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Water utilization of typical plant communities in desert steppe,China

Journal of Arid Land 2022年第9期14卷 1038-1054页

作者： CHEN Juan WANG Xing SONG Naiping WANG Qixue WU Xudong School of Agriculture Ningxia UniversityYinchuan 750021China Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in northwestern China Yinchuan 750021China Key Laboratory of Restoration and Reconstruction of Degraded Ecosystems in northwestern China of Ministry of Education Yinchuan 750021China School of Ecology and Environment Ningxia UniversityYinchuan 750021China Institute of Desertification Control Ningxia Academy of Agricultural and Forestry SciencesYinchuan 750002China

Water is a limiting factor in the restoration and construction of desert steppe.Exploring plant water sources is necessary to understand soil-plant interactions and species coexistence;however,water sources of major plant communities within the desert steppe of Ningxia Hui Autonomous Region,China remain poorly understood.In this study,we analyzed the water uptake of plants in four typical communities:Agropyron mongolicum Keng.;Sophora alopecuroids Linn.;Stipa breviflora Griseb.,and Achnatherum splendens(Trin.)Nevski communities.stable isotopesδD andδ^(18)O in the xylem of plant and soil water at different soil depths were analyzed.An IsoSource model was used to determine the soil depths from which plants obtained water.Results showed that A.mongolicum community obtained water predominantly from 0–20 and 40–80 cm depth,S.alopecuroids community from 0–20 cm depth,S.breviflora community from 0–40 cm depth,and A.splendens community from 0–20 and 80–140 cm depths.S.alopecuroides had a wider range of soil depths for water extraction,i.e.,utilizing different water sources depending on habitat,and the plasticity of its water uptake pattern determined its role in different communities.Water source of plants relayed heavily on the distribution of their roots.Competition for soil water exists between different plant life forms in the sierozem habitat(A.mongolicum,S.alopecuroids,and S.breviflora communities),and in the sandy soil habitat(A.splendens community).The use of soil water by A.splendens community is more spatially differentiated,and shrubs and herbs can coexist stably.Under the pattern of extended drought period in the future,sierozem habitat may be more favorable for the formation of a dominant monoculture community type of perennial fibrous plants.In aeolian sandy soil habitat,A.splendens had a strong competitive advantage,and the growth of shallow-rooted plants was easily suppressed.

关键词： stable isotope water source IsoSource model soil water desert steppe

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Indiscriminate Dietary Compositions of Two Asian Horseshoe Crabs,Tachypleus tridentatus and Carcinoscorpius rotundicauda:Evidence from Hemolymph stable isotopes

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Journal of Ocean University of China 2022年第3期21卷 583-590页

作者： LI Yuhong FENG Jianxiang KWAN Kit Yue TAN Yiran WENG Bosen JIA Ruiling Department of Environmental Science and Engineering Huaqiao UniversityXiamen361021China School of Marine Sciences Sun Yat-sen UniversityZhuhai519082China College of Marine Sciences Beibu Gulf UniversityQinzhou535011China

Knowledge of dietary compositions is essential to the recovery of the dwindling populations of horseshoe crabs in China.The feeding habits of Tachypleus tridentatus and Carcinoscorpis rotundicauda of Pearl Bay in southwestern China were studied by stable isotope analysis.Hemolymph samples of the two species were obtained from two age groups living in different habitats(inner,central,and outer Bay).In addition,their potential food source samples were collected in May 2019.Results showed that the mean values ofδ^(13)C andδ^(15)N in C.rotundicauda individuals ranged from−19.01‰to−16.47‰and from 10.49‰to 13.5‰,respectively,and those of T.tridentatus ranged from−19.12‰to−14.96‰and from 8.78‰to 13.48‰,respectively.These values indicated that the horseshoe crabs have a wide variety of food sources and therefore are highly omnivorous.No remarkably correlations were found betweenδ^(13)C andδ^(15)N values and individual widths in the two species.Thirteen potential food sources were selected,in which Sipunculus nudus,Batillaria zonalisi,and Ulva lactuca contributed largely to the dietary compositions of the two species of horseshoe crabs.No significant correlation was found between the feeding habits and habitat geochemical characteristics of the horseshoe crabs.All these results possibly indicate the high diversity of their food sources and the indiscriminate dietary compositions of the two Asian horseshoe crabs.

