Figure 3.

Inter‐organ signaling via the vasculature in drought stress responses.

Various inter‐organ signals are transmitted via the vasculature as part of drought stress response. Xylem and phloem are important for inter‐organ signaling. Soil water deficit and low humidity may induce drought stress responses in roots and guard cells, respectively. Osmotic changes, reactive oxygen species (ROS), and Ca²⁺ transients function in stress signaling from roots to leaves. Peptides and metabolites are synthesized in roots in response to drought stress and transported via the xylem to leaves. Among them, the roles of CLE25 peptide have been precisely analyzed (Takahashi et al., 2018b).