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Table of Content
    Volume 38 Issue 9
    01 September 2014

    View of Salix psammophila community in Yuan Shangdu region (42.25° N, 115.53° E), Nei Mongol, China. Yan et al. investigated the colonization of arbuscular mycorrhizal fungi and dark septate endophytes in roots of desert-grown S. psammophila and the correlations with soil factors (Pages 949–958 of this issue) (Photographed by HE Xue-Li).

      
    Comparison of adaptive strategies to phosphorus-deficient soil between dominant species Artemisia frigida and Stipa krylovii in typical steppe of Nei Mongol
    LIU Na-Na,TIAN Qiu-Ying,ZHANG Wen-Hao
    Chin J Plant Ecol. 2014, 38 (9):  905-915.  doi:10.3724/SP.J.1258.2014.00085
    Abstract ( 1376 )   Full Text ( 105 )   PDF (46997KB) ( 1449 )   Save
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    Aims Artemisia frigida and Stipa krylovii are two dominant species in the typical steppe of northern China, and highly adapted to the local edaphic conditions. However, little is known about their ecophysiological traits in terms of adaptation to soil nutrient regimes in general and low available phosphorus (P) in particular. To understand the ecophysiological mechanisms by which the two species adapt to low P availability in soil, root morphological traits, acid phosphatase (APase) activity secreted by roots, exudation of organic acid, P uptake rate and P utilization efficiency in the two species were measured under varying concentrations of P supply in pot experiments.
    Methods Pot experiments were conducted to investigate the responses of the two species to varying concentrations of P supply by determining biomass, shoot and root morphology, average P uptake rate, P utilization efficiency, exudation of organic acid and acid phosphatase in A. frigida and S. krylovii.
    Important findings Phosphorus deficiency induced root-secreted APase activity and acidification of rhizosphere in A. frigida, while S. krylovii exhibited an enhanced exudation of malate from roots under phosphorus-deficient conditions. Stipa krylovii displayed similar P uptake rate to that of A. frigida, but its P utilization efficiency was markedly higher than in A. frigida under phosphorus-deficient conditions. The two species showed similar growth patterns in response to P deficiency, but A. frigida seedlings required higher external P level for their maximal growth than those of S. krylovii, suggesting that the two species have different physiological requirement for P. The different adaptive strategies between A. frigida and S. krylovii to the low soil P availability may provide an ecophysiological explanation for their co-existence in the infertile grassland in northern China.

    Assembly patterns of plant functional traits in alpine meadow under disturbances by mowing and fertilization
    LÜ Mei-Qiang,ZHU Zhi-Hong,LI Ying-Nian,YAO Tian-Hua,PAN Shi-Yu,KONG Bin-Bin
    Chin J Plant Ecol. 2014, 38 (9):  916-928.  doi:10.3724/SP.J.1258.2014.00086
    Abstract ( 992 )   Full Text ( 104 )   PDF (3009KB) ( 2141 )   Save
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    Aims Fully understanding the assembly patterns of plant functional traits in plant communities is a big challenge in the study of community ecology. The assembly patterns in alpline meadow and driving factors are still poorly known. In this study, experiments with different mowing intensities and various treatments of fertilization were conducted in alpline meadow for the purpose of improving the understanding of the assembly patterns of plant functional traits in plant community.
    Methods Data on functional diversity of 10 traits for 33 species from 108 quadrats (with varying combinations of mowing and fertilization) were analyzed by randomizations tests, ANCOVA and regression analysis, respectively, for the trait convergence/divergence.
    Important findings None of the traits studied showed consistently significant convergence or divergence pattern in integral gradients of fertilization and mowing treatments, while the ratios of quadrats assembled under deterministic and stochastic processes were 82.7% and 17.3%, respectively. Among the functional traits tested, growth form, life cycle, aboveground dry mass per plant, leaf area and leaf dry mass showed a stochastic pattern of assembly, but they were not affected by variations in mowing treatments and community characteristics (i.e. aboveground net primary productivity, biomass loss and vegetation height). Convergence or divergence patterns were shown in traits such as plant inclination, reproductive modes, nitrogen fixation, plant height and specific leaf area, which were affected by variations in mowing treatments and community characteristics. Among them, assembly patterns of plant inclination and specific leaf area were only affected by community characteristics, while nitrogen fixation, reproductive modes and plant height were affected by both mowing treatments and community characteristics. Moreover, the patterns of assembly varied by traits. Aboveground net primary productivity and biomass loss well explained variations in the assembly pattern of plant functional traits. Mowing and fertilization showed the reversed effects on the assembly pattern of plant height, while no significant interaction was found between mowing and fertilization. The results suggested that there were different assembly patterns of functional traits in the community: stochastic pattern of assembly was the primary, and the deterministic pattern was secondary. Deterministic pattern was trait-dependent and correlated with variations in mowing treatments and community characteristics. The balancing effect of opposite selection forces, on the other hand, could lead to stochastic assembly patterns in plant functional traits.

