Evidence for root adaptation to a spatially discontinuous water availability in the absence of external water potential gradients
Kara R. Lind, Oskar Siemianowski, Bin Yuan, Tom Sizmur, Hannah VanEvery, Souvik Banerjee, Ludovico Cademartiri
Abstract
(∼4 orders of magnitude smaller than in conventional hydrotropism assays). Despite such minuscule gradients (which greatly limit the possible influence of the well-understood gradient-driven hydrotropic response), our results show that 1) 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 2) 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 3-5 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.