关键词： Tachypleus tridentatus Carcinoscorpius rotundicauda stable isotope hemolymph growth stage

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Water use characteristics of different pioneer shrubs at different ages in western Chinese Loess Plateau:Evidence from δ^(2)H offset correction

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Journal of Arid Land 2022年第6期14卷 653-672页

作者： ZHANG Yu ZHANG Mingjun QU Deye WANG Shengjie Athanassios A ARGIRIOU WANG Jiaxin YANG Ye College of Geography and Environmental Science Northwest Normal UniversityLanzhou 730070China Key Laboratory of Resource Environment and Sustainable Development of Oasis Gansu ProvinceNorthwest Normal UniversityLanzhou 730070China Laboratory of Atmospheric Physics Department of PhysicsUniversity of PatrasGR-26500 PatrasGreece

Caragana korshinskii Kom.and Tamarix ramosissima Ledeb.are pioneer shrubs for water and soil conservation,and for windbreak and sand fixation in arid and semi-arid areas.Understanding the water use characteristics of different pioneer shrubs at different ages is of great importance for their survival when extreme rainfall occurs.In recent years,the stable isotope tracing technique has been used in exploring the water use strategies of plants.However,the widespreadδ^(2)H offsets of stem water from its potential sources result in conflicting interpretations of water utilization of plants in arid and semi-arid areas.In this study,we used three sets of hydrogen and oxygen stable isotope data(δ^(2)H andδ^(18)O,correctedδ^(2)H_c1 based on SW-excess andδ^(18)O,and correctedδ^(2)H_c2 based on−8.1‰andδ^(18)O)as inputs for the MixSIAR model to explore the water use characteristics of C.korshinskii and T.ramosissima at different ages and in response to rainfall.The results showed thatδ^(2)H_c1 andδ^(18)O have the best performance,and the contribution rate of deep soil water was underestimated because ofδ^(2)H offset.During the dry periods,C.korshinskii and T.ramosissima at different ages both obtained mostly water from deeper soil layers.After rainfall,the proportions of surface(0-10 cm)and shallow(10-40 cm)soil water for C.korshinskii and T.ramosissima at different ages both increased.Nevertheless,there were different response mechanisms of these two plants for rainfall.In addition,C.korshinskii absorbed various potential water sources,while T.ramosissima only used deep water.These flexible water use characteristics of C.korshinskii and T.ramosissima might facilitate the coexistence of plants once extreme rainfall occurs.Thus,reasonable allocation of different plants may be a good vegetation restoration program in western Chinese Loess Plateau.

关键词： stable isotope Caragana korshinskii Tamarix ramosissima water uptake pattern isotope depletion

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stable isotopes and chloride ion of precipitation events in the northeastern Tibetan Plateau, China

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Journal of Mountain Science 2021年第4期18卷 834-846页

作者： CUI Bu-li LI Dong-sheng JIANG Bao-fu WANG Ying WANG Ya-xuan WANG Long-sheng LI Xiao-yan State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China School of Resources and Environmental Engineering Ludong UniversityYantai 264025China State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China

stable isotopes and chloride ion of precipitation are ideal environmental tracers to explain and reveal the formation and evolution mechanisms of water bodies. It is crucial to investigate the stable isotopes and chloride in precipitation events in the northeastern part of the Tibetan Plateau(NETP) due to the limitation of available data. This study sampled each event of precipitation during the period from July 2018 to June 2019 and the monthly dustfall in the NETP to investigate the temporal changes of stable isotopes and chloride in precipitation, and to reveal the moisture source of precipitation over the NETP using a back trajectory model. Results showed that the δ^(2)H values of precipitation ranged from-183.51‰ to 17.75‰, and the δ^(18)O values ranged from-25.18‰ to 0.48‰. The slope of the Local Meteoric Water Line was slightly lower than 8 due to the effect of belowcloud secondary evaporation on the precipitation process. Most d-excess values were higher than 10‰ because moisture recycled from the continent and Qinghai Lake surface mixed with precipitation. The chloride in precipitation accounted for 86.5% of the annual total deposition mass of chloride(1329.64 mg/m2), indicating that precipitation was the main source of chloride in the NETP. The temperature and amount effects of stable isotope in the precipitation were obvious in the NETP. The precipitation was predominantly derived from the Westerly Circulation from September through May and the East Asian Monsoon from June to August, with precipitation amounts of 246.5 mm and 178.0 mm, respectively, indicating that the precipitation over the NETP brought by the Westerly Circulation was more than that brought by the East Asian Monsoon. The air mass over the NETP transited in late May and early September, and a slight change in transition period would mainly be related to the intensity of the East Asian Monsoon, which is strongly influenced by El Ni?o-Southern Oscillation. These results provide not only baseline data for hydrological and climatological s

