When South African botanist Lyall Watson claimed in his 1973 best-seller "Supernature" that plants had emotions that could register on a lie detector, scientists scoffed and branded it as hippie nonsense.

However, a new Australian research at The University of Western Australia has claimed to have discovered that plants appear to react to sounds and may even make clicking noises to communicate with each other.

UWA Postdoctoral Research Fellow, Monica Gagliano has teamed with colleagues Daniel Robert at the University of Bristol (UK) and Stefano Mancuso at the University of Florence (Italy) to show that the roots of young plants emit and react to particular sounds.

"Everyone knows that plants react to light, and scientists also know that plants use volatile chemicals to communicate with each other, for instance, when danger - such as a herbivore - approaches," Gagliano said in an university statement released recently.

"I was working one day in my herb garden and started to wonder if maybe plants were also sensitive to sounds - why not? - so I decided as a scientist to find out.

"Gagliano and fellow researchers established that young roots of corn made regular clicking sounds.

They also found that young corn roots suspended in water leaned toward the source of a continuous sound emitted in the region of 220Hz, which is within the frequency range that the same roots emitted themselves.

Their findings, published in the leading international journal Trends in Plant Science, conclude that the role of sound in plants has yet to be fully explored, "leaving serious gaps our current understanding of the sensory and communicatory complexity of these organisms".

In addition to other forms of sensory response, "it is very likely that some form of sensitivity to sound and vibrations also plays an important role in the life of plants". Gagliano said she hoped publication of her work would attract further funding for more research into how plants make and react to sounds.