Research On Phytoremediation Of Petroleum-contaminated Soil By Field Crops

5 field crops (Zea mays, Sorghum bicolor, Gossypium hirsutum, Triticum aestivum and Arachis hypogaea) 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 T-Salt of tested soils were between 0.37% and 0.45%, and the pH were all higher than 8. So they were all saline-sodic soils.2) The germination rates of the field crops were higher than 67%in the treatment of 10%. With the increase of the concentration of petroleum, the germination rates of sorghum, peanut and winter wheat were all increased and the germination time of seeds were short. Peanut and winter wheat had lower germination rates the treatment of 0%and 1%. The responses of seeding growth and so on of maize, sorghum and cotton to petroleum contamination were emphatically studied in the next experiments.3) During the seedling growth initial stage (10d), high concentrations of petroleum (5% and 10%) might improve the growth of maize, sorghum and cotton. Then during later stage, high concentrations of petroleum improved the growth of maize and sorghum, but obviously stunted the growth of cotton. The root elongations of maize and sorghum were increased with the increase of the concentrations of petroleum, but the root elongation and root/shoot ratio of cotton were appeared contrary trends. The root elongation had significant positive correlation with plant height.4) With the increase of the concentrations of petroleum, the contents of malondialdehyd (MDA) in cotton leaves were increased during two stages (50d and 90d), the activities of superoxide dismutase (SOD) were significantly increased except maize, and the activities of peroxidase (POD) and ascorbate peroxidase (AsA-Apx) in were decreased in maize and sorghum leaves. The activities of antioxidant enzymes in maize leaves were significantly negative correlated to the plant height. The cytochrome P450 contents in leaves had significant negative correlation with plant height.5) The existence of petroleum pollution had not limited the activities of edaphon, but mostly stimulated the activity of three kinds of soil enzymes (dehydrogenase, polyphenoloxidase and lipase in soils). The stimulation to the lipase was the smallest. The activity of soil-dehydrogenase had significant positive correlation with petroleum concentrations.6) Test field crops planted in petroleum-contaminated soils showed high petroleum degradation rate within short growth period. Sorghum and cotton could fit in with the both stresses of salinization and petroleum pollution, thus displaying the potential of remedying petroleum contaminated soils. Maize had shorter growth cycle but made greater contribution to the degradation of petroleum hydrocarbon.