Plant Soil (2009) 317:93–101 DOI 10.1007/s11104-008-9790-2
REGULAR ARTICLE
Antimony accumulation and antioxidative responses in four fern plants Renwei Feng & Chaoyang Wei & Shuxin Tu & Fengchang Wu & Linsheng Yang
Received: 29 June 2008 / Accepted: 20 September 2008 / Published online: 9 October 2008 # Springer Science + Business Media B.V. 2008
Abstract Antimony (Sb) toxicity and contamination has become a growing concern in recent years. Remediation of Sb contamination using plants may be an effective approach. This study aimed to investigate the potential of antimony (Sb) tolerance and accumulation by plants, as well as to understand the antioxidative responses to Sb. One set of hydroponic trials was set up using four species of fern plants, including Pteris cretica (PCA), Microlepia hancei (MH), Cyrtomium fortunei (CYF) and Cyclosorus dentatus (CYD). Ferns were grown for 2 weeks in nutrient solution containing a medium (5 mg L−1) and a high (20 mg L−1) rate of Sb, with no Sb added as the control. The biomass of fern PCA remained constant with Sb addition, whereas the
: S. :Tu Feng R. W. Feng S. X. Tu College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
biomass of ferns CYF, MH and CYD at the high Sb rate exposure decreased by 12.5%, 35.0% and 38.3%, respectively as compared with their controls. This suggests a high to low Sb tolerance order for these four fern plants. For all of these fern plants, more Sb was accumulated in the roots than in the fronds. Antimony concentration in the roots at the high rate of Sb addition was recorded, on average, as 358 mg kg−1 for fern PCA, 224 mg kg−1 for fern CYF, 124 mg kg−1 for fern CYD and 123 mg kg−1 for fern MH. A high rate of addition of Sb increased the contents of malondialdehyde (MDA) by 41.3% and 171.6% for ferns MH and CYD, respectively, as compared with their controls. No changes for MDA contents were observed in ferns PCA and CYF with Sb addition, indicating no lipid peroxidation reaction in these two plants. At a medium rate of Sb addition, the activities of peroxidase, catalase and ascorbate peroxidase in fern PCA were much higher than those in ferns CYF, CYD and MH, demonstrating the important role of these three enzymes in resisting Sb toxicity. The consistency in unchanged biomass, high accumulation of Sb in roots, lower MDA contents, as well as high enzyme production in fronds, indicated that fern PCA was more tolerant to Sb than the other three fern plants. Antioxidative enzymes (peroxidase, catalase and ascorbate peroxidase) might be involved in Sb toxicity resistance of fern PCA.
F. Wu C. Wu Chinese Research Academy of Environmental Sciences, Beijing 100012, China
Keywords Arsenic hyperaccumulator . Antimony . Antioxidants . Tolerance . Phytoremediation
Responsible Editor: Juan Barcelo.
: C.:Wei : L. S. Yang Yang Feng R. W. Feng C. Y.(*) Wei: L. (*) Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China e-mail:
[email protected]
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Abbreviations PCA Pteris cretica CYF Cyrtomium fortunei CYD Cyclosorus dentatus MH Microlepia hancei MDA malondialdehyde SOD superoxide dismutase POD peroxidase CAT catalase APX ascorbate peroxidase GR glutathione reductase
Introduction Antimony (Sb) is a toxic and carcinogenic element (Gebel 1998). Although the metal antimony, and antimony compounds, were listed as priority contaminants by USEPA and the EU early in the 1970s (EU 1998, USEPA 1979), concerns about antimony have been raised only in recent years because of increasing levels of Sb pollution in the environment. This pollution is primarily due to anthropogenic activities and the extensive use of Sb compounds (Brun et al. 2008, Shotyk et al. 2005). Antimony is widely used in many commercial products, including flame retardants, semiconductors, alloys and tracer bullets (Filella et al. 2002). Metal mining, smelting and burning of municipal waste have caused severe Sb contamination in some localities, such as Kellogg, Idaho, USA; southern Tuscany, Italy, and the Hunan province of China (Baroni et al. 2000, He 2007, Ragaini et al. 1977). Various studies have reported high concentrations of Sb in soils and vegetation, as well as herbivorous and insectivorous mammals at sites around Sb smelters (Ainsworth et al. 1990a, b, De Gregori et al. 2003, Wilson et al. 2004). Antimony has an estimated average abundance of 0.2 mg kg−1 in the earth’s crust (Smith & Huyck 1999) and background concentrations of CYF (Fig. 2c–e). Antimony addition enhanced the activities of these three enzymes in plants, with only exceptions in fern CYF for POD and fern MH for APX. Although medium to high rates of Sb addition trigged evident
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0 mg L-1 5 mg L-1 20 mg L-1
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POD activity (U / gFW)
Fig. 2 Effect of antimony of lipid peroxidation and activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) in fronds of fern PCA (Pteris cretica), CYF (Cyrtomium fortune), CYD (Cyclosorus dentate) and MH (Microlepia hancei). Bars are means and standard error for the mean of three replications. Different letters above bars indicate significant difference at P
