Fig. 1. Wound-induced slow wave potentials (SWPs) in distal leaves of Arabidopsis mslΔ5 and Col-0.

(A) Hypothetical wound signaling network. Severe wounding of L8 triggers a signal that is transmitted to L13 via electrical and calcium waves as well as mechanical cues. Distinct GLRs function in parallel signaling pathways in xylem and phloem (2, 35). Four phases of wound signaling can be assigned (green): signal initiation, distal transmission, perception and decoding of the signal, and triggering of responses (defense and leaf movements). AHA1 functions in SWP repolarization (46). X₁ refers to a process or protein that initiates the chain of events, e.g., apoplasmic glutamate elevation; X₂ refers to a protein involved in signal propagation; X₃ refers to a putative signal receptor. (B) Schematic representation of experimental setup. L8 was wounded, and surface potential dynamics were recorded on the petiole of L13 (distal leaf). e = electrode (blue dot). (C) Representative SWP recordings in distal leaves after wounding (orange bar) Col-0 or mslΔ5 plants. Quantitative analysis of SWP parameters extracted from raw traces provided in fig. S2. (D) Duration of distal SWP (median ± SEM: Col-0: 82.6 ± 12.1 s; mslΔ5: 20.3 ± 1.7 s). Displayed P values were calculated by Mann-Whitney U test (n = 7 to 16). (E) Individual SWP recordings were aligned by derivative minima and averaged; averaged SWP trace of mslΔ5 was superimposed onto averaged SWP trace of Col-0; error bands, SEM.