A study on the activities of a few free radicals scavenging enzymes present in five roadside plants

The road side plants are continuously exposed to the high levels of oxides of nitrogen and sulphur dioxide, emitted from automobile. Resistance to automobile exhaust pollution was studied with Nerium indicum Mill, Boerhaavia diffusa L., Amaranthus spinosus L., Cephalandra indica Naud., and Tabernaemontana divaricata L., growing on the edges of Delhi Road, National Highway 2 (NH 2) near Dankuni, West Bengal. By analysing the activities of a few enzymes like superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and phenolic peroxidase, it appears that among the five plants examined,Amaranthus and Cephalandra are equipped with a very good scavenging system to combat effects of air pollution.     

Exposure assessment of particulate matter and blood chromium levels in people living near a cement plant

This study evaluates the effect of air pollution caused by cement plants on nearby residential areas and performs an exposure assessment of particulate matter (PM) and total Cr, Cr⁶⁺, Pb, and Al. Further, the blood Cr levels of residents exposed to PM released by cement plants are also assessed. Nine buildings (eight residential and one elementary school building) close to cement plants were selected for this study, which were located in Pyeongtaek port, in west of Gyeonggi Province, South Korea. A total of 51 suspended particulate samples were collected at a flow rate of 2.0 L/min. Total Cr was more widely detected in residents’ houses and elementary schools. PM levels were higher at distances of 4.1 and 4.8 km than those at closer distances of 2.7 km. This was due to the influence of wind direction. The estimated mean blood level of Cr for the study participants was 3.80 μg/L, which is higher than levels estimated by other studies on Cr blood levels. Therefore, cement plants could cause an increase in total Cr and blood Cr levels in residential areas, and more continuous monitoring is necessary to better understand their impacts.     

Phytoremediation potential of indigenous plants from Thai Nguyen province, Vietnam

This study was focused on determining Arsenic (As), Lead (Pb), Cadmium (Cd) and Zinc (Zn) in 33 indigenous plants and 12 soil in-situ plant samples in Thai Nguyen Province, Vietnam. The results showed that the soils of surveyed mining areas contained 181.2- 6754.3 mg kg(-1) As, 235.5-4337.2 mg kg(-1) Pb, 0.8- 419 mg kg(-1) Cd and 361.8-17565.1 mg kg(-1) Zn depending on the characteristics of each mining site. These values are much higher than those typical for normal soil. The heavy metal uptake into shoots and roots of 33 indigenous plant species was also determined. Two species of the plants investigated, Pteris vittata L. and Pityrogramma calomelanos L. were As hyperaccumulators, containing more than 0.1% heavy metals in their shoots. Eleusine indica L., Cynodon dactylon L., Cyperus rotundus L. and Equisetum ramosissimum (Vauch) accumulate very high Pb (0.15-0.65%) and Zn (0.22-1.56%) concentration in their roots. Additional experiments to clarify the potential of six these plants as good candidates for phytoremediation of heavy metal pollution soil are being carried out in our laboratory.     

Evaluation of air pollution tolerance index of selected plant species along roadsides in Thiruvananthapuram, Kerala

To develop the usefulness of plants as bioindicators requires an appropriate selection of plant species which entail an utmost importance for a particular situation. In the present study a periodic evaluation of air pollution tolerance index [APTI] of selected tree species such as Polyalthia longifolia, (Sonner) Thw., Alstonia scholaris, R. Br., Mangifera indica, L., and shrubs Clerodendron infortunatum, L., Eupatorium odoratum, L., and Hyptis suaveolens, (L.) Poit., growing adjacent to the National Highway-47 passing through Thiruvananthapuram District which lies on the south-west coast of India, was carried out with a view to find out the air pollution tolerance as well as sensitivity of the plant species during different seasons. Among the trees in the roadside areas studied, Polyalthia longifolia, (Sonner) Thw., expressed highest APTI values and proved to be a tolerant variety and the others as sensitive species to air pollutants. In the case of shrubs, Clerodendron infortunatum, L., exhibited highest APTI values (7.34) and found to be more tolerant compared to the other two shrub species studied.     

