Correlation between Acoustic Emissions Generated from Cavitation in Rubber Tree Leaf Veins

Abstract

Cavitation causes embolisms followed by a considerable decrease in xylem conductance: embolisms pose a serious obstacle to the continued uptake of water. Assuming that acoustic emissions (AEs) with high similarity would be generated from cavitation at the same element when refilling occurred, this study investigated the generation of such an AE in a rubber tree's leaf vein. Cross-correlation analyses between the filtered AE waveforms showed the existence of AEs with a cross-correlation coefficient greater than 0.97. That result indicated that some AEs came from the same element in a leaf vein where cavitation and refilling occurred repeatedly. Assuming that a pair of AEs with a high cross-correlation coefficient corresponded to the same embolism, the relationship between daily diameter change (DDC) and number of embolisms showed a better linear relation than that between DDC and total events of AE.