    Biomass allocation and leaf stoichiometric characteristics in four desert herbaceous plants during different growth periods in the Gurbantünggüt Desert, China
    XIAO Yao,TAO Ye,ZHANG Yuan-Ming
    Chin J Plant Ecol. 2014, 38 (9):  929-940.  doi:10.3724/SP.J.1258.2014.00087
    Abstract ( 1343 )   Full Text ( 106 )   PDF (13119KB) ( 1792 )   Save
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    Aims Plant biomass allocation and elemental homeostasis have recently become a focus in ecological studies. Herbaceous plants are a major component of species diversity in desert ecosystems. Study on biomass allocation and leaf stoichiometry with growth will be beneficial to further understanding the survival strategy and functional features of desert herbs.
    Methods Four dominant species, including two ephemeral plants (Erodium oxyrrhynchum and Hyalea pulchella) and two annals (Agriophyllum squarrosum and Ceratocarpus arenarius), were selected for in situ and multiple- time investigations. Changes in the characteristics of biomass allocation and leaf N-P stoichiometry, as well as their relationships were analyzed.
    Important findings Root to shoot ratio decreased gradually during the accumulation of plant biomass in all the four species. The allometric relationships between above- and belowground biomass, however, varied among the four species; the allometric scaling exponents in H. pulchella and C. arenarius initially increased and then decreased, and tended to become stable toward the later period, whereas the allometric scaling exponents in E. oxyrrhynchum and A. squarrosum initially increased and then tended to be isometry in later period. The leaf N and P contents tended to increase in H. pulchella, but declined in other three species with growth, indicating that the leaf N-P stoichiometry of the plants studied changed and showed weak correlations with biomass indices.

    Effects of warming on carbon, nitrogen and phosphorus stoichiometry in tundra soil and leaves of typical plants
    JIANG Xiao-Jie,HU Yan-Ling,HAN Jian-Qiu,ZHOU Yu-Mei
    Chin J Plant Ecol. 2014, 38 (9):  941-948.  doi:10.3724/SP.J.1258.2014.00088
    Abstract ( 1083 )   Full Text ( 10 )   PDF (4238KB) ( 2214 )   Save
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    Aims Our objective was to investigate how warming affected C, N and P contents and C: N: P ratios in leaves of dominant tundra plants in Changbai Mountain.
    Methods Open-top chambers (OTCs) were used to raise the air and soil temperature in the Changbai Mountain tundra. Eight hexagon OTCs were established according to the standard of International Tundra Experiment (ITEX). The C, N and P contents and C:N:P ratios in soils and leaves of Dryas octopetala var. asiatica, Vaccinium uliginosum, Rhododendron aureum were measured during growing season (July to September).
    Important findings Warming increased the soil N and P contents by 5.88% and 4.83%, respectively, but reduced the C content by 13.19%. The contents of C, N and P in leaves showed significant variations for plants in both OTCs and control plots during growing season. The P content in V. uliginosum, R. aureum was increased by 10.34% and 12.87%, respectively, but decreased by 16.26% in D. octopetala var. asiatica, by warming. The C:N ratio in leaves of D. octopetala var. asiatica and R. aureum grown in OTCs showed an increasing trend. Warming resulted in increases in soil available N and P. The ratio of C:N in the three plants, the P content in R. aureum and V. uliginosum, and the ratio of C:P in D. octopetala var. asiatica were significantly affected by warming. The results indicate that warming would increase the P limitation to plant growth in this area. The pattern and magnitude of leaf stoichiometry of the three tundra plant species respond differently to warming in Changbai Mountain.

