【摘要】 超富集植物与农作物套作修复重金属污染农田的效应尚需进一步探讨。作者课题组前期的研究结果表明蜈蚣草(Pteris vittata)-玉米(Zea mays)套作模式下玉米对砷的吸收显著减弱,为探明其生理作用机制,该研究采用土培试验,设置单作、限制性套作、开放性套作3种处理,及水培试验,设置玉米单作、蜈蚣草-玉米套作2个处理,探讨了套作模式对玉米生长、根际土壤As生物有效性、根系分泌有机酸及抗氧化酶活性等的影响。结果表明:限制性套作和开放性套作对玉米产量无显著影响,开放性套作下玉米总根长和总表面积显著降低16.25%和19.61%,而根系平均直径显著增加24.24%;玉米根际土壤有效态As含量分别显著降低9.1%和9.3%。与单作相比,套作模式下玉米根系的乙酸和草酸的分泌量分别显著增加844.68%和59.49%,且与根、茎、叶及籽粒As含量呈显著负相关;玉米SOD(Superoxide Dismutase)和CAT(Catalase)活性分别显著降低18.21%和44.67%,MDA(Malondialdehyde)含量显著降低21.51%。蜈蚣草-玉米套作模式改变了玉米根系形态,促进玉米根系有机酸的分泌,并显著降低了玉米根际土壤中As的生物有效性,缓解了As胁迫带来的活性氧损伤。该研究将为农田污染土壤的修复及作物安全生产提供技术指导。更多还原

【Abstract】 The intercropping of hyperaccumulators with crops remedying the farmlands polluted with the heavy metal has become a hot topic in the field of soil remediation. Our previous research showed that the As content of maize decreased significantly in the maize(Zea mays L.)-Pteris vittata L. intercropping system. To study the physiological mechanism, the effects of monoculture,restrictive intercropping and open intercropping on biomass, root morphology in maize were investigated in a soil culture experiment, meanwhile, the effects of monoculture and intercropping on root organic acid secretion, antioxidant enzyme activities and MDA content in maize were also investigated in a hydroponic experiment. The results showed that it had no significant difference on the yield of maize in open intercropping and restrictive intercropping system, but the total length and surface area of roots were significantly reduced by 16.25% and 19.61% respectively, and the average diameter of roots was increased by 24.24% compared with restrictive intercropping system. The content of available As in maize rhizosphere soil were significantly decreased by 9.1% and 9.3% respectively in open intercropping and restrictive intercropping system. The acetic acid and oxalic acid from root exudates of maize in the intercropping system were significantly increased by 844.68% and 59.49% respectively compared to monoculture, which was negative correlation with As content in roots, stems, leaves and grains. The SOD(superoxide dismutase) and CAT(catalase) activities in maize were significantly decreased by 18.21% and 44.67% in the intercropping patterns over the monoculture, respectively. The intercropping patterns significantly reduced MDA(Malondialdehyde) content in maize by 21.51%.The intercropping of Pteris vittata with maize changed the root morphology of maize and promoted the secretion of organic acids of maize roots, and significantly reduced the bioavailability of As in maize rhizosphere soil, alleviating the oxidative damage caused by As stress. The results would provide technical guidance for soil remediation and crop safety production.更多还原