Abstract: Heavy metal contamination has become a serious environmental issue in China. Phytoremediation, as a green and safe bioremediation technology, has attracted much attention to researchers. Root exudates play an important role in nutrient cycling and signal transduction amongplant soilmicroorganisminteraction, as well as in the responses of plants to environmental stress during phytoremediation. Root exudates could regulate rhizosphere microenvironment, enhance plant tolerance, and affect the environmental behaviors of heavy metals in rhizosphere soils. Previous studies on rhizosphere ecology have focused more on nutrient regulation, but less on the effects of root exudates on phytoremediation of contaminated sites. We reviewed the effects of root exudations on soil physical and chemical properties, soil microorganisms, plant physiological metabolism, and mobilization of heavy metals in the soilplant system. We systematically summarized the physiological and ecological responses of root exudates to heavy metal contamination, and pointed out promising direction and aspects for further studies.

Key words: root exudate, heavy metal, phytoremediation, soil-plant system, ecological effect.