A team of scientists at Tel-Aviv University says that plants, while not having ears and brains, have a kind of 'hearing' that allows them to hear the buzzing of bees in the vicinity, and consequently produce a sweeter nectar to attract insects. The hypothesis that plants were able to detect the vibrations of sound waves emitted by insects was born from the observation that the flowers of many species have a 'cup' shape that resembles that of animal ears.
Scientists have 'played' 650 examples of Oenothera drummondii, silence and four different types of sound, including the buzzing of bees, each time measuring the concentration of sugar in their nectar. It was found that with lower frequency sounds (the most similar to those emitted by insects), plants increased, in just three minutes, the concentration of sugar in their nectar, up to 20%.
Scientists say that the time it takes to sweeten the nectar is consistent with the time it takes for bees to stand in the vicinity of the flowers. Then they repeated the experiment after having removed some petals, not observing in this case any modification in the nectar; this confirms that flowers acted as an auditory organ.
The same team says that other species of plants, tomatoes and tobacco, would even be able to make sounds perceivable by some animals even several meters away.
These works increase the knowledge in the field of vegetable communication, a concept still considered quite controversial. There are some pseudoscientific statements according to which, for example, plants would grow better if exposed to classical music or if their grower is emotionally well disposed. The fact is that many plants are able to send chemical signals into the air and interact with each other through their roots, which form the so-called wood-wide web. So there is nothing to suggest that they may actually use sound as well.