Features and applications of a field imaging chlorophyll fluorometer to measure stress in agricultural plants

Abstract

Most non-destructive methods for plant stress detection do not measure the primary stress response but reactions of processes downstream of primary events. For instance, the chlorophyll fluorescence ratio Fv/Fm, which indicates the maximum quantum yield of photosystem II, can be employed to monitor stress originating elsewhere in the plant cell. This article describes the properties of a sensor to quantify herbicide and pathogen stress in agricultural plants for field applications by the Fv/Fm parameter. This dedicated sensor is highly mobile and measures images of pulse amplitude modulated (PAM) chlorophyll fluorescence. Special physical properties of the sensor are reported, and the range of its field applications is defined. In addition, detection of herbicide resistant weeds by employing an Fv/Fm-based classifier is described. The PAM-imaging sensor introduced here can provide in-field estimation of herbicide sensitivity in crops and weeds after herbicide treatment before any damage becomes visible. Limitations of the system and the use of a classifier to differentiate between stressed and non-stressed plants based on sensor data are presented. It is concluded that stress detection by the Fv/Fm parameter is suitable as an expert tool for decision making in crop management.

PACMan: A software package for automated single‐cell chlorophyll fluorometry

“…Chlorophyll fluorometry is a widely used fluorescence-based technique to study plant and algae photophysiology at the macro-and micro-level [1][2][3]. This non-invasive technique has provided data on important photophysiological processes within a range of phototrophs and has been a crucial tool for researching plant physiology and the effects of climate change [4][5][6]. PAM is also frequently used within agricultural sciences to select crops with desirable photophysiological characteristics such as decreased sensitivity to herbicides [6].…”

“…This non-invasive technique has provided data on important photophysiological processes within a range of phototrophs and has been a crucial tool for researching plant physiology and the effects of climate change [4][5][6]. PAM is also frequently used within agricultural sciences to select crops with desirable photophysiological characteristics such as decreased sensitivity to herbicides [6]. The majority of PAM systems apply pulse-amplitude-modulated flashlets of non-actinic light to measure the minimal fluorescence of photosystem II (PSII) reaction centers (= F 0 ) and apply a strong saturation pulse (SP) to saturate PSII and measure its maximal fluorescence emission (= F m ).…”

“…Among the most common chlorophyll fluorometry systems is the IMAGING-PAM series from Walz. These systems allow operators to repeatedly probe photophysiological parameters of photosynthetic organisms, including agricultural crops [6], wild plants [8] and microalgae [9,10]. The MICROSCOPY-PAM version is often used for researching phototrophs at the microscale, yet both the hardware and software of this system remains hand-operated, which severely limits the throughput of this platform.…”

Handheld Multifunctional Fluorescence Imager for Non-invasive Plant Phenotyping

“…Nowadays, several fluorescence imagers and sensors are commercially available for non-invasive PSA monitoring, such as Walz Imaging-PAM, Photon Systems Instrument FluorCams, and LI-COR (Cen et al, 2017;van Tol et al, 2017;Wang et al, 2017;Backes et al, 2021;Linn et al, 2021). However, none of the above-mentioned imaging devices can be used to quantify anthocyanin content.…”

Impact of Web Blight on Photosynthetic Performance of an Elite Common Bean Line in the Western Amazon Region of Colombia

“…However, in most cases, severity is measured based on the subjectivity of the evaluator, often lacking precision, efficiency/productivity, and traceability [ 25 , 26 , 27 ]. However, there are now other phenotyping methods that are based on the photosynthetic response to the degree of disease incidence [ 28 , 29 ], and these can allow for the identification of moderately disease-resistant bean lines using a disease susceptibility index (DSI) [ 30 ]. Thus, the degree of sensitivity of a given bean cultivar to the degree of disease severity is reflected at the physiological level, based on the pathogen-specific or non-specific mechanisms it uses to maintain its photosynthetic activity [ 31 , 32 ].…”