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Ecological and environmental problems including heavy metal pollution have received increasing concerns. Given the shortage of physical and chemical remediation methods in high cost and secondary pollution, using plants and microorganisms for joint remediation of environment has become one of the most important strategies. Root exudates are an important medium for information and nutrient exchange between plants and soil. The roles of plant root exudates in remediation of polluted and degradated soil have been widely studied. In this review, we described the composition, secretion mechanism and functions of root exudates and summarized the functions of root exudate in heavy metal absorption, allelopathy, interaction between roots and rhizosphere microorga-nisms, and changes in soil physical and chemical properties. The progress, challenges and prospect of applying root exdudates and rhizosphere microorganisms in the remediation of ecology and environment have also been discussed. This review could provide theoretical support for the application of plant-microorganism based environmental remediation.

Objective: To determine the independent prognostic factors of primary synovial sarcoma., Methods: The clinical data of 52 patients followed up from 66 patients with synovial sarcoma treated between September 1997 and September 2008 was analyzed retrospectively. There were 28 male and 24 female patients aged from 11 to 71 years old. Three and five-year overall survival (OS), recurrence rate and 9 prognostic factors were analyzed in this study. Univariate and multivariate analysis were performed to determine the prognostic factors of OS., Results: Fifty-two patients were followed up with the follow-up time ranged from 6 to 88 months (median 32 months). The 3-, 5-year overall survival rate and local recurrence rate were 52.8%, 30.3% and 32.7% respectively. Univariate showed tumor size < 5 cm, tumor located at extremities, adequate surgical margin and radical resection combined with radiotherapy had better survival rate (P < 0.05). Multivariate analysis demonstrated that tumor size, primary site and adequate surgical margin were independent prognostic factors for OS. Patients received radical resection combined with radiotherapy have longer median relapse time (25 months) compared with marginal resection combined with radiotherapy (18 months) and single radical resection (12 months). Thirty-five (67%) patients were treated with chemotherapy and seventeen (33%) patients received no chemotherapy for the primary tumor. Treatment with chemotherapy was not associated with an improved OS (P = 0.52)., Conclusions: The independent prognostic factors of synovial sarcoma are tumor size, primary site and adequate surgical margin. Doxorubicin and ifosfamide based chemotherapy was not associated with an improved OS in patients with synovial sarcoma. Radical resection combined with radiotherapy can best control local condition.