To test the patterns of the root morphology and architecture indexes of Tamarix chinensis in response to water and salt changes in the two media of the groundwater and soil,three-year-old T.chinensis seedlings were ch...To test the patterns of the root morphology and architecture indexes of Tamarix chinensis in response to water and salt changes in the two media of the groundwater and soil,three-year-old T.chinensis seedlings were chosen as the research object.Groundwater with four salinity levels was created,and three groundwater level(GL)were applied for each salinity treatment to measure the root growth and architecture indexes.In the fresh water and brackish water treatments,the topological index(TI)of the T.chinensis roots was close to 0.5,and the root architecture was close to a dichotomous branching pattern.In the saline water and saltwater treatments,the TI of the T.chinensis roots was large and close to 1.0,and the root architecture was close to a herringbone-like branching pattern.Under different GLs and salinities,the total root length was significantly greater than the internal link length,the external link length was greater than the internal link length,and the root system showed an outward expansion strategy.The treatment with fresh water and a GL of 1.5 m was the most suitable for T.chinensis root growth,while the root growth of T.chinensis was the worst in the treatment with saline water and a GL of 0.3 m.T.chinensis can adapt to the changes in soil water and salt by regulating the growth and morphological characteristics of the root system.T.chinensis can adapt to high-salt environments by reducing its root branching and to water deficiencies by expanding the distribution and absorption area of the root system.展开更多
To explore the critical relationships of photosynthetic efficiency and stem sap flow to soil moisture,two-year-old poplar saplings were selected and a packaged stem sap flow gauge,based on the stem-heat balance method...To explore the critical relationships of photosynthetic efficiency and stem sap flow to soil moisture,two-year-old poplar saplings were selected and a packaged stem sap flow gauge,based on the stem-heat balance method,and a CIRAS-2 portable photosynthesis system were used.The results show that photosynthetic rates(P_(n)),transpiration rates(T_(r)),instantaneous water use efficiency(WUE)and the stem sap flow increased initially and then decreased with decreasing soil water,but their critical values were different.The turning point of relative soil water content(W_(r))from stomatal limitation to nonstomatal limitation of P_(n)was 42%,and the water compensation point of P_(n)was 13%.Water saturation points of P_(n)and T_(r)were 64%and 56%,respectively,and the WUE was 71%.With increasing soil water,the apparent quantum yield(AQY),light saturation point(LSP)and maximum net photosynthetic rate(P_(n)max)increased first and then decreased,while the light compensation point(LCP)decreased first and then increased.When W_(r)was 64%,LCP reached a lower value of 30.7µmol m^(-2)s^(-1),and AQY a higher value of 0.044,indicating that poplar had a strong ability to utilize weak light.When W_(r)was 74%,LSP reached its highest point at 1138.3µmol·m^(-2)s^(-1),indicating that poplar had the widest light ecological amplitude and the highest light utilization efficiency.Stem sap flow and daily sap flow reached the highest value(1679.7 g d^(-1))at W_(r)values of 56%and 64%,respectively,and then declined with increasing or decreasing W_(r),indicating that soil moisture significantly affected the transpiration water-consumption of poplar.Soil water was divided into six threshold grades by critical values to maintain photosynthetic efficiency at different levels,and a W_(r)of 64-71%was classified to be at the level of high productivity and high efficiency.In this range,poplar had high photosynthetic capacity and efficient physiological characteristics for water consumption.The saplings had characteristics of water tolerance and were not drought resistant.Full attention should be given to the soil water environment in the Yellow River Delta when planting Populus.展开更多
The Yellow River Delta(YRD) is a typical agricultural and petrochemical industrial area of China.To assess the current status of soil dichlorodiphenyltrichloroethane(DDT) and polychlorinated biphenyls(PCB) residues,to...The Yellow River Delta(YRD) is a typical agricultural and petrochemical industrial area of China.To assess the current status of soil dichlorodiphenyltrichloroethane(DDT) and polychlorinated biphenyls(PCB) residues,topsoil samples(0-15 cm)(n = 82) were collected in Bincheng District,at the geographic center of the YRD.The total concentrations of six DDT homologues were within 3.3-3819 μg/kg,with a mean concentration of 191 μg/kg,showing significant increase along urban-rural gradient.Soil concentrations of seven indicator PCBs in the area ranged from non-detectable to 87.0 μg/kg,dominated by heavily chlorinated PCBs(PCB-101 and-118).Soil PCBs concentrations were significantly greater in urban than suburban and rural areas.Principal component and multiple linear regression analysis suggest that 86.4% of soil DDTs originate from past DDT usage,and 13.6% originate from dicofol application.Soil PCBs most likely originate from the petrochemical industry(77.1%),municipal solid waste disposal(16.5%),local commercial PCB homologues usage(5.2%),and long-range atmospheric deposition(1.2%).In general,soil DDTs pollution was classified as low level,and mean PCBs concentrations were below the severe contamination classification range.Because PCB-118 is a dioxin-like congener,monitoring and remediation is advised to assess and reduce negative environmental and human health effects from soil DDTs and dioxin-like congeners in the study area.展开更多
