Visualization of Hg 2+ Stress on Plant Health at the Subcellular Level Revealed by a Highly Sensitive Fluorescent Sensor

The presence of Hg²⁺ causes substantial stress to plants, adversely affecting growth and health by disrupting cell cycle divisions, photosynthesis, and ionic homeostasis. Accurate visualization of the spatiotemporal distribution of Hg²⁺ in plant tissues is crucial for the management of Hg pollution; however, the related research is still at its early stage. Herein, a small-molecule amphiphilic fluorescent probe (termed LJTP2) was developed for the specific detection of Hg²⁺ with a high sensitivity (~16 nM). Fluorescent imaging applications with LJTP2 not only detected the dynamic distribution of Hg²⁺ within plant cells at the subcellular level but also enabled the understanding of cell membrane health under Hg²⁺ stress. This study introduces a valuable imaging tool for elucidating the molecular mechanism of Hg²⁺ stress in plants, demonstrating the potential of the application of small-molecule fluorescent probes in plant science.