title: Mercury-induced oxidative stress in Indian mustard (Brassica juncea L.).
abstract: Mercury, a potent neurotoxin, is released to the environment in significant amounts by both natural processes and anthropogenic activities. No natural hyperaccumulator plant has been reported for mercury phytoremediation. Few studies have been conducted on the physiological responses of Indian mustard, a higher biomass plant with faster growth rates, to mercury pollution. This study investigated the phytotoxicity of mercury to Indian mustard (Brassica juncea L.) and mercury-induced oxidative stress in order to examine the potential application of Indian mustard to mercury phytoremediation. Two common cultivars (Florida Broadleaf and Longstanding) of Indian mustard were grown hydroponically in a mercury-spiked solution. Plant uptake, antioxidative enzymes, peroxides, and lipid peroxidation under mercury stress were investigated. Antioxidant enzymes (catalase, CAT; peroxidase, POD; and superoxide dismutase, SOD) were the most sensitive indices of mercury-induced oxidative response of Indian mustard plants. Indian mustard effectively generated an enzymatic antioxidant defense system (especially CAT) to scavenge H(2)O(2), resulting in lower H(2)O(2) in shoots with higher mercury concentrations. These two cultivars of Indian mustard demonstrated an efficient metabolic defense and adaptation system to mercury-induced oxidative stress. A majority of Hg was accumulated in the roots and low translocations of Hg from roots to shoots were found in two cultivars of Indian mustard. Thus Indian mustard might be a potential candidate plant for phytofiltration/phytostabilization of mercury contaminated waters and wastewater.
authors.affiliation: Institute for Clean Energy Technology, Mississippi State University, 205 Research Blvd., Starkville, Mississippi 39759, USA.
authors.forename: Safwan
authors.initials: S
authors.lastname: Shiyab
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.forename: Fengxiang X
authors.initials: FX
authors.lastname: Han
authors.forename: David L
authors.initials: DL
authors.lastname: Monts
authors.forename: Fank B
authors.initials: FB
authors.lastname: Matta
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Gu
authors.forename: Yi
authors.initials: Y
authors.lastname: Su
authors.forename: Motasim A
authors.initials: MA
authors.lastname: Masad
mesh_terms: D001673:Biodegradation, Environmental; D002374:Catalase / Q000378:metabolism; D019015:Geologic Sediments / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008628:Mercury / Q000633:toxicity*; D009149:Mustard Plant / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D018384:Oxidative Stress; D009195:Peroxidase / Q000378:metabolism; D012989:Soil Pollutants / Q000633:toxicity*; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014867:Water / Q000737:chemistry
chemical_list: D012989:Soil Pollutants; D017392:Thiobarbituric Acid Reactive Substances; D014867:Water; D006861:Hydrogen Peroxide; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase; D008628:Mercury