The impact of the invasive shrub Lonicera maackii on the decomposition dynamics of a native plant community

Invasive plants may have variable effects within a given environment depending on their interactions with the dominant native species, yet little research has examined such species-species interactions within a site. Savanna trees with nonoverlapping canopies offer an ideal opportunity to assess associated changes in the ecosystem processes that result from interactions between an invasive species and different native tree species. We examined the influence of the exotic invasive shrub Lonicera maackii on decomposition dynamics under three native tree species: Fraxinus quadrangulata, Quercus muehlenbergii, and Carya ovata. Litter decomposition rates and litter C and N were evaluated over two years using single- and mixed-species litterbags (L. maackii and individual tree species litter); microarthropod abundance was measured at 6 weeks using Tulgren funnels. Litter from the invasive L. maackii decomposed and lost N more rapidly than the litter of the three native tree species. The rate at which L. maackii decomposed depended on its location, with L. maackii litter decomposing and losing N more rapidly under C. ovata than under the other two native tree species. Mixing L. maackii with the native species' litter did not accelerate litter mass loss overall but did result in synergistic N losses at variable times throughout the experiment, further highlighting the variable interaction between native species and L. maackii. Nitrogen loss was significantly higher than expected in mixtures of C. ovata + L. maackii litter at 6 weeks, in F. quadrangulata + L. maackii litter at 12 weeks, and in Q. muehlenbergii + L. maackii litter at 24 weeks. If the effects of invasive species on certain ecosystem processes, such as litter decomposition, are strongly influenced by their association with native species, this could suggest the need for a more nuanced understanding of the vulnerability of ecosystem processes to invasions of L. maackii and potentially other invasive species.     

开阳磷矿10种木本植物叶片重金属富集特征

植物对重金属具有一定的吸附能力,植物修复是生态修复不可或缺的一部分,利用植物减缓和治理重金属污染具有重要意义.选取开阳磷矿马路坪矿区生命周期较长的木本植物及其土壤作为研究对象,探究木本植物受Cu、Zn、Pb、Cd、As等5种重金属污染土壤的效应,对植物重金属含量及其富集特性进行研究分析,筛选出累积重金属的植物,作为矿区...     

Phytoremediation of petroleum-contaminated soils: Pre-screening for suitable plants and rhizospheral fungi

A field study was conducted in a petroleum-contaminated site in Kermanshah refinery (Iran) to find the petroleum-resistant plant species and the rhizospheral fungi for being used in bioremediation. Results showed that the amounts of petroleum pollution in non-vegetated areas is 6.8% and in vegetated areas is 2.2%. Plant samples were collected from petroleum-polluted areas and determined using morphological characters. It was found that eight plant species were growing on the contaminated sites: Polygonum aviculare, Amaranthus retroflexus, Noea mucronata, Alhaji cameleron, Crozophora heirosolymitrana, Poa sp., Convolvulus arvensis and Trifolium repense. The rhizospheral fungi of the plants were collected and determined using microscopic studies and taxonomical keys. The results determined the presence of 21 species in the rhizosphere of the plants growing in the polluted areas; three of these species were common in all of the plants and the others have species-specific distribution within the plants. The highest number of rhizospheral fungi (11 species) were determined for P. aviculare in non-polluted areas and nine species in polluted areas. It seems that the plant is the best candidate for using phytoremediation. However, the variation of fungi in petroleum-polluted areas was more than non-polluted zones. The culture of fungi in oil-contaminated media showed that, although all the studied fungi were resistant to low petroleum pollution (1% v/v), a few species, especially Fusarium species, showed higher resistance to petroleum pollution (10% v/v) and hence they may be suitable for mycoremediation in highly polluted areas.     

Antifeedant activity of aqueous extract of Gnidia glauca Gilg. and Toddalia asiatica Lam. on the gram pod borer, Helicoverpa armigera (Hbn)

Aqueous leaf extracts of two plants namely Gnidia glauca Gilg. and Toddalia asiatica Lam., have been screened for their antifeedant activity against the sixth instar larvae of Helicoverpa armigera (Hbn) by applying the aqueous leaf extracts at various concentrations viz., 0.2, 0.4, 0.6, 0.8 and 1.0 percent on young tomato leaves. The larval mortality of more than 50 percent at higher concentrations (0.8 and 1.0 percent) was observed in the aqueous extracts. Among the two aqueous leaf extracts tested, T. asiatica was found to show higher rate of mortality (86.1%) at 1.0 percent concentration. A reduction in the rate of food consumption and growth was observed in the larvae of H. armigera after 48 hours of treatments in both the aqueous extracts. Since this insect pest species have developed resistance and resurgence to synthetic insecticides, the only alternate is the usage of bio-pesticides for they are eco-friendly, pollution free and easily degradable.     

