Open-source LED lamp for the LI-6800 photosynthesis system

ABSTRACT Premise Controlling light flux density during carbon dioxide assimilation measurements is essential in photosynthesis research. Commercial lamps are expensive and are based on monochromatic light emitting diodes (LEDs), which deviate significantly in their spectral distribution compared to sunlight. Methods and Results Using a LED emitting white light with a color temperature similar to sunlight, we developed a cost-effective lamp compatible with the LI-6800 photosynthesis measuring system. When coupled with customized software, the lamp can be controlled via the LI-6800 console by a user or Python scripts. Testing and calibration show that the lamp meets the quality needed to estimate photosynthesis parameters. Conclusions The lamp can be built using a basic electronics lab and a 3D printer. Calibration instructions are supplied and only require equipment commonly available at plant science laboratories. The lamp is a cost-effective alternative to perform photosynthesis research coupled with the popular LI-6800 photosynthesis measuring system.