Complexity of Chlorophyll Fluorescence Dynamic Response as an Indicator of Excessive Light Intensity
Paper i proceeding, 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



feedback control

plant sensing

step function responses

method development


Johan Lindqvist

Heliospectra AB

Daniel Bånkestad

Heliospectra AB

Anna-Maria Carstensen

Chalmers, Signaler och system, System- och reglerteknik

Björn Lundin

Göteborgs universitet

Torsten Wik

Chalmers, Signaler och system, System- och reglerteknik


24058963 (eISSN)

Vol. 49 16 392-397



Atom- och molekylfysik och optik

Annan fysik



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