[Effects of different concentration ammonium-n on Hydrilla verticillata antioxidant enzymes under Cd stress].
In this paper, submersed plant Hydrilla verticillata was cultivated in a 1/10 Hoagland culture medium added with different concentration NH4 + -N (0, 0. 5, 2. 0, 4. 0 mg x L(-1)) and 10 mg x L(-1) cadmium to study the effects of NH4 + -N on H. verticillata growth and its antioxidant enzyme system under Cd stress, and approach the degradation mechanism of submersed macrophyte in eutrophic and polluted water bodies. The results showed that under 10 mg x L(-1) Cd stress, the chlorophyll content of H. verticillata decreased obviously, and SOD and POD activities increased first but declined then. NH4 + -N accelerated the stress effect of Cd. Under 0. 5 h joint stress of Cd and NH4 + -N, SOD activity increased significantly, while such an increase needed 3 hours under single Cd stress. Relative to chlorophyll and protein, antioxidant enzyme system was an early sensitive index, and SOD was more sensitive than POD. After two days exposure to Cd plus NH4 -N, H. verticillata was mainly stressed by Cd, and NH4+ -N stress could be neglected.
Xu
Qiu-jin
QJ
State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Eco-environment , Chinese Research Academy of Environmental Sciences, Beijing 100012, China. xu_qiujin@yahoo.com.cn
Jin
Xiang-can
XC
Wang
Xing-min
XM
Hu
Xue-wen
XW
Chen
Shu-qin
SQ
Yan
Chang-zhou
CZ
D002104:Cadmium / Q000494:pharmacology*; D031321:Hydrocharitaceae / Q000254:growth & development* / Q000378:metabolism; D009584:Nitrogen / Q000494:pharmacology*; D018384:Oxidative Stress; D009195:Peroxidase / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000378:metabolism*
D000644:Quaternary Ammonium Compounds; D002104:Cadmium; D009195:Peroxidase; D013482:Superoxide Dismutase; D009584:Nitrogen