Heavy metal induced ecophysiological function alterations in the euhalophyte Suaeda salsa
Heavy metal accumulation affects the physiological status of plants. Suaeda salsa L. is used to investigate the toxic effects of cadmium (Cd) and lead (Pb) either alone or mixtures under the static test conditions. Cd-Pb mixture exposure can decrease lignin content and weaken the increase. Mitochondrial calcium content significantly reduced at 30 µM Cd and Pb exposure. Cd-Pb mixture exposure can increase calcium content under the same concentration exposure. Soluble sugar levels noted a significant decrease in Cd, Pb and Cd-Pb mixture exposure. The accumulations of Cd, Pb in S. salsa were significantly increased with exposure time. Soluble protein (SP) in S. salsa at 30 µM concentration treatments decreased with exposure time. Heat shock protein 70 (HSP70) was enhanced lightly along with the increase of added Cd-Pb from 30 to 70 &3181;M and then decreased below the controls which present a synergistic effect. Heat shock protein 60 (HSP60) increased slightly with the increase of Cd-Pb from 30 to 110 µM, and then decreased hereafter and significantly inhibited at 150 ƒÊM (p<0.05). Moreover, Cd-Pb mixture exposure significantly increased the Rubisco activity under lower concentration and presented antagonistic effect. At the same time, the viability percent decreased as increase Cd-Pb concentration exposure (p0.05), it presents a dose-dependent manner. Mitochondrial cells treated with Cd-Pb exposure obviously reduced the reactive oxygen species (ROS) levels in mitochondrial cells.
Key words: Suaeda salsa, heavy metal, ecophysiological function.