Simple Phenotypic Sensor for Visibly Tracking H 2 O 2 Fluctuation to Detect Plant Health Status.

Hydrogen peroxide (H 2 O 2 ), as a main component of reactive oxygen species (ROS), serves as a key signaling molecule relevant to plant stress response and health status. Many strategies have been developed for detecting or quantifying H 2 O 2 concentration. However, reports on simply, visibly tracking H 2 O 2 fluctuation in vivo are limited. Here, for visibly tracking the plant H 2 O 2 wave, a green fluorescent phenotypic probe was designed by merging a H 2 O 2 -sensitive tertiary amine moiety with the core fluorophore tetraphenylethene skeleton. The green fluorescence emission is quenched up to 52% by H 2 O 2 with good sensitivity, selectivity, and reversibility within the plant physiological range of 10-100 μM H 2 O 2 . In response to various abiotic stresses, including mechanical damage, high salt, strong light and drought, fluorescence fluctuations, response to H 2 O 2 concentration alterations in vivo was visible to the naked eye under irradiation of commercially available UV light (365 nm) after simple injection of this H 2 O 2 probe solution into seedling leaves. This phenotypic fluorescent H 2 O 2 probe illustrates great potential as early sensors of plant health under stress without the aid of skillful operation and specialized equipment.