甜菜与牧草间作对多环芳烃污染土壤的修复作用

通过盆栽试验方法，选择经济作物甜菜和牧草类黑麦草、苏丹草、香根草为供试植物，研究了甜菜与3种牧草分别间作及各自单作对多环芳烃（PAHs）菲、荧蒽、芘和苯并a]芘污染土壤修复作用。结果显示：经6个月连续两茬种植试验后，所有种植植物的处理中土壤PAHs的去除率均高于无植物种植组，间作种植土壤PAHs的去除率高于单作，黑麦草、苏丹草、香根草与甜菜间作对土壤PAHs的去除率分别达到84.85%、79.96%、84.11%；在土壤污染条件下，间作模式更有利于甜菜生长；种植植物增强了土壤中多酚氧化酶和过氧化氢酶的活性，间作模式下二者活性高于单作4.37%~43.07%，过氧化氢酶较多酚氧化酶对PAHs土壤污染更敏感，可作为关键酶用于评价土壤PAHs污染状况。在不影响农业生产的前提下，修复植物牧草和经济作物甜菜间作种植模式显著提高了土壤PAHs的降解率。

Phytoremediation of polycyclic aromatic hydrocarbons(PAHs)-contaminated soil by intercropped beet-grasses

A pot experiment was conducted to investigate removal mechanisms and remediation efficiencies of polycyclic aromatic hydrocar-bons(PAHs)under beet and grass intercropping systems in a greenhouse. Representative PAHs, phenanthrene, fluoranthene, pyrene and benzo(a)pyrene, were used, and four plant species, cash crops(beet)and gramineae(ryegrass, sudangrass and vetiver grass)selected. The experiment lasted 180 days and two harvests were performed. Plants grew normal at initial concentrations of phenanthrene(101.23±6.63) mg·kg-1, fluoranthene(99.79±4.21)mg·kg-1, pyrene(105.41±4.59)mg·kg-1 and benzo(a)pyrene(50.12±7.75)mg·kg-1. The efficiencies of PAHs removal were greater in treatments with plants than in no-plant control, and higher in beet-grass intercropping than in single crop-ping. The reduction of PAHs was 84.85%, 84.11%, and 79.96%for beet-ryegrass, beet-vetiver grass and beet-sudangrass, respectively. Beet plants grew even better when intercropped with other plants in contaminated soil. Soil polyphenol oxidase and catalase activities were enhanced by growing plants, with 4.37%~43.07% higher activities in intercropping system than in single-cropping system. Catalase was relatively more sensitive than polyphenol oxidase to soil pollution, which may serve as an indicator to evaluate the risk of polycyclic aromatic hydrocarbon contaminated soil. Therefore, the present results suggest that grasses and beet intercropping is a feasible technique for phytore-mediating PAHs contaminated soils.