The aim of this work was to analyze the effect of the magnetic field generated by the household appliances on the airborne microbial surrounding these equipment located on indoor environments with particular interest ...The aim of this work was to analyze the effect of the magnetic field generated by the household appliances on the airborne microbial surrounding these equipment located on indoor environments with particular interest in the environmental fungi.A simultaneous environmental study was carried out in locals of three different geographical places of Havana,Cuba,which have televisions,computers and an electric generator.The air samples were made by a sedimentation method using Malt Extract Agar.The concentration of total aerobic mesophilic as well as fungi and yeasts were determined in rainy and little rainy seasons by applying as factors:exposure time of dishes(5 to 60 min)and distance to the wall(0 and 1 m)at a height of 1 m above the floor.The predominant fungal genera were Cladosporium,Penicillium and Aspergillus.In the dishes that were placed at 0 and 0.5 m from the emitting sources were observed that some bacteria colonies formed inhibition halos,a great diversity of filamentous fungi and an increase in the mycelium pigmentation as well as the pigments excretion.In the rainy season,the highest amounts of fungi were obtained in all samples.In the little rain season the count of the Gram-negative bacilli increased three times the Gram-positive cocci.展开更多
Alnus trabeeulosa, a rhizobia-nodulating tree, was introduced into the Chongxi tidal wetland in the Yangtze River estuary of China to increase the biodiversity of plants and restore tidal wetland functions. However, t...Alnus trabeeulosa, a rhizobia-nodulating tree, was introduced into the Chongxi tidal wetland in the Yangtze River estuary of China to increase the biodiversity of plants and restore tidal wetland functions. However, the effect of the introduced plant on soil bacterial communities and restoration outcomes remains unknown. In this study, the rhizosphere bacterial community structure and diversity were compared between Phragrnites australis monospecific community and A. trabeculosa-P, australis mixed communities, aiming to assess whether A. trabeculosa influenced the rhizosphere bacterial communities of P. australis and to investigate whether different taxonomic groups within a soil community may respond similarly to the presence of an introduced exotic plant. Among the 14 phylogenetic phyla detected, Proteobacteria and Acidobacteria were the dominant bacterial taxa in the rhizosphere. Phylogenetic analysis of the predominant Proteobacteria showed that the clones from the rhizosphere soils of A. trabeculosa and P. australis in A. trabeculosa-P, australis mixed communities were more diverse than those in the rhizosphere soil of P. australis in P. australis monospecific community. The rhizosphere community in the wetland potentially included active microbial community related to carbon, nitrogen, and sulfur cycling in the Yangtze River estuary. The rhizosphere soil of P. australis in A. trabeculosa-P, australis mixed communities exhibited the highest Shannon diversity index （Hr） and Simpson diversity index （l/D） （H = 4.52, 1/D = 253）. Correspondence analyses revealed that the bacterial community structures were altered after A. trabeculosa was introduced.展开更多
Background The extent of natural salt-laden groundwaters used for irrigation is increasing worldwide,which is a fast-emerging threat to agroecosystems and global food security.The salt buildup in the soil is linked to...Background The extent of natural salt-laden groundwaters used for irrigation is increasing worldwide,which is a fast-emerging threat to agroecosystems and global food security.The salt buildup in the soil is linked to deteriorated soil chemical,physical,and biological health and decreased land productivity.Alkali waters with high residual sodium carbonate(RSC)is one of the severe poor-quality waters that deteriorate soil.We evaluated soil microbial dynamics and soil health at critical growth stages of rice crop receiving two-decade-long irrigation with three levels of alkali water and two reclamation strategies.These included good-quality water(GQW),alkali water(ALKW)with an RSC concentration of 5 me L^(-1)(ALKW1),ALKW with an RSC concentration of 10 me L^(-1)(ALKW2),ALKW2 treated to neutralize RSC to 5 me L^(-1)using gypsum(CaSO_(4)·2H_(2)O;ALKW2+GYP),and ALKW2 treated with sulfuric acid(H_(2)SO_(4);ALKW2+SA).Eleven microbial parameters were used to develop a soil microbial activity index(SMAI),and eight soil health indicators were correlated with changes in SMAI and crop productivity.Results The SMAI peaked under good-quality water(GQW)conditions(0.84–0.89),while the lowest values were recorded under ALKW_(2)(0.06–0.18).Neutralized alkali waters,ALKW_(2)+SA and ALKW2+GYP,signifcantly improved SMAI with corresponding values of 0.25–0.35 and 0.13–0.32,respectively.SMAI across all stages correlated positively(R^(2)=0.91–0.98)with rice yield.Microbial activity varied with the crop growth stage,peaking at tillering.Gypsum application alone,aimed at neutralizing alkalinity from an RSC of 10 to 5 me L^(-1),proved insufcient in bringing the SMAI up to the ALKW1(RSC level of 5 me L^(-1)).Conclusions The application of dilute sulfuric acid demonstrated better results in restoring the soil microbial activity index than gypsum amendment;however,sulfuric acid treatment depends on native calcium carbonate(CaCO_(3))dissolution for its efectiveness.It may not sufce for soil stability improvement in the long term,especially when native CaCO_(3)is low.Therefore,integrating gypsum and dilute sulfuric acid for RSC neutralization is worthwhile;however,further assessment is needed to confrm their combined impact on soil biochemical and physical properties.展开更多
基金the Ministry of Science,Technology and Environment,Cuba(PCA-2118025001)。
文摘The aim of this work was to analyze the effect of the magnetic field generated by the household appliances on the airborne microbial surrounding these equipment located on indoor environments with particular interest in the environmental fungi.A simultaneous environmental study was carried out in locals of three different geographical places of Havana,Cuba,which have televisions,computers and an electric generator.The air samples were made by a sedimentation method using Malt Extract Agar.The concentration of total aerobic mesophilic as well as fungi and yeasts were determined in rainy and little rainy seasons by applying as factors:exposure time of dishes(5 to 60 min)and distance to the wall(0 and 1 m)at a height of 1 m above the floor.The predominant fungal genera were Cladosporium,Penicillium and Aspergillus.In the dishes that were placed at 0 and 0.5 m from the emitting sources were observed that some bacteria colonies formed inhibition halos,a great diversity of filamentous fungi and an increase in the mycelium pigmentation as well as the pigments excretion.In the rainy season,the highest amounts of fungi were obtained in all samples.In the little rain season the count of the Gram-negative bacilli increased three times the Gram-positive cocci.
