex plant response to mechano-stimulation","publication":"Journal of Experimental Botany","doi":"10.1093/jxb/ern315","source_type":"peer-reviewed review","relevance":"Establishes the biological basis for measuring plant responses to repeated mechanical stimulation.","verification":"Publisher, PubMed, ISO or official proceedings metadata checked 2026-07-26","url":"https://doi.org/10.1093/jxb/ern315","verified_on":"2026-07-26","verification_status":"DOI METADATA CHECKED","verified_against":"Publisher, DOI landing page, PubMed or official repository where available"},{"id":"R22","authors":"Kiss, John Z.; Wolverton, Chris; Wyatt, Sarah E.; Hasenstein, Karl H.; van Loon, Jack J. W. A.","year":2019,"title":"Comparison of Microgravity Analogs to Spaceflight in Studies of Plant Growth and Development","publication":"Frontiers in Plant Science","doi":"10.3389/fpls.2019.01577","source_type":"peer-reviewed review","relevance":"Defines limitations of clinostats and related microgravity analogues and supports conservative gravity claims.","verification":"Publisher, PubMed, ISO or official proceedings metadata checked 2026-07-26","url":"https://doi.org/10.3389/fpls.2019.01577","verified_on":"2026-07-26","verification_status":"DOI METADATA CHECKED","verified_against":"Publisher, DOI landing page, PubMed or official repository where available"},{"id":"R32","authors":"Böhmer, Maik; Schleiff, Enrico","year":2019,"title":"Microgravity research in plants: A range of platforms and options allow research on plants in zero or low gravity that can yield important insights into plant physiology","publication":"EMBO Reports, 20, e48541","doi":"10.15252/embr.201948541","source_type":"peer-reviewed review","relevance":"Explains real, simulated and partial-gravity platforms and the limits of ground-based rotation systems.","verification":"Publisher and PubMed metadata checked 2026-07-26","url":"https://doi.org/10.15252/embr.201948541","verified_on":"2026-07-26","verification_status":"DOI METADATA CHECKED","verified_against":"Publisher, DOI landing page, PubMed or official repository where available"},{"id":"R63","authors":"Nakamura, Moritaka; Nishimura, Takeshi; Morita, Miyo Terao","year":2019,"title":"Gravity sensing and signal conversion in plant gravitropism","publication":"Journal of Experimental Botany, 70(14), 3495–3506","doi":"10.1093/jxb/erz158","url":"https://doi.org/10.1093/jxb/erz158","source_type":"peer-reviewed review","relevance":"Explains amyloplast sedimentation, gravity signalling, directional auxin transport and differential growth in roots and shoots after reorientation.","verification":"Oxford Academic article metadata, abstract and mechanism sections checked 2026-07-29","verified_on":"2026-07-29","verification_status":"DOI AND PRIMARY PUBLISHER RECORD CHECKED","verified_against":"Oxford Academic, Journal of Experimental Botany"}]}