Effect of chlorsulfuron on growth of submerged aquatic macrophyte Potamogeton pectinatus (sago pondweed)

Research has been conducted on the effect of chlorsulfuron on non-target plants but little information is available on its effects on aquatic macrophytes. Potamogeton pectinatus (sago pondweed) is an ecologically important submerged aquatic macrophyte found in freshwater bodies. Many species of wildlife use this plant as a food source. The objective of this study was to measure the phytotoxic effects of chlorsulfuron on sago pondweed. P. pectinatus plants were exposed to chlorsulfuron at 0, 0.25, 0.50, 1.0, or 2.0 ppb, in an environmental growth chamber. Plants exposed to 0.25 ppb chlorsulfuron showed a reduction in length (76%), number of leaves (50%), and number of stems (50%), compared to control plants. A reduction (47%) was also observed in the length of stems produced by plants treated with > or = 0.50 ppb chlorsulfuron. Significant reductions in wet and dry weights, and increased mortality were observed on treatments with > or = 1.0 ppb chlorsulfuron.     

Effects of 3-chlorobiphenyl on photosynthetic oxygen production, glutathione content and detoxication enzymes in the aquatic macrophyte Ceratophyllum demersum

Organic contaminants of environmental concern such as polychlorinated biphenyls have dispersed widely throughout the ecosystems and accumulate in living organisms, and a variety of adverse biological effects have been reported. In this study, we investigated the effects of 3-chlorobiphenyl in the aquatic macrophyte Ceratophyllum demersum and the capacity of its detoxication system. After 24 h of exposure to various concentrations of 3-chlorobiphenyl, the total glutathione content (tGSH) was determined and the dose-response curves for glutathione reductase (GR) and microsomal/cytosolic glutathione S-transferases (m- and c-GSTs, respectively) were established. C. demersum showed a decrease of photosynthesis after exposure to 3-chlorobiphenyl, although only significantly at 5 microgl(-1). At 0.005 and 0.05 microgl(-1) the GR, m-GST and c-GST activities were significantly increased and concomitantly a non-significant effect on total GSH was observed. At 0.5 microgl(-1), GR as well as c-GST were still significantly induced, while at 5 microgl(-1) none of the enzymes were activated. These results show that detoxication through glutathione conjugation takes place at low concentrations of 3-chlorobiphenyl, while concentrations in the order of parts per billion cause the inactivation of the enzymatic systems evaluated, enough to place C. demersum in an important physiological stress condition.     

Formation of methyl mercury in an aquatic macrophyte

In the nature, inorganic forms of mercury (Hg) may be transformed to the organic, very toxic, methyl-Hg. Occasionally methyl-Hg has been detected in plants, also so in the aquatic macrophyte water spinach (Ipomoea aquatica), which is a popular vegetable in tropical regions. The objectives of this study were to investigate if methyl-Hg is formed and/or degraded in water spinach. Water spinach plants were exposed to inorganic Hg via spiked soil or spiked nutrient solution. Tests were performed in a climate chamber and in experimental units, one for each individual plant, that were equipped with separated shoot and root compartments. Plant tissues were analysed for total- and methyl-Hg. The results showed that methyl-Hg was accumulated in water spinach, especially in young metabolically active parts, when exposed to external inorganic Hg, even at sterilized conditions. Results also showed that methyl-Hg was formed in water spinach in the absence of external Hg, i.e., during recovery in a not Hg-spiked medium following after HgCl₂-exposure. There was however, no sign of demethylation. Summarizing, most of the Hg that is taken up by the plants is bound in the roots, but of the comparatively small amounts of Hg that reach the young growing shoots, a part will be methylated. Since the young shoots of this plant make a delicious and very appreciated vegetable, Hg in I. aquatica may contribute to human health problems.     

