Table 1.

List of literature studies of secondary metabolite production in the presence of sound exposure

Region	Species	Sound Frequency	Exposure Time	Changes of Secondary Metabolites	Refs
China	taxus chinensis	50 Hz	30 min	Increased taxuyunnanine C and phenolics content	[10]
China	Chinese cabbage and cucumber	20 kHz; 75 dB	3 h / day	Increased polyamines and vitamin C levels in Chinese cabbage, as well as elevated polyamine levels in cucumber. “Green music” increased cucumber vitamin C content, sound waves decreased cucumber vitamin C content	[11]
China	chrysanthemum	1.4 kHz; 95 dB	1 h / day, twice a day, 20 days	Increased biosynthesis of 3-indoleacetic acid	[12]
Korea	alfalfa; broccoli; red young radish	250, 800, 1000, 1500 Hz; 80 dB	Short-term: twice daily for 1 h; Long-term: twice daily for 1 h, 2–4 days	Both short-term and long-term treatments increase total flavonoid content	[13]
Korea	tomato	1 kHz; 100 dB	6 h	Reduced ethylene production in tomato fruits	[14]
Korea	alfalfa	250, 500, 800, 1000, 1500 Hz; 80 dB	2 h / day, twice a day	Increased L-ascorbic acid content of alfalfa sprouts	[15]
Iran	saffron corms	0.5, 1, 2, 4, 8, 12, 16 kHz; 77 dB	15 min / day, 1–4 mouths	Crocin, picrocrocin, and safranal were lowest at 1 kHz and highest at 2 kHz. During the flowering stage, high frequencies increased the content of crocin, picrocrocin, and safranal	[16]
Iran	savory	Iranian music: 800–2000 Hz, 80 dB; rock music: 1100–7000 Hz, 80 dB; urban/traffic noise: 800–2000 Hz, 80 dB	three times a day for 1 h, two weeks	Increased total phenolic and soluble phenol concentrations. Urban/traffic noise treatment increased total flavonoid concentrations and the other treatments decreased total flavonoid concentrations	[7]
Turkey	strawberry plants	1000 Hz; 95, 100, 105 dB	1 h / day, 30 days	Total sugar content was highest at 100 dB, while total phenolic content and ascorbic acid increased with sound intensity	[17]