Study On The Tolerance And Restoring Effect Of Several Crops On Oil-contaminated Soil

With the expanding of the soil contaminated by crude oil, phytoremediationgradually caused a lot attention in oil contamination treatment due to low cost andavoidance of secondary contamination. Phytoremediation is based on choosing tolerantplant of excessively accumulating oil contaminants. In this paper,5of concentrationgradients were set to study the effects of oil-contaminated soil on the seed germinationand seedling growth of winter wheat (Triticum aestivum), soybean (Glycine max) andsunflower (Helianthus annuus) by the pot-planting experiment, and then the soybeanand sunflower were screened. To study further,3of concentration gradients weredesigned to investigate the growth and physiological characteristics of crops screened,and soil microbial activity and repair effects of crops were evaluated. The resultsshowed that increasing crude oil concentration from0.8%~2.4%had a little effect onplant height of soybean and oil in soil (0.8%and1.6%) also had no siginificant effect onthe above-ground fresh weight of soybean. The plant height of sunflower wassignificantly lower than the control at the2.4%crude oil level, however, oil stressobviously inhibited the above-ground fresh weight of sunflower at all treatments. So thetolerance of soybean was stronger than sunflower. Increasing crude oil concentrationfrom0.8%~2.4%significantly reduced chlorophyll contents, peroxidase (POD) activity,superoxide dismutase (SOD) activity, soluble protein contents and root activity ofsunflowers, while obviously boosted malonaldehyde (MDA) contents. Then the damageof sunflower was more and more severe. With the continuous growth of soybean, itschlorophyll contents, soluble protein contents, MDA, SOD and root activity had nosignificant difference with the control in low and medium concentration level. POD ofsoybean leaves was significantly higher than the control at all treatments. So soybeanhad stronger tolerability and adaptability to oil-contaminated soil. Oil degradation ratesof soybean and sunflower were respectively57.18%and71.55%in low concentrationoil-contaminated soil, which was higher than the control. In summary, soybean hadstronger tolerability and adaptability to oil-contaminated soil, and its remediation effectwas better than the sunflower during the concentration range of0.8%~2.4%.