Studies On The Resistant Responses Of Zizania Latifolia Turcz To LAS-Cd Pollution And The Absorption And Biodegradation Of LAS

Water bamboo (Zizania caduciflora Turcz Hand-Mazz) is one of the unique aquatic vegetables with great importance in China. People have concerned more about our environmental problems and shifted the priority to those compound pollutions, especially those by organic and heavy mental. In this paper, we studied the combined impacts of linear alkylbenzene sulfonate (LAS) and heavy mental (Cd) on water bamboo - soil system, the resistance response to the compound pollution and the abilities of water bamboo of absorption and degradation for LAS pollution. The results were reported as follows:1. Impacts of the compound pollution by linear alkylbenzene sulfonate (LAS) and Cd on water bamboo - soil system: Impacts of different concentrations of LAS (0, 60, 120, 240mg·L^-1) and Cd (0,50,100mg·L^-1) on growth, soluble protein content and antioxidant system in the leave of Zizania latifolia Turcz at different periods were studied. The results showed that with the continuously increasing concentrations of LAS, the activities of APX and SOD increased observably at the early period and declined later with the lower concentration of LAS, while the activity of POD kept increasing. The contents of MDA always increased with the increasing concentration of LAS with the days going on. Under single Cd polluted conditions, the activities of POD and SOD in leaves were enhanced and the contents of MDA were added. Under the compound pollutions with the same level of Cd concentration, the activities and the MDA contents went similarly with that under single LAS treatment. We can find that the detoxification effects were relatively remarkable under lower LAS concentrations but enhanced the damage under higher concentrations..2. The absorption and degradation of LAS in the leaves and swelling stems of water bamboo, and the relative residue in the soil. In this experiment, the contents of LAS in the plant leaves descended firstly and then increased with the different concentrations at different periods. The contents of LAS in the swelling stems were at a lower standard. The results showed that Zizania latifolia Turcz had the stronger power of absorbing and degrading LAS compared with the single soil environment. The plant might absorb, assimilate and degrade the LAS through its own bio-repairing function. Within certain extent of pollution, the water bamboo can not only reduce the LAS contents in the soil, but also maintain a relative low level of LAS contents in its bodies. However, the high concentrations of LAS reaching 480mg·L^-1 may lead the accumulation of LAS in the soil. The results showed that there is a limit to the self-repairing ability in resisting LAS pollution near the LAS level of 240mg·L^-1.