Ammonia triggers the promotion of oxidative stress in the aquatic macrophyte Myriophyllum mattogrossense

The effect of increased ammonia content on sub-acute biochemical responses was assessed in the rooted submersed aquatic macrophyte Myriophyllum mattogrossense (common name: "Brazil Milfoil" or "Matogrosso Milfoil"), in a seven day aquarium experiment. The pH and temperature were monitored in order to determine the proportions of both ionized (NH4+) and un-ionized (NH3) forms of ammonia. Specific activities of several enzymes such as catalase (CAT), guaiacol peroxidase (POD), glutathione peroxidase (GPx) and glutathione S-transferase (GST's) were measured as well as the content of the soluble antioxidant glutathione and lipid peroxidation were determined as these parameters are considered as indicators of cell-level disorder. The results showed that ammonia is able to generate oxidative stress, expressed through an elevated GSH content and the enhancement of CAT, POD, GPx and GST's activities in treatments with elevated ammonia content. As the toxic mechanism of ammonia is a complex phenomenon, this work adds an additional point of view to explain in parts the oxidative stress generating effect of ammonia promoting oxidative stress. Additionally the different modes of action proposed by other research groups are discussed, thus trying to combine the various points of view.     

The sorptive capacity of an aquatic macrophyte for the pesticide aminocarb

Ceratophyllum demersum exposed to a constant 1 microgram/ml aminocarb exhibited a large capacity for the sorption of the pesticide, up to 400 micrograms/g fresh weight in the dark and 1000 micrograms/g fresh weight in the light. Smaller, actively growing sprigs sorbed 5 times more pesticide per gm fresh weight than larger, older sprigs, although total uptake per plant was greater in the larger plants. Membrane conformation and integrity appear to be important factors in determining the capacity of this aquatic plant for pesticide sorption.     

The sorptive capacity of an aquatic macrophyte for the pesticide aminocarb

Abstract

Ceratophyllum demersum exposed to a constant 1 μg/rnl aminocarb exhibited a large capacity for the sorption of the pesticide, up to 400 μg/g fresh weight in the dark and 1000 μg/g fresh weight in the light. Smaller, actively growing sprigs sorbed 5 times more pesticide per gm fresh weight than larger, older sprigs, although total uptake per plant was greater in the larger plants. Membrane conformation and integrity appear to be important factors in determining the capacity of this aquatic plant for pesticide sorption.     

Growth rate effects, responses of antioxidant enzymes and metabolic fate of the herbicide Propanil in the aquatic plant Lemna minor

Propanil (3,4-dichloropropionanilide) is a selective contact pesticide, recommended for post-emergence use in rice. This herbicide may end up in surface waters and present potential risk for aquatic vascular plants. Therefore, its toxicity was evaluated on Lemna minor L., an aquatic plant regularly used for toxicological studies, during time- and concentration-dependent exposure. Toxicity assessments were based on inhibition of growth of L. minor cultures after 24 days. The obtained results showed that the growth of Lemna was affected by the herbicide. The responses of the guaiacol peroxidase (G-POD) and glutathione S-transferase (GST) involved in the xenobiotic metabolism and antioxidative system were also investigated following Propanil exposure. Our results showed that Propanil has not induced enzymatic antioxidative defenses of L. minor. Both 3,4-dichloroaniline (3,4-DCA) and 3,4-dichloroacetanilide are the major metabolites in this plant. On the contrary, only 3,4-DCA was found in culture media after 4 days. Probably, the enzymatic hydrolysis by acyl acylamidase and the acetylation by acetyl-CoA are the major pathways for these transformation products, respectively. The results of this study showed that the selected aquatic plant has the potential to accumulate and metabolize rice herbicide, like Propanil. Based on these toxicity data this herbicide should impair the establishment of non-target aquatic plants.     

Development and validation of a new fluorescence-based bioassay for aquatic macrophyte species

