New research on rice reveals that the acoustic vibrations from falling droplets have the ability to stimulate dormant seeds, marking the first direct evidence that plants can detect natural sounds.
Rice and its related seed types can detect the sound of rain hitting the soil or water, accelerating germination when the sound intensity is adequate to displace stationary stones away from cell membrane receptors, thereby facilitating gravitropic growth mechanisms.
Plants are remarkably sensitive organisms. To thrive, they have developed mechanisms to perceive and react to various environmental stimuli.
For instance, certain plants snap shut upon contact, while others retract when exposed to harmful odors.
Moreover, most plants exhibit phototropism, reaching for sunlight to optimize growth.
Plants also respond to gravity, with roots growing downward and shoots rising upward against the gravitational pull.
One important method of gravity perception involves stationary stones within plant cells.
These “stillstones” are denser than the cell’s cytoplasm, floating or sinking inside the cell, similar to sand in water.
When the stones settle at the bottom, they rest against the cell membrane, signaling the direction of gravity and guiding root and shoot growth.
Research has shown that removing the stationary stones can further stimulate seed growth.
“Our findings indicate that seeds can perceive sound as a vital survival mechanism,” stated Professor Nicholas Makris from the Massachusetts Institute of Technology (MIT).
“The energy generated by rain sounds is potent enough to trigger seed growth.”
Professor Makris and fellow MIT researcher Cadine Navarro conducted experiments involving rice seeds, which naturally thrive in shallow rice fields.
During multiple trials, they submerged approximately 8,000 rice seeds in a shallow bath, exposing a subset to dripping water.
By varying the droplet size and height, they simulated light, medium, and heavy rainfall.
The team deployed hydrophones to capture the acoustic vibrations generated by the water droplets underwater.
These laboratory measurements were validated against records taken in natural environments, such as puddles, ponds, wetlands, and storm-influenced soils.
The comparison confirmed that laboratory conditions replicate rain-induced acoustic vibrations seen in nature.
Moreover, they observed that rice seeds subjected to water sounds germinated 30 to 40 percent faster than those without sound exposure but in identical conditions.
Those seeds positioned nearer to the water surface demonstrated heightened sensitivity to droplet sounds and exhibited faster growth than their deeper counterparts.
This research indicates a clear link between acoustic vibrations from rain and enhanced seed growth.
Scientists speculate that seeds capable of sensing rain may gain evolutionary advantages. Seeds that are close enough to the surface to detect raindrop sounds are likely positioned optimally to absorb moisture and safely push through to the surface.
The research team conducted calculations to verify if the physical vibrations from the droplets could perturb the micro resting stones within the seeds.
Such findings would provide insights into how sound directly influences plant growth.
The calculations considered factors like droplet size and terminal velocity to evaluate the amplitude of acoustic vibrations generated by falling droplets.
Based on this data, the team assessed how vibrations affect submerged seeds and the impact on their biological dynamics.
The experiments on rice seeds aligned with their theoretical predictions, confirming that the sound of rain could indeed displace hard seeds’ resting stones, leading to collisions.
This phenomenon may underlie plants’ capacity to “hear” rain sounds and respond with growth.
“Extensive research worldwide continues to delve into the mechanisms facilitating plants’ gravity sensitivity,” noted Professor Makris.
“Our study revealed that these same mechanisms empower seeds to discern their submerged depth in soil or water, enhancing survival through sound detection of rain.”
“Titled Falling Rain Awakens the Soil, this insight offers a fresh perspective on Japan’s Fourth Microseason.”
A study detailing this research is featured in this week’s edition of Scientific Reports.
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N.C. Makris and C. Navarro. 2026. Seeds detect the sound of rain to promote germination at the appropriate planting depth. Science Officer 16, 11248; doi: 10.1038/s41598-026-44444-1
Source: www.sci.news
