Stress Detection Using Proximal Sensing of Chlorophyll Fluorescence on the Canopy Level
Journal article, 2021

Chlorophyll fluorescence is interesting for phenotyping applications as it is rich in biological information and can be measured remotely and non-destructively. There are several techniques for measuring and analysing this signal. However, the standard methods use rather extreme conditions, e.g., saturating light and dark adaption, which are difficult to accommodate in the field or in a greenhouse and, hence, limit their use for high-throughput phenotyping. In this article, we use a different approach, extracting plant health information from the dynamics of the chlorophyll fluorescence induced by a weak light excitation and no dark adaption, to classify plants as healthy or unhealthy. To evaluate the method, we scanned over a number of species (lettuce, lemon balm, tomato, basil, and strawberries) exposed to either abiotic stress (drought and salt) or biotic stress factors (root infection using Pythium ultimum and leaf infection using Powdery mildew Podosphaera aphanis). Our conclusions are that, for abiotic stress, the proposed method was very successful, while, for powdery mildew, a method with spatial resolution would be desirable due to the nature of the infection, i.e., point-wise spread. Pythium infection on the roots is not visually detectable in the same way as powdery mildew; however, it affects the whole plant, making the method an interesting option for Pythium detection. However, further research is necessary to determine the limit of infection needed to detect the stress with the proposed method.

lemon balm


biotic stress




fluorescence dynamics

Abiotic stress



Linnéa Ahlman

Chalmers, Electrical Engineering, Systems and control, Automatic Control

Daniel Bånkestad

Heliospectra AB

Sammar Khalil

Swedish University of Agricultural Sciences (SLU)

Karl-Johan Bergstrand

Swedish University of Agricultural Sciences (SLU)

Torsten Wik

Chalmers, Electrical Engineering, Systems and control, Automatic Control


2624-7402 (eISSN)

Vol. 3 3 648-668

Driving Forces

Sustainable development

Areas of Advance


Subject Categories

Plant Biotechnology

Control Engineering

Signal Processing



More information

Latest update