Ultrasound combined with slightly acid electrolytic water elicited an increase in cell membrane permeability of R. stolonifer observed by SYTOX green staining. US, ultrasound; SAEW, slightly acid electrolytic water. Treatment 1, US500 + SAEW50 (40 °C, 10 min); Treatment 2, US500 + SAEW50 (55 °C, 10 min). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)