Chromium is a common harmful pollutant with high toxicity and low bearing capacity of soil and water.Excellent salinity resistance,a wide pH range,and high regeneration capacity were essential for qualified adsorbents...Chromium is a common harmful pollutant with high toxicity and low bearing capacity of soil and water.Excellent salinity resistance,a wide pH range,and high regeneration capacity were essential for qualified adsorbents used in removing hexavalent chromium(Cr(VI))from polluted water.Herein,iron oxalate modified weak basic resin(IO@D301)for the removal of Cr(VI)was prepared by the impregnation method.The IO@D301 was characterized by scanning electron microscope(SEM),Fourier transform infrared spectroscopy(FTIR),X-Ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).Owing to abundant amine,carboxyl groups and iron ions existing on the surface,IO@D301 possesses high adsorption and salinity resistance capacity for Cr(VI).The maximum adsorption capacity of IO301 towards Cr(VI)reached 201.30 mg·g^(-1) at 293 K and a pH of 5.The adsorption equilibrium was well fitted by the Freundlich model,and the adsorption process was described by the pseudofirst-order kinetics model as spontaneous and exothermic.The mechanism may be identified as electrostatic attraction,coordination,and reduction,which was confirmed by FT-IR and X-ray photoelectron spectroscopy.展开更多
vegetation restoration is a main ecological remediation technology for greening saline and alkaline soils.The objectives of this study were to determine the effect of1-aminobenzotriazole(ABT-1) on the growth and physi...vegetation restoration is a main ecological remediation technology for greening saline and alkaline soils.The objectives of this study were to determine the effect of1-aminobenzotriazole(ABT-1) on the growth and physiology of Tamarix chinensis under salt stress and to determine a suitable ABT-1 concentration and soil salinity(Sc) for propagating T.chihehsis-cuttings.Cuttings were soaked in water and ABT-1 solutions at three concentrations(50,100,and 200 mg L^(-1)) and propagated in pots containing four soil salinity levels,mild(0.3%),moderate(0.6%),and severe(0.9% and 1.2%),and compared with a control.The cuttings were measured to determine growth indices and physiological and biochemical indices(e.g.,chlorophyll content,superoxide dismutase activity,peroxidase activity,and malondialdehyde content).ABT-1 was effective in improving survival,growth,and physiological processes of cuttings under salt stress.However,there was a threshold effect when using ABT-1 to facilitate propagation under salt stress.ABT-1 effects were insignificant when applied at low concentrations(<100 mg L^(-1)).At a high concentration(> 100 mg L^(-1)),ABT-1 limited growth and physiological activities.Under a salt stress level(Sc ≤0.9%),ABT applied at a 100 mg L^(-1)concentration increased chlorophyll content and superoxide dismutase and peroxidase activities in the leaves and reduced malondialdehyde accumulation and membrane lipid peroxidation effects.As a result,ABT-1 enhanced the resistance of T.chinensis to salt stress.However,under high salt stress(>0.9%) and ABT-1 concentration(> 100 mg L^(-1)),the physiological regulatory ability of T.chinensis seedlings weakened.T.chinensis grew well at a salt stress ≤0.9% and ABT ≤100 mg L^(-1) and exhibited relatively high physiological regulatory ability and high salt adaptability.展开更多
The fungus Shiraia bambusicola GZ19 M1 is biotechnologically important due to its ability to biosynthesis the pigment hypocrellins.Results showed that ethyl methane sulfonate( EMS) was effective mutagenic agent for st...The fungus Shiraia bambusicola GZ19 M1 is biotechnologically important due to its ability to biosynthesis the pigment hypocrellins.Results showed that ethyl methane sulfonate( EMS) was effective mutagenic agent for strain and potentially produced large numbers of random mutations broadly and uniformly over the whole genome to generate unique strains. Wild-type cultures of S. bambusicola GZ19 were subjected to EMS( 80 mM) induction targeted at approximately 20% spores' survival. When surviving spores were selected in sufficient numbers and cultured on PDA medium for 7 d at 26℃,five novel mutagenized S. bambusicola strains were obtained. A mutant GZ19 M1 that exhibited an activity of more than two times over the wild strain was obtained. Also,batch experiments were carried out to achieve the suitable conditions for hypocrellin. Glucose and rice extract were the most favorable carbon and nitrogen sources for hypocrellin production by submerged culture of S. bambusicola GZ19 M1,and initial glucose and rice extract concentrations were at 35 and 250 g/L,respectively. The optimal surfactant were found to be 0. 008 V/V Tween 80,it was added into cultivation medium at 24 h. Hypocrellin concentration reached 498. 89 mg/L under optimal nutritional conditions,an increment of about 8. 70 times of hypocrellins production was observed compared with that of in non-optimized medium by the wild strain.展开更多
