| Pollution of of water by heavy metals has imposed an increasingly serious risk to environmental and human health.The toxic effects of Cu、Cd、Pb were stronger in the water, which often existed with combined pollution in the water, difficult to control. In this paper, experiments were done to make studies on canna indica germinated in Cu、Cd、Pb pollution nutrition liquid, including the single and composite toxicity effect on the concentration of heavy metals. The diversity on the physiological of the canna indica such as survival adaptability, leaf chlorophyll and malondialdehyde, antioxidant enzymes was analysed under the single and composite heavy metal pollution stress. A research on the accumulation capacity to Cu, Cd and Pb of the canna indica on the water and the connection between processing time and heavy metal toxicity was also carried out. The major findings could be summarized as following:(1) The influence on the growth of canna indica under single and composite pollution of heavy metals (Cu. Cd, Pb).This study examined the growth status of canna indica under single and composite pollution of heavy metals (Cu, Cd. Pb). Results have shown that, single Cd under contrations no more than10mg·L-1had no significant effects on growth, fresh weight and biomass of Canna, plant heigh、fresh weight and dry weight reach39.6cm、618.4g、61.16g. with the concentration of heavy metals improving and the processing time extended, the greater the toxicity to plants. When the Cd was30mg·L-1, the plant height, fresh and dry weight of Canna were only72.96%、72.09%、78.03%of CK, respectively. At the single pollution of Cu, Cd and Pb, the primary toxic effect on canna was Cd. While the growth status of canna indica has not been greatly affected under the joint treamment of Cu and Pb. The toxic effects of heavy metals on canna was sequenced as Cd> Cu> Pb.The toxic effecs of combined pollution of Cu、Cd、Pb were related to their concentrations、processing time. the toxicity of compound pollution was ordered:(Cu-Cd-Pb)>(Cu-Cd, and Cd-Pb, and Cu-Pb)>(Cu-Cd-Pb).(2) The effects of physiological and biochemistry properties of Canna indica under single and compound pollution of Cu、Cd、Pd.Effect of physiological characteristics of Canna indica under single and compound pollution of Cu、Cd、Pd. The result shows:As the increase of the concentration of Cu、Cd、 Pd, MDA and proline contents in leaves increase, content of chlorophyll decrease. Superoxide dismutase (SOD) and peroxidase (POD) of Canna indica to remove efficiency the Ros of plant, has a very important protective enzymes in the antioxidant defense system, the activity of POD and SOD increase in the lower concentration, but decrease in the higher concentration and later day(3) The hyperaccumulating characteristics of Canna indica under single and compound pollution of Cu、Cd、PdThe removal and hyper-accumulation of Cu2+、Cd2+、Pd2+in Canna indica was carried out under single and compound pollution of Cu, Cd and Pd in the nutrient. Results showed that, under the same concentration treatments, the removal efficiency for single heavy metal pollution was in the order of Cu2+>Cd2+>Pb2+, the accumulation volume in Canna indica was sequenced as Cu2+>Pb2+>Cd2+, and the mobility among root-stem-leaf gradually decreased with the increasing dispose concentration. Cu-Cd-Pb combined pollution had a synergistic effect on the growth of Canna indica. According to the intercomparison of the single pollution, it is also significantly apparent that the removal rate of Cu2+, Cd2+and Pd2+were respectively descended17.99%、43.82%、25.07%under the compound pollution of Cu-Pb and Cu-Cd-Pb. and the accumulate volume in the root of Canna indica were also decreased480.67mg·kg-1、568.69mg·kg-1and249.54mg-kg-1, respectively. The interaction effects of Cu-Cd-Pb related with a variety of factors, including the combined concentrations between heavy metals, the plant tolerance and the process-time, which behaved very complex, not just pure adduct, antagonism and synergistic effect. |
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