Interactions of mycorrhizal fungi with Pteris vittata (As hyperaccumulator) in As-contaminated soils H.M. Leung a , Z.H. Ye a,b , M.H. Wong a, * a Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, PR China b School of Life Sciences, Zhongshan University, Guangzhou 510275, PR China Received 7 September 2004; accepted 13 May 2005 Indigenous mycorrhizal fungi play an important role in As tolerance. Abstract A greenhouse trial was conducted to investigate the role of arbuscular mycorrhizas (AM) in aiding arsenic (As) uptake and tolerance by Pteris vittata (As hyperaccumulator) and Cynodon dactylon (a multi-metal root accumulator). Plants inoculated with lived and killed native mycorrhizas isolated from an As mine site were grown in a sterile and slightly acidic soil. The infectious percentage of mycorrhizas (0 mg/kg As: 26.4%, 50 mg/kg As: 30.3%, 100 mg/kg As: 40.6%) and the average biomass of shoots in infected P. vittata increased (0 mg/kg As: 2.45 g/pot, 50 mg/kg As: 2.48 g/pot, 100 mg/kg As: 10.9 g/pot) according to the increase of As levels when compared to control. The indigenous mycorrhizas enhanced As accumulation (0 mg/kg As: 3.70 mg/kg, 50 mg/kg As: 58.3 mg/kg; 100 mg/kg As: 88.1 mg/kg) in the As mine populations of P. vittata and also sustained its growth by aiding P absorption. For C. dactylon, As was mainly accumulated in mycorrhizal roots and translocation to shoots was inhibited. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: Arsenic; Brake fern; Hyperaccumulator; Mycorrhizae; Phosphate 1. Introduction Mining activities produce a huge amount of waste materials (such as tailings) which frequently contain excessive concentrations of heavy metals. These waste materials have created a significant pollution problem, and resulted in severe land dereliction. In China, there are over 8000 national and 230,000 private mining compa- nies presently operating, resulting in 200,000 km of derelict land, which includes the loss of 370,000 ha of agricultural land (Young, 1988; Wong and Bradshaw, 2002). Restoration of metalliferous mine tailings is necessary for long-time stability of the land surface (Wong, 2003). The concept of phytoremediation has been developed since 1980. By definition, it is a biotechnology that uses plants for environmental restoration and it is an emerging cleanup technology. Metal tolerance plants, including hyperaccumulators, are desirable for stabiliz- ing the tailings on the surface of the land and extracting metals from contaminated soils (Williamson et al., 1982; Ritcey, 1989; Tordoff et al., 2000). Mycorrhizas are integral, functional parts of plant roots and the fungi involved play an important role in alleviating metal toxicity in plants. The dominant form of mycorrhizas for symbiosis with plants is arbuscular mycorrhizas (AM), which belongs to the groups of endomycorrhiza (Read, 2001). Recently, the colonization * Corresponding author. Tel.: C852 3411 7746; fax: C852 3411 7743. E-mail address: mhwong@hkbu.edu.hk (M.H. Wong). 0269-7491/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.envpol.2005.05.009 Environmental Pollution 139 (2006) 1e8 www.elsevier.com/locate/envpol