Dissimilatory iron reduction(DIR)coupled with carbon cycling is increasingly being recognized as an influential process in freshwater wetland soils and sediments.The role of DIR in organic matter(OM)mineralization,how...Dissimilatory iron reduction(DIR)coupled with carbon cycling is increasingly being recognized as an influential process in freshwater wetland soils and sediments.The role of DIR in organic matter(OM)mineralization,however,is still largely unknown in lake sediment environments.In this study,we clarified rates and pathways of OM mineralization in two shallow lakes with seasonal hydrological connectivity and different eutrophic situations.We found that in comparison with the domination of DIR(55%)for OM mineralization in Lake Xiaoxingkai,the contribution of methanogenesis was much higher(68%)in its connected lake(Lake Xingkai).The differences in rates and pathways of sediment OM mineralization between the two lakes were attributed to higher concentrations of carbonate associated iron oxides(Fecarb)in Lake Xiaoxingkai compared to Lake Xingkai(P=0.002),due to better deposition mixing,more contributions of terrigenous detrital materials,and higher OM content in Lake Xiaoxingkai.Results of structural equation modeling showed that Fecarb and total iron content(TFe)regulated 25%of DIR in Lake Xiaoxingkai and 76%in Lake Xingkai,accompanied by a negative effect of TFe on methanogenesis in Lake Xingkai.The relative abundance and diversity of Fe-reducing bacteria were significantly different between the two lakes,and showed a weak effect on sediment OM mineralization.Our findings emphasize the role of iron minerals and geochemical characterizations in regulating rates and pathways of OM mineralization,and deepen the understanding of carbon cycling in lake sediments.展开更多
Increasing human demands for Earth’s resources are hastening many environmental changes and creating a need to incorporate the routine monitoring of ecosystem functions into forest management.Under global change and ...Increasing human demands for Earth’s resources are hastening many environmental changes and creating a need to incorporate the routine monitoring of ecosystem functions into forest management.Under global change and anthropogenic disturbances,soil carbon(C)cycling in terrestrial ecosystems is undergoing substantial changes that result in the transformation between soil C sources and sinks.Therefore,the forest C budget requires an understanding of the underlying soil C dynamic under environmental disturbances.The present review focuses on the response and feedback of soil C cycling to global change(climate warming and nitrogen(N)deposition)and human disturbances(fire and logging)and detects the association of soil C cycling with soil C and N efflux and inflow in boreal forests.The effects of climate warming and N deposition on soil C cycling are complex,especially at short-term temporal scales.Climate warming can decay soil organic matter(SOM)to emit substantial amounts of CO2,and differing warming durations result in different effects on soil C loss,ranging from ca.1 to 15 Mg C ha−1.Short-term soil warming mainly reduces the labile soil C pool and increases the decomposition of recalcitrant soil C compounds(e.g.,lignin),whereas longer-term warming may limit soil C loss due to impoverished soil C substrate and microbial communities.Moderate N addition is conducive to enhancing soil C storage(ca.2–22 Mg C ha−1),by increasing plant productivity including above-and belowground biomass;however,chronic N deposition or excess N addition can result in soil acidity,reducing N use efficiency and plant growth and further resulting in no changes or declines in soil C pool.Fire and logging lead to a large quantity of soil C loss via impaired plant productivity and increased organic matter degradation,exacerbating global warming.In particular,severe fire can cause a large amount of soil C loss,ca.16–34 Mg C ha−1 in the data we reviewed.Meanwhile,the black C input induced by fire and the plant residual C input from the roots of logged trees can increase the proportion of recalcitrant soil C and enhance the stability of soil C pool.We also highlight the positive feedback of forest restoration to soil C storage after fire and logging disturbances,indicating that effective forest restoration projects(e.g.,afforestation and natural forest recovery)are necessary to sequester soil C belowground.Additionally,combined with microbial technologies and metagenomics-and metabolomics-based approaches,soil microorganisms are proved crucial for driving soil C cycling via C capture and the N recycling of plants and soil.We,therefore,suggest that clarifying the relationship among plant,SOM,and microorganisms is essential to better evaluate soil C cycling and to predict how boreal forests respond to global change and human disturbances.Further work is needed to assess long-term soil C feedback from high-latitude forests to broader regions.展开更多
