Root phonotropism: Early signalling events following sound perception in Arabidopsis roots

Plants can hear. We know plants respond to touch, can perceive day and night, and respond to volatile compounds, water and nutrients. Moreno et al. studied root phonotropism (not phototropism). They showed that roots of Arabidopsis plants can perceive and respond to sound waves. Arabidopsis roots grew towards a sound source even in the absence of light, and sound caused an increase in cytosolic calcium. Continuous sound treatment for 9-10 days could reduce the K+ content in the roots, which was verified using electrophysiological measurements. Additionally, in Arabidopsis cells sound could increase superoxide production. The authors suggest that perception of sound is regulated by changes in Ca2+ and K+ ion fluxes with reactive oxygen species such as superoxide involved in signal amplification. This phenomenon throws light on how plants hear and perceive the sound of a distant water source in soil to direct roots to grow towards it. (Summary by Edna Anthony) Plant Science