Natural and laser-induced cavitation in corn stems: On the mechanisms of acoustic emissions

E. Fernández; R. J. Fernández; Gabriel Mario Bilmes

doi:10.4279/pip.040003

Authors

E. Fernández IFEVA - Facultad de Agronomía, Univ. Buenos Aires, CONICET
R. J. Fernández IFEVA - Facultad de Agronomía, Univ. Buenos Aires, CONICET
Gabriel Mario Bilmes Centro de Investigaciones Opticas (CONICET, CIC, UNLP)

DOI:

https://doi.org/10.4279/pip.040003

Keywords:

Cavitation in plants, Laser induced Ultrasonic Acoustic Emissions, Xylem Cavitation, Zea mays, Corn Stem, Embolism

Abstract

Water in plant xylem is often superheated, and therefore in a meta-stable state. Under certain conditions, it may suddenly turn from the liquid to the vapor state. This cavitation process produces acoustic emissions. We report the measurement of ultrasonic acoustic emissions (UAE) produced by natural and induced cavitation in corn stems. We induced cavitation and UAE in vivo, in well controlled and reproducible experiments, by irradiating the bare stem of the plants with a continuous-wave laser beam. By tracing the source of UAE, we were able to detect absorption and frequency filtering of the UAE propagating through the stem. This technique allows the unique possibility of studying localized embolism of plant conduits, and thus to test hypotheses on the hydraulic architecture of plants. Based on our results, we postulate that the source of UAE is a transient "cavity oscillation"' triggered by the disruptive effect of cavitation inception.

Received: 14 March 2011, Accepted: 23 April 2012; Edited by: V. Lakshminarayanan; Reviewed by: C. Negreira, Laboratorio de Acústica Ultrasonora, Universidad de la República, Uruguay; DOI: http://dx.doi.org/10.4279/PIP.040003

Cite as: E. Fernández, R. J. Fernández, G. M. Bilmes, Papers in Physics 4, 040003 (2012)