Sonication (Ultrasound) Affects In Vitro Growth of Hybrid Cymbidium

Abstract The use of ultrasound or sonication has been shown to stimulate growth and development of several plant species. No study exists on the impact of sound on Cymbidium growth in vitro. Using sonication at 60 Hz for several time periods, the response on new protocorm-like body (neo-PLB) formation on Teixeira Cymbidium (TC) medium was examined, as was the response on in vitro plant organogenesis. Sonication for 5 or 10 min stimulated neo-PLB formation significantly more than plant growth regulator (PGR)-free TC medium without sonication (negative control) and more than 1, 20 or 45 min sonication, but significantly less than control TC medium containing PGRs NAA and Kin (positive control) after 60 days in culture. Sonication, when applied to PLBs, did not influence most plantlet-related growth parameters. Flow cytometric analyses registered an increase in endoreduplication in sonicated PLB tissues. Sonication at 60 Hz has a PLB-promoting effect, but is not as effective as PGRs.