The desert plant Hedysarum scoparium uses leaflets and rachises as its photosynthetic organs. The abundance of leaflets was lower under unfavorable environmental conditions and higher with improved water conditions. T...The desert plant Hedysarum scoparium uses leaflets and rachises as its photosynthetic organs. The abundance of leaflets was lower under unfavorable environmental conditions and higher with improved water conditions. To examine the characteristics associated with the adaptation of H. scoparium to its environment, we selected plants with both compound leaves and rachis without leaflets to study the anatomical structures and gas exchange characteristics of the two organs. The results show that the water storage tissues in rachises were more developed compared with the leaflets. The diurnal courses of the net photosynthetic rate for the rachis and the leaflet were both in a bimodal pattern. Meanwhile, both two peak values of the rachis were significantly higher than those of the leaflet. The daily average transpiration rate was significantly higher in the rachis than in the leaflet in order to lower the temperature of the rachises. It was concluded that under desert drought conditions, the leaflets of H. scoparium were partially or completely degraded to reduce the transpiration area as an adaptive response to water deficit, and only the rachises were retained as photosynthetic organ. The rachises were found to be better suited to a desert habitat than the leaflets.展开更多
Accumulation of vegetation biomass is a crucial process for carbon fixation in the early stage of afforestation and a primary driving force for subsequent ecological functions.Accurately assessing the storage and allo...Accumulation of vegetation biomass is a crucial process for carbon fixation in the early stage of afforestation and a primary driving force for subsequent ecological functions.Accurately assessing the storage and allocation of elements in plantations is essential for their management and estimating carbon sink capacity.However,current knowledge of the storage and allocation patterns of elements within plant organs at the community level is limited.To clarify the distribution patterns of elements in plant organs at the community level,we measured the biomass within plant organs of five typical plantations in the early stage of afforestation in the loess hilly-gully region.We assessed the main drivers of element accumulation and distribution by employing redundancy analysis and random forest.Results revealed significant differences in biomass storages among plantations and a significant effect of plantation type on the storages of elements within plant organs.Furthermore,the dominant factors influencing C–N–P storage and allocation at the community level were found to be inconsistent.While the storage of elements was mainly influenced by stand openness,total soil nitrogen,and plant diversity,the allocation of elements in organs was mainly influenced by stand openness and soil water content.Overall,the spatial structure of the community had an important influence on both element storage and allocation,but soil conditions played a more important role in element allocation than in storage.Random forest results showed that at the community level,factors influencing element storage and allocation within plant organs often differed.The regulation of elemental storage could be regulated by the major growth demand resources,while the allocation was regulated by other limiting class factors,which often differed from those that had a significant effect on element storage.The differences in plant organ elemental storage and allocation drivers at the community level reflect community adaptation strategies and the regulation of resources by ecosystems in combination with plants.Our study provides valuable insights for enhancing plantation C sink estimates and serves as a reference for regulating element storage and allocation at the local scale.展开更多
[Objective] In this study,the secretion of organic acids from plant roots under soil nutrient and water stress and the effects of organic acids on ecological adaptability of plants were investigated,which provided the...[Objective] In this study,the secretion of organic acids from plant roots under soil nutrient and water stress and the effects of organic acids on ecological adaptability of plants were investigated,which provided theoretical basis for improving the adaptability of plants to a variety of stress conditions.The results showed that,under nutrient and water stress,the content of organic acids secreted from plant roots increased significantly as a common active adaptive response.Organic acids could improve the activities of a variety of antioxidant enzymes,contents of osmotic regulatory substances,contents of chlorophyll and photosynthesis levels,promote nutrient absorption and transportation in plants,and ultimately contribute to plant growth and biomass accumulation,reduce the toxicity of stress conditions to plants and improve the stress resistance and adaptability of plants.展开更多