Bioassays with unicellular algae are frequently used as ecotoxicological test systems to evaluate the toxicity of contaminated environmental samples or chemicals. In contrast, aquatic macrophyte test systems are still rarely used as they are laborious to handle because species exhibit distinct ecological requirements. The aim of this study was to establish a fast and reproducible measuring system for aquatic macrophyte species to overcome those limitations for use. Thus, a newly developed pulse-amplitude modulated chlorophyll fluorometer (Imaging-PAM) was applied as an effect detection in short-term bioassays with aquatic macrophyte species. This multiwell-plate-based measuring device enables the incubation and measurement of up to 24 samples in parallel. The Imaging-PAM was used (i) to establish and validate the sensitivity of the test systems to three Photosystem II (PSII) inhibitors (atrazine, prometryn, isoproturon), (ii) to compare the test systems with established biotests for macrophytes and (iii) to define necessary time scales in aquatic macrophyte testing. The results showed that fluorescence-based measurements with the Imaging-PAM allow rapid and parallel analysis of large amounts of aquatic macrophyte samples and of toxicants effects of the PSII inhibitors tested on aquatic macrophytes. Measurements revealed a good correlation between obtained median effective concentrations (EC50s) for the new and the established biotest systems. Hence, the Imaging-PAM measuring device is a promising tool to allow fast chemical effect screening for high amounts of samples with little time and material and thus offers scope for high-throughput biotesting using aquatic macrophyte species.     

Potamogeton crispus responses to varying water depth in morphological plasticity and physiological traits

Environmental Science and Pollution Research - Submerged macrophytes, important primary producers in shallow lakes, play a crucial role in maintaining ecosystem structure and function. By altering...     

Chlorophyll a fluorescence, antioxidant enzymes and lipid peroxidation in tomato in response to ozone and benomyl.

Ozone is a widely distributed phytotoxic air pollutant and is known to reduce the yield of several important agricultural crops in Spain. However, benomyl has been found to lessen the adverse impact of ozone on plants. We studied the effects of ozone and benomyl on chlorophyll a fluorescence, antioxidant enzymes, and lipid peroxidation in tomato (Lycopersicon esculentum Mill. cv. Tiny Tim) grown in open-top chambers in the field. Our results indicate that benomyl prevented the peroxidation of membrane lipids and increased protection of PSII from ozone. There was also a significant reduction in the activity of the antioxidant enzyme superoxide dismutase in ozone-exposed plants that had not been treated with benomyl. Comparing plants treated with benomyl to untreated plants we found that, on exposure to ozone, a greater fraction of light absorption energy was cycled through the photosynthetic system in benomyl-treated plants, as shown by the higher PSII-mediated electron flow and the higher fraction of open PSII reaction centers. The values analyzed in the fluorescence parameters and lipid peroxidation were similar for plants without benomyl grown in a charcoal-filtered environment and benomyl-treated plants exposed to ozone.     

The extract of aquatic macrophyte Carex cinerascens induced colony formation in bloom-forming cyanobacterium Microcystis aeruginosa

Environmental Science and Pollution Research - Colony formation in Microcystis aeruginosa played important roles in blooms formation. To study the effects of plant allelopathy on colony formation...     

Uptake and distribution of Zn, Cu, Cd, and Pb in an aquatic plant Potamogeton natans

A better understanding of metal uptake and translocation by aquatic plants can be used to enhance the performance of constructed wetland systems for stormwater treatment. Specifically, this study examines whether the uptake of Zn, Cu, Cd, and Pb by Potamogeton natans is via the leaves, stems, or roots, and whether there is translocation from organs of uptake to other plant parts. Competition between the metals at uptake and at the level of the cell wall-bound part of the metals accumulated in stem and leaf tissue was also examined. The results show that Zn, Cu, Cd, and Pb were taken up by the leaves, stems, and roots, with the highest accumulation found in the roots. At the elevated metal concentrations common in stormwater the uptake of Cu, but not of Zn, Cd, or Pb, by the roots was somewhat limited at uptake due to competition with other metals. Between 24% and 59% of the metal content was bound to the cell walls of the plant. Except in the case of Pb, the cell wall-bound fraction was generally smaller in stems than in leaves. No translocation of the metals to other parts of the plant was found, except for Cd which was translocated from leaf to stem and vice versa. Dispersion of metals from sediment to water through P. natans is therefore unlikely.     

