Tuned in: plant roots use sound to locate water
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Because water is essential to life, organisms have evolved a wide range of strategies to cope with water limitations, including actively searching for their preferred moisture levels to avoid dehydration. Plants use moisture gradients to direct their roots through the soil once a water source is detected, but how they first detect the source is unknown. We used the model plant Pisum sativum to investigate the mechanism by which roots sense and locate water. We found that roots were able to locate a water source by sensing the vibrations generated by water moving inside pipes, even in the absence of substrate moisture. When both moisture and acoustic cues were available, roots preferentially used moisture in the soil over acoustic vibrations, suggesting that acoustic gradients enable roots to broadly detect a water source at a distance, while moisture gradients help them to reach their target more accurately. Our results also showed that the presence of noise affected the abilities of roots to perceive and respond correctly to the surrounding soundscape. These findings highlight the urgent need to better understand the ecological role of sound and the consequences of acoustic pollution for plant as well as animal populations.
KeywordsForaging behavior Hydrotropism Moisture sensing Bioacoustics Directional root growth
We thank R. Creasy, W. Piasini, H. Etchells, T. Betts, N. Clairs, R. Malkin and P. Tallai for their assistance, and H. Heilmeier and two anonymous reviewers for valuable comments on the manuscript. This work was supported by Research Fellowships from the University of Western Australia and the Australian Research Council (ARC grant n. DE130100018) to MG*.
Author contribution statement
MG* conceived and designed the experiments. MG* and MG performed the experiments and collected data MG*, MD and MR analyzed and interpreted the data. MG* and MR drafted the paper. All authors edited and critically revised the final version, and approved its publication.
Compliance with ethical standards
Conflict of interest
The authors declare no competing interests.
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