Complexity of Chlorophyll Fluorescence Dynamic Response as an Indicator of Excessive Light Intensity
Paper in proceedings, 2016

The controllability of LED lighting systems for greenhouses and plant factories offers a possibility for light induced diagnose of plant status. Here, a novel method for proximal remote detection of plant light tolerance is investigated. The method is based on an identification of a transfer function model for the measured chlorophyll fluorescence response to a small step variation in blue LED light. It is postulated that the least required model order decreases as the plants become light stressed due to saturation effects at excess light conditions. We apply this method to basil and lettuce plants under different background light intensities, and the results are compared to measured effective quantum yield (y(II)), relative electron transport rate through PSII (ETR(II)) and non-photochemical quenching (NPQ), all reflecting the photosynthetic performance. For both species it is indeed found that the required model order decreases with increasing background light intensity at the same time as the measured reference parameters indicates a decreased photosynthetic efficiency. It is suggested that the light intensity should be such that the chlorophyll fluorescence response requires a model order of 3 or higher to avoid ineffective irradiation of the plants.



dynamic behaviour

system identification

step function responses

feedback control

method development

plant sensing


Johan Lindqvist


Daniel Bånkestad


Anna-Maria Carstensen

Chalmers, Signals and Systems, Systems and control, Automatic Control

Björn Lundin

University of Gothenburg

Torsten Wik

Chalmers, Signals and Systems, Systems and control, Automatic Control


24058963 (eISSN)

Vol. 49 16 392-397

Subject Categories


Atom and Molecular Physics and Optics

Other Physics Topics



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9/6/2018 1