La—Gly—VB6对Pb—Cd复合胁迫下植物的影响

研究Pb-Cd复合污染对5种树木叶片的生理伤害和La-Gly-VB6对Pb-Cd污染胁迫的缓解作用。实验结果表明,La-Gly-VB6能明显减轻Pb-Cd污染造成的植物叶片叶绿素含量下降、质膜透性增加,过氧化氢酶活性改变和Pb富集量上升。说明La-Gly-VB6对Pb-Cd污染胁迫具有一定的防护作用。     

Phytoremediation potential of weed plants’ oxidative biomarker and antioxidant responses

The purpose of this study was to assess the oxidative biomarkers responses, antioxidant potential and metal accumulation tendency of weed plants collected from the control and metal-contaminated site. The metal contamination was found to be higher in soil and plant parts collected from contaminated site and the most serious problem seemed to be metal elevations above than the safe limit for Cd, Pb and Ni in the aerial parts of weed plants. There were variations in metal accumulation in different weed plants that was justified by principal component analysis. The enzymatic and non-enzymatic antioxidants were found to be higher in plant parts collected from contaminated site. Based upon metal accumulation tendency, weed plants showed a translocation ratio (>1) that reflect their potential for metal remediation. The values of metal pollution index also showed higher tendency of metal accumulation in weed plants, particularly in Solanum nigrum, Euphorbia hirta, Amaranthus hybridus and Xanthium strumarium, and they can also flourish at contaminated sites with more production of antioxidants. So, it suggests that studied weed species can be classified as phytoremediation plants and can be used as eco-friendly and economically feasible technique for restoring the land contaminated with toxic metals.     

Untersuchungen zum Vorkommen polycyclischer Moschus-Duftstoffe in verschiedenen Umweltkompartimenten

In addition to the three compounds discussed in our first communication (UWSF 6/4, 183–189, 1994) this paper mentions another four substances from the group of the polycyclic musk flavors analysed in a number of detergents and cosmetics, in surface waters, in waste waters from municipal sewage treatment plants and in fish. These four substances are: 6-acetyl-1,1,2,3,3,5-hexamethylindane (AHMI, known for instance under the trade name Phantolide^®), 6,7-dihydro-1,1,2,3,3-pentamethyl-4 (5H)-indanone (DPMI, known for instance under the trade name Cashmeran^®), 7-acetyl-1,1,4,4-tetramethyl-6-ethyltetraline (ATTN, known for instance under the trade name Versalide^®) and 5-acetyl-1,1,2,6-tetramethyl-3-isopropylindane (ATII, known for instance under the trade name Traseolide^®). The results of these analyses show that except for ATTN, the manufacture of which was discontinued some ten years ago, these substances are considered to have an ubiquitous distribution in surface waters. This pollution evidently comes from the use of these flavors in various detergents and cosmetics, from where they enter surface waters via the waste waters from municipal sewage treatment plants. Choosing the Ruhr river as an example, the authors demonstrate that the pollution level is constant and that — due to their lipophilic nature — the compounds accumulate in fish leading to concentrations which markedly exceed those known, e.g., for nitromusk flavors in environmental samples. Two of the main contaminants are HHCB and AHTN, which have the highest concentrations both in the detergents analyzed and in environmental samples.     

In-vitro antimicrobial activity and synergistic/antagonistic effect of interactions between antibiotics and some spice essential oils

Spices and herbs have been used for many years by different cultures. The aim of the present study is (1) to investigate in-vitro antimicrobial effects of different spices and herbs (5 species: Rosmarinus officinalis (Rosemary), Coriandrum sativum (coriander), Micromeria fruticosa (L.) Druce subsp. Brachycalyx P.H. Davis (White micromeria), Cumium cyminum (cumin), Mentha piperita (Peppermint) against different bacteria and fungi species, and (2) to discuss the in-vitro possible effects between the plants and antibiotics. The microorganisms used were Micrococcus luteus LA 2971, Bacillus megaterium NRS, Bacillus brevis FMC 3, Enterococcus faecalis ATCC 15753, Pseudomonas pyocyaneus DC 127, Mycobacterium smegmatis CCM 2067, Escherichia coil DM, Aeromonas hydrophila ATCC 7966, Yersinia enterocolitica AU 19, Staphylococcus aureus Cowan 1, Streptococcus faecalis DC 74 bacteria, and Saccharomyces cerevisiae WET 136, Kluvyeromyces fragilis DC 98 fungi in this study. The results indicated that essential oils of Rosmarinus officinalis, Coriandrum sativum L., Micromeria fruticosa (L.) Druce subsp. brachycalyx P.H. Davis, Cumium cyminum L., Mentha piperita L. were shown antimicrobial activity in the range of 7-60 mm 2 microl(-1) inhibition zone to the microorganisms tested, using disc diffusion method. Standard antibiotic such as Gentamicin (10 microg), Cephalothin (30 microg), Ceftriaxone (10 microg), Nystatin (10 U) discs were used for comparison with the antimicrobial activities of essential oils of these plants. In addition, antibacterial activity of essential oils of these plants was researched by effects when it was used together with these standard antibiotics in vitro. However, antibacterial activity changed also by in vitro interactions between these standard antibiotics and essential oils of these plants. Synergic, additive or antagonist effects were observed in antibacterial activity.     