    Colonization of arbuscular mycorrhizal fungi and dark septate endophytes in roots of desert Salix psammophila
    YAN Jiao,HE Xue-Li,ZHANG Ya-Juan,XU Wei,ZHANG Juan,ZHAO Li-Li
    Chin J Plant Ecol. 2014, 38 (9):  949-958.  doi:10.3724/SP.J.1258.2014.00089
    Abstract ( 1113 )   Full Text ( 83 )   PDF (5132KB) ( 1543 )   Save
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    Aims Salix psammophila is an excellent shrub for afforestation and sand dune fixation and is mainly distributes in the arid zones in North China. The objective of this study was to determine the colonization of arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE), and the relationships among AMF, DSE and soil factors in the rhizosphere of S. psammophila, in order to provide information guiding the recovery of desert vegetation and ecological reconstruction.
    Methods Soil and root samples were collected from different soil layers (0-10, 10-20, 20-30, 30-40 and 40-50 cm) in the rhizosphere of S. psammophila in June, August and October 2013 at Yuan Shangdu in Nei Mongol. The colonization and distribution of AMF and DSE were assessed, and the relationships among AMF, DSE and soil factors were determined and tested by variance analysis, correlation analysis and principal component analysis.
    Important findings The roots of S. psammophila could be highly infected by AMF and DSE, and the average colonization of AMF and DSE were 77% and 84%, respectively. Sampling time and soil depth significantly influenced the AMF and DSE colonization. The maximum colonization of AMF was found in the 0-20 cm soil layer and DSE in the 0-10 cm soil layer, respectively, and the effects of sampling time on colonization were in the order of October > August > June. Two-way ANOVA showed that sampling time and soil layer had significant interactive effects on the colonization and distribution of AMF and DSE as well as soil factors. Principal component analysis showed that soil humidity, pH value, alkaline phosphatase and easily extractable glomalin were the main factors of AMF and DSE colonization in desert environments.

    Effects of intercropping with soybean on bacterial and nitrogen-fixing bacterial diversity in the rhizosphere of sugarcane
    PENG Dong-Hai,YANG Jian-Bo,LI Jian,XING Yong-Xiu,QIN Liu-Dong,YANG Li-Tao,LI Yang-Rui
    Chin J Plant Ecol. 2014, 38 (9):  959-969.  doi:10.3724/SP.J.1258.2014.00090
    Abstract ( 1424 )   Full Text ( 7 )   PDF (3250KB) ( 1200 )   Save
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    Aims In order to investigate the effects of intercropping with soybean on the diversities of bacteria and nitrogen- fixing bacteria in the rhizosphere of sugarcane (Saccharum officinarum), to collect and exploit nitrogen-fixing bacterial resources, and to screen for efficient sugarcane-associative nitrogen fixation system, an experiment was conducted by cultivating three sugarcane cultivars ‘ROC22’, ‘GT21’, and ‘B8’ with a soybean (Glycine max) cultivar ‘Guizao 2’.
    Methods Rhizospheric soil bacteria and nitrogen-fixing bacteria were measured in the rhizosphere of sugarcane intercropped with soybean by using a nested-PCR combined with denaturing gradient gel electrophoresis (DGGE) technique. The specific bacterial 16S rRNA gene fragments and nitrogen-fixing bacteria nifH gene fragments were amplified for phylogenetic and diversity analyses.
    Important findings Cluster analysis of bacterial communities showed that the sugarcane-soybean intercropping changed the community composition of rhizospheric soil bacteria and nitrogen-fixing bacteria, with the effect being greater on nitrogen-fixing bacterial communities than on the soil bacterial communities. The intercropping system had a significant effect on the diversity of the rhizospheric bacteria and nitrogen-fixing bacteria; the impact on the diversity of nitrogen-fixing bacteria was greater than on the soil bacteria, and was only minor on the dominance of the bacterial species. Analyses of Shannon-Wiener index and Simpson index showed that the nitrogen-fixing bacteria differed in diversity among the treatments with different sugarcane varieties, and that the sugarcane cultivar ‘ROC22’-soybean intercropping had the greatest diversity. The diversity of soil bacteria in the rhizosphere of sugarcane varied greatly among different stages of crop growth; the booming stage of soybean had the greatest diversity and variations in the diversity among treatments in soil bacteria in the rhizosphere of sugarcane, and thereafter the two variables decreased. In conclusion, the sugarcane-soybean intercropping system had significant effects on the community structures and diversities of soil bacteria and nitrogen-fixing bacteria in the rhizosphere of sugarcane. This is of help for understanding the beneficial effects of sugarcane-soybean intercropping and for identifying efficient sugarcane-associative nitrogen fixation systems.

