| Plant bio re mediation, which has been widely used in polluted water, soil and other natural environment restoration project, is of very importance method in Environmental Remediation. But the fact is that it is the lack of the bioremediation in the saline environment. In this study, We collected natural sea water from intertidal zone of Zhoushan Changzhi island with a small amount of sewage as the background, discussed the purification effect of NH4+-N, TIN, PO43--P and growth conditions of different kinds of salt-tolerant wetland plants. In addition, The impact of the external environment on plant growth and development is mainly Related to the physiological and biochemical processes of plants. Plants also protect themselves by physiological and biochemical changes to endure or withstand the impact from external environment. Therefore, these two aspects of the research not only helps us understand the operational status of phytoremediation, but also provides us a theoretical basis of improving the efficiency of salt-tolerant plants for environmental remediation.With hydroponic experiment, we explore the purification effects of NH4+-N, TIN, PO43--P, COD and growth conditions of Scirpus tabernaemontani, Phragmites australis (Cav.) Trin. ex Steud., Canna indica, Suaeda glauca Bge and Alternanther a philoxeroides (Mart.) Griseb in three different saline gradient waste water(5.0‰,7.5‰and10.0‰).Meanwhile, salt resistance of5plants have also been studied. We also test Superoxide dismutase (SOD), Pro line (Pro) and Malondialdehyde (MDA) of5plants in the different salty water(5.0‰,7.5‰and10.0‰). The Conclusions are as follows:Firstly, The relative growth rate (RGR) of five kinds of wetland plants in low salinity gradient was greater than that in high salinity gradient, which showed that high salinity wastewater can produce more stress to the wetland plants than that in low one. Therefore the relative growth rate (RGR) order of five kinds of plants in the saline wastewater was Scirpus tabernaemontani>Phragmites australis (Cav.) Trin.ex Steud>Canna indica> Suaeda glauca Bge>Alternanthera philoxeroides (Mart.) Griseb. Secondly,with hydroponic experiment, we discussed purification effects of NH4+-N, TIN, PO43-P and COD of Scirpus tabernaemontani, Canna indica, Phragmites australis (Cav.) Trin. ex Steud, Suaeda glauca Bge and Alternanthera philoxeroides (Mart.) Griseb in three different saline gradient waste water(5.0‰,7.5‰and10.0‰). The results showed that in the removal rate of NH4+-N, Scirpus tabernaemontani showed the highest removal efficiency which was76.42%and72.72%in salinity gradient of5.0‰and7.5‰, while in salinity gradient of10.0‰, Phragmites australis (Cav.) Trin. ex Steud. showed the highest removal efficiency which was66.71%. In the removal rate of TIN, Scirpus tabernaemontani still showed the best removal efficiency which was79.45%and71.42%, while in salinity gradient of10.0‰,Phragmites australis (Cav.) Trin. ex Steud. showed the highest removal efficiency which was62.83%. In the removal rate of PO43--P, Scirpus tabernaemontani still showed the highest removal efficiency which was68.37%and66.28%, while in salinity gradient of10.0‰, Phragmites australis (Cav.) Trin. ex Steud. showed the highest removal efficiency which was67.29%. In the removal efficiency of COD, Phragmites australis (Cav.) Trin. ex Steud, Scirpus tabernaemontani, Suaeda glauca Bge showed the highest removal rate in three different kinds of saline water, respectively,61.36%,54.88%and50.72%. Because of Hydroponics, the organic compound removal rate in each experimental group did not exceed62%. Without constructed wetland padding, the purification of COD was becoming more and more limited.Thirdly, the trend of Leaves of Scirpus tabernaemontani, Phragmites australis (Cav.) Trin. ex Steud, Canna indica, Suaeda glauca Bge and Alternanthera philoxeroides (Mart.) Griseb was studied by measuring the SOD activity, free proline and malondialdehyde (MDA) under the treatments with the different salt stress. The result was as follows:Under salt stress, with the gradual increase of salinity,SOD activity of leaves of Scirpus tabernaemontani, Canna indica and Phragmites australis (Cav.) Trin. ex Steud. gradually increased, which Under10.0‰salinity content was respectively up to the initial319%.302%and371%. The incremental of SOD activity became slow in Suaeda glauca Bge and Alternanthera philoxeroides (Mart.) Griseb; With the gradual increase of salinity, the growth of proline content in Scirpus tabernaemontani and Phragmites australis (Cav.) Trin. ex Steud. were significantly increased. When salinity was between5.0‰-10.0‰, they were respectively increased181.43%and83.52%. But in the same salinity,there was no significant increase between Canna indica, Suaeda glauca Bge and Alternanthera philoxeroides (Mart.) Griseb (respectively83.52%,35.16%and40.80%).The proline increase of leaves in Alternanthera philoxeroides (Mart.) Griseb was not obvious between7.5‰and10.0‰, growth was only1.73%; with the salinity gradient increases, The MDA content of leaves in Canna indica and Alternanthera philoxeroides (Mart) Griseb was continuously increased. Compared with check, the content of MDA had unobviously been increased in Scirpus tabernaemontani and Phragmites australis (Cav.) Trin. ex Steud., Only between0.45%-9.76%. After the test, we can draw a conclusion that the relatively ability of salt tolerance from high to low was Scirpus tabernaemontani, Phragmites australis (Cav.) Trin. ex Steud., Canna indica, Suaeda glauca Bge, and Alternanthera philoxeroides (Mart.) Griseb.In conclusion, the studies of physiological and biochemical for5kinds of wetland plants explained the strength of the salt resistance and the purification of waste water.It can provide plants for applications in coastal water or reference for saline area repair needs. |
PDF Full Text Request