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Ultrasonic emissions during ice nucleation and propagation in plant xylem
Author(s) -
Charrier Guillaume,
Pramsohler Manuel,
CharraVaskou Katline,
Saudreau Marc,
Améglio Thierry,
Neuner Gilbert,
Mayr Stefan
Publication year - 2015
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13361
Subject(s) - xylem , ice nucleus , nucleation , ultrasonic sensor , environmental science , atmospheric sciences , materials science , botany , chemical physics , chemistry , mineralogy , geology , biology , physics , thermodynamics , acoustics
Summary Ultrasonic acoustic emission analysis enables nondestructive monitoring of damage in dehydrating or freezing plant xylem. We studied acoustic emissions ( AE ) in freezing stems during ice nucleation and propagation, by combining acoustic and infrared thermography techniques and controlling the ice nucleation point. Ultrasonic activity in freezing samples of Picea abies showed two distinct phases: the first on ice nucleation and propagation (up to 50 AE s −1 ; reversely proportional to the distance to ice nucleation point), and the second (up to 2.5 AE s −1 ) after dissipation of the exothermal heat. Identical patterns were observed in other conifer and angiosperm species. The complex AE patterns are explained by the low water potential of ice at the ice–liquid interface, which induced numerous and strong signals. Ice propagation velocities were estimated via AE (during the first phase) and infrared thermography. Acoustic activity ceased before the second phase probably because the exothermal heating and the volume expansion of ice caused decreasing tensions. Results indicate cavitation events at the ice front leading to AE . Ultrasonic emission analysis enabled new insights into the complex process of xylem freezing and might be used to monitor ice propagation in natura .