有机氯农药六六六污染土壤的植物修复研究

我国20世纪六七十年代大量施用的有机氯农药,由于其性质极其稳定,在土壤至今仍有残留。植物修复有机农药污染土壤并不多见,但具有广阔的应用前景。此项研究对提高土壤环境质量、保证农产品的安全、实现农业可持续发展等有着重要的理论和现实意义。文章以多花黑麦草(Lolium multiforum Lan.)、紫花苜蓿(Medicago sativa L.)和籽粒苋(Amaranthus hypochondriacus L.)作为供试植物,在有机氯农药六六六(HCH)质量分数为1.09 mg.kg-1的污染土壤中种植3个月,研究了种植不同植物条件下土壤中HCH的消解情况。研究结果表明,与对照相比,种植植物大大提高了土壤中微生物数量和酶的活性,并且微生物的数量和酶的活性与土壤中HCH的消解密切相关。试验结束后,不同处理中HCH及其4种异构体的总含量降低幅度为43.87%~65.79%,其中种植紫花苜蓿和多花黑麦草的处理中HCH消解较快,对HCH污染土壤修复的效果较好。可见,植物修复技术是一种可行的环境友好的修复六六六污染土壤的技术。     

Sustainability of agricultural and wild cereals to aerotechnogenic exposure

In recent decades, the problem of the constantly increasin level of anthropogenic load on the environment is becoming more and more acute. Some of the most dangerous pollutants entering the environment from industrial emissions are heavy metals. These pollutants are not susceptible to biodegradation over time, which leads to their accumulation in the environment in dangerous concentrations. The purpose of this work is to study the sustainability of cultivated and wild plants of the Poaceae family to aerotechnogenic pollution in the soil. The content of heavy metals in couch grass (Elytrigia repens (L.) Nevski), meadow bluegrass (Poa pratensis L.) and soft wheat (Triticum aestivum) plants grown in the impact zone of Novocherkassk Power Station has been analyzed. Contamination of cultivated and wild cereals with Pb, Zn, Ni and Cd has been established. It has been shown that the accumulation of heavy metals is individual for each plant species. An average and close correlation have been established between the total HM content and the content of their mobile forms in the soil and their content in plants. For the plants studied, the translocation factor (TF) and the distribution coefficient (DC) of HM have been calculated. The TF is formed by the ratio of the concentration of an element in the root plant dry weight to the content of its mobile compounds in the soil. The DC value makes it possible to estimate the capacity of the aboveground parts of plants to absorb and accumulate elements under soil pollution conditions and is determined as the ratio of the metal content in the aboveground biomass to its concentration in the roots. TF and DC values have shown a significant accumulation of elements by plants from the soil, as well as their translocation from the root system to the aboveground part. It has been revealed that even within the same Poaceae family, cultural species are more sensitive to man-made pollution than wild-growing ones.

     

Translocation and biotoxicity of metal (oxide) nanoparticles in the wetland-plant system

