Evidence for root adaptation to a spatially discontinuous water availability in the absence of external water potential gradients

Lind, K., Siemianowski, O., Yuan, B., Sizmur, T. ORCID: https://orcid.org/0000-0001-9835-7195, VanEvery, H., Banerjee, S. and Cademartiri, L. (2021) Evidence for root adaptation to a spatially discontinuous water availability in the absence of external water potential gradients. Proceedings of the National Academy of Sciences, 118 (1). e2012892118. ISSN 1091-6490 doi: 10.1073/pnas.2012892118

Abstract/Summary

We hereby show that root systems adapt to a spatially discontinuous pattern of water availability even when the gradients of water potential across them are vanishingly small. A paper microfluidic approach allowed us to expose the entire root system of Brassica rapa plants to a square array of water sources, separated by dry areas. Gradients in the concentration of water vapor across the root system were as small as 10-4 mM·m-1 (~4 orders of magnitude smaller than in conventional hydrotropism assays). In spite of such minuscule gradients (which greatly limit the possible influence of the well-understood gradient-driven hydrotropic response), our results show that (i) individual roots as well as the root system as a whole adapt to the pattern of water availability to maximize access to water, and that (ii) this adaptation increases as water sources become more rare. These results suggest that either plant roots are more sensitive to water gradients than humanmade water sensors by 3 to 5 orders of magnitude, or they might have developed, like other organisms, mechanisms for water foraging that allow them to find water in the absence of an external gradient in water potential.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/94481
Item Type	Article
Refereed	Yes
Divisions	Science > School of Archaeology, Geography and Environmental Science > Earth Systems Science Science > School of Archaeology, Geography and Environmental Science > Department of Geography and Environmental Science
Publisher	National Academy of Sciences
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