An Overview of Chlorophyll Fluorescence Measurement Process, Meters and Methods

The process of photosynthesis implies the transformation of light into chemical energy in photosynthetic organisms. One of the procedures of utilizing the light reaching the plant leaf for chemical energy production is via the chlorophyll (CF) molecules that enable biochemical processes. Chlorophyll fluorescence measurement technique is used to assess the photosynthetic performance of plants and the main principle is based on light energy distribution. Although the plant physiological status is monitored and influenced with agricultural practices like crop rotation and fertilization, various deviations might happen in the agro-ecosphere. Fluorescence transient is monitored through different parameters like maximum fluorescence and different states of dark-adapted fluorescence are measured. Fluorescence is commonly measured using fluorometers like Pocket plant efficiency analyzer (PEA) and Handy PEA. Novel solutions include satellite observations and IoT solutions. Cost-efficient solutions based on a single sensor node provide less accuracy, while sensor networks acquire results comparable to reference data. This short review presents an overview of available sensors, methods and algorithms for measurements of chlorophyll fluorescence and identifies open issues and research directions for the future work.