Study On Toxic Effect Of Organophosphorus Pesticides, Heavy Metals To Porphyra Haitanensis

This dissertation studied the effects on growth of somatic cell,soluble protein content,Chla content,RNA and DNA content and peroxidase (POD) activity in Porphyra hahnanensis exposed to mcthmidophos,phoxim,bivalent cadmium,bivalent copper and the mixture ofmethmidophos and bivalent cadmium at concentrations of 0.1,0.5,1,10,20 mg/L in experimental conditions. Samples were taken after exposure for 12h,24h,48h and 72h. Time-effect and dose-effect relationships of the physiological and biological indicators were investigated to look into the toxic mechanism of pollutants to the alga,to compare the toxicity of pollutants and to understand the combined toxicity ofmethmidophos and bivalent cadmium. The results showed:1) The morality of somatic cell rises along with increasing dose of the pollutants. In the same conditions,the toxicities of pollutants to growth of somatic cell:Cu2+ > phoxi,pi > Cd2+ > methmidophos +Cd2+> melhmidophos. Combined toxicity analysis shows that the interactive effect between methmidophos and Cd2+ is synergistic.2) The POD activky almost is induced first,then inhibited or only induced during the prolonging of the exposure time. In the same conditions,the toxicities of pollutants to POD activity:phoxim > Cu2+ > Cd2+ > methmidophos > methmidophos +Cd2+. Combined toxicity analysis shows that the interactive effect between methmidophos and Cd2+ is antagonistic.3) There are good time-effect and dose-effect relationships between the pollutants and Chla contents,which is the Chla content of most of group decreases with the increasing of dose and prolonging of the exposure,beside exposed the Img/L group of Cu2+,the Chla content increases with the prolonging of exposure. In the same conditions,the toxicities of pollutants to Chla content:phoxim > methmidophos +CcP>Cu2f > Cd2+ > methmidophos. Combined toxicity analysis shows that the interactive effect between methmidophos and Cd2+ is synergistic.4) All groups didn't show out the significant time-effect and close-effect relationships between pollutants and (he soluble protein. But with the prolonging of exposure,the effect of all pollutants on RNA and DNA contents almost is that the content first increases and then decreases,and the larger the concentrations of the same pollutant,the earlier the decrease turns up. At the same time,there are significant dose-effect relationships between pollutants and RNA and DNA contents,which is the contents first increase and then decrease or completely decrease with the increasing of dose.Because the POD activity and Chla content have good time-effect and dose-effect relationships with pollutants,they both can act as biological and physiological indicators for Porphyra haitanensis stressed by environmental pollution. And the changes of mortality of somatic cell,Chla content,soluble protein content and RNA and DNA content caused by organophosphorus pesticides,heavy metals and the mixture,show that these environmental pollutants have caused harm to the growth and physiological slate of Porphyra haitancnsis.