Heracleum dissectum Ledeb.(HD)with high edible and medicinal values is distributed in Northeast Asia.To provide a reference for selecting appropriate parts and periods to harvest HD,the nutrient contents in different ...Heracleum dissectum Ledeb.(HD)with high edible and medicinal values is distributed in Northeast Asia.To provide a reference for selecting appropriate parts and periods to harvest HD,the nutrient contents in different parts of HD at three growth stages were determined.The nutrients being determined are essential nutrients closely related to human needs,and the crude protein content of HD was 3.58‒28.43 g•100 g^(-1)DW(dry weight),sugar content was 2.33‒30.92 g•100 g^(-1)DW,and soluble dietary fiber content was 9.71‒26.09 g•100 g^(-1)DW.Crude protein was mainly distributed in leaf blades and inflorescences,sugar was primarily found in roots,and dietary fiber was predominantly located in leaves.From the leaf development stage to the flowering stage and then to the late seed harvest stage,the content of moisture,crude protein and soluble sugar first decreased and then increased.In contrast,the content of dietary fiber and crude fat first increased and then decreased.展开更多
Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt...Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt marshes were selected to study the effects of Spartina alterniflora invasion on soil organic carbon(SOC) contents and stocks in the Yellow River Delta. Results showed that the SOC contents(g/kg) and stocks(kg/m^2) were significantly increased(P < 0.05) after Spartina alterniflora invasion of seven years, especially for the surface soil layer(0–20 cm). The SOC contents exhibited an even distribution along the soil profiles in native salt marshes, while the SOC contents were gradually decreased with depth after Spartina alterniflora invasion of seven years. The natural ln response ratios(Ln RR) were applied to identify the effects of short-term Spartina alterniflora invasion on the SOC stocks. We also found that Spartina alterniflora invasion might cause soil organic carbon losses in a short-term phase(2–4 years in this study) due to the negative Ln RR values, especially for 20–60 cm depth. And the SOCD in surface layer(0–20 cm) do not increase linearly with the invasive age. Spearman correlation analysis revealed that silt + clay content was exponentially related with SOC in surface layer(Adjusted R^2 = 0.43, P < 0.001), suggesting that soil texture could play a key role in SOC sequestration of coastal salt marshes.展开更多
We studied the uptake of ammonium, nitrate, and a variety of amino acids by alpine plant species in the Kobresia humil alpine meadow ecosystem in situ. We examined the extent of niche separation in uptake of N source ...We studied the uptake of ammonium, nitrate, and a variety of amino acids by alpine plant species in the Kobresia humil alpine meadow ecosystem in situ. We examined the extent of niche separation in uptake of N source by different plant species in alpine communities, and investigated the contribution of symbiotically fixed N to the total N in alpine meadow. The results are （1） δ15N natural abundance values of 13 plant species lie between -2.680‰ and 5.169‰, and the scope is 7.849‰. （2） Le- guminous plants, such as Trigonella ruthenica, Gueldenstaedtia diversiffolia, and Oxytyopis ochrocephala, and non-legumi- nous plant Gentiana straminea uptake low amounts of 15N labeled ammonium, nitrate, glycine or aspartate in soil. （3） As far as the plant uptake of organic N is concerned, Kobresia humilis, Poa pratensis, and Gentiuna spathutifolta can effectively uptake organic nitrogen, and about 37%-40% of the nitrogen of these species comes from soil organic nitrogen sources （such as glycine and aspartate）. Stipa aliena can effectively uptake nitrate, and 60% of its nitrogen comes from soil nitrate. Potentilla anserina, Poa pratensis, and Thalictrum alpinum can effectively absorb ammonium in comparason to other plant species in the meadow, and about 25%-27% of the nitrogen in these plants comes from soil ammonium. （4） The contribution of leguminous fixed N to total N is 7.48%-9.26% in Kobresia humilis alpine meadow. （5） These data show many plant species of alpine meadow may effectively utilize dissolved organic nitrogen such as amino acids, and these plants have diverse ways to uptake soil nitrogen in alpine meadows. Based on the results we can partly explain why there are abundant biodiversities and how plants at alpine habitat utilize the limited soil N sources.展开更多
