Time filter

Source Type

He M.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Dijkstra F.A.,University of Sydney | Zhang K.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Tan H.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | And 4 more authors.
Plant and Soil | Year: 2015

Aim: Desert herbs, a crucial component of desert ecosystems, are sensitive to water and nutrient availability and therefore to environmental change. We aimed to determine element concentrations in desert herbs and their relationships with life form, taxonomy, climate, and soil environment. Methods: We measured concentrations of 11 elements in shoots and roots of 26 dominant desert herb species from 45 sites in a temperate desert. Results: Shoots of desert herbs had greater concentrations of elements related to photosynthesis and water use efficiency (N, P, Mg, K) than roots. Concentrations of these elements (except N and P) were also greater in annual herbs than in perennial herbs. Greater Mg, K, and Na concentrations were observed in shoots of Chenopodiaceae (mostly C4 species) than in Poaceae (mostly C3 species). Soil properties and taxonomy explained 3.6–26 % and 2.8–24 % of the variation in shoot element concentrations, respectively, whereas climate factors explained only 0.05–6.5 % of the variation. Conclusions: Water and nutrient availability, which are affected by environmental change, influence concentrations of mineral elements in desert plants and their biogeochemical cycles in desert ecosystems. © 2015 Springer International Publishing Switzerland


Hu Y.,Chinese Academy of Sciences | Hu Y.,Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province | Wang Z.,Chinese Academy of Sciences | Wang Z.,Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province | And 9 more authors.
Journal of Soils and Sediments | Year: 2016

Purpose: Changes in bioactive soil C pools and their temperature sensitivities will dominate the fate of soil organic C in a warmer future, which is not well understood in highland ecosystems. This study was conducted in order to evaluate climate change, especially cooling effects, on soil labile organic C (LOC) pools in a Tibetan alpine meadow. Materials and methods: A short-term reciprocal translocation experiment was implemented to stimulate climate warming (downward translocation) and cooling (upward translocation) using an elevation gradient on the Tibetan Plateau. Variations in soil microbial biomass C (MBC), dissolved organic C (DOC) and LOC were analyzed. Results and discussion: Over the range of soil temperature from 0.02 to 5.5 °C, warming averagely increased soil MBC, DOC and LOC by 15.3, 17.0 and 3.7 % while cooling decreased them by 11.0, 11.9 and 3.2 %, respectively. Moreover, warming generally increased the proportion of DOC in LOC but cooling had an opposite effect, while the response of the MBC proportion to DOC and LOC varied depending on vegetation type. Soil MBC, DOC and LOC pools were positively related to soil temperature and showed a hump-shaped relationship with soil moisture with a threshold of about 30–35 %. Although soil DOC was more sensitive to warming (5.1 % °C−1) than to cooling (3.0 % °C−1), soil LOC showed a symmetrical response due to regulation by soil moisture. Conclusions: Our results indicated that climate change would not only change the size of soil LOC pools but also their quality. Therefore, cooling effects and regulation of soil moisture should be considered to evaluate the fate of soil organic C in Tibetan alpine meadows in a warmer future. © 2016 Springer-Verlag Berlin Heidelberg


Zhang Z.S.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Zhang Z.S.,Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province | Chen Y.L.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Chen Y.L.,Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province | And 7 more authors.
Journal of Arid Land | Year: 2014

Biological soil crusts (BSCs) play an important role in surface soil hydrology. Soils dominated with moss BSCs may have higher infiltration rates than those dominated with cyanobacteria or algal BSCs. However, it is unnown whether improved infiltration in moss BSCs is accompanied by an increase in soil hydraulic conductivity or water retention capacity. We investigated this question in the Tengger Desert, where a 43-year-old revegetation program has promoted the formation of two distinct types of BSCs along topographic positions, i.e. the moss-dominated BSCs on the interdune land and windward slopes of the fixed sand dunes, and the algal-dominated BSCs on the crest and leeward slopes. Soil water retention capacity and hydraulic conductivity were measured using an indoor evaporation method and a field infiltration method. And the results were fitted to the van Genuchten-Mualem model. Unsaturated hydraulic conductivities under greater water pressure (<-0.01 MPa) and water retention capacities in the entire pressure head range were higher for both crust types than for bare sand. However, saturated and unsaturated hydraulic conductivities in the near-saturation range (>-0.01 MPa) showed decreasing trends from bare sand to moss crusts and to algal crusts. Our data suggested that topographic differentiation of BSCs significantly affected not only soil water retention and hydraulic conductivities, but also the overall hydrology of the fixed sand dunes at a landscape scale, as seen in the reduction and spatial variability in deep soil water storage. © 2015, Xinjiang Institute of Ecology and Geography, the Chinese Academy of Sciences and Springer - Verlag GmbH.


