Short-term toxic effects of chlorobenzenes on broadbean (Vicia faba) seedlings.
The root growth, changes in superoxide dismutase (SOD, EC 1.15.1.1) activity, malonyldialdehyde (MDA) and total soluble protein level of broadbean (Vicia faba) seedlings were researched at different soil concentrations of chlorobenzene (CB), 1,2,4-trichlorobenzene (TCB) and hexachlorobenzene (HCB). The results showed that root growth of seedlings was interrupted after 5 d of 50-200 microg x g(-1) TCB treatment. During a 3 d recovery period, root growth was, however, restored to some extent although there was a delay in returning to the control level. The total soluble protein content in seedlings increased with TCB concentration and duration of exposure. Effect of TCB stress on SOD activity in seedlings displayed a significant dose-effect relationship for 1-5 d of 50-200 microg x g(-1) treatment. When broadbean seedlings were placed in clean tap water for 3 d following exposure to 5 d of TCB stress to clear tap water for 3 d, SOD activity at 50 microg x g(-1) TCB recovered towards control level (P>0.05) while a significant increase in SOD activity was observed at 100 and 200 microg x g(-1) TCB compared to control (P<0.05). The experiments also revealed that a significant increase of MDA level in seedlings occurred after 3 and 5 d of 100 and 200 microg x g(-1) TCB treatment (P<0.05 and P<0.01), and there was a positive correlation between TCB concentration and MDA level. All the above results showed that SOD activity and MDA level of broadbean seedlings might be proposed as the biomarkers for short-term TCB contamination in soil. Compared to TCB, the toxicity of 50-1000 microg x g(-1) CB or HCB in soil to broadbean seedlings was not observed after a 3 d exposure.
Liu
Wan
W
Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
Li
Peijun
P
Zhou
Qixing
Q
Sun
Tieheng
T
Tai
Peidong
P
Xu
Huaxia
H
D002722:Chlorobenzenes / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005659:Fungicides, Industrial / Q000633:toxicity; D006581:Hexachlorobenzene / Q000633:toxicity; D008315:Malondialdehyde / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors; D031307:Vicia faba / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
D002722:Chlorobenzenes; D005659:Fungicides, Industrial; D010940:Plant Proteins; C009947:1,2,4-trichlorobenzene; D008315:Malondialdehyde; D006581:Hexachlorobenzene; D013482:Superoxide Dismutase; C031294:chlorobenzene