Deciphering acoustic emission signals in drought stressed branches: the missing link between source and sensor

Area of Science:

• Plant Physiology
• Acoustics
• Biophysics

Background:

• Drought stress in plants induces acoustic emission (AE) signals, but their precise origins remain unclear.
• Understanding AE signal sources is crucial for investigating plant physiological responses to stress.
• Waveform distortion during signal propagation from source to sensor hinders AE research in plants.

Purpose of the Study:

• To investigate acoustic emission wave propagation in plant branches.
• To identify the characteristics of AE sources and their relation to physiological processes.
• To provide recommendations for future AE research in plant science.

Main Methods:

• Utilized finite element modeling (FEM) to simulate wave propagation.
• Employed a pencil lead break (PLB) as a known AE source.
• Analyzed wave propagation in polyvinyl chloride (PVC) and wooden rods to identify theoretical modes.

Main Results:

• Identified two distinct wave propagation modes in cylindrical rods.
• FEM successfully interpreted the behavior of these modes concerning source position in both PVC and wooden rods.
• Observed both identified wave propagation modes in AE signals from drought-stressed woody branches.

Conclusions:

• Wave propagation analysis using FEM is effective for understanding AE signals in plant tissues.
• The identified wave propagation modes are relevant to drought-induced AE signals in plants.
• Insights gained can guide future research on using AE for plant stress monitoring.