Effect of sound and sound frequency associated with lightning strikes on the promotion of fruiting body development in shiitake mushrooms

Abstract

Since ancient times in Japan, it has been said that mushrooms grow abundantly after lightning strikes. To verify this mysterious causal relationship, previous studies have reported that artificial lightning exposure can stimulate fruiting body formation, suggesting that fruiting bodies are affected by factors other than electrical stimulation. In this study, it was hypothesized that the stimulation by air-borne sound during lightning strikes is a factor. As a result of cultivation by applying different sound pressures, it was found that the application of 110 dB had the best effect of promoting the onset of fruit body formation. In order to identify the frequency band of the air-borne sound associated with lightning strikes that is effective for promoting fruit body development, we conducted cultivation experiments by extracting and applying different frequency bands and confirmed that fruit body yield peaked by applying sound at frequencies of between 1.5 kHz and 2.5 kHz. These results confirm that the sound of lightning strikes promotes the growth of shiitake mushrooms, and that vibration at specific frequencies of thunder is also one of the factors that promotes fruiting body formation.