Salt marsh plants play a vital role in mediating nitrogen(N)biogeochemical cycle in estuarine and coastal ecosystems.However,the effects of invasive Spartina alterniflora on N fixation and removal,as well as how these...Salt marsh plants play a vital role in mediating nitrogen(N)biogeochemical cycle in estuarine and coastal ecosystems.However,the effects of invasive Spartina alterniflora on N fixation and removal,as well as how these two processes balance to determine the N budget,remain unclear.Here,simultaneous quantifications of N fixation and removal via^(15)N tracing experiment with native Phragmites australis,invasive S.alterniflora,and bare flats as well as corresponding functional gene abundance by qPCR were carried out to explore the response of N dynamics to S.alterniflora invasion.Our results showed that N fixation and removal rates ranged from 0.77±0.08 to 16.12±1.13 nmol/(g·h)and from 1.42±0.14 to 16.35±1.10 nmol/(g·h),respectively,and invasive S.alterniflora generally facilitated the two processes rates.Based on the difference between N removal and fixation rates,net N_(2)fluxes were estimated in the range of-0.39±0.14 to 8.24±2.23 nmol/(g·h).Estimated net N_(2)fluxes in S.alterniflora stands were lower than those in bare flats and P.australis stands,indicating that the increase in N removal caused by S.alterniflora invasion may be more than offset by N fixation process.Random forest analysis revealed that functional microorganisms were the most important factor associated with the corresponding N transformation process.Overall,our results highlight the importance of N fixation in evaluating N budget of estuarine and coastal wetlands,providing valuable insights into the ecological effect of S.alterniflora invasion.展开更多
Soil inorganic carbon(SIC),including mainly carbonate,is a key component of terrestrial soil C pool.Autotrophic microorganisms can assimilate carbonate as the main or unique C source,how microorganisms convert SIC to ...Soil inorganic carbon(SIC),including mainly carbonate,is a key component of terrestrial soil C pool.Autotrophic microorganisms can assimilate carbonate as the main or unique C source,how microorganisms convert SIC to soil organic carbon(SOC)remains unclear.A systematic field survey(n=94)was performed to evaluate the shift in soil C components(i.e.,SIC,SOC,and microbial residues)along a natural salinity gradient(ranging from 0.5‰to 19‰),and further to explore how microbial necromass as an indicator converting SIC into SOC in the Yellow River delta.We observed that SIC levels linearly decreased with increasing salinity,ranging from~12 g kg^(-1)(salinity<6‰)to~10 g kg^(-1)(salinity>6‰).Additionally,the concentrations of SOC and microbial residues exponentially decreased from salinity<6‰ to salinity>6‰,with the decline of 39%and 70%,respectively.Microbial residues and SOC was tightly related to the variations in SIC.The structural equation model showed the causality on explanation of SOC variations with SIC through microbial residues,which can contribute 89% of the variance in SOC storage combined with SIC.Taken together,these two statistical analyses can support that microbial residues can serve as an indicator of SIC transition to SOC.This study highlights the regulation of microbial residues in SIC cycling,enhancing the role of SIC playing in C biogeochemical cycles and enriching organic C reservoirs in coastal saline soils.展开更多
基金financially supported by the Joint Funds of the National Natural Science Foundation of China(U2006215)the National Natural Science Foundation of China(31770761)+2 种基金the Shandong Key Laboratory of Coastal Environmental Processes,YICCAS(2019SDHADKFJJ16)the Natural Science Foundation of Shangdong Province(ZR2020QD003)Taishan Scholars Program of Shandong Province,China(TSQN201909152)。
文摘To test the patterns of the root morphology and architecture indexes of Tamarix chinensis in response to water and salt changes in the two media of the groundwater and soil,three-year-old T.chinensis seedlings were chosen as the research object.Groundwater with four salinity levels was created,and three groundwater level(GL)were applied for each salinity treatment to measure the root growth and architecture indexes.In the fresh water and brackish water treatments,the topological index(TI)of the T.chinensis roots was close to 0.5,and the root architecture was close to a dichotomous branching pattern.In the saline water and saltwater treatments,the TI of the T.chinensis roots was large and close to 1.0,and the root architecture was close to a herringbone-like branching pattern.Under different GLs and salinities,the total root length was significantly greater than the internal link length,the external link length was greater than the internal link length,and the root system showed an outward expansion strategy.The treatment with fresh water and a GL of 1.5 m was the most suitable for T.chinensis root growth,while the root growth of T.chinensis was the worst in the treatment with saline water and a GL of 0.3 m.T.chinensis can adapt to the changes in soil water and salt by regulating the growth and morphological characteristics of the root system.T.chinensis can adapt to high-salt environments by reducing its root branching and to water deficiencies by expanding the distribution and absorption area of the root system.