Li X.R.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Li X.R.,Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province | Zhang Z.S.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Zhang Z.S.,Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province | And 8 more authors.
Science China Life Sciences | Year: 2014

The main prevention and control area for wind-blown sand hazards in northern China is about 320000 km2 in size and includes sandlands to the east of the Helan Mountain and sandy deserts and desert-steppe transitional regions to the west of the Helan Mountain. Vegetation recovery and restoration is an important and effective approach for constraining wind-blown sand hazards in these areas. After more than 50 years of long-term ecological studies in the Shapotou region of the Tengger Desert, we found that revegetation changed the hydrological processes of the original sand dune system through the utilization and space-time redistribution of soil water. The spatiotemporal dynamics of soil water was significantly related to the dynamics of the replanted vegetation for a given regional precipitation condition. The long-term changes in hydrological processes in desert areas also drive replanted vegetation succession. The soil water carrying capacity of vegetation and the model for sand fixation by revegetation in aeolian desert areas where precipitation levels are less than 200 mm are also discussed. © 2014 The Author(s).


Liu M.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Liu M.,Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province | Zhu R.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Zhang Z.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | And 8 more authors.
Arid Land Research and Management | Year: 2016

A combination of dune-scale observation to distinguish psammophyte distribution, field experiments to determine gradients of soil moisture and physicochemical properties, and controlled quantitative manipulation for psammophytes water use traits was employed to study an arid desert margin area in China. This study aims to: (1) interpret the survival mechanisms of plants in arid desert ecosystems, especially for pioneer species; (2) interpret the links among distribution pattern, stress-gradients, and water use traits; (3) discuss the mechanisms and probable succession processes under natural fixation for artificial ecosystem rehabilitation; and (4) discuss the possibility of recognizing quantified water use traits as a predictor to compare the variations in adaptability among different species. We classified seven psammophytes into three major types in terms of water use: prodigal, moderate, and frugal plants. Results showed that vegetation cover of all the dominant species, including shrubs and herbs, was negatively correlated with diurnal transpiration at rhizosphere moisture (P < 0.01, R2 = 0.94). Herbaceous pioneer species (e.g., Agriophyllum squarrosum) survive harsh environments (shifting, hot and arid surface of dunes) by prodigal water use (high transpiration rate), low species cover, and fast production (high water use efficiency, which peaks at low soil moisture). By contrast, intrusive species (e.g., Eragrostis poaeoides) behaved as frugal plants to survive drought, thereby maintaining high vegetation cover and biomass, as well as soil water equilibration. © 2016, Copyright © Taylor & Francis Group, LLC.


Zhao X.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Zhao X.,Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province | Wang Y.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Shang Q.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | And 14 more authors.
PLoS ONE | Year: 2015

The genes of collagen-like proteins (CLPs) have been identified in a broad range of bacteria, including some human pathogens. They are important for biofilm formation and bacterial adhesion to host cells in some human pathogenic bacteria, including several Bacillus spp. strains. Interestingly, some bacterial CLP-encoding genes (clps) have also been found in non-human pathogenic strains such as B. cereus and B. amyloliquefaciens, which are types of plant-growth promoting rhizobacteria (PGPR). In this study, we investigated a putative cluster of clps in B. amyloliquefaciens strain FZB42 and a collagen-related structuralmotif containing glycine-X-threonine repeats was found in the genes RBAM-007740, RBAM-007750, RBAM-007760, and RBAM-007770. Interestingly, biofilm formation was disrupted when these genes were inactivated separately. Scanning electronmicroscopy and hydrophobicity value detection were used to assess the bacterial cell shape morphology and cell surface architecture of clps mutant cells. The results showed that the CLPs appeared to have roles in bacterial autoaggregation, as well as adherence to the surface of abiotic materials and the roots of Arabidopsis thaliana. Thus, we suggest that the CLPs located in the outer layer of the bacterial cell (including the cell wall, outer membrane, flagella, or other associated structures) play important roles in biofilm formation and bacteria-plant interactions. This is the first study to analyze the function of a collagen-like motif-containing protein in a PGPR bacterium. Knocking out each clp gene produced distinctive morphological phenotypes, which demonstrated that each product may play specific roles in biofilm formation. Our in silico analysis suggested that these four tandemly ranked genes might not belong to an operon, but further studies are required at the molecular level to test this hypothesis. These results provide insights into the functions of clps during interactions between bacteria and plants. © 2015 PLOS ONE.


Huang L.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Huang L.,Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province | Zhang Z.S.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Zhang Z.S.,Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province | And 2 more authors.
Journal of Arid Land | Year: 2014

Biological soil crusts (BSCs) are an important type of land cover in arid desert landscapes and play an important role in the carbon source-sink exchange within a desert system. In this study, two typical BSCs, moss crusts and algae crusts, were selected from a revegetated sandy area of the Tengger Desert in northern China, and the experiment was carried out over a 3 year period from January 2010 to November 2012. We obtained the effective active wetting time to maintain the physiological activity of BSCs based on the continuous field measurements and previous laboratory studies on BSCs photosynthesis and respiration rates. And then we developed a BSCs carbon fixation model that is driven by soil moisture. The results indicated that moss crusts and algae crusts had significant effects on soil moisture and temperature dynamics by decreasing rainfall infiltration. The mean carbon fixation rates of moss and algae crusts were 0.21 and 0.13 g C/(m2·d), respectively. The annual carbon fixations of moss crusts and algae crusts were 64.9 and 38.6 g C/(m2·a), respectively, and the carbon fixation of non-rainfall water reached 11.6 g C/(m2·a) (30.2% of the total) and 8.8 g C/(m2·a) (43.6% of the total), respectively. Finally, the model was tested and verified with continuous field observations. The data of the modeled and measured CO2 fluxes matched notably well. In desert regions, the carbon fixation is higher with high-frequency rainfall even the total amount of seasonal rainfall was the same. © 2014 Xinjiang Institute of Ecology and Geography, the Chinese Academy of Sciences and Springer - Verlag GmbH.