    Patterns of dust retention by five common tree species for urban greening in Aksu City, Northwest China
    Aliya BADRULLA,Umut HALIK,Tayierjiang AISHAN,Akram UBUL,Kahaer ZHAYIMU,Jin HUA
    Chin J Plant Ecol. 2014, 38 (9):  970-977.  doi:10.3724/SP.J.1258.2014.00091
    Abstract ( 1475 )   Full Text ( 102 )   PDF (7532KB) ( 1355 )   Save
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    Aims Air pollution poses a long-term threat to human health and life quality of urban residents. In particular, dust pollution in oasis cities of arid regions has been associated with reduced life expectancy. Trees (especially their leaves) in cities can absorb airborne particulate matter and reduce the impacts of air pollution on people and urban environment. This study examined dust retention capacity of the leaves of Platanus × acerifolia, Populus alba var. pyramidalis, Ulmus densa, Fraxinus sogdiana, and Salix babylonica in different functional areas in Aksu City, Northwest China. Our objectives were to determine that how much dust can be removed on unit leaf area basis by each of the tree species and that how the patterns of dust removal may vary with time, among different sites, and the height where leaves are positioned.
    Methods Dust samples were washed off the leaf surfaces and weighed by electronic scales with an accuracy of 1 μg (PTX-FA-210, Polestar, Hartford, USA). Individual leaf area was measured with a Laser Leaf Area Meter and the sediments on each leaf were analyzed by a Laser Particle Size Analyzer. Data were tested by multiple comparisons (ANOVA) using procedures in SPSS, with the level of significance set at p < 0.05.
    Important findings The amount of dust per unit leaf area differed among the five tree species and the four functional areas. The leaves of Platanus × acerifolia had the highest dust retention, and those of Salix babylonica had the lowest dust retention. Among different areas, the amount of dust retention ranked in the order of industrial area > transportation hub area > residential area > clean area. Leaves at a height of 1 m retained the most dust as compared with leaves at 2 m and 4 m, with the pattern being consistent across sites and among species.

    Physiological and biochemical responses of Syntrichia caninervis at a snowfall event in different desert habitats
    YIN Ben-Feng,ZHANG Yuan-Ming
    Chin J Plant Ecol. 2014, 38 (9):  978-989.  doi:10.3724/SP.J.1258.2014.00092
    Abstract ( 1398 )   Full Text ( 80 )   PDF (8953KB) ( 1294 )   Save
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    Aims Water is the most constraining factor to the growth of plants in arid and semiarid regions of China. Biological soil crusts (BSCs) develop well in Gurbantünggüt Desert and Syntrichia caninervis is a dominant species in the moss crusts of this cold desert. Compared to other desert ecosystems, the Gurbantünggüt desert is home to stable and abundant snow cover in winter. The moisturizing and warming effects of snow cover provide the desert mosses with optimal growth conditions. Our objective in this study was to determine how S. caninervis shoots utilize the special snow resources under different microhabitats in early winter.
    Methods The experiments were conducted from prior to the snowfall and until following the snow thawing at a long-term study site of the Gurbantünggüt Desert. We measured the physiological and biochemical characteristics in S. caninervis in three habitats: the live shrub, the dead shrub, an exposed area. The shoot water content, chlorophyll fluorescence, proline content, soluble sugar content, soluble protein content, malonyldialdehyde (MDA) content, peroxidase (POD) and superoxide dismutase (SOD) activity were compared.
    Important findings The results showed that snowfall increased moss water content, the maximal photochemical efficiency of PSII (Fv/Fm), soluble sugar content, SOD and POD activity. The content of proline and MDA were reduced with snow melting. Microhabitats influenced the physiological characteristics in S. caninervis, with the effects varying with snowfall event. The water content and chlorophyll fluorescence activity were significantly higher in samples under the living shrub, while in the exposed area S. caninervis had lower water content and chlorophyll fluorescence activity regardless of the snowfall cover. These findings suggested that the S. caninervis plants under the loving shrub experienced the least stress and had the best physiological performance but weak resistance, and that those in exposed area were more stress tolerant and had poorer physiological performance. Following the snowfall, proline content, MDA content, POD and SOD activity all had significantly negative correlations with plant water content; whereas the soluble sugar and protein content displayed significantly positive correlations with plant water content. The results indicated that snowfall reduced the water stress in S. caninervis, and enhanced their physiological performance and photosynthesis, with the effects being facilitated by the low temperature of the early winter.

