title: Response mechanisms of antioxidants in bryophyte (Hypnum plumaeforme) under the stress of single or combined Pb and/or Ni.
abstract: The short-term responses and mechanisms of antioxidants in moss Hypnum plumaeforme subjected to single or combined Pb and/or Ni stress has been revealed in this study, in order to clarify (1) the relationship between the stress intensity and antioxidant fluctuation, (2) the difference between single and combined stress, and (3) the possibility of biomonitoring by the application of antioxidant fluctuation under stress. The results showed that the stress induced dose dependent formation of reactive oxygen species (ROS) and subsequent lipid peroxidation. Total chlorophyll (Chl) content and superoxide dismutase (SOD) activity were initiated under lower stress but were inhibited under higher stress. Both single and combined stress decreased catalase (CAT) activity but increased peroxidase (POD) activity, indicating POD in the moss played an important role in resisting the oxidative stress induced by Pb and Ni. The accumulation of (.)O2(-) and H2O2 in H. plumaeforme was respectively related to the low activity of SOD and the decreased activity of CAT. The study indicated that Pb and Ni had synergistic effect in inducing the oxidative stress in moss H. plumaeforme, especially under the combination of high concentration of Ni (0.1, 1.0 mM) and Pb. POD and CAT activity, as well as H2O2 and MDA content, which increased or decreased regularly with a dose dependent under Pb and Ni stress, could be used as an effective indicator in moss biomonitoring, especially in the case of light pollution caused by heavy metals without the changes in the appearance of mosses.
authors.affiliation: School of Agriculture and Biology, Shanghai Jiaotong University, Dongchuan Road 800, Shanghai 200240, China.
authors.forename: Shou-Qin
authors.initials: SQ
authors.lastname: Sun
authors.forename: Ming
authors.initials: M
authors.lastname: He
authors.forename: Tong
authors.initials: T
authors.lastname: Cao
authors.forename: You-Chi
authors.initials: YC
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Han
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D044002:Bryophyta / Q000737:chemistry*; D002374:Catalase / Q000378:metabolism; D002681:China; D006861:Hydrogen Peroxide / Q000737:chemistry; D007854:Lead / Q000737:chemistry*; D015227:Lipid Peroxidation; D009532:Nickel / Q000737:chemistry*; D018384:Oxidative Stress; D010544:Peroxidases / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000737:chemistry; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D007854:Lead; D009532:Nickel; D006861:Hydrogen Peroxide; D010544:Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase