Mutually reinforcing and transpiration-dependent propagation of H2O2 and variation potential in plants revealed by fiber organic electrochemical transistors

Public summary

• Plants use hydrogen peroxide (H₂O₂), variation potential (VP), and xylem flow for cell signaling and adaptation.

• Microfiber-shaped organic electrochemical transistors (fOECTs) reveal interplays among VP, H₂O₂, and xylem flow.

• A transpiration- and intensity-dependent H₂O₂-VP mutual-reinforcing propagation mechanism is proposed.

• Microfiber electronics enable the in situ study of plant physiological processes with high temporospatial resolution.

Plants use hydrogen peroxide (H2O2) and variation potential (VP) waves as well as chemical transport by transpiration-driven xylem flow to facilitate cell signaling, cell-to-cell communication, and adaptation to environmental stresses. The underlying mechanisms and complex interplay among H2O2, VP, and transpiration are not clearly understood because of the lack of bioengineering tools for continuous in planta monitoring of the dynamic biological processes. Here, we tackle the challenge by developing microfiber-shaped organic electrochemical transistors (fOECTs) that can be threaded into the plants. The sensorized microfiber revealed that both H2O2 and VP waves propagate faster toward the leaves than toward the roots because of the directional long-distance transport of H2O2 in the xylem. In addition, the revealed interplays among VP, H2O2, and xylem flow strongly suggest a transpiration- and intensity-dependent H2O2-VP mutual-reinforcing propagation mechanism. The microfiber electronics offer a versatile platform for the in situ study of dynamic physiological processes in plants with high temporospatial resolution.