四氯乙烯污染对小麦幼苗抗氧化酶系的影响

通过室内模拟试验,采用愈创木酚法、高锰酸钾滴定法、氮蓝四唑法分别测定了四氯乙烯(PCE)污染小麦幼苗的过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物岐化酶(SOD)等抗氧化物酶系,研究了PCE污染对植物生物学指标的影响,以评价土壤PCE污染的生态毒性效应,为土壤性质的变化趋势提供依据.结果表明,PCE浓度较低时,POD、SOD活性被激活,表现出明显的抗氧化能力,但PCE浓度过高时则抑制POD和SOD的活性诱导作用;小麦幼苗中CAT活性只有在PCE为0.10mg/kg时被激活,其他浓度时CAT活性均受到抑制;随着时间的延长,POD、CAT的活性均呈激活态势,而SOD活性在PCE浓度较低时呈降低趋势,在PCE浓度较高时,SOD活性升高.     

利用响应曲面法研究蓖齿眼子菜克藻效应的环境因子

水生植物的克藻效应受到多种环境因子的影响.利用响应曲面法,对影响沉水植物蓖齿眼子菜对铜绿微囊藻克藻效应的3个环境因子进行实验研究.通过对曲面模型分析,得出蓖齿眼子菜对铜绿微囊藻的藻细胞个数的相对抑制率在温度、光照强度、全盐莒3个环境因子分别为24℃、2 891 lx、4 407 mg/L时达到最大值.曲面模型经过方差分...     

Effects of cadmium exposure on digestive enzymes, antioxidant enzymes, and lipid peroxidation in the freshwater crab Sinopotamon henanense

In this study, the effects of cadmium (Cd) stress on the activities of disaccharidases (sucrase, lactase, and maltase), amylase, trypsin, pepsase, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and malondialdehyde (MDA) content in the alimentary system of freshwater crabs Sinopotamon henanense were studied. Results showed that the enzyme activities in the stomach, intestine, and hepatopancreas changed with Cd concentration. In terms of digestive enzymes, Cd exposure had an inhibitory effect on the activities of the disaccharidases, amylase, and pepsase (only in the stomach). Significant induction of trypsin activity by Cd at a lower concentration was observed, but as Cd concentration increased, trypsin activity decreased. Maltase activity showed a slight recovery after inhibition by Cd. The activities of SOD and CAT increased initially and decreased subsequently. Cd significantly inhibited the activity of GPx. MDA content increased with increasing concentration of Cd. These results showed that acute Cd exposure led to harmful effects on the alimentary system of crabs, which are likely linked to Cd induced oxidative stress.     

Effects of herbicides on two submersed aquatic macrophytes, Potamogeton pectinatus L. and Myriophyllum sibiricum Komarov, in a prairie wetland

Clopyralid, picloram, 2,4-D and a mixture of 2,4-D plus picloram, (Tordon 202C) were added to the water of 1 m square enclosures in a prairie wetland in Saskatchewan, Canada to produce concentrations of 0.01 and 0.1 mg active ingredient litre(-1). Effects on the submersed macrophytes, Potamogeton pectinatus and Myriophyllum sibiricum, were monitored by taking repeated measurements of plant weight, flower and tuber production and inspecting for injuries at 30 and 60 days after application. Clopyralid did not inhibit weight gain (growth) in either species, but stimulated growth and flowering by M. sibiricum at 0.01 mg litre(-1) and tuber production by P. pectinatus at both rates. The low rate of 2,4-D stimulated flowering by M. sibiricum and tuber production by P. pectinatus, whereas the high rate inhibited growth of M. sibiricum and injured both species. Picloram did not affect growth of either species, but injured M. sibiricum at both concentrations and inhibited flowering at 0.1 mg litre(-1). Tordon 202C at 0.1 mg litre(-1) caused reduced growth and flowering in M. sibiricum and injured both species; 0.01 mg litre(-1) also injured M. sibiricum. Mortality resulted only from Tordon 202C and 2,4-D. Field data are lacking to assess the extent to which submerged macrophytes in prairie ponds are exposed to harmful concentrations of herbicide from aerial spraying, drift from ground application, runoff or wind erosion of soil.     

