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Soil heavy metal pollution is an important environmental problem threatening people’s health and sustainable economic development. Phytoremediation has become an important technology for the treatment of heavy metal contaminated soil with the characteristics of economy and environmental protection. This paper mainly analyzed the role of microbial community in heavy metal contaminated soil remediation process. Bacterias mainly strengthen the remediation effect of plants on heavy metal contaminated soil in two ways: first, bacterias have adsorption effect on heavy metals and reduce the toxicity of heavy metals to plants in soil; Two is to secrete organic acids and nutrients needed for plant growth to promote the absorption of heavy metals by hyperaccumulators.

By means of constructing on the hyperbola xy = N a triangle whose shape is changed under the rule that one vertex is fixed at the vertex of the hyperbola, one vertex is moving on the hyperbola and the two laterals with respect to the fixed and the moving vertices respectively keep their directions unchanged, it is discovered that the loci of the triangle's centroid and orthocenter are respectively a hyperbola and a line, the locus of the circumcenter is a new cubic algebraic curve, and those of the incenter and ex-centers are planar curves that have not been reported before. All the loci of the centers form a fantastic graph like a ying insect. Meanwhile, the discovered hyperbola and curves are merely N-dependant and can be used to estimate the distribution of y divided by x with respect to xy = N.