Growth and antioxidant response in Hydrocharis dubis (Bl.) Backer exposed to linear alkylbenzene sulfonate

Abstract

A two-week exposure experiment was designed to investigate the toxicity of linear alkylbenzene sulfonate (LAS) on the aquatic plant Hydrocharis dubis (Bl.) Backer, focusing on growth, photosynthetic pigments and the activities of antioxidant enzymes. No significant differences were observed in the growth parameters of H. dubis when H. dubis was exposed to lower LAS doses (<or=10 mg l(-1)). However, lower LAS doses remarkably promote the dry weight accumulation of H. dubis. Higher doses of LAS (>10 mg l(-1)) resulted in significant decreases in all growth parameters of H. dubis. No significant effect on pigment contents was observed at up to 50 mg l(-1) LAS, beyond which pigment contents declined gradually. Malondialdehyde (MDA) content did not show obvious differences when H. dubis plants were exposed to <or=50 mg l(-1) LAS. Peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) activities showed a concentration-dependent increase up to LAS concentrations of 0.1-10 mg l(-1), followed by a clear decrease. The results of this study suggest that LAS significantly inhibited the growth and physiology of H. dubis when the dose of LAS exceeded 10 mg l(-1) . Therefore, LAS at current environmental concentrations dose not appear to cause evident phytotoxic effects on H. dubis.

Responses and toxin bioaccumulation in duckweed (Lemna minor) under microcystin-LR, linear alkybenzene sulfonate and their joint stress

“…2a), especially at high exposure concentrations (MCLR ≥3 g/ml, or LAS ≥20 g/ml or their mixture ≥3 + 10 g/ml), indicating that individual and joint exposure to the two toxicants in L. minor triggered antioxidant reactions. Increased SOD activity with MCLR treatment was consistent with other results [11,[48][49][50], but little research has focused on SOD activity after LAS exposure [24]. SOD activity was more strongly reduced after 8 d exposure compared with 2 d (Fig.…”

“…In raw sewage, the range in LAS levels was 1-15 g/ml [44]. In China, the effluent standard of LAS in sewage plants is 10 g/ml [24]. In fact, many sewage effluents in China were out of the standard.…”

“…Adverse effects of LAS on aquatic organisms have been widely reported [17][18][19][20]. The possible toxic mechanism of LAS is that they can affect membrane permeability, enzyme (including antioxidase and phosphatase) and lysosomal activity of organisms [21][22][23][24]. Because LAS can change the membrane permeability, probably affects the accumulation and toxicity of other toxicants in the organisms.…”

Varietal differences in the growth of rice seedlings exposed to perchlorate and their antioxidative defense mechanisms

“…Change in lipid peroxidation serves as a sensitive indicator of the extent of oxidative damage under stress in plant leaves, and also could be used as a toxicity bioassay for plants [35]. The results suggest that lower ClO 4 could have a negligible effect on these parameters for gannuoxiang.…”

“…Superoxide dismutase and CAT activities decreased, but the contents of MDA increased in IR65598-112-2 at higher concentrations of ClO 4 -, but not in gannuoxiang. Increased CAT activity can be explained by an increase in substrate levels, such as evidence of an adaptive mechanism of the plants that serves to maintain the level of H 2 O 2 [35,37]. Increased POD activity indicated that exposure to ClO 4 induced the formation of H 2 O 2 , which in turn stimulated the biosynthesis of POD.…”