Ultrasound Pulse Emission Spectroscopy Method to Characterize Xylem Conduits in Plant Stems

Area of Science:

• Plant Physiology
• Bioacoustics
• Biophysics

Background:

• Plants emit ultrasound pulses when under drought stress.
• The precise source of these acoustic signals within plant structures remains unclear.
• Understanding this source is crucial for noninvasive plant monitoring.

Purpose of the Study:

• To identify the origin of ultrasound pulse waveforms in stressed plants.
• To correlate acoustic signal characteristics with xylem conduit dimensions.
• To develop a noninvasive method for plant internal structure characterization.

Main Methods:

• Utilized a model linking vessel resonant vibrations to dimensions and viscoelasticity.
• Analyzed ultrasound pulse waveforms to extract xylem radii.
• Validated measurements against optical microscopy and scanning electron cryomicroscopy.
• Applied the method to ten diverse vascular plant species.

Main Results:

• Established a strong correlation between ultrasound waveform characteristics and xylem conduit dimensions.
• Xylem radii extracted from acoustic data closely matched optical microscopy results.
• Successfully extracted vessel element lengths for *Hydrangea quercifolia*, agreeing with cryomicroscopy.
• Demonstrated the method's applicability across multiple plant species.

Conclusions:

• Ultrasound pulse waveforms are directly linked to xylem conduit dimensions.
• Noninvasive ultrasonic analysis offers a rapid and accurate method for plant phenotyping.
• This technique advances plant stress detection and internal structure analysis.