. The authors reported that optimum plant growth occurred when the plant was exposed to pure tone sound in which the wavelength coincided with the average of major leaf dimensions. The plant growth was decreased when exposed to random noise (Collins and Foreman, 2001).
... In the last few decades, there have been an increasing number of studies dealing with the emission and perception of sound by plants both in audio acoustic (10–240 Hz) and ultrasonic ranges (20–300 kHz) (Laschimke et al. 2006; Gagliano et al. 2012a; Gagliano 2013)
... As a further refinement, several researchers have started using SVs of variable single frequencies. Collins and Foreman (2001) applied different frequencies (500, 5000, 6000, 12 000, 14 000 Hz) of SV with the same pressure level (91-94 decibel, dB) to common beans (Phaseolus vulgaris) and impatiens (Impatiens sp.) and noted frequency-specific responses. Although growth was enhanced in both cases, beans showed maximum growth at 5000 Hz whereas impatiens responded best at 12 000 Hz. Similar results were found in Chinese cabbage and cucumber
... Sound and US, which plants perceive as an external mechanical force or as an abiotic stressor, can modify growth and development as a way to adjust to their environment, including the effect of US with low frequency (≤ 60 kHz) in seed germination (Creath and Schwartz 2004), seedling and plant growth (Collins and Foreman 2001;Qi et al. 2010)
https://www.researchgate.net/publication/267559091_The_effect_of_sound_on_the_growth_of_plants