    Comprehensive evaluation of low-temperature tolerance in soybean cultivars of different eco-types at seedling stage in Shanxi Province
    GUO Shu-Jin,LI Wei-Yu,MA Yan-Yun,ZHAO Heng,QIAO Ling,LI Gui-Quan
    Chin J Plant Ecol. 2014, 38 (9):  990-1000.  doi:10.3724/SP.J.1258.2014.00093
    Abstract ( 997 )   Full Text ( 105 )   PDF (40450KB) ( 1067 )   Save
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    Aims Low temperature at the seedling stage is the key factor constraining growth and yield in spring-sowing soybeans (Glycine max) in North China. The objectives of this research were to explore responses of soybean cultivars of different eco-types in Shanxi Province to low temperatures at the seedling stage, to develop indices and approaches for comprehensive evaluation of low-temperature tolerance in soybeans, and ultimately to provide theoretical basis for breeding soybean cultivars of low-temperature tolerance in order to maintain stable yield under the conditions of low temperature stress at the seedling stage.
    Methods We selected three soybean cultivars (‘Jinda 53’, ‘Jinda 70’ and ‘Jindou 24’) bred and grown widely in Shanxi Province. At the seedling stage, the plant materials were subjected to stress treatments at three levels of low temperatures and a control treatment in growth cabinets. The low temperature treatments were set for 14, 17 and 20 °C, respectively, and the control treatment was maintained at 23 °C. Upon completion of the temperature treatments, the seedlings were transplanted into larger pots and grown in a greenhouse. Values of photosynthetic traits (including net photosynthetic rates (Pn), intercellular CO2 concentration (Ci), stomatal conductance (Gs) and transpiration rate (Tr)) were determined on seedlings. The yield traits (plant height, plant mass, pods per plant and yield per plant) were assessed after harvesting. Furthermore, the genotype main effect plus genotype-environment interaction (GGE) biplot was employed to analyze the effects of various traits on different cultivars and correlations among the traits. Then, subordinate function was applied for comprehensive evaluation of low-temperature tolerance of the three cultivars studied.
    Important findings (1) The seedling stage of all three cultivars was extended by 1-12 days by the low tempera- ture treatments. (2) Values of the four photosynthetic traits were reduced in seedlings subjected to low temperature treatments; the rate of reduction was significantly greater for Gs and Tr than for the other two traits. Reductions in the values of photosynthetic traits were significantly smaller in the cultivar ‘Jinda 53’ than in other two cultivars, suggesting the stronger low temperature tolerance of this cultivar in terms of photosynthetic capacity. Additionally, ‘Jinda 70’ maintained higher Pn values than the other two cultivars, which was beneficial to greater dry matter accumulation in this cultivar. (3) Values of the four yield traits were all significantly reduced in plants subjected to low temperature treatments at the seedling stage. The rates of reduction were significantly greater for plant mass and pods per plant than for the other two traits. Among the three cultivars tested, the rates of reduction in plant mass and pods per plant were significantly smaller in ‘Jinda 70’ than in other two cultivars. Furthermore, the yield per plant in ‘Jinda 70’ was reduced by less than 50% as a result of low temperature treatments at the seedling stage, indicating that the low temperature stress at the seedling stage had the least effect on the yield in ‘Jinda 70’. (4) GGE biplot analysis revealed the rates of reduction in Tr and Gs had the most apparent effects on ‘Jinda 70’, the rate of reduction in Pn had the most apparent effects on ‘Jindou 24’, and the rate of reduction in Ci affected both ‘Jinda 70’ and ‘Jindou 24’, and that ‘Jinda 53’ was not affected by reductions in any of the photosynthetic traits. Meanwhile, the biplot indicated that there were significant positive correlations among the reduction rates of Tr, Gs, Ci, and Pn. Analysis of the yield traits using the biplot showed that the reduction rates of plant height and plant mass had the most apparent effects on ‘Jinda 53’, the reduction rate of yield per plant had the most apparent effects on ‘Jindou 24’, and the reduction rate of pods per plant affected both ‘Jinda 53’ and ‘Jindou 24’, and that the reduction rates of yield trait values had no apparent effects on ‘Jinda 70’. There were significant positive correlations among the reduction rates of plant mass, plant height, pods per plant, and yield per plant. Hence, the photosynthetic and yield traits can be used as indices for evaluation of low-temperature tolerance. Using subordinate function, the ranking of low-temperature tolerance of the three cultivars at the seedling stage is in the ascending order of ‘Jinda 70’, ‘Jinda 53’, and ‘Jindou 24’.