Hu Y.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Hu Y.,Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province | Wang Q.,CAS Institute of Tibetan Plateau Research | Wang Q.,University of Chinese Academy of Sciences | And 10 more authors.
Plant and Soil | Year: 2016

Aims: A lacking of understanding about cooling effects on methane (CH4) fluxes and potential asymmetrical responses to warming and cooling causes uncertainty about climate change effects on the atmospheric CH4 concentration. We investigated CH4 fluxes in an alpine meadow on the Tibetan Plateau in response to climate warming and cooling. Methods: A 2-year reciprocal translocation experiment was implemented to simulate climate warming (i.e. downward translocation) and cooling (i.e. upward translocation) along an elevation gradient with four different vegetation types (at 3200, 3400, 3600 and 3800 m elevation) during the growing season (May to October) in 2008 and 2009. Results: Although the effects of warming and cooling varied depending on vegetation type, elevation and timescale (i.e., daily and seasonally), warming increased average seasonal CH4 uptake by 60 %, while cooling reduced it by 19 % across all vegetation types, based on a 1.3–5.1 °C difference in soil temperature at 20 cm depth. Soil temperature over the range of 4–10 °C explained 11–25 % of the variation in average seasonal CH4 fluxes, while there was no relationship with soil moisture over the range of 13–39 % and soil NH4 +-N and NO3 −N content. Methane uptake was more sensitive to warming than to cooling. Conclusions: Because of warming and cooling spells in the alpine region, warming effects on CH4 uptake would be over-estimated by 64 % if cooling effects on it are not considered. Our findings suggest that asymmetrical responses of CH4 fluxes to warming and cooling should be taken into account when evaluating the effects of climate change on CH4 uptake in the alpine meadow on the Tibetan plateau. © 2016 Springer International Publishing Switzerland


He M.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Dijkstra F.A.,University of Sydney | Zhang K.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Li X.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | And 5 more authors.
Scientific Reports | Year: 2014

In desert ecosystems, plant growth and nutrient uptake are restricted by availability of soil nitrogen (N) and phosphorus (P). The effects of both climate and soil nutrient conditions on N and P concentrations among desert plant life forms (annual, perennial and shrub) remain unclear. We assessed leaf N and P levels of 54 desert plants and measured the corresponding soil N and P in shallow (0-10 cm), middle (10-40 cm) and deep soil layers (40-100 cm), at 52 sites in a temperate desert of northwest China. Leaf P and N5P ratios varied markedly among life forms. Leaf P was higher in annuals and perennials than in shrubs. Leaf N and P showed a negative relationship with mean annual temperature (MAT) and no relationship with mean annual precipitation (MAP), but a positive relationship with soil P. Leaf P of shrubs was positively related to soil P in the deep soil. Our study indicated that leaf N and P across the three life forms were influenced by soil P. Deep-rooted plants may enhance the availability of P in the surface soil facilitating growth of shallow-rooted life forms in this N and P limited system, but further research is warranted on this aspect.


He M.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Zhang K.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Tan H.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Tan H.,Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province | And 8 more authors.
Ecology and Evolution | Year: 2015

Besides water relations, nutrient allocation, and stoichiometric traits are fundamental feature of shrubs. Knowledge concerning the nutrient stoichiometry of xerophytes is essential to predicting the biogeochemical cycling in desert ecosystems as well as to understanding the homoeostasis and variability of nutrient traits in desert plants. Here, we focused on the temperate desert species Reaumuria soongorica and collected samples from plant organs and soil over 28 different locations that covered a wide distributional gradient of this species. Carbon (C), nitrogen (N), and phosphorus (P) concentrations and their stoichiometry were determined and subsequently compared with geographic, climatic, and edaphic factors. The mean leaf C, N, and P concentrations and C/N, C/P, and N/P ratios were 371.6 mg g-1, 10.6 mg g-1, 0.73 mg g-1, and 59.7, 837.9, 15.7, respectively. Stem and root C concentrations were higher than leaf C, while leaf N was higher than stem and root N. Phosphorus concentration and N/P did not differ among plant organs. Significant differences were found between root C/N and leaf C/N as well as between root C/P and leaf C/P. Leaf nutrient traits respond to geographic and climatic factors, while nutrient concentrations of stems and roots are mostly affected by soil P and pH. We show that stoichiometric patterns in different plant organs had different responses to environmental variables. Studies of species-specific nutrient stoichiometry can help clarify plant-environment relationships and nutrient cycling patterns in desert ecosystems. © 2015 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.

Loading Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province collaborators
Loading Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province collaborators