| The study on prevention and restoration of heavy metal's pollution in the soil is one of the emphases in the recent year's research. This experiment, from the point of ecological renovation strategy and economic benefit , that is, using this special soil resource rationally polluted by Cr, based on the large-scale Cr pollution in the cropland in Henan Xinxiang as well as the whole country, through the way of sterilizing the soil, used the ordinary lawn grasses as indicator to study sterilization's restraint effect on heavy metal's menace to the vegetation's growth in the pot experiment, it roundly investigated sterilization's negative impact on heavy metal's effect on the vegetation's growth from the grasses'modality index, physics and chemistry index, total Cr accumulation and trauma symptom, and analyzed the correlation of heavy metal's pollution and poison in the plant to illuminate that through sterilizing the soil can change the environment contaminated by heavy metal, which is advantaged of improving the resistance and tolerance of the plant'reaction on heavy metal's pollution, and aimed to provide partially support in the restoration of the soil polluted by heavy metal, and support in the technique of the lawn grasses'effect on improving the region polluted by Cr.The results showed that:(1)With the consistency of Cr(â…¢) stress increasing, the germination rate of the two kind of lawn grasses declined gradually, and their germinating postponed obviously, with the same consistency, the germination rate in the sterilized soil was clearly higher than that in the non- sterilized soil, meanwhile, evaluated the suitability value, critical value and extremity value of Cr(â…¢) stress through vitality index of grass seeds, they in the sterilized soil respectively were 257.3,371.5,485.8(tall fescue), 286.8,417.5,548.3(ryegrass) , and in the non-sterilized soil 70.9,135.9,200.9(tall fescue),125.3,228.5,331.8(ryegrass).(2)The grasses'modality indexes (height, root's number and length, total biomass) were all negatively correlative with Cr(â…¢) stress markedly, and the series of sterilized soil were evidently better than that of non- sterilized soil, low levels of Cr(â…¢) stress had no obvious influence on the grasses'physics and chemistry index, with the consistency increasing, the restraint effect of chlorophyll, root activity, SOD appeared gradually.(3)Cr(â…¢) accumulation in the lawn grass was positively correlative with Cr(â…¢) stress markedly, total Cr accumulation in the sterilized series was evidently lower than that in the non- sterilized series, which explained the phenomenon that the grasses in the non- sterilized series were injured more observably .(4)The creativity in this experiment : it alleviated the injury of Cr(â…¢) pollution on the grasses through sterilizing the soil, heightened the lowest consistency of Cr(â…¢) which was toxic to the plant, especially enhanced the resistibility of the grasses, with the same Cr(â…¢) stress, the injuries that the grasses suffered were: tall fescue in the non-sterilized soil>ryegrass in the non-sterilized soil>tall fescue in the sterilized soil>ryegrass in the sterilized soil. With regard to the trauma symptom, in the non-sterilized group, tall fescue begun to be injured slightly at the consistency of 90 mg?kg-1, and was injured heavily at 300mg?kg-1, ryegrass begun to be injured slightly at 200 mg?kg-1, and was injured heavily at 500mg?kg-1, in the sterilized group, tall fescue begun to be injured slightly at the consistency of 200 mg?kg-1, and was injured heavily at 500mg?kg-1, ryegrass begun to be injured slightly at 300 mg?kg-1, and was injured heavily at 600mg?kg-1.(5)From the conclusion that sterilizing the soil improved the resistance and tolerance of the plant'reaction on heavy metal's pollution, based on the significance of crops, advised adopting reasonable physical sterilizing measures to available for crops and preventing the biology amplificatory effect on crops.(6)From the point of using the polluted cropland with high consistency Cr, advised using the absorbable ability of lawn grass, then planting them to disperse and dilute the Cr pollution, and as the product, the grass seeds can output Cr continuously, which can reduce the pollution to achieve high economic benefits.
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