Laser-induced ultrasonic guided waves in water-stressed leaves

• Published in: Computers and electronics in agriculture Vol. 216; p. 108524
• Main Authors: Collazos-Burbano, David A., Ealo, Joao L., Villagrán-Muniz, Mayo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2024
• Subjects: Guided waves; Photoacoustics; Plant leaves; Vegetal index; Water content; Wave attenuation; Guided waves; Plant leaves; Wave attenuation; Vegetal index; Water content; Photoacoustics
• ISSN: 0168-1699; 1872-7107
• DOI: 10.1016/j.compag.2023.108524

In this work, we studied the properties of acoustic guided waves travelling through plant leaves under water stress. We used a laser-based ultrasound technique to study the relationship between the sample water content and wave propagation characteristics along the midrib and through the lamina. We found that the effective viscoelastic modulus and density in these tissues have different behaviour. Accordingly, we assessed how the acoustic attributes of the guided wave, i.e., the instantaneous phase, attenuation and energy, are modified in both tissues. In addition, we demonstrate that such attributes are highly sensitive to the moisture content and provide quantitative information about the water status of the leaves. As a result, we put forward the use of acoustic vegetal indices as a tool in smart agriculture strategies. This work paves the way to jointly apply commonly used non-destructive techniques to the online and long-distance study of plant hydraulics, as well as the real-time evaluation of the turgor loss point in plants using noncontact methods. •Laser-based ultrasound is useful to determine water content in plant leaves.•Midrib and lamina in a plant leaf perform differently under water stress.•Leaves’ water status can be obtained from the instantaneous phase and attenuation.•Vegetation indices are obtained from the elastic response of water-stressed leaves.•Resonance is not mandatory to study the water content of plant leaves.