Organic matter-induced black blooms （hypoxia and an offensive odor） are a serious ecosystem disasters that have occurred in some large eutrophic shallow lakes in China. In this study, we investigated two separate bl...Organic matter-induced black blooms （hypoxia and an offensive odor） are a serious ecosystem disasters that have occurred in some large eutrophic shallow lakes in China. In this study, we investigated two separate black blooms that were induced by Potamogeton crispus in Lake Taihu, China. The main physical and chemical characteristics, including color- and odor-related substances, of the black blooms were analyzed. The black blooms were characterized by low dissolved oxygen concentration （close to 0 mg/L）, low oxidation-reduction potential, and relatively low pH of overlying water. Notably higher Fe^2＋ and ∑S2- were found in the black-bloom waters than in waters not affected by black blooms. The black color of the water may be attributable to the high concentration of these elements, as black FeS was considered to be the main substance causing the black color of blooms in freshwater lakes. Volatile organic sulfur compounds, including dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, were very abundant in the black-bloom waters. The massive anoxic degradation of dead Potamogeton crispus plants released dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, which were the main odor-causing compounds in the black blooms. The black blooms also induced an increase in ammonium nitrogen and soluble reactive phosphorus levels in the overlying waters. This extreme phenomenon not only heavily influenced the original lake ecosystem but also greatly changed the cycling of Fe, S, and nutrients in the water column.展开更多
Organic planting bag has been developed to overcome both weaknesses of plastic polybags,contaminating the soil and damaging the plant’s root when transplanting.The improvement in this stage was achieved by inserting ...Organic planting bag has been developed to overcome both weaknesses of plastic polybags,contaminating the soil and damaging the plant’s root when transplanting.The improvement in this stage was achieved by inserting coconut fiber to strengthen a bag.The main purpose of this study was to investigate the effectiveness of seedling and transplanting by using organic planting bags,employed,three woody plants,i.e.,Albizia(Albizia julibrissin),Cadam(Neolamarckia cadamba)and Gmelina(Gmelina arborea).Performance testing of organic plant bags was conducted on three compositions of coconut fiber and water hyacinth.Two stages of experiments were conducted to know bag performance.First,the testing of organic plant bags during the nursery was conducted for 50 d from day 0 to day 50.Second,the testing of organic plant bags after transplanting and observed on days 60,70,and 80,after transplanted on the field.The parameters in this study were plant height,a total of roots that penetrate the organic plant bags and a total of leaves and stem diameters of plant grown in the organic bag and transplanting on land.The results showed that organic planting bag with the composition 155 g of coconut fiber and 505 g of water hyacinth(A3B3)has 0.020 kg/cm^(2) compressive strength and provides the best plant growth rates.Compressive strength affects the number of roots which penetrate the organic bag.Generally,the growth of seed in organic bags is faster than that in polybags.Albizia shows a higher growth rate(0.379 cm/d)compared to Cadam and Gmelina.展开更多
Aims Carbon(C)and nitrogen(N)stoichiometry contributes to under-standing elemental compositions and coupled biogeochemical cycles in ecosystems.However,we know little about the temporal patterns of C:N stoichiometry d...Aims Carbon(C)and nitrogen(N)stoichiometry contributes to under-standing elemental compositions and coupled biogeochemical cycles in ecosystems.However,we know little about the temporal patterns of C:N stoichiometry during forest development.The goal of this study is to explore the temporal patterns of intraspecific and ecosystem components’variations in C:N stoichiometry and the scaling relationships between C and N at different successional stages.Methods Along forest development in a natural temperate forest,northeastern China,four age gradients were categorized into ca.10-,30-,70-and 200-year old,respectively,and three 20 m×20 m plots were set up for each age class.Leaves,branches,fine roots and fresh litter of seven dominant species as well as mineral soil at depth of 0-10 cm were sampled.A Universal CHN Elemental Analyzer was used to determine the C and N concentrations in all samples.Important Findings Intraspecific leaf C,N and C:N ratios remained stable along forest development regardless of tree species;while C,N concentrations and C:N ratios changed significantly either in branches or in fine roots,and they varied with tree species except Populus davidiana(P<0.05).For ecosystem components,we discovered that leaf C:N ratios remained stable when stand age was below ca.70 years and dominant tree species were light-demanding pioneers such as Betula platyphylla and Populus davidiana,while increased signifi-cantly at the age of ca.200 years with Pinus koraiensis as the dom-inant species.C:N ratios in branches and fresh litter did not changed significantly along forest development stages.C concentrations scaled isometrically with respect to N concentrations in mineral soil but not in other ecosystem components.Our results indicate that,leaf has a higher intraspecific C:N stoichiometric stability compared to branch and fine root,whereas for ecosystem components,shifts in species composition mainly affect C:N ratios in leaves rather than other components.This study also demonstrated that C and N remain coupled in mineral soils but not in plant organs or fresh litter during forest development.展开更多
