The Primary Study On Bioremoval Of Copper, Cadmium From Aqueous Solutions By Gracilaria Tenuistipitata And Its Physiological And Biochemical Responses

As the study of bioremoval come in vogue, the algae is widely concerned because of its excellent feature. Gracilaria is the type of strong adaptability and fast growth, high yield, simple cultivation method and promotion easily. It can be used to remove the heavy metal pollution from the aquaculture ponds.Cu and Cd removal in Gracilaria tenuistipitata var.liui and Gracilaria lemaneiformis were studied cultures exposed to different metal concentrations .The results shown that: the two aglae's efficency of removal in low concentration Cu(0.05mg·L-1) are separate 99.9% and 99.7%,and the two aglae's efficency of removal in low concentration Cd(0.05mg·L-1) are separate 93.1% and 94.7%; a specified concentration of Cu and Cd will inhibit growth of the two algae; but the effection to Gracilaria tenuistipitata var.liui is lower than Gracilaria lemaneiformis, it indicated that as a bioremediation ,Gracilaria tenuistipitata var.liui is better than Gracilaria lemaneiformis.This articl also studied the physiological and biochemical responses to Cu and Cd stress in Gracilaria tenuistipitata var.liui.The results shown that: the content of chlorophyll and GSH,and the activity of SOD,GR and GST incerssed in low concentration of Cu and Cd,then decreased in high concentration of Cu and Cd, the content of chlorophyll to max at 0.05mg·L-1 Cu and 0.5mg·L-1Cd,the max of GSH,SOD and GR at 0.25mg·L-1 Cu and 2.5mg·L-1Cd;all of those index are significantly lower when treated with Cu than Cd;So the Gracilaria tenuistipitata have tolerance to Cu at the concentration less than 0.25mg·L-1and to Cd at the concentration less than 2.5mg·L-1 .The content of MDA and pro and the activity of POD increased with the metal concentration increase,all of those index are significantly higher when treated with Cu than Cd;the activity of GPX decreased with the metal concentration increase, this index are significantly lower when treated with Cu than Cd. All of these results indicated that: Gracilaria tenuistipitata var.liui can be used as a biologicaldetector to Cu and Cd, and it is more sensitive to Cu.In addition, we studied the physiological and biochemical responses to Cu and Cd stress in Gracilaria tenuistipitata var.liui under different iron nutrition levels.The results shown that: the content of chlorophyll and phycobiliprotein were significantly higher when added Fe; the activity of SOD and POD and the congtent of MDA and pro are significantly lower when added Fe. The results also showen that:Fe could increase the content of GSH,and it also can increase the activity of GR and GPX,but decreased GST. All of these results above mentioned indicated that Fe could inhance the tolerance of Gracilaria tenuistipitata var.liui in metal, and the better concentration of Fe is 100μg·L-1.