Whether plant coexistence can reduce the impacts of lead （Pb） on crops in agroecosystems has not been well understood. We conducted a factorial experiment to investigate the effects of weeds coexisting with maize （...Whether plant coexistence can reduce the impacts of lead （Pb） on crops in agroecosystems has not been well understood. We conducted a factorial experiment to investigate the effects of weeds coexisting with maize （Zea mays L.） on Pb accumulation in maize and soil microbes at two Pb levels （ambient and 300 mg/kg）. Elevated Pb tended to increase the Pb concentration in maize and decreased soil microbial activity （indicated by the average well color development, AWCD）, functional group diversity, as well as arbuscular mycorrhizal （AM） colonization and vesicle number of maize. Compared to the monoculture, weeds coexisting with maize reduced the Pb concentrations in the root, leaf, sheath and stem of maize at both seedling and mature stages. In maize-weed mixtures, soil microbial activity and functional group diversity tended to increase for both Pb treatments relative to the monoculture. Furthermore, principal component analysis revealed that the soil microbial community structure changed with the introduction of weeds. The highest Pb accumulation in weeds occurred for the elevated Pb treatment in a three species mixture. The results suggest that multiple plant species coexistence could reduce lead accumulation in crop plants and alleviate the negative impacts on soil microbes in polluted land, thereby highlighting the significance of plant diversity in agroecosystems.展开更多
基金supported by the National Natural ScienceFoundation of China (No. 30970477)the Key Laboratory of Ministry of Agriculture, the People’s Republic ofChina (No. KYJD09021)+2 种基金the Natural Science Foundation of Zhejiang Province (No. Y307418)the Scienceand Technology Department of Zhejiang Province (No.2007C13063)and the Education Department of ZhejiangProvince (No. Y200805536)
文摘Whether plant coexistence can reduce the impacts of lead （Pb） on crops in agroecosystems has not been well understood. We conducted a factorial experiment to investigate the effects of weeds coexisting with maize （Zea mays L.） on Pb accumulation in maize and soil microbes at two Pb levels （ambient and 300 mg/kg）. Elevated Pb tended to increase the Pb concentration in maize and decreased soil microbial activity （indicated by the average well color development, AWCD）, functional group diversity, as well as arbuscular mycorrhizal （AM） colonization and vesicle number of maize. Compared to the monoculture, weeds coexisting with maize reduced the Pb concentrations in the root, leaf, sheath and stem of maize at both seedling and mature stages. In maize-weed mixtures, soil microbial activity and functional group diversity tended to increase for both Pb treatments relative to the monoculture. Furthermore, principal component analysis revealed that the soil microbial community structure changed with the introduction of weeds. The highest Pb accumulation in weeds occurred for the elevated Pb treatment in a three species mixture. The results suggest that multiple plant species coexistence could reduce lead accumulation in crop plants and alleviate the negative impacts on soil microbes in polluted land, thereby highlighting the significance of plant diversity in agroecosystems.
