Short-term toxic effects of chlorobenzenes on broadbean (Vicia faba) seedlings

Abstract

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.

Rhizosphere mediated biodegradation of 1,4-dichlorobenzene by plant growth promoting rhizobacteria of Jatropha curcas

“…The growth of plants is adversely affected by the presence of chlorobenzene and dichlorobenzene. The root growth, changes in superoxide dismutase activity and total protein of plant seedlings were greatly affected and interrupted by DCB (Liu et al, 2005). However the application of DCB degrading microorganisms may enhance the growth of plant seedlings as compared to uninoculated seedlings, in presence of DCB.…”

“…However the application of DCB degrading microorganisms may enhance the growth of plant seedlings as compared to uninoculated seedlings, in presence of DCB. The recovery of plant growth by bacteria in presence of DCB depends on the duration of exposer and concentration of the toxic substance (Liu et al, 2005). Saharan and Nehra (2011) reported 100% germination of Gossypium hirsutum seeds by isolate SVC 67, followed by SVC38 and SVC 34.…”

Biodegradation of 2,4-dichlorophenol using Mycoplana dimorpha extracts and evaluation of kinetic parameters

“…Other compounds are carcinogenic; phenanthrene, benzo(a)pyrene and benzo(a)anthracene are among the polycyclic aromatic hydrocarbons (PAHs) shown to cause cancer (Samanta et al, 2002;Finlayson-Pitts and Pitts 1997). The impacts of chlorinated compounds on human being as well on environment have been studied (Leslie et al, 2004;Liu et al, 2005;Liu et al, 2004;Mortimer and Connell 1994;Thrall et al, 2004;Vorkamp et al, *Corresponding author. E-mail: rmanikandan1968@gmail.com, rmanikandan1968@yahoo.com.…”