基金This study was supported by the National Natural Science Foundation of China(No.31770761,No.31870379)the Forestry Science and Technology Innovation Project of Shandong Province(No.2019LY006)+1 种基金the Science and Technology Projects of Shandong Province(No.2017CXGC0316)the Taishan Scholars Program of Shandong Province,P.R.China(No.TSQN201909152).
文摘To explore the critical relationships of photosynthetic efficiency and stem sap flow to soil moisture,two-year-old poplar saplings were selected and a packaged stem sap flow gauge,based on the stem-heat balance method,and a CIRAS-2 portable photosynthesis system were used.The results show that photosynthetic rates(P_(n)),transpiration rates(T_(r)),instantaneous water use efficiency(WUE)and the stem sap flow increased initially and then decreased with decreasing soil water,but their critical values were different.The turning point of relative soil water content(W_(r))from stomatal limitation to nonstomatal limitation of P_(n)was 42%,and the water compensation point of P_(n)was 13%.Water saturation points of P_(n)and T_(r)were 64%and 56%,respectively,and the WUE was 71%.With increasing soil water,the apparent quantum yield(AQY),light saturation point(LSP)and maximum net photosynthetic rate(P_(n)max)increased first and then decreased,while the light compensation point(LCP)decreased first and then increased.When W_(r)was 64%,LCP reached a lower value of 30.7µmol m^(-2)s^(-1),and AQY a higher value of 0.044,indicating that poplar had a strong ability to utilize weak light.When W_(r)was 74%,LSP reached its highest point at 1138.3µmol·m^(-2)s^(-1),indicating that poplar had the widest light ecological amplitude and the highest light utilization efficiency.Stem sap flow and daily sap flow reached the highest value(1679.7 g d^(-1))at W_(r)values of 56%and 64%,respectively,and then declined with increasing or decreasing W_(r),indicating that soil moisture significantly affected the transpiration water-consumption of poplar.Soil water was divided into six threshold grades by critical values to maintain photosynthetic efficiency at different levels,and a W_(r)of 64-71%was classified to be at the level of high productivity and high efficiency.In this range,poplar had high photosynthetic capacity and efficient physiological characteristics for water consumption.The saplings had characteristics of water tolerance and were not drought resistant.Full attention should be given to the soil water environment in the Yellow River Delta when planting Populus.
基金supported by the Scientific Award Fund for the Excellent Middle-Aged and Young Scientists of Shandong Province(No.2008BS09024)the Science and Technology Development Project of Binzhou City(No. 200818)the Science and Technology Development Project of Shandong Province(No.2009GG10006012)
文摘The Yellow River Delta(YRD) is a typical agricultural and petrochemical industrial area of China.To assess the current status of soil dichlorodiphenyltrichloroethane(DDT) and polychlorinated biphenyls(PCB) residues,topsoil samples(0-15 cm)(n = 82) were collected in Bincheng District,at the geographic center of the YRD.The total concentrations of six DDT homologues were within 3.3-3819 μg/kg,with a mean concentration of 191 μg/kg,showing significant increase along urban-rural gradient.Soil concentrations of seven indicator PCBs in the area ranged from non-detectable to 87.0 μg/kg,dominated by heavily chlorinated PCBs(PCB-101 and-118).Soil PCBs concentrations were significantly greater in urban than suburban and rural areas.Principal component and multiple linear regression analysis suggest that 86.4% of soil DDTs originate from past DDT usage,and 13.6% originate from dicofol application.Soil PCBs most likely originate from the petrochemical industry(77.1%),municipal solid waste disposal(16.5%),local commercial PCB homologues usage(5.2%),and long-range atmospheric deposition(1.2%).In general,soil DDTs pollution was classified as low level,and mean PCBs concentrations were below the severe contamination classification range.Because PCB-118 is a dioxin-like congener,monitoring and remediation is advised to assess and reduce negative environmental and human health effects from soil DDTs and dioxin-like congeners in the study area.
