Lead(Pb) is recorded as the second most hazardous pollutant of the environment.Previous cases of Pb bioremediation has been reported using single biosystem,but very few reports are available in biological approaches u...Lead(Pb) is recorded as the second most hazardous pollutant of the environment.Previous cases of Pb bioremediation has been reported using single biosystem,but very few reports are available in biological approaches using multi-biosystems to achieve an enhanced bioremoval of Pb.The present study evaluated the capacity of a unique association of Pennisetum purpureum,a hyperaccumulator plant,and Lumbricus terrestris(earthworm)bioaugmented with a Pb-resistant bacterium,obtained from an industrially contaminated site and identified as isolate VITMVCJ1 Klebsiella variicola,to bioremediate Pb.The Pb-resistant gene was amplified in the bacterial isolate VITMVCJ1.The study was conducted for 60 d.Results verified that the bioaugmentation process enhanced1)root and shoot length of the plants,2)chlorophyll content of the plants,and 3)biofilm-producing ability of the microbes from the rhizosphere region of the plants.The total phenolic and flavonoid contents were found to be lower in the plants in the bioaugmented setup.The study also observed a reduction in the toxic effects of Pb on earthworm and plant.The earthworm was used to assess the Pb-induced stress syndrome after exposure to sublethal concentrations of Pb in the soil.A reduction in the content of malondialdehyde,a potential biomarker,on exposure to Pb demonstrated the role of the inoculum to alleviate heavy metal-induced stress in earthworms.All three symbionts accumulated Pb;Pb was accumulated mainly in the root of the plant,and poorly in the shoot of the plant and body mass of the earthworm.The bioaugmentation system exhibited stable and excellent uptake of Pb from the contaminated soils.The results of the present study suggest the positive effect of the synergistic association of the plant and earthworm with appropriate microbes for the bioremoval of Pb.展开更多
The variations of antioxidant enzyme activities including superoxide dismutase （SOD： EC 1.15.1.1）, peroxidase （POD： EC 1.11.1.7） and catalase （CAT： EC 1.11.1.6）, lipid peroxidation and major electrolytes in A...The variations of antioxidant enzyme activities including superoxide dismutase （SOD： EC 1.15.1.1）, peroxidase （POD： EC 1.11.1.7） and catalase （CAT： EC 1.11.1.6）, lipid peroxidation and major electrolytes in Aloe vera irrigated for three years with seawater having different salinity were studied. The results indicate that POD activity increased significantly at 10% seawater level, whereas decreased at higher seawater levels. The SOD activity decreased with increasing seawater concentration except for treatment with 100% seawater （denoted as T100%） under long-term salt stress. Salinity decreased CAT activity,and increased lipid peroxidation and cell membrane injury. In addition, Ca^2＋ content was high in Aloe irrigated by seawater of low salinity level, but low in Aloe irrigated by seawater of high salinity level. An opposite trend was observed for the effect of seawater on Na^＋ content of plants. K^＋ and Mg^2＋ contents remain relatively stable under various seawater levels, which benefit plant growth.展开更多
文摘Lead(Pb) is recorded as the second most hazardous pollutant of the environment.Previous cases of Pb bioremediation has been reported using single biosystem,but very few reports are available in biological approaches using multi-biosystems to achieve an enhanced bioremoval of Pb.The present study evaluated the capacity of a unique association of Pennisetum purpureum,a hyperaccumulator plant,and Lumbricus terrestris(earthworm)bioaugmented with a Pb-resistant bacterium,obtained from an industrially contaminated site and identified as isolate VITMVCJ1 Klebsiella variicola,to bioremediate Pb.The Pb-resistant gene was amplified in the bacterial isolate VITMVCJ1.The study was conducted for 60 d.Results verified that the bioaugmentation process enhanced1)root and shoot length of the plants,2)chlorophyll content of the plants,and 3)biofilm-producing ability of the microbes from the rhizosphere region of the plants.The total phenolic and flavonoid contents were found to be lower in the plants in the bioaugmented setup.The study also observed a reduction in the toxic effects of Pb on earthworm and plant.The earthworm was used to assess the Pb-induced stress syndrome after exposure to sublethal concentrations of Pb in the soil.A reduction in the content of malondialdehyde,a potential biomarker,on exposure to Pb demonstrated the role of the inoculum to alleviate heavy metal-induced stress in earthworms.All three symbionts accumulated Pb;Pb was accumulated mainly in the root of the plant,and poorly in the shoot of the plant and body mass of the earthworm.The bioaugmentation system exhibited stable and excellent uptake of Pb from the contaminated soils.The results of the present study suggest the positive effect of the synergistic association of the plant and earthworm with appropriate microbes for the bioremoval of Pb.
文摘The variations of antioxidant enzyme activities including superoxide dismutase （SOD： EC 1.15.1.1）, peroxidase （POD： EC 1.11.1.7） and catalase （CAT： EC 1.11.1.6）, lipid peroxidation and major electrolytes in Aloe vera irrigated for three years with seawater having different salinity were studied. The results indicate that POD activity increased significantly at 10% seawater level, whereas decreased at higher seawater levels. The SOD activity decreased with increasing seawater concentration except for treatment with 100% seawater （denoted as T100%） under long-term salt stress. Salinity decreased CAT activity,and increased lipid peroxidation and cell membrane injury. In addition, Ca^2＋ content was high in Aloe irrigated by seawater of low salinity level, but low in Aloe irrigated by seawater of high salinity level. An opposite trend was observed for the effect of seawater on Na^＋ content of plants. K^＋ and Mg^2＋ contents remain relatively stable under various seawater levels, which benefit plant growth.
