Stereoselective phytotoxicity of HCH mediated by photosynthetic and antioxidant defense systems in Arabidopsis thaliana.
BACKGROUND
Hexachlorocyclohexane (HCH) has been used for plant protection and sanitation world-widely, and its isomers have been detected in water, soil, and air as well as in vegetation. As a sink for lipophilic pollutants, vegetation is very important for the degradation and fate of organic contamination; however, little was known about their phytotoxicity and mechanisms of toxic effect. In this study, the stereoselective phototoxicity of four isomers (α, β, γ, and δ) of HCHs mediated by independent as well as interconnecting systems of photosynthesis and enzymatic antioxidant defense system in Arabidopsis thaliana were assessed.


RESULTS
Our results revealed that all the HCHs not only stimulated the activities of catalase (CAT) and peroxidase (POD), but also inhibited the activity of superoxide dismutase (SOD). In photosynthesis system, the photosynthetic efficiency of PSI and PSII were all down regulated. Meanwhile, results from both systems showed that δ-HCH was the most toxic one, while α-HCH the least in Arabidopsis thaliana.


CONCLUSIONS
For the first time, stereoselective effects of different isomers of HCH in plant were demonstrated. And the results suggest that it requires further research to fully elucidate the environmental toxicity and their mechanisms.
College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, China.
Qiong
Q
Zhang
Cong
C
Zhou
Quan
Q
Zhang
Haifeng
H
Qian
Weiping
W
Liu
Meirong
M
Zhao
D000975:Antioxidants / Q000378:metabolism*; D017360:Arabidopsis / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D004785:Environmental Pollutants / Q000737:chemistry / Q000633:toxicity; D001556:Hexachlorocyclohexane / Q000737:chemistry* / Q000633:toxicity*; D008315:Malondialdehyde / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D010788:Photosynthesis / Q000187:drug effects*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D018570:Risk Assessment; D013237:Stereoisomerism; D018675:Toxicity Tests
D000975:Antioxidants; D004785:Environmental Pollutants; D008315:Malondialdehyde; D001556:Hexachlorocyclohexane