基金The research has been funded by the National Key Research&Development Program of China(2017YFC0505904)National Natural Science Foundation of China(51808040)Taishan Scholars Program of Shandong Province.
文摘Chromium is a common harmful pollutant with high toxicity and low bearing capacity of soil and water.Excellent salinity resistance,a wide pH range,and high regeneration capacity were essential for qualified adsorbents used in removing hexavalent chromium(Cr(VI))from polluted water.Herein,iron oxalate modified weak basic resin(IO@D301)for the removal of Cr(VI)was prepared by the impregnation method.The IO@D301 was characterized by scanning electron microscope(SEM),Fourier transform infrared spectroscopy(FTIR),X-Ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).Owing to abundant amine,carboxyl groups and iron ions existing on the surface,IO@D301 possesses high adsorption and salinity resistance capacity for Cr(VI).The maximum adsorption capacity of IO301 towards Cr(VI)reached 201.30 mg·g^(-1) at 293 K and a pH of 5.The adsorption equilibrium was well fitted by the Freundlich model,and the adsorption process was described by the pseudofirst-order kinetics model as spontaneous and exothermic.The mechanism may be identified as electrostatic attraction,coordination,and reduction,which was confirmed by FT-IR and X-ray photoelectron spectroscopy.
基金supported financially by the National Natural Science Foundation of China (No.31770761)the Forestry Science and Technology Innovation Project of Shandong province (2019LY006)+1 种基金the Natural Science Foundation of Shandong province (No.ZR2017LEE023)the Taishan Scholars Program of Shandong province,P.R.China(No.TSQN201909152)。
文摘vegetation restoration is a main ecological remediation technology for greening saline and alkaline soils.The objectives of this study were to determine the effect of1-aminobenzotriazole(ABT-1) on the growth and physiology of Tamarix chinensis under salt stress and to determine a suitable ABT-1 concentration and soil salinity(Sc) for propagating T.chihehsis-cuttings.Cuttings were soaked in water and ABT-1 solutions at three concentrations(50,100,and 200 mg L^(-1)) and propagated in pots containing four soil salinity levels,mild(0.3%),moderate(0.6%),and severe(0.9% and 1.2%),and compared with a control.The cuttings were measured to determine growth indices and physiological and biochemical indices(e.g.,chlorophyll content,superoxide dismutase activity,peroxidase activity,and malondialdehyde content).ABT-1 was effective in improving survival,growth,and physiological processes of cuttings under salt stress.However,there was a threshold effect when using ABT-1 to facilitate propagation under salt stress.ABT-1 effects were insignificant when applied at low concentrations(<100 mg L^(-1)).At a high concentration(> 100 mg L^(-1)),ABT-1 limited growth and physiological activities.Under a salt stress level(Sc ≤0.9%),ABT applied at a 100 mg L^(-1)concentration increased chlorophyll content and superoxide dismutase and peroxidase activities in the leaves and reduced malondialdehyde accumulation and membrane lipid peroxidation effects.As a result,ABT-1 enhanced the resistance of T.chinensis to salt stress.However,under high salt stress(>0.9%) and ABT-1 concentration(> 100 mg L^(-1)),the physiological regulatory ability of T.chinensis seedlings weakened.T.chinensis grew well at a salt stress ≤0.9% and ABT ≤100 mg L^(-1) and exhibited relatively high physiological regulatory ability and high salt adaptability.