• Aquatic plants are more likely to absorb TiO₂ NPs that are beneficial to them. • Ag NPs inhibited the growth of aquatic plants under both 5- and 60-day exposure. • CeO₂ NPs had positive/negative impact on plant in 5/60-day exposure, respectively. • TiO₂ NPs presence could enhance the photosynthesis and increase the plant biomass. • The ENPs changed plant activity, which resulted in changes of wetland performance. Engineered nanoparticles (ENPs) threaten the environment through wastewater discharging. Generally, constructed wetlands (CWs) are efficient methods for ENPs removal. However, the biotoxicity of ENPs on plants in CWs is unclear. Here, we investigated the distribution and bio-impacts of different ENPs (Ag NPs, TiO₂ NPs, and CeO₂ NPs) in plants under 5- and 60-day exposure to 1 and 50 mg/L concentrations. Results showed that ENPs appeared in the vascular bundle and mesophyll cell space, which induced the variation in antioxidase activities (e.g., superoxide dismutase [SOD], peroxidase [POD], and catalase [CAT] activities) as well as overproduction of malondialdehyde (MDA). Additionally, Ag NPs inhibited photosynthesis rate and root activity during two exposure phases. CeO₂ NPs had positive and negative impacts on plants in 5- and 60-day exposure, respectively. Inversely, TiO₂ NPs enhanced photosynthesis and root activity under 60-day exposure. Finally, the contents of the C, N, and P elements in plants fluctuated in response to ENPs stress. All results have a positive correlation with the wetland performance under ENPs exposure except for TiO₂ NPs treatment. Overall, our study systematically reveals aquatic plants' responses to ENPs and provides a reference for building ecological treatment systems to purify wastewater containing ENPs.     

四种植物提取物的杀螺效果研究

福寿螺是我国华南地区一种危害十分严重的外来入侵生物。采用分布广泛的四种植物：水蜈蚣（Kyllinga brevifolia Rottb.）、红花酢浆草（Oxalis corymbosa DC）、红叶乌桕（Euphorbia cotinifolia L.）和辣蓼草（Polygonum flaccidum Meissn.）作为原料,在实验室内通过人工研磨方法提取植物体内的有效成分作为药剂,分别对福寿螺幼螺进行室内毒杀及刺激其上爬的效果研究。结果表明：水蜈蚣提取物的杀螺效果不明显,而红花酢浆草、红叶乌桕、辣蓼草等三种植物提取物具有较好的杀螺效果。72h的毒性实验表明,这三种植物提取物在质量浓度为400mg·L-1时,均能全部杀死福寿螺幼螺;其中,红花酢浆草的杀螺效果最强,质量浓度为100mg·L-1时的杀螺率就达到80%,200mg·L-1的质量浓度下已能全部杀死福寿螺,红叶乌桕在200mg·L-1质量浓度时的杀螺率为56.67%,而在此质量浓度下辣蓼草仅为26.67%。另外,提取物刺激福寿螺上爬实验结果表明,红花酢浆草和红叶乌桕均有刺激福寿螺向上爬的作用,且红花酢浆草刺激作用稍强于红叶乌桕。综合杀螺和刺激福寿螺上爬作用的效果,可以得出在控制福寿螺上红花酢浆草和红叶乌桕是比较理想的备选植物。     

Effects of Al3+ on pollutant removal and extracellular polymeric substances (EPS) under anaerobic,anoxic and oxic conditions

The highest removal efficiencies of COD and TN were achieved under 10 mg/L of Al³⁺. The highest TP removal efficiency occurred under 30 mg/L of Al³⁺. EPS, PS and PN concentrations increased with the addition of Al³⁺. Sludge properties significantly changed with the addition of Al³⁺. Aluminum ions produced by aluminum mining, electrolytic industry and aluminum-based coagulants can enter wastewater treatment plants and interact with activated sludge. They can subsequently contribute to the removal of suspended solids and affect activated sludge flocculation, as well as nitrogen and phosphorus removal. In this study, the effects of Al³⁺ on pollutant removal, sludge flocculation and the composition and structure of extracellular polymeric substances (EPS) were investigated under anaerobic, anoxic and oxic conditions. Results demonstrated that the highest chemical oxygen demand (COD) and total nitrogen (TN) removal efficiencies were detected for an Al³⁺ concentration of 10 mg/L. In addition, the maximal dehydrogenase activity and sludge flocculation were also observed at this level of Al³⁺. The highest removal efficiency of total phosphorus (TP) was achieved at an Al³⁺ concentration of 30 mg/L. The flocculability of sludge in the anoxic zone was consistently higher than that in the anaerobic and oxic zones. The addition of Al³⁺ promoted the secretion of EPS. Tryptophan-like fluorescence peaks were detected in each EPS layer in the absence of Al³⁺. At the Al³⁺ concentration of 10 mg/L, fulvic acid and tryptophan fluorescence peaks began to appear, while the majority of protein species and the highest microbial activity were also detected. Low Al³⁺ concentrations (<10 mg/L) could promote the removal efficiencies of COD and TN, yet excessive Al³⁺ levels (>10 mg/L) weakened microbial activity. Higher Al³⁺ concentrations (>30 mg/L) also inhibited the release of phosphorus in the anaerobic zone by reacting with PO₄^3-.     

