Stomatal closure prevents the drop in soil water potential around roots

In summary, the results of Rodriguez-Dominguez & Brodribb (2020) show that stomatal closure prevents the formation of large gradients in water potential around the roots. They demonstrate the importance of hydraulic processes at the root–soil interface and call for accurate measurements of the hydraulic properties of the rhizosphere and approaches linking belowground and aboveground hydraulic properties. According to their measurements, the loss of conductance of the root–soil interface and of the rhizosphere, more than that of the soil, impacts the total hydraulic conductance of the soil–plant continuum; and this result is partly explained by the prompt closure of stomata. Testing this result across plant species, soil types and for variable atmospheric conditions should be a research priority for understanding the coordination between stomata and soil drying.