基金Supported by Shandong Provincial Natural Science Foundation(ZR2016BL16&ZR2016CL01)Doctor Foundation of Binzhou University(2016Y17&2016Y02)+2 种基金Project of Shandong Province Higher Educational Science and Technology Program(J17KA120)Research Project of the University-level Teaching Reform of Binzhou University in 2017(BYJYYB201736)Schoolenterprise Co-construction Course Project of Binzhou University in 2017(BYXQGJ201706)
文摘The fungus Shiraia bambusicola GZ19 M1 is biotechnologically important due to its ability to biosynthesis the pigment hypocrellins.Results showed that ethyl methane sulfonate( EMS) was effective mutagenic agent for strain and potentially produced large numbers of random mutations broadly and uniformly over the whole genome to generate unique strains. Wild-type cultures of S. bambusicola GZ19 were subjected to EMS( 80 mM) induction targeted at approximately 20% spores' survival. When surviving spores were selected in sufficient numbers and cultured on PDA medium for 7 d at 26℃,five novel mutagenized S. bambusicola strains were obtained. A mutant GZ19 M1 that exhibited an activity of more than two times over the wild strain was obtained. Also,batch experiments were carried out to achieve the suitable conditions for hypocrellin. Glucose and rice extract were the most favorable carbon and nitrogen sources for hypocrellin production by submerged culture of S. bambusicola GZ19 M1,and initial glucose and rice extract concentrations were at 35 and 250 g/L,respectively. The optimal surfactant were found to be 0. 008 V/V Tween 80,it was added into cultivation medium at 24 h. Hypocrellin concentration reached 498. 89 mg/L under optimal nutritional conditions,an increment of about 8. 70 times of hypocrellins production was observed compared with that of in non-optimized medium by the wild strain.
基金the Key Program of the National Natural Science Foundation of China(42230516)National Natural Science Foundation of China(42271129,42101071,42171107)+2 种基金Natural Science Foundation of Jilin Province(YDZJ202201ZYTS480)Jilin Province Education Department Science and Technology Research Project(JJKH20210289KJ)International Wetlands Research League,Alliance of International Science Organizations(ANSO-PA-2020-14).
文摘Dissimilatory iron reduction(DIR)coupled with carbon cycling is increasingly being recognized as an influential process in freshwater wetland soils and sediments.The role of DIR in organic matter(OM)mineralization,however,is still largely unknown in lake sediment environments.In this study,we clarified rates and pathways of OM mineralization in two shallow lakes with seasonal hydrological connectivity and different eutrophic situations.We found that in comparison with the domination of DIR(55%)for OM mineralization in Lake Xiaoxingkai,the contribution of methanogenesis was much higher(68%)in its connected lake(Lake Xingkai).The differences in rates and pathways of sediment OM mineralization between the two lakes were attributed to higher concentrations of carbonate associated iron oxides(Fecarb)in Lake Xiaoxingkai compared to Lake Xingkai(P=0.002),due to better deposition mixing,more contributions of terrigenous detrital materials,and higher OM content in Lake Xiaoxingkai.Results of structural equation modeling showed that Fecarb and total iron content(TFe)regulated 25%of DIR in Lake Xiaoxingkai and 76%in Lake Xingkai,accompanied by a negative effect of TFe on methanogenesis in Lake Xingkai.The relative abundance and diversity of Fe-reducing bacteria were significantly different between the two lakes,and showed a weak effect on sediment OM mineralization.Our findings emphasize the role of iron minerals and geochemical characterizations in regulating rates and pathways of OM mineralization,and deepen the understanding of carbon cycling in lake sediments.
基金supported by the National Natural Science Foundation of China(Nos.32001134,41671297,and 32101387)the Shandong Provincial Natural Science Foundation of China(Nos.ZR2020QC040 and ZR2020QD004)the CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation,Yantai Institute of Coastal Zone Research,Chinese Academy of Sciences(No.2019KJD010).
文摘Increasing human demands for Earth’s resources are hastening many environmental changes and creating a need to incorporate the routine monitoring of ecosystem functions into forest management.Under global change and anthropogenic disturbances,soil carbon(C)cycling in terrestrial ecosystems is undergoing substantial changes that result in the transformation between soil C sources and sinks.Therefore,the forest C budget requires an understanding of the underlying soil C dynamic under environmental disturbances.The present review focuses on the response and feedback of soil C cycling to global change(climate warming and nitrogen(N)deposition)and human disturbances(fire and logging)and detects the association of soil C cycling with soil C and N efflux and inflow in boreal forests.The effects of climate warming and N deposition on soil C cycling are complex,especially at short-term temporal scales.Climate warming can decay soil organic matter(SOM)to emit substantial amounts of CO2,and differing warming durations result in different effects on soil C loss,ranging from ca.1 to 15 Mg C ha−1.Short-term soil warming mainly reduces the labile soil C pool and increases the decomposition of recalcitrant soil C compounds(e.g.,lignin),whereas longer-term warming may limit soil C loss due to impoverished soil C substrate and microbial communities.Moderate N addition is conducive to enhancing soil C storage(ca.2–22 Mg C ha−1),by increasing plant productivity including above-and belowground biomass;however,chronic N deposition or excess N addition can result in soil acidity,reducing N use efficiency and plant growth and further resulting in no changes or declines in soil C pool.Fire and logging lead to a large quantity of soil C loss via impaired plant productivity and increased organic matter degradation,exacerbating global warming.In particular,severe fire can cause a large amount of soil C loss,ca.16–34 Mg C ha−1 in the data we reviewed.Meanwhile,the black C input induced by fire and the plant residual C input from the roots of logged trees can increase the proportion of recalcitrant soil C and enhance the stability of soil C pool.We also highlight the positive feedback of forest restoration to soil C storage after fire and logging disturbances,indicating that effective forest restoration projects(e.g.,afforestation and natural forest recovery)are necessary to sequester soil C belowground.Additionally,combined with microbial technologies and metagenomics-and metabolomics-based approaches,soil microorganisms are proved crucial for driving soil C cycling via C capture and the N recycling of plants and soil.We,therefore,suggest that clarifying the relationship among plant,SOM,and microorganisms is essential to better evaluate soil C cycling and to predict how boreal forests respond to global change and human disturbances.Further work is needed to assess long-term soil C feedback from high-latitude forests to broader regions.
