Seeds may come alive to the soothing sound of rainfall, sensing the drops while they are still beneath the surface, suggests a new study. A series of experiments at the Massachusetts Institute of Technology demonstrated that rice seeds sprouted faster to the sound of rainfall. The sound of falling droplets effectively shook the seeds out of a dormant state, stimulating them to germinate at a faster rate compared with seeds that were not exposed to the same sound vibrations. The findings, published yesterday in the journal Scientific Reports, are the first direct evidence that plant seeds and seedlings can sense sounds in nature. Rice seeds can germinate in either soil or water, and these experiments involved seeds submerged in shallow water. The researchers suspect that many similar seed types may also respond to the sound of rain. The MIT team found that when a raindrop hits the surface of a puddle or the ground, it generates a sound wave that makes the surroundings vibrate, including any shallowly submerged seeds. The vibrations can be strong enough to dislodge a seed's "statoliths", tiny gravity-sensing organelles within certain cells of a seed. When the statoliths are jostled, their movement is a signal for seeds and seedlings to grow and sprout. The groups of seeds that were exposed to the sound of water drops were able to germinate 30% to 40% faster than the seed groups that were not exposed to rain sounds but were otherwise in identical conditions.