A high-performance instrumentation system to measure the fluorescence kinetics of plants for in vivo photosynthesis research

This paper presents the design and application of a new type of pulse amplitude modulated fluorimeter (PAM) that uses an optical system based on an integrating sphere to improve the rapid assessment of in vivo photosynthesis in green plants and algae. The lightweight instrument was designed for rechargeable battery operation and can easily be transported for field measurements. Its integrating sphere can accept whole plants in order to reduce plant stress due to cutting before measurements. Also, the excitation light is focused outside of the sphere and brought in by an optical fiber, allowing the use of high light intensities to saturate the photosynthesis process. Finally, the integrating sphere is equipped with an airflow device for the circulation of air pollutants inside the sphere, thus allowing the study of continuous air pollution in green plants via fluorescence emission. The paper concludes by presenting the results of measuring the fluorescence parameters of barley, a plant of interest for agricultural and environmental studies.