关键词： stable isotope Chloride ion Precipitation Moisture source Northeastern Tibetan Plateau

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A 60-year sedimentary record of natural and anthropogenic impacts on Lake Chenghai,China

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Journal of Environmental Sciences 2012年第4期24卷 602-609页

作者： Fengyu Zan Shouliang Huo Beidou Xi Jingtian Zhang Haiqing Liao Yue Wang Kevin M.Yeager School of Environment Beijing Normal UniversityBeijing 100875China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental ScienceBeijing 100012China College of Environmental Science and Engineering Anhui Normal UniversityWuhu 241000China Department of Marine Science University of Southern MississippiStennis Space CenterMS 39529USA

Recent sediments from Lake Chenghai, China, were investigated at high temporal resolution to trace both natural and anthropogenic effects on the lake using total organic carbon （TOC）, total nitrogen （TN）, total phosphorus （TP）, organic phosphorus （Po）, inorganic phosphorus （Pi） and organic carbon and nitrogen stable isotopes （~13Corg and 615N） in a 137Cs-dated sediment core. The results indicated that the sedimentary record covers the last 60 years, during which the lake had undergone apparent changes in nutrient sources and productivity in response to nutrient loading. Prior to the late 1980s, the nutrient contents in sediments mainly originated from algae and lake productivity was relatively stable. Since the late 1980s, increasing TOC, TN and TP concentrations together with the change of 613Corg and 615N suggested anthropogenic perturbations in nutrient loading and lake productivity. Endogenic nutrients derived from algae and anthropogenic inputs were two important sources of sedimentary nutrients. The anthropogenic nutrients mainly originated from the discharge of industrial wastewater and artificial cultivation of Spirulina after the middle 1980s, and domestic wastewater discharged from Yongsheng County since 1993.

关键词： stable isotope C/N ratio organic matter lake productivity anthropogenic impacts

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Distinctive diet-tissue isotopic discrimination factors derived from the exclusive bamboo-eating giant panda

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Integrative Zoology 2016年第6期11卷 447-456页

作者： Han HAN Wei WEI Yonggang NIE Wenliang ZHOU Yibo HU Qi WU Fuwen WEI Key Laboratory of Animal Ecology and Conservational Biology Institute of ZoologyChinese Academy of SciencesBeijingChina University of Chinese Academy of Sciences BeijingChina

stable isotope analysis is very useful in animal ecology,especially in diet reconstruction and trophic studies.Differences in isotope ratios between consumers and their diet,termed discrimination factors,are essential for studies of stable isotope ecology and are species-specific and tissue-specific.Given the specialized bamboo diet and clear foraging behavior,here,we calculated discrimination factors for carbon and nitrogen isotopes from diet to tissues(tooth enamel,hair keratin and bone collagen)for the giant panda(Ailuropoda melanoleuca),a species derived from meat-eating ancestors.Our results showed that carbon discrimination factor obtained from giant panda tooth enamel(ε^(13)C_(diet-enamel)=10.0‰)and nitrogen discrimination factors from hair keratin(Δ^(15)N_(diet-hair)=2.2‰)and bone collagen(Δ^(15)N_(diet-collagen)=2.3‰)were lower,and carbon discrimination factors from hair keratin(Δ^(13)C_(diet-hair)=5.0‰)and bone collagen(Δ13Cdiet-collagen=6.1‰)were higher than those of other mammalian carnivores,omnivores and herbivores.Such distinctive values are likely the result of a low-nutrient and specialized bamboo diet,carnivore-like digestive system and exceptionally low metabolism in giant pandas.