Nitrogen use efficiency （NUE） was very low in China and a loss of as much as 7070 of the applied nitrogen fertilizers was reported in high-yielding rice fields. In order to investigate the molecular basis of high-af...Nitrogen use efficiency （NUE） was very low in China and a loss of as much as 7070 of the applied nitrogen fertilizers was reported in high-yielding rice fields. In order to investigate the molecular basis of high-affinity ammonium transport or uptake into rice （Oryza sativa L.）, we analyzed the expression profiles of nine ammonium transporters （AMT）, three each of OsAMT1, OsAMT2 and OsAMT3, at two different N requirement stages （young seedling stage and tillering stage） of rice growth as well as the changes in these expression patterns according to external N status using real-time reverse transcription polymerase chain reaction （RT-PCR）. The results suggested that the nine OsAMT genes were expressed in different organs of rice plants, including mature roots, new roots, stems, old leaves and new leaves and that the expression patterns were organ specific and independent of the positions of the corresponding proteins in the phylogenetic tree. OsAMT1;1, 3;2 and 3;3 were expressed in the roots and shoots, primarily old leaves, OsAMT1;2 and 1;3 mainly in the roots, and OsAMT2;1, 2;2, 2;3 and 3;1 mainly in the shoots, primarily in new leaves, and relatively more in the stems than other genes. The expression patterns at the two different N requirement stages were the same; however, at the tillering stage with greater N requirements, the OsAMTs transcript levels were greater than those at the young seedling stage with low N requirements. N starvation for 48 h up-regulated OsAMT1;1, 1;2, 3;1, 3;2, 3;3 and down-regulated OsAMT1;3 mRNA abundance. Following N starvation, NH4＋ and NH4NO3 re-supply down-regulated OsAMT1;2 and 3;3 and up-regulated OsAMT1;3, whereas NO3 re-supply down-regulated OsAMT1;1 and 1;2. These suggested that the organ-specific expression pattern of OsAMT could be regulated by N requirement and external N status.展开更多
Olive fly（Bactrocera oleae R.） is the most harmful insect pest of olive（Olea europaea L.） which strongly affects fruits and oil production. Despite the expanding economic importance of olive cultivation, up to now...Olive fly（Bactrocera oleae R.） is the most harmful insect pest of olive（Olea europaea L.） which strongly affects fruits and oil production. Despite the expanding economic importance of olive cultivation, up to now, only limited information on plant responses to B. oleae is available. Here,we demonstrate that olive fruits respond to B. oleae attack by producing changes in an array of different defensive compounds including phytohormones, volatile organic compounds（VOCs）, and defense proteins. Bactrocera oleaeinfested fruits induced a strong ethylene burst and transcript levels of several putative ethylene-responsive transcription factors became significantly upregulated. Moreover, infested fruits induced significant changes in the levels of 12-oxophytodienoic acid and C12 derivatives of the hydroperoxide lyase. The emission of VOCs was also changed quantitatively and qualitatively in insect-damaged fruits, indicating that B.oleae larval feeding can specifically affect the volatile blend offruits. Finally, we show that larval infestation maintained high levels of trypsin protease inhibitors in ripe fruits, probably by affecting post-transcriptional mechanisms. Our results provide novel and important information to understand the response of the olive fruit to B. oleae attack; information that can shed light onto potential new strategies to combat this pest.展开更多
基金supported by the National Natu-ral Sciences Foundation of China (40771005 30870382)+1 种基金the CAS (Chinese Academy of Sciences) Action Plan for West Development Project (KZCX2-XB2-04-01KZCX2-XB2-09-03)
文摘The desert plant Hedysarum scoparium uses leaflets and rachises as its photosynthetic organs. The abundance of leaflets was lower under unfavorable environmental conditions and higher with improved water conditions. To examine the characteristics associated with the adaptation of H. scoparium to its environment, we selected plants with both compound leaves and rachis without leaflets to study the anatomical structures and gas exchange characteristics of the two organs. The results show that the water storage tissues in rachises were more developed compared with the leaflets. The diurnal courses of the net photosynthetic rate for the rachis and the leaflet were both in a bimodal pattern. Meanwhile, both two peak values of the rachis were significantly higher than those of the leaflet. The daily average transpiration rate was significantly higher in the rachis than in the leaflet in order to lower the temperature of the rachises. It was concluded that under desert drought conditions, the leaflets of H. scoparium were partially or completely degraded to reduce the transpiration area as an adaptive response to water deficit, and only the rachises were retained as photosynthetic organ. The rachises were found to be better suited to a desert habitat than the leaflets.
