Fluorescence probes evaluated the hydrogen peroxide level in rice roots under cadmium ion stress

Abiotic stress and oxidative stress are closely related to the health status of plants. Plants will produce oxidative stress under abiotic stress, induce mitochondrial dysfunction, cause programmed cell death, and decrease plant survival rate. It is well known that rice is an essential crop for humans, but its cadmium tolerance is poor. Therefore, it is crucial to determine whether cadmium stress causes oxidative stress in rice in order to guide rice cultivation. Hydrogen peroxide (H₂O₂), a highly reactive oxygen species (ROS), is one of the most critical signals in corps under oxidative stress. In this work, we adopted a near-infrared (NIR) H₂O₂ fluorescent probe YFE-1 and a cadmium ion (Cd²⁺) fluorescent probe SCP to observe the fluctuation of H₂O₂ in rice roots under Cd²⁺ co-incubation conditions. Due to the advantages of fast response (within 2 min), a large Stokes shift (181 nm), good selectivity, and a low detection limit (LOD:26.4 nM), YFE-1 achieved the visualization of H₂O₂ produced by Cd²⁺ stress in rice roots. This study provides a new idea for assessing the risk of oxidative stress of Cd²⁺ in rice roots. It is expected to guide the control of Cd²⁺ in the rice planting industry to improve rice yield.