关键词： bone collagen discrimination factor giant panda hair keratin stable isotope

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Characterization of ^(68)Zn uptake,translocation,and accumulation into developing grains and young leaves of high Zn-density rice genotype

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2011年第5期12卷 408-418页

作者： Md.Jahidul Islam SHOHAG MOE Key Lab of Environmental Remediation and Ecosystem Health College of Environmental and Resource SciencesZhejiang University

Zinc(Zn) is an essential micronutrient for humans,but Zn deficiency has become serious as equally as iron(Fe) and vitamin A deficiencies nowadays.Selection and breeding of high Zn-density crops is a suitable,cost-effective,and sustainable way to improve human health.However,the mechanism of high Zn density in rice grain is not fully understood,especially how Zn transports from soil to grains.Hydroponics experiments were carried out to compare Zn uptake and distribution in two different Zn-density rice genotypes using stable isotope technique.At seedling stage,IR68144 showed higher 68Zn uptake and transport rate to the shoot for the short-term,but no signifi-cant difference was observed in both genotypes for the long-term.Zn in xylem sap of IR68144 was consistently higher,and IR68144 exhibited higher Zn absorption ratio than IR64 at sufficient(2.0 μmol/L) or surplus(8.0 μmol/L) Zn supply level.IR64 and IR68144 showed similar patterns of 68Zn accumulation in new leaves at seedling stage and in de-veloping grains at ripening stage,whereas 68Zn in new leaves and grains of IR68144 was consistently higher.These results suggested that a rapid root-to-shoot translocation and enhanced xylem loading capacity may be the crucial processes for high Zn density in rice grains.

关键词： Zinc stable isotope High Zn-density rice genotype Translocation Remobilization

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Gene expression and physiological responses to salinity and water stress of contrasting durum wheat genotypes

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Journal of Integrative Plant Biology 2016年第1期58卷 48-66页

作者： Salima Yousfi Antonio J.Marquez Marco Betti Jose Luis Araus Maria Dolores Serret Unit of Plant Physiology Department of Plant BiologyFaculty of BiologyUniversity of Barcelona08028Spain Department of Plant Biochemistry and Molecular Biology Faculty of ChemistryUniversity of SevilleSevilla 41012Spain

Elucidating the relationships between gene expression and the physiological mechanisms remains a bottleneck in breeding for resistance to salinity and drought. This study related the expression of key target genes with the physiological performance of durum wheat under different combinations of salinity and irrigation. The candidate genes assayed included two encoding for the DREB（dehydration responsive element binding） transcription factors Ta DREB1 A and Ta DREB2 B, another two for the cytosolic and plastidic glutamine synthetase（Ta GS1 and Ta GS2）, and one for the specific Na^＋/H^＋ vacuolar antiporter（Ta NHX1）. Expression of these genes was related to growth and different trait indicators of nitrogen metabolism（nitrogen content, stable nitrogen isotope composition, and glutamine synthetase and nitrate reductase activities）, photosynthetic carbon metabolism（stable carbon isotope composition and different gas exchange traits） and ion accumulation. Significant interaction between genotype and growing conditions occurred for growth, nitrogen content, and the expression of most genes.In general terms, higher expression of Ta GS1, Ta GS2,Ta DREB2 B, and to a lesser extent of Ta NHX1 were associated with a better genotypic performance in growth, nitrogen, and carbon photosynthetic metabolism under salinity and water stress. However, Ta DREB1 A was increased in expression under stress compared with control conditions, with tolerant genotypes exhibiting lower expression than susceptible ones.