基金This work was supported by the National Key Research and Development Program of China(No.2019YFA0607304).
文摘Accumulation of vegetation biomass is a crucial process for carbon fixation in the early stage of afforestation and a primary driving force for subsequent ecological functions.Accurately assessing the storage and allocation of elements in plantations is essential for their management and estimating carbon sink capacity.However,current knowledge of the storage and allocation patterns of elements within plant organs at the community level is limited.To clarify the distribution patterns of elements in plant organs at the community level,we measured the biomass within plant organs of five typical plantations in the early stage of afforestation in the loess hilly-gully region.We assessed the main drivers of element accumulation and distribution by employing redundancy analysis and random forest.Results revealed significant differences in biomass storages among plantations and a significant effect of plantation type on the storages of elements within plant organs.Furthermore,the dominant factors influencing C–N–P storage and allocation at the community level were found to be inconsistent.While the storage of elements was mainly influenced by stand openness,total soil nitrogen,and plant diversity,the allocation of elements in organs was mainly influenced by stand openness and soil water content.Overall,the spatial structure of the community had an important influence on both element storage and allocation,but soil conditions played a more important role in element allocation than in storage.Random forest results showed that at the community level,factors influencing element storage and allocation within plant organs often differed.The regulation of elemental storage could be regulated by the major growth demand resources,while the allocation was regulated by other limiting class factors,which often differed from those that had a significant effect on element storage.The differences in plant organ elemental storage and allocation drivers at the community level reflect community adaptation strategies and the regulation of resources by ecosystems in combination with plants.Our study provides valuable insights for enhancing plantation C sink estimates and serves as a reference for regulating element storage and allocation at the local scale.
基金Supported by National Natural Science Foundation of China(31370613)Major State Basic Research Development Program of China(973 Program)(2011CB403202)Fundamental Research Funds for the Central Universities(DL12CA01)~~
文摘[Objective] In this study,the secretion of organic acids from plant roots under soil nutrient and water stress and the effects of organic acids on ecological adaptability of plants were investigated,which provided theoretical basis for improving the adaptability of plants to a variety of stress conditions.The results showed that,under nutrient and water stress,the content of organic acids secreted from plant roots increased significantly as a common active adaptive response.Organic acids could improve the activities of a variety of antioxidant enzymes,contents of osmotic regulatory substances,contents of chlorophyll and photosynthesis levels,promote nutrient absorption and transportation in plants,and ultimately contribute to plant growth and biomass accumulation,reduce the toxicity of stress conditions to plants and improve the stress resistance and adaptability of plants.
基金Supported by the Heilongjiang Provincial Natural Science Foundation of China(YQ2020C028)the Science and Technology Basic Resources Investigation Program of China(2019FY100503)+2 种基金the Science and Technology Development Project of Jilin Province(YDZJ202402007CXJD)the Key Special Project of the"Science and Technology Revitalization of Mongolia"Action(2022EEDSKJXM001)Shen-nong Talent Plan of the Ministry of Agriculture and Rural Affairs(SNYCQN138-2022)。
文摘Heracleum dissectum Ledeb.(HD)with high edible and medicinal values is distributed in Northeast Asia.To provide a reference for selecting appropriate parts and periods to harvest HD,the nutrient contents in different parts of HD at three growth stages were determined.The nutrients being determined are essential nutrients closely related to human needs,and the crude protein content of HD was 3.58‒28.43 g•100 g^(-1)DW(dry weight),sugar content was 2.33‒30.92 g•100 g^(-1)DW,and soluble dietary fiber content was 9.71‒26.09 g•100 g^(-1)DW.Crude protein was mainly distributed in leaf blades and inflorescences,sugar was primarily found in roots,and dietary fiber was predominantly located in leaves.From the leaf development stage to the flowering stage and then to the late seed harvest stage,the content of moisture,crude protein and soluble sugar first decreased and then increased.In contrast,the content of dietary fiber and crude fat first increased and then decreased.
