PHYTOREMEDIATION OF SOIL CONTAMINATED WITH PYRENE BY MAIZE CT38 (ZEA MAYS L.)

The mechanisms of the removal and accumulation of pyrene by maize CT38(ZEA MAYS L.) were studied by pot experiment in greenhouse.Pyrene in both planted and unplanted soil diminished significantly at the end of 60-day culture.About 81.9%—89.3% of pyrene were removed from the planted soil.As compared with control M series soils (unplanted spiked soils with addition of NaN3) and control W series soils (unplanted spiked soils),maize removed 67.5%—70.9% and 26.2%—47.0% more pyrene,respectively,which indicated that the removal of pyrene was enhanced by the presence of vegetation.Although the roots and shoots of maize could accumulate pyrene,contribution of plant off-take of pyrene to the total remediation enhancement in the presence of vegetation was less than 0.3%.A significant positive correlation was observed between soil enzyme activities (dehydrogenase and urease) and the removal rate of pyrene.Plant root exudates appear to promote the number of rhizosphere microorganisms and enzyme activity,thereby improving biodegradation of pyrene.Maize CT38 can grow in soils with high concentrations of pyrene (10—100 mg·kg-1)and remove pyrene effectively.The results indicate that the removal of pyrene from contaminated soils by maize may be a feasible approach to soil remediation.