基金supported by the National Natural Science Foundation of China (Nos. 41101230, 40771203 and 40871243)the Shanghai Municipal Science and Technology Commission of China (No. 10231201600)
文摘Alnus trabeeulosa, a rhizobia-nodulating tree, was introduced into the Chongxi tidal wetland in the Yangtze River estuary of China to increase the biodiversity of plants and restore tidal wetland functions. However, the effect of the introduced plant on soil bacterial communities and restoration outcomes remains unknown. In this study, the rhizosphere bacterial community structure and diversity were compared between Phragrnites australis monospecific community and A. trabeculosa-P, australis mixed communities, aiming to assess whether A. trabeculosa influenced the rhizosphere bacterial communities of P. australis and to investigate whether different taxonomic groups within a soil community may respond similarly to the presence of an introduced exotic plant. Among the 14 phylogenetic phyla detected, Proteobacteria and Acidobacteria were the dominant bacterial taxa in the rhizosphere. Phylogenetic analysis of the predominant Proteobacteria showed that the clones from the rhizosphere soils of A. trabeculosa and P. australis in A. trabeculosa-P, australis mixed communities were more diverse than those in the rhizosphere soil of P. australis in P. australis monospecific community. The rhizosphere community in the wetland potentially included active microbial community related to carbon, nitrogen, and sulfur cycling in the Yangtze River estuary. The rhizosphere soil of P. australis in A. trabeculosa-P, australis mixed communities exhibited the highest Shannon diversity index （Hr） and Simpson diversity index （l/D） （H = 4.52, 1/D = 253）. Correspondence analyses revealed that the bacterial community structures were altered after A. trabeculosa was introduced.
基金support for this work was provided by Indian Council of Agricultural Research(ICAR)NICRA project(National Innovations in Climate Resilient Agriculture)supported the work through grant no.ICAR-DARE-NICRA-03.
文摘Background The extent of natural salt-laden groundwaters used for irrigation is increasing worldwide,which is a fast-emerging threat to agroecosystems and global food security.The salt buildup in the soil is linked to deteriorated soil chemical,physical,and biological health and decreased land productivity.Alkali waters with high residual sodium carbonate(RSC)is one of the severe poor-quality waters that deteriorate soil.We evaluated soil microbial dynamics and soil health at critical growth stages of rice crop receiving two-decade-long irrigation with three levels of alkali water and two reclamation strategies.These included good-quality water(GQW),alkali water(ALKW)with an RSC concentration of 5 me L^(-1)(ALKW1),ALKW with an RSC concentration of 10 me L^(-1)(ALKW2),ALKW2 treated to neutralize RSC to 5 me L^(-1)using gypsum(CaSO_(4)·2H_(2)O;ALKW2+GYP),and ALKW2 treated with sulfuric acid(H_(2)SO_(4);ALKW2+SA).Eleven microbial parameters were used to develop a soil microbial activity index(SMAI),and eight soil health indicators were correlated with changes in SMAI and crop productivity.Results The SMAI peaked under good-quality water(GQW)conditions(0.84–0.89),while the lowest values were recorded under ALKW_(2)(0.06–0.18).Neutralized alkali waters,ALKW_(2)+SA and ALKW2+GYP,signifcantly improved SMAI with corresponding values of 0.25–0.35 and 0.13–0.32,respectively.SMAI across all stages correlated positively(R^(2)=0.91–0.98)with rice yield.Microbial activity varied with the crop growth stage,peaking at tillering.Gypsum application alone,aimed at neutralizing alkalinity from an RSC of 10 to 5 me L^(-1),proved insufcient in bringing the SMAI up to the ALKW1(RSC level of 5 me L^(-1)).Conclusions The application of dilute sulfuric acid demonstrated better results in restoring the soil microbial activity index than gypsum amendment;however,sulfuric acid treatment depends on native calcium carbonate(CaCO_(3))dissolution for its efectiveness.It may not sufce for soil stability improvement in the long term,especially when native CaCO_(3)is low.Therefore,integrating gypsum and dilute sulfuric acid for RSC neutralization is worthwhile;however,further assessment is needed to confrm their combined impact on soil biochemical and physical properties.