基金Under the auspices of the National Key R&D Program of China(No.2017YFC0505906)the National Natural Science Foundation of China(No.51639001,51379012)the Interdiscipline Research Funds of Beijing Normal University
文摘Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt marshes were selected to study the effects of Spartina alterniflora invasion on soil organic carbon(SOC) contents and stocks in the Yellow River Delta. Results showed that the SOC contents(g/kg) and stocks(kg/m^2) were significantly increased(P < 0.05) after Spartina alterniflora invasion of seven years, especially for the surface soil layer(0–20 cm). The SOC contents exhibited an even distribution along the soil profiles in native salt marshes, while the SOC contents were gradually decreased with depth after Spartina alterniflora invasion of seven years. The natural ln response ratios(Ln RR) were applied to identify the effects of short-term Spartina alterniflora invasion on the SOC stocks. We also found that Spartina alterniflora invasion might cause soil organic carbon losses in a short-term phase(2–4 years in this study) due to the negative Ln RR values, especially for 20–60 cm depth. And the SOCD in surface layer(0–20 cm) do not increase linearly with the invasive age. Spearman correlation analysis revealed that silt + clay content was exponentially related with SOC in surface layer(Adjusted R^2 = 0.43, P < 0.001), suggesting that soil texture could play a key role in SOC sequestration of coastal salt marshes.
基金supported by National Natural Science Foundation of China(Grant Nos.30660120 and 41030105)National Basic Research Program of China (Grant No. 2009CB421102)International Cooperation Program of Science and Technology Department of Qinghai Province (Grant No. 2010-H-809)
文摘We studied the uptake of ammonium, nitrate, and a variety of amino acids by alpine plant species in the Kobresia humil alpine meadow ecosystem in situ. We examined the extent of niche separation in uptake of N source by different plant species in alpine communities, and investigated the contribution of symbiotically fixed N to the total N in alpine meadow. The results are （1） δ15N natural abundance values of 13 plant species lie between -2.680‰ and 5.169‰, and the scope is 7.849‰. （2） Le- guminous plants, such as Trigonella ruthenica, Gueldenstaedtia diversiffolia, and Oxytyopis ochrocephala, and non-legumi- nous plant Gentiana straminea uptake low amounts of 15N labeled ammonium, nitrate, glycine or aspartate in soil. （3） As far as the plant uptake of organic N is concerned, Kobresia humilis, Poa pratensis, and Gentiuna spathutifolta can effectively uptake organic nitrogen, and about 37%-40% of the nitrogen of these species comes from soil organic nitrogen sources （such as glycine and aspartate）. Stipa aliena can effectively uptake nitrate, and 60% of its nitrogen comes from soil nitrate. Potentilla anserina, Poa pratensis, and Thalictrum alpinum can effectively absorb ammonium in comparason to other plant species in the meadow, and about 25%-27% of the nitrogen in these plants comes from soil ammonium. （4） The contribution of leguminous fixed N to total N is 7.48%-9.26% in Kobresia humilis alpine meadow. （5） These data show many plant species of alpine meadow may effectively utilize dissolved organic nitrogen such as amino acids, and these plants have diverse ways to uptake soil nitrogen in alpine meadows. Based on the results we can partly explain why there are abundant biodiversities and how plants at alpine habitat utilize the limited soil N sources.