Dermal exposure to pesticides modifies antioxidant enzymes in tissues of rats

Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities were determined in rat tissues after dermal exposure to pesticides. Two experiments were conducted in male SD rats, 190-210 g body weight. Acephate (ACP), methamidophos (MAP) and nicotine (NIC) were dissolved either individually or together in 0.25 mL of 50% ethanol, which contained: AP = 12.6 or MAP 1.3 or NIC = 9.6 mg; EXP 1--individual pesticide exposure; 64 rats, 16/group; EXP 2--mixture of AP + MAP + NIC at levels of 1X, 2X, 3X; 48 rats, 12/group; 0.25 mL of solution or ethanol (Controls) was applied to 25 mm2 area of shaved skin 3 times a week. Half the rats were terminated after 4 weeks and the rest after 4 weeks of stopping exposure. Single pesticides decreased erythrocyte (RBC) SOD by 17% after exposure and in the NIC group after post exposure (P#0.05). Increasing concentrations of AP + MAP + NIC mixture elevated RBC SOD by 22% in the 2X and 3X groups and CAT by 13% in the 3X group (P#0.05); post exposure increased RBC SOD by 2-3 fold and CAT activity by 13% in all 3 groups. Liver GPX increased by 30-40% and CAT decreased by 12% in all exposed and post exposed groups (P#0.05). The results suggest that dermal exposure to mixtures of pesticides can selectively induce SOD, CAT and GPX activities in RBC and liver.     

Alterations in liver marker enzymes and recovery ability of cyprinids as indicators of aquatic pollution

Information on the detection of pesticides in fresh water Lakes of Kashmir (Dal and Mansbal) through GC–MS technique is scarce, and also the recovery in biochemical parameters (AST, ALT and ALP) of fish after transferring them to clean media has not been reported yet. The water samples were collected from three sites and analyzed for their pesticide profile by dispersive liquid–liquid micro extraction (DLLME) followed by GC–MS. Influence of pesticides on liver marker enzymes of Cyprinus carpio and Carassius carassius was also investigated. The results obtained showed the presence of three main pesticides viz. chlorpyrifros, dimethoate and dichlorvos in waters of Dal Lake whereas no pesticide was detected in waters of Mansbal. The higher values for AST, ALT and ALP activities and decrease in protein content were obtained in the samples from the Dal Lake compared with those from Mansbal Lake (p < 0.05). These data when compared with the values found in C. carpio and C. carassius from both the Dal Lake and Mansbal Lake kept under laboratory conditions after 15, 30, 45 and 60 days of maintenance in clean media found that during depuration, all the enzyme activities came down significantly (p < 0.05) indicating the compensatory response by the fish against the pesticide stress. Therefore, these parameters could be used as indicators of pesticide pollution in aquatic organisms and were recommended for environmental monitoring for investigating the mechanism involved in the recovery pattern.

     

Dermal exposure to pesticides modifies antioxidant enzymes in tissues of rats

Abstract

Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities were determined in rat tissues after dermal exposure to pesticides. Two experiments were conducted in male SD rats, 190–210 g body weight. Acephate (ACP), methamidophos (MAP) and nicotine (NIC) were dissolved either individually or together in 0.25 mL of 50% ethanol, which contained: AP=12.6 or MAP 1.3 or NIC= 9.6 mg; EXP 1 ‐ individual pesticide exposure; 64 rats, 16/group; EXP 2 ‐ mixture of AP+MAP+NIC at levels of IX, 2X, 3X; 48 rats, 12/group; 0.25 mL of solution or ethanol (Controls) was applied to 25 mm² area of shaved skin 3 times a week. Half the rats were terminated after 4 weeks and the rest after 4 weeks of stopping exposure. Single pesticides decreased erythrocyte (RBC) SOD by 17 % after exposure and in the NIC group after post exposure (P#0.05). Increasing concentrations of AP+MAP+NIC mixture elevated RBC SOD by 22 % in the 2X and 3X groups and CAT by 13 % in the 3X group (P#0.05); post exposure increased RBC SOD by 2–3 fold and CAT activity by 13 % in all 3 groups. Liver GPX increased by 30–40 % and CAT decreased by 12 % in all exposed and post exposed groups (P#0.05). The results suggest that dermal exposure to mixtures of pesticides can selectively induce SOD, CAT and GPX activities in RBC and liver.