A SiPM-Enabled Portable Delayed Fluorescence Photon Counting Device: Climatic Plant Stress Biosensing

Area of Science:

• Plant science
• Biophysics
• Agricultural technology

Background:

• Plant delayed fluorescence (DF) offers insights into plant health and stress responses.
• Traditional photon counting methods using photomultiplier tubes (PMTs) are costly and complex for field use.
• Emerging silicon photomultiplier (SiPM) technology enables compact, low-cost, and user-friendly photon counting.

Purpose of the Study:

• To develop and validate a portable, field-deployable photon counting device for measuring plant delayed fluorescence.
• To assess the device's capability in detecting plant stress responses under varying environmental conditions.
• To demonstrate a novel instrument for minimally invasive plant health assessment.

Main Methods:

• Fabrication of a novel SiPM-based photon counting device with integrated excitation LED and miniaturized sample chamber.
• Measurement of ultra-weak delayed fluorescence lifetime response from plant leaves.
• Application of varying temperature conditions (heat/cold shock) and drought stress to plants.

Main Results:

• The SiPM-based device successfully captured weak delayed fluorescence signals.
• Delayed fluorescence measurements correlated with the inactivation of photosystem II in plants under heat, cold, and drought stress.
• The device demonstrated sensitivity to both acute and chronic environmental stresses.

Conclusions:

• A simple, effective, and portable photon counting instrument for in-field plant stress assessment has been achieved.
• The developed device enables rapid and minimally invasive evaluation of plant physiological status.
• This technology has potential applications in precision agriculture and climate change impact studies on crops.