Dual-channel fluorescent probe for detecting SO2 and Hg2+, and dynamic imaging SO2 under Cd2+ in alfalfa (Medicago sativa)

Abstract

BackgroundAs an antioxidant, SO2 plays a critical role in maintaining the plant's redox balance. At the same time, Hg2+ as heavy metals, will accumulate in plants through soil, often disrupting physiological processes in plants. However, few studies have been reported to examine changes in Hg2+ and SO2 in plants. Here, we developed a dual-channel fluorescent probe NYD, which can differentiate between the detection of Hg2+ and SO2. ResultsThe probe exhibits high sensitivity (LOD, 44 nM for Hg2+ and 26 nM for SO2). When Hg2+ and HSO3− deprotect and attack the double bond by nucleophilic addition, significant emission of fluorescence at 475 nm and 574 nm with blue and red fluorescence respectively. In addition, NYD has the capability to detect the levels of Hg2+ and SO2 in cells and alfalfa seedlings. Meanwhile, the findings indicated that alfalfa seedlings were exposed to Cd2+, which led to redox imbalance and increased endogenous SO2 production. SignificanceWe anticipate that this research will contribute to a better understanding of the functions of SO2 under oxidative stress induced by Cd2+.