基金supported by the Major National Science and Technology Programs on Water Pollution Control and Treatment (No. 2012X0713-005)the Innovation Program of the Chinese Academy of Sciences (No. KZCX2-EW-314)+2 种基金the 135 Project of Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences (No. NIGLAS2012135008)the National Natural ScienceFoundation of China (No. 41103033)the IndustryUniversity-Research Prospective Joint Research Projects of Jiangsu Province (No. BY2011165)
文摘Organic matter-induced black blooms （hypoxia and an offensive odor） are a serious ecosystem disasters that have occurred in some large eutrophic shallow lakes in China. In this study, we investigated two separate black blooms that were induced by Potamogeton crispus in Lake Taihu, China. The main physical and chemical characteristics, including color- and odor-related substances, of the black blooms were analyzed. The black blooms were characterized by low dissolved oxygen concentration （close to 0 mg/L）, low oxidation-reduction potential, and relatively low pH of overlying water. Notably higher Fe^2＋ and ∑S2- were found in the black-bloom waters than in waters not affected by black blooms. The black color of the water may be attributable to the high concentration of these elements, as black FeS was considered to be the main substance causing the black color of blooms in freshwater lakes. Volatile organic sulfur compounds, including dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, were very abundant in the black-bloom waters. The massive anoxic degradation of dead Potamogeton crispus plants released dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, which were the main odor-causing compounds in the black blooms. The black blooms also induced an increase in ammonium nitrogen and soluble reactive phosphorus levels in the overlying waters. This extreme phenomenon not only heavily influenced the original lake ecosystem but also greatly changed the cycling of Fe, S, and nutrients in the water column.
基金The authors acknowledge that this work was supported by the Department of Agricultural Engineering,Brawijaya University for laboratory facilities as well as the International Scientific Publication Office of Brawijaya University for helpful comments to improve this paper.
文摘Organic planting bag has been developed to overcome both weaknesses of plastic polybags,contaminating the soil and damaging the plant’s root when transplanting.The improvement in this stage was achieved by inserting coconut fiber to strengthen a bag.The main purpose of this study was to investigate the effectiveness of seedling and transplanting by using organic planting bags,employed,three woody plants,i.e.,Albizia(Albizia julibrissin),Cadam(Neolamarckia cadamba)and Gmelina(Gmelina arborea).Performance testing of organic plant bags was conducted on three compositions of coconut fiber and water hyacinth.Two stages of experiments were conducted to know bag performance.First,the testing of organic plant bags during the nursery was conducted for 50 d from day 0 to day 50.Second,the testing of organic plant bags after transplanting and observed on days 60,70,and 80,after transplanted on the field.The parameters in this study were plant height,a total of roots that penetrate the organic plant bags and a total of leaves and stem diameters of plant grown in the organic bag and transplanting on land.The results showed that organic planting bag with the composition 155 g of coconut fiber and 505 g of water hyacinth(A3B3)has 0.020 kg/cm^(2) compressive strength and provides the best plant growth rates.Compressive strength affects the number of roots which penetrate the organic bag.Generally,the growth of seed in organic bags is faster than that in polybags.Albizia shows a higher growth rate(0.379 cm/d)compared to Cadam and Gmelina.
基金This work was supported by the National Natural Science Foundation of China(31290223)the Special Research Program for Public-welfare Forestry of China(201404201)+2 种基金the Ministry of Science and Technology(2015DFA31440,2012BAD22B01)the Lecture and Study Program for Outstanding Scholars from Home and Abroad(CAFYBB2011007)the State Key Laboratory of Forest and Soil Ecology(LFSE2014-01)and the CFERN&GENE Award Funds on Ecological Paper.