关键词： Durum wheat （Triticum turgidum ssp. durum） geneexpression nitrogen metabolism salinity stable isotope

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Paludification reduces black spruce growth rate but does not alter tree water use efficiency in Canadian boreal forested peatlands

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Forest Ecosystems 2021年第2期8卷 373-386页

作者： Joannie Beaulne Étienne Boucher Michelle Garneau Gabriel Magnan Geotop Research Center Université du Québec à MontréalMontréalQuébec H3C 3P8Canada Department of Geography Université du Québec à MontréalMontréalQuébec H3C 3P8Canada GRIL-UQAM Université du Québec à MontréalQuébec H3C 3P8Canada Centre d'études nordiques Université LavalMontréalQuébec G1V 0A6Canada

Background:Black spruce(Picea mariana(Mill.)BSP)-forested peatlands are widespread ecosystems in boreal North America in which peat accumulation,known as the paludification process,has been shown to induce forest growth decline.The continuously evolving environmental conditions(e.g.,water table rise,increasing peat thickness)in paludified forests may require tree growth mechanism adjustments over time.In this study,we investigate tree ecophysiological mechanisms along a paludification gradient in a boreal forested peatland of eastern Canada by combining peat-based and tree-ring analyses.Carbon and oxygen stable isotopes in tree rings are used to document changes in carbon assimilation rates,stomatal conductance,and water use efficiency.In addition,paleohydrological analyses are performed to evaluate the dynamical ecophysiological adjustments of black spruce trees to site-specific water table variations.Results:Increasing peat accumulation considerably impacts forest growth,but no significant differences in tree water use efficiency(iWUE)are found between the study sites.Tree-ring isotopic analysis indicates no iWUE decrease over the last 100 years,but rather an important increase at each site up to the 1980 s,before iWUE stabilized.Surprisingly,inferred basal area increments do not reflect such trends.Therefore,iWUE variations do not reflect tree ecophysiological adjustments required by changes in growing conditions.Local water table variations induce no changes in ecophysiological mechanisms,but a synchronous shift in iWUE is observed at all sites in the mid-1980 s.Conclusions:Our study shows that paludification induces black spruce growth decline without altering tree water use efficiency in boreal forested peatlands.These findings highlight that failing to account for paludification-related carbon use and allocation could result in the overestimation of aboveground biomass production in paludified sites.Further research on carbon allocation strategies is of utmost importance to understand the carbon sink capac

关键词： Black spruce growth Boreal biome Carbon allocation Ecophysiological mechanisms Forested peatland Paludification stable isotope Water use efficiency

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Trace glucose fluxes in individuals with prediabetes using stable isotopes

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Chinese Medical Journal 2014年第9期127卷 1726-1731页

作者： Du Shichun Xia Fangzhen Xu Xiao Zhang Huixin Zhu Chunfang Lu Yingli Institute and Department of Endocrinology and Metabolism Shanghai Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine Shanghai 200011 China

Background The glucose fluxes of individuals with prediabetes in Chinese population are not clear.This study was to determine whether the endogenous glucose production （EGP）,oral glucose rate of appearance （Ra） and glucose rate of disappearance （Rd） were different in Chinese individuals with prediabetes under fasting conditions and following an oral glucose challenge.Methods Five subjects with type 2 diabetes,5 subjects with prediabetes and 5 non-diabetic subjects matched for age,weight,fat free mass and body mass index underwent a 180 minute stable glucose isotope tracing （[6,6-2H2] glucose,[1-13C] glucose,and [U-13C] glucose） study under fasting and after ingestion of a 75 g oral glucose load.isotope glucose enrichment was measured by gas chromatography-mass spectrometry.Insulin sensitivity was estimated using the oral glucose tolerance test （OGTT）-derived insulin sensitivity index,β cell function was determined by the insulinogenic index （△I30/△G30）.Results The insulin sensitivity index （P=0.043） and insulinogenic index （P=0.021） were decreased in subjects with prediabetes compared with non-diabetes.Fasting EGP was slightly higher （P=0.29） and postprandial EGP was comparable in subjects with prediabetes and non-diabetes during 120 minutes after glucose ingestion,but nadir EGP occurred later in prediabetic than non-diabetic subjects.Ra did not differ among the three groups.Rd was substantially lower in subjects with prediabetes than non-diabetes after glucose intake （P=0.013）.Conclusion The mild hyperglycemia observed among individuals with prediabetes may result from decreased Rd during the postprandial state.

关键词： prediabetes glucose metabolism stable isotope triple tracer

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