Complementarity of co-planting a hyperaccumulator with three metal(loid)-tolerant species for metal(loid)-contaminated soil remediation.

Co-planting with multiple plant species has great value for the remediation of soil co-contaminated with metal(loid)s. A pot experiment has been conducted to study the growth, phytoextraction of metal(loid) and complementarity by co-planting Pteris vittata L. with three metal(loid)-tolerant species with large biomass (namely Arundo donax L., Morus alba L., and Broussonetia papyrifera L.) on soil co-contaminated with As, Cd, Pb, and Zn. The results showed that the co-planting can favor the growth and uptake of As in hyperaccumulator P. vittata L., and improve comprehensive extraction of metal(loid). The total biomass and content of As in the roots of P. vittata L. under the co-planting system were significantly (p < 0.05) improved by 117.5% and 122.0%, respectively, compared with that in monoculture, while the content of As, Cd, Pb and Zn in the tissues of A. donax L., M. alba L. and B. papyrifera L. was slightly increased. The comprehensive accumulation amounts for As, Cd, Pb, and Zn by the four plants co-planting in contaminated soil were higher than that in part of plant's monoculture. Moreover, availability of As, Cd, and Zn in the contaminated soil was decreased in the co-planting system, meanwhile soil urease and acid phosphatase activities in soil significantly (p < 0.05) promoted as compared to the monocultures. The results suggested that positive interaction between hyperaccumulator and three metal(loid)-tolerant species can effectively enhance the growth of P. vittata L., regulate the comprehensive metal(loid)s accumulation capacity, and improve the environmental quality of contaminated soil, which drives high phytoremediation potential for metal(loid)s-contaminated soil by the co-planting.