文摘Aims Carbon(C)and nitrogen(N)stoichiometry contributes to under-standing elemental compositions and coupled biogeochemical cycles in ecosystems.However,we know little about the temporal patterns of C:N stoichiometry during forest development.The goal of this study is to explore the temporal patterns of intraspecific and ecosystem components’variations in C:N stoichiometry and the scaling relationships between C and N at different successional stages.Methods Along forest development in a natural temperate forest,northeastern China,four age gradients were categorized into ca.10-,30-,70-and 200-year old,respectively,and three 20 m×20 m plots were set up for each age class.Leaves,branches,fine roots and fresh litter of seven dominant species as well as mineral soil at depth of 0-10 cm were sampled.A Universal CHN Elemental Analyzer was used to determine the C and N concentrations in all samples.Important Findings Intraspecific leaf C,N and C:N ratios remained stable along forest development regardless of tree species;while C,N concentrations and C:N ratios changed significantly either in branches or in fine roots,and they varied with tree species except Populus davidiana(P<0.05).For ecosystem components,we discovered that leaf C:N ratios remained stable when stand age was below ca.70 years and dominant tree species were light-demanding pioneers such as Betula platyphylla and Populus davidiana,while increased signifi-cantly at the age of ca.200 years with Pinus koraiensis as the dom-inant species.C:N ratios in branches and fresh litter did not changed significantly along forest development stages.C concentrations scaled isometrically with respect to N concentrations in mineral soil but not in other ecosystem components.Our results indicate that,leaf has a higher intraspecific C:N stoichiometric stability compared to branch and fine root,whereas for ecosystem components,shifts in species composition mainly affect C:N ratios in leaves rather than other components.This study also demonstrated that C and N remain coupled in mineral soils but not in plant organs or fresh litter during forest development.
基金Supported by the National Natural Science Foundation of China (No. 30800702)the National Basic Research Program of China (No. 2007CB109303)the National Key Technology R&D Program of China (No. 2012BAD15B03)
文摘Nitrogen use efficiency （NUE） was very low in China and a loss of as much as 7070 of the applied nitrogen fertilizers was reported in high-yielding rice fields. In order to investigate the molecular basis of high-affinity ammonium transport or uptake into rice （Oryza sativa L.）, we analyzed the expression profiles of nine ammonium transporters （AMT）, three each of OsAMT1, OsAMT2 and OsAMT3, at two different N requirement stages （young seedling stage and tillering stage） of rice growth as well as the changes in these expression patterns according to external N status using real-time reverse transcription polymerase chain reaction （RT-PCR）. The results suggested that the nine OsAMT genes were expressed in different organs of rice plants, including mature roots, new roots, stems, old leaves and new leaves and that the expression patterns were organ specific and independent of the positions of the corresponding proteins in the phylogenetic tree. OsAMT1;1, 3;2 and 3;3 were expressed in the roots and shoots, primarily old leaves, OsAMT1;2 and 1;3 mainly in the roots, and OsAMT2;1, 2;2, 2;3 and 3;1 mainly in the shoots, primarily in new leaves, and relatively more in the stems than other genes. The expression patterns at the two different N requirement stages were the same; however, at the tillering stage with greater N requirements, the OsAMTs transcript levels were greater than those at the young seedling stage with low N requirements. N starvation for 48 h up-regulated OsAMT1;1, 1;2, 3;1, 3;2, 3;3 and down-regulated OsAMT1;3 mRNA abundance. Following N starvation, NH4＋ and NH4NO3 re-supply down-regulated OsAMT1;2 and 3;3 and up-regulated OsAMT1;3, whereas NO3 re-supply down-regulated OsAMT1;1 and 1;2. These suggested that the organ-specific expression pattern of OsAMT could be regulated by N requirement and external N status.
基金financially supported by the OLEA Project-Genomics and Breeding of Olivefunded by MIPAF,Italyby the Max Plank Society
文摘Olive fly（Bactrocera oleae R.） is the most harmful insect pest of olive（Olea europaea L.） which strongly affects fruits and oil production. Despite the expanding economic importance of olive cultivation, up to now, only limited information on plant responses to B. oleae is available. Here,we demonstrate that olive fruits respond to B. oleae attack by producing changes in an array of different defensive compounds including phytohormones, volatile organic compounds（VOCs）, and defense proteins. Bactrocera oleaeinfested fruits induced a strong ethylene burst and transcript levels of several putative ethylene-responsive transcription factors became significantly upregulated. Moreover, infested fruits induced significant changes in the levels of 12-oxophytodienoic acid and C12 derivatives of the hydroperoxide lyase. The emission of VOCs was also changed quantitatively and qualitatively in insect-damaged fruits, indicating that B.oleae larval feeding can specifically affect the volatile blend offruits. Finally, we show that larval infestation maintained high levels of trypsin protease inhibitors in ripe fruits, probably by affecting post-transcriptional mechanisms. Our results provide novel and important information to understand the response of the olive fruit to B. oleae attack; information that can shed light onto potential new strategies to combat this pest.
