玉米修复芘污染土壤的初步研究

采用60d室内盆栽试验,研究了玉米CT38(ZEAMAYSL.)对多环芳烃芘污染土壤的修复作用.结果表明,无论种植玉米土P系列、无植物对照土M系列(无植物且添加叠氮化钠的灭菌土)和对照土W系列(无植物未灭菌土)中芘的可提取浓度都随着时间的推移逐渐减少,种植玉米加快了土壤中可提取态芘浓度的下降.在芘处理浓度为10—100mg.kg-1的污染土壤中,种植玉米CT38的土壤中芘的去除率达81.9%—89.3%,分别比无植物对照土M系列和对照W系列中芘的去除率高67.5%—70.9%和26.2%—47.0%.玉米也可积累少量芘,但积累量所占芘去除量的比例不足0.3%,植物吸收不是芘去除的主要机理.种植玉米增强了土壤中脱氢酶和脲酶等酶活性,从而促进了植物-根圈微生物体系对芘的生物降解.

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 NaN_3)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.