基金supported by the Natural Science Foundation of China(grant numbers:42030411,42206237,41725002,41671463,41601530,and 41730646)supported by grants from China Postdoctoral Science Foundation(2021M691020).
文摘Salt marsh plants play a vital role in mediating nitrogen(N)biogeochemical cycle in estuarine and coastal ecosystems.However,the effects of invasive Spartina alterniflora on N fixation and removal,as well as how these two processes balance to determine the N budget,remain unclear.Here,simultaneous quantifications of N fixation and removal via^(15)N tracing experiment with native Phragmites australis,invasive S.alterniflora,and bare flats as well as corresponding functional gene abundance by qPCR were carried out to explore the response of N dynamics to S.alterniflora invasion.Our results showed that N fixation and removal rates ranged from 0.77±0.08 to 16.12±1.13 nmol/(g·h)and from 1.42±0.14 to 16.35±1.10 nmol/(g·h),respectively,and invasive S.alterniflora generally facilitated the two processes rates.Based on the difference between N removal and fixation rates,net N_(2)fluxes were estimated in the range of-0.39±0.14 to 8.24±2.23 nmol/(g·h).Estimated net N_(2)fluxes in S.alterniflora stands were lower than those in bare flats and P.australis stands,indicating that the increase in N removal caused by S.alterniflora invasion may be more than offset by N fixation process.Random forest analysis revealed that functional microorganisms were the most important factor associated with the corresponding N transformation process.Overall,our results highlight the importance of N fixation in evaluating N budget of estuarine and coastal wetlands,providing valuable insights into the ecological effect of S.alterniflora invasion.
基金This work was supported by the National Natural Science Foundation of China(41971119,41871089)the Natural Science Foundation of Shandong Province(ZR2020QD004,ZR2019MD-024)the Youth Innovation and Technology Foundation of Shandong Higher Education Institutions(2019KJD010).
文摘Soil inorganic carbon(SIC),including mainly carbonate,is a key component of terrestrial soil C pool.Autotrophic microorganisms can assimilate carbonate as the main or unique C source,how microorganisms convert SIC to soil organic carbon(SOC)remains unclear.A systematic field survey(n=94)was performed to evaluate the shift in soil C components(i.e.,SIC,SOC,and microbial residues)along a natural salinity gradient(ranging from 0.5‰to 19‰),and further to explore how microbial necromass as an indicator converting SIC into SOC in the Yellow River delta.We observed that SIC levels linearly decreased with increasing salinity,ranging from~12 g kg^(-1)(salinity<6‰)to~10 g kg^(-1)(salinity>6‰).Additionally,the concentrations of SOC and microbial residues exponentially decreased from salinity<6‰ to salinity>6‰,with the decline of 39%and 70%,respectively.Microbial residues and SOC was tightly related to the variations in SIC.The structural equation model showed the causality on explanation of SOC variations with SIC through microbial residues,which can contribute 89% of the variance in SOC storage combined with SIC.Taken together,these two statistical analyses can support that microbial residues can serve as an indicator of SIC transition to SOC.This study highlights the regulation of microbial residues in SIC cycling,enhancing the role of SIC playing in C biogeochemical cycles and enriching organic C reservoirs in coastal saline soils.
基金This research was supported by the Joint Funds of the National Natural Science Foundation of China(U2006215)the Natural Science Foundation of Shandong Province(ZR2019PDO08,ZR2020MDOO7)+1 种基金the National Nature Science Foundation of China(41971126)Taishan Scholars Program of Shandong Province,China(TSQN201909152).
