Fig. 2

Effects of sound on the germination rate of maize seeds. Each point shows a mean of ten independent samples. Each sample included 20 seeds placed in water during 8 h and then subjected to sound at 22 °C in the dark, and were left germinate in silence at 22 °C in the dark. Germination percentages were measured at 7 days. Radicle protusion was taken as the criterion for germination. Vertical bars indicate standard error. Asterisks indicate significant differences respect to the control (untreated seeds) according to the T test (p < 0.05). a Seeds were exposed to 80 dB sounds of different frequencies during 10 h. Cont silence control, Treat sound treated at the indicated frequencies. b Seeds were exposed to 300 Hz 80 dB during different times. Cont silence control, Treat sound treated at the indicated times. c Intact seeds (with pericarp) or seeds from which the pericarp was removed (without pericarp). Cont silence control, Sound exposed to 300 Hz 80 dB during 10 h