Figure 1.

Conceptual diagram of root-to-shoot, shoot-to-shoot, and local signals in response to drought stress conditions. Mobile signals such as hydraulic pressure, ROS/Ca²⁺ waves, peptides, and phytohormones mediate tissue-to-tissue and long-distance communication for the acquisition of drought stress resistance at the whole-plant level. The red line indicates the root-to-shoot signals such as hydraulic pressure, ROS/Ca²⁺ waves, and peptides signals under dehydration stress conditions. The orange line indicates the shoot-to-shoot signals of ROS/Ca²⁺ waves to mediate stomatal closure under stress conditions. The blue line indicates the local signals of ROS/Ca²⁺ waves, peptide, or ABA signals that mediate stomatal control under stress conditions.