What effect sound has on plants remains debated.
The debate about what effect sound may have on plants can include the arguments that Peter Tompkins and Christopher Bird present in their 1973 book, "The Secret Life of Plants." They claim that the whole vegetal world can "distinguish between sounds inaudible to the human ear." The effect that different frequencies can have on plant growth and health remain studied in a field that has come to be known as "acoustic biology." Does this Spark an idea?
Growth
Illustrating the effect that sound frequency could have on plant growth remains a favorite science fair project. Despite the topic's popularity, the statistically valid and scientifically rigorous experiments needed to isolate sound's possible effects are difficult to find. Other factors contributing to the sound being studied could be equally or more responsible for conspicuous plant growth. For example, if someone talking or singing to a plant provides its sound source, its growth would demonstrate the effect of increased carbon dioxide, which has been scientifically reproduced. Higher carbon dioxide concentration in the air without a change in the temperature means that the plant can more efficiently use its water for photosynthesis and thus growth.
Experiments that use recorded music as the plant's sound source typically reflect cultural presumptions that classical music is "more soothing" than other kinds of music and thus more effective at stimulating whatever noted growth can be recorded.
Experiments that use ultrasonic stimulation, or sounds inaudible to human beings, can produce quantifiable results. One 28-day study shows that after seeds stimulated with ultrasonic sound sprout, the plants that grow out of them can average 87 percent taller than those in the "quiet" control group. Some can grow as much as 150 percent taller.
Fruiting
Another focus of acoustic biology is the effect that sound can have on the production of a plant's blooms and fruit. Some experiments claim to have produced a 4.4-lb. tomato through the effect of sound on a plant. These experiments presume that plants, like humans, operate according to the ancient Chinese meridian theory, which organizes the human body into acupuncture points that connect the body's 12 principle organs. The meridian system connects the circulatory, nervous and digestive systems. A sound-sensitive plant meridian system would connect with its vascular system that transports resources throughout the plant. According to University of Washington professor Linda Chalker-Scott, Ph.D., assuming that plants operate like humans produces flawed science. (See Reference 4).
Experiments presuming a plant meridian system search for frequencies to match those of the plant and cause it to produce larger fruit. According to French physicist and composer Joel Sternheimer, tomatoes grow over twice as large when serenaded three times a day. He argues that music notes create inaudible quantum vibrations that happen "when amino acids join the protein chain."
Movement
Other experiments that presume a fruit meridian system note plants' independent movement, not growth, in reaction to sound. For example, a Chinese study of legume grasses in the country's Yunnan province noted that the grasses' symmetric leaves "dance rhythmically to harmonious music" but do not respond if blown or touched.
Tags: meridian system, effect sound, effect that, plant growth, acoustic biology, carbon dioxide