Response of sulfhydryl compounds in subcells of Cladophora rupestris under Pb stress.

This study aimed to determine the role of sulfhydryl compounds in the subcells of C. rupestris under Pb stress. Different concentrations (0, 0.5, 1.0, 2.5, 5.0, 7.5, and 10 mg/L) and different exposure days (1, 3, 5, and 7 days) were designed to analyze the subcellular distribution of non-protein thiols (NPT), glutathione (GSH), and phytochelatins (PCs) in C. rupestris. NPT, GSH, and PCs increased significantly with increasing Pb stress in the cell wall and soluble fraction, especially NPT. NPT and GSH slowly increased, and PCs showed no significant difference in the organelle of C. rupestris at low concentrations (< 5.0 mg/L). PCs slightly increased under 5.0 mg/L of Pb stress. PCs/NPT gradually increased with Pb stress at a low Pb concentration. GSH detoxification response lagged behind those of NPT and PCs in response to time. PCs/NPT initially increased and then decreased with Pb stress duration. This study suggested that NPT, GSH, and PCs played an important role in the detoxification of the cell wall and the soluble fraction of C. rupestris under Pb stress. PCs were important in the organelle.