Study On The Effects Of Eco-toxicity Of Petroleum-Contaminated Soil On Plants Growth

With the increase of petroleum extraction and usage, a large amount of petroleum and its products were entry into the environment which inevitably polluted the environment and seriously harmed creatures and human. How to repair petroleum-contaminated soil has been attracting considerable public attention for petroleum may lead to a series of problems such as changing physicochemical property and microflora of soils, penetrating into underground and then polluting groundwater and so on. The phytoremediation technique of petroleum-contaminated soil is becoming an important research area for the advantage of low cost, high maneuverability, wide adaptability, removing or degrading pollutant in soil, atmosphere and water at the same time, no secondary contamination and so on.6 plants (Lolium perenne., Festuca arundinacea, Elymus dahuricus, Medicago sativa, Astragalus adsurgens, S. hetroptera Kitag) planted in contaminated soils were observed at 4 pollution concentration levels (a serial petroleum concentration of 0,1%,5% and 10% by dry weight) in greenhouse pot experiments. Analyze seeding growth and serials biochemical indexes of soil, in order to identify remediation plants from these field crops and provide theoretical basis for the phytoremediation of petroleum-contaminated soil. The main results were as follows:1) The results showed that these seeds significantly differentresponses to petroleum pollution. Compared with those planted in clean soils, the germination of most seeds planted in the contaminated soils was obviously inhibited. Medicago sativa L., Astragalus adsurgens Pall., S. hetroptera Kitag were the ornamental affected most adversely. Fortunately, strong endurance and high seed germination were observed for the other seeds under 4 different levels of petroleum pollution, thus displaying the potential of remedying petroleum contaminated soils. The responses of seeding growth and so on of Lolium perenne L.,Festuca arundinacea and Elymus dahuricus Turcz. to petroleum contamination were emphatically studied in the next experiments.2) During the seedling growth initial stage, results show that the variation of oil concentration of soil has different effects on each plant growth. Crude oil restrains growth of them when its content is high. All treatments have less effect on seed germination, individual height and fresh weight of Lolium perenne L., Festuca arundinacea and Elymus dahuricus Turcz.. They can be fit to grow on the crude oil-contaminated soils by itself and with the biggest experimental potential to phytoremediation of oil-contaminated soils in this experiment.3) With the increase of the concentrations of petroleum, the activities of superoxide dismutase (SOD) and the activities of peroxidase (POD) in all leaves were increased during stages, the contents of malondialdehyd (MDA) were significantly increased too. The activities of antioxidant enzymes in maize leaves were significantly negative correlated to the plant height. The activities of superoxide dismutase (SOD), the activities of peroxidase (POD) and the contents of malondialdehyd (MDA) were more sensitively changes in the environment.4) The existence of petroleum pollution had mostly stimulated the activity of three kinds of soil enzymes (dehydrogenase, polyphenoloxidase and lipase in soils). The activity of dehydrogenase and polyphenoloxidase in soils were increased with the increase of the the concentrations of petroleum, and the activity of them were also more sensitively changes in the environment.5) The phytoremediation of petroleum-contaminated soil harm obviously for growth indexes, seed quality of the three seeds, which can promote on the bacteria growth in the soil. With the increase of the concentrations of petroleum, the degradation rate was increased.