Like other living organisms, plants also respond
to light, temperature, moisture, and sound. It is claimed that sound and
music has positive effects on plant growth and development. In addition, sound
also alerts plants of potential danger and aids in defense and facilitates mutualistic interactions such as buzz
pollination. Studies report that exposure
to specific biotic sounds elicits different physiomorphological changes in
plants, suggesting that plants can perceive and respond to animal sound. Arabidopsis plants
infested by caterpillar Pieris rapae defend themselves by producing higher levels of anthocyanin and
glucosinolates. By contrast, however, exposure to other environmental sounds
such as wind and leafhopper sound did not elicit such a response.
Similarly, Nicotiana tabacum produces nicotine to deter
herbivores. Plants treated with the
chewing sound of the caterpillar Phtorimaea operculella showed
a significantly elevated nicotine
concentration.
In addition to protection against herbivory, sound perception by
plants could also facilitate plant–animal mutualism. For example buzz
pollination. Different bees produce buzz sounds with different frequencies and
intensities. Plants perceive these vibrations and release the pollen only if
the insect is a true pollinator. In some other cases, acoustic interaction
between plants and animals presents a necessity for plant reproduction as well
as nutrition. Both the bat-pollinated plant Marcgravia evenia and
the carnivorous species Nepenthes hemsleyana possess
structures that reflect ultrasonic sounds produced by bats for echolocation.
Studies suggest that plants sense a multitude of different sound
frequencies, regardless of whether these are playbacks of recorded natural
sounds or artificially produced frequencies. Plants also perceive environmental
sounds of abiotic origin for example sound of water. Water is one of the most
important necessities for plant survival; it could be advantageous for a plant
to detect specific water sounds. Arabidopsis roots grow
towards unilateral sound of 200 Hz, which is considered to be in the range of
the sound of running water. Likewise, Zea mays seedlings were
shown to direct their roots towards a unilateral sound source (220 Hz).
Interestingly, roots of Pisum sativum sensed the sound of
water flowing inside a pipe, redirecting their root growth towards the sound
source. It was even suggested that plants can also perceive the sound of
thunder, which often precedes torrential rains, and prepare themselves for
upcoming precipitation. Further, it may also alert plants to close their
flowers to prevent damage to floral structures and pollen by heavy rain. In a
recent study, human-generated noises underwater were shown to cause
morphological and ultrastructural changes that can negatively affect health
status in the seagrass Posidonia oceanica.
How plants communicate with each other?
It is well known that plants communicate with each other through
volatile organic compounds and via vast fungal networks connecting their roots.
Plants can also communicate with each other through sound. Foeniculum
vulgare is known to inhibit growth of Capsicum annuum through
allelopathy. Intriguingly, the negative effect of F. vulgare on
the germination of C. annuum seeds was present even when all
known communication channels between plants, including chemicals that cause
allelopathy, were cut off. The apparent modality of this communication was
suggested to be sound.
Source
Marie Liesbeth Demey, Ratnesh Chandra Mishra, Dominique Van Der Straeten, Sound perception in plants: from ecological significance to molecular understanding, Trends in Plant Science, 2023, ISSN 1360-1385, https://doi.org/10.1016/j.tplants.2023.03.003.