Effect of desiccation on potassium and anion currents from young root hairs: Implication on tip growth

Little is known about the early response of roots to desiccation. Young growing root hairs of Arabidopsis thaliana, Vigna unguiculata and Phaseolus vulgaris were used to study the early response of roots to desiccation since they behave like sensors that are able to perceive environmental signals. In control conditions, root hairs were polarized around −120 mV and displayed inward rectifying K+ currents. When submitted to short‐term desiccation, root hairs stopped their tip growth and their membrane became depolarized. Under these conditions, the K+ influx carried by the inward rectifying K+ channels was not maintained and instead slow deactivating anion channels were recorded. The inhibition of K+ influx and the large anion efflux due to the activation of slow anion currents could participate in the inhibition of tip growth.