Pb超富集植物对营养元素N、P、K的响应

利用富集重金属或对重金属具有耐性的植物修复重金属污染土壤，是治理土壤重金属污染的新途径。本研究通过温室土培方法，研究了营养元素N、P、K对3种Pb超富集植物绿叶苋菜、紫穗槐和羽叶鬼针草生长发育及Pb吸收的影响。结果表明，少量的N和K会促进富集植物叶片叶绿素值和干质量的增加，促进植物对Pb的吸收；随着N和K水平的增加，虽然叶绿素值和干质量一直在增加，但植物对Pb的吸收能力降低；K对植株Pb的吸收能力的抑制作用不如N显著。土壤供P会降低植物对Pb的吸收，且下降极显著。少量的N、P、K均使富集植物中的Pb迁移总量增加，高质量分数时则抑制。但K的抑制作用不如N及P的显著。     

Field crops for phytoremediation of metal-contaminated land. A review

The use of higher plants to remediate contaminated land is known as phytoremediation, a term coined 15 years ago. Among green technologies addressed to metal pollution, phytoextraction has received increasing attention starting from the discovery of hyperaccumulator plants, which are able to concentrate high levels of specific metals in the above-ground harvestable biomass. The small shoot and root growth of these plants and the absence of their commercially available seeds have stimulated study on biomass species, including herbaceous field crops. We review here the results of a bibliographical survey from 1995 to 2009 in CAB abstracts on phytoremediation and heavy metals for crop species, citations of which have greatly increased, especially after 2001. Apart from the most frequently cited Brassica juncea (L.) Czern., which is often referred to as an hyperaccumulator of various metals, studies mainly focus on Helianthus annuus L., Zea mays L. and Brassica napus L., the last also having the greatest annual increase in number of citations. Field crops may compensate their low metal concentration by a greater biomass yield, but available data from in situ experiments are currently very few. The use of amendments or chelators is often tested in the field to improve metal recovery, allowing above-normal concentrations to be reached. Values for Zn exceeding 1,000 mg kg⁻¹ are found in Brassica spp., Phaseolus vulgaris L. and Zea mays, and Cu higher than 500 mg kg⁻¹ in Zea mays, Phaseolus vulgaris and Sorghum bicolor (L.) Moench. Lead greater than 1,000 mg kg⁻¹ is measured in Festuca spp. and various Fabaceae. Arsenic has values higher than 200 mg kg⁻¹ in sorghum and soybean, whereas Cd concentrations are generally lower than 50 mg kg⁻¹. Assisted phytoextraction is currently facilitated by the availability of low-toxic and highly degradable chelators, such as EDDS and nitrilotriacetate. Currently, several experimental attempts are being made to improve plant growth and metal uptake, and results are being achieved from the application of organic acids, auxins, humic acids and mycorrhization. The phytoremediation efficiency of field crops is rarely high, but their greater growth potential compared with hyperaccumulators should be considered positively, in that they can establish a dense green canopy in polluted soil, improving the landscape and reducing the mobility of pollutants through water, wind erosion and water percolation.     

Impact of rhizobacteria on growth and chromium accumulation in Scirpus lacustris L. grown under chromium supplementation

Four chromate tolerant rhizobacterial strains viz., RZB-01, RZB-02, RZB-03 and RZB-04 were isolated from rhizosphere of Scirpus lacustris collected from Cr-contaminated area. These strains characterized at morphological and biochemical levels. The most efficient chromate tolerant strain RZB-03 was inoculated to fresh plant of S. lacustris and grown in 2 microg ml(-1) and 5 microg ml(-1) of Cr+6 supplemented nutrient solution under controlled laboratory condition. The effects of rhizobacterial inoculation on growth and chromium accumulation in S. lacustris were evaluated. The inoculation of rhizobacteria increased biomass by 59 and 104%, while total chlorophyll content by 1.76 and 15.3% and protein content increased by 23 and 138% under 2 microg ml(-1) and 5 microg ml(-1) concentrations of Cr+6, respectively after 14 d as compared to non-inoculated plant. Similarly, the Cr accumulation also increased by 97 and 75% in shoot and 114 and 68% in root of inoculated plants as compared to non inoculated plants at 2 microg ml(-1) and 5 microg ml(-1) Cr+6 concentrations, respectively after 14 d. The chromate tolerant rhizobacteria which play an important role in chromium uptake and growth promotion in plant may be useful in development of microbes assisted phytoremediation system for decontamination of chromium polluted sites.