    Effects of arbuscular mycorrhizal fungi on growth and anatomical properties of stomata and xylem in poplars
    LIU Ting,TANG Ming
    Chin J Plant Ecol. 2014, 38 (9):  1001-1007.  doi:10.3724/SP.J.1258.2014.00094
    Abstract ( 1180 )   Full Text ( 95 )   PDF (1161KB) ( 1428 )   Save
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    Aims Arbuscular mycorrhizal fungi (AMF) were previously reported to afford some plant species with greater resistance to drought stress. Most of the mycorrhizal studies have been focused on physiological responses of host plants affected by AMF. However, characteristics of stomata, vessel and fibre are also closely related to plant water use efficiency. Hence, this study was conducted to examine the effects of AMF on anatomical properties of stomata and xylem in poplars.
    Methods A controlled pot-experiment was carried out to investigate the effects of an AMF, Rhizophagus irregularis, on the anatomical properties of stomata and xylem in Populus × canadensis (P. nigra × P. deltoides) ‘Neva’ under drought and well watered conditions.
    Important findings Results showed that AMF increased the biomass production, stomatal length, vessel diameter and fibre length of the poplar seedlings. The effects of AMF on biomass and vessel diameter were greater under drought condition than under well watered condition; whereas the effects on stomatal length were greater under well watered condition than under drought condition. AMF imposed a positive effect on stomatal density and a negative effect on fibre length, but did not affect water deficit in seedlings under well watered condition. Under drought, the effects of AMF were positive on fibre diameter, negative on water deficit, and not significant on stomatal density. In summary, the effects of AMF on vessel properties were greater under drought condition than under well watered condition; whereas the effects on stomatal properties were stronger under well watered condition than under drought condition. This might be beneficial for plants to maintain water and reduce water deficit when suffering from drought. Hence, AMF could promote the drought tolerance in poplars.

    Effects of extreme rainfall and drought events on grassland ecosystems
    ZHANG Bin,ZHU Jian-Jun,LIU Hua-Min,PAN Qing-Min
    Chin J Plant Ecol. 2014, 38 (9):  1008-1018.  doi:10.3724/SP.J.1258.2014.00095
    Abstract ( 1670 )   Full Text ( 79 )   PDF (393KB) ( 2332 )   Save
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    Global atmospheric circulations are greatly affected by anthropogenic activities. Several atmospheric circulation models predict that the frequencies of extreme rainfall events and extreme droughts will increase in the future. Water is one of the most limiting resources for growth and development of plants in arid and semi-arid ecosystems. Furthermore, grassland ecosystems have been proven to be very sensitive to changing precipitation regimes. However, our understanding on the effects of extreme climatic events on the structure and functioning of grassland ecosystems is inadequate. By far, the definitions of extreme climatic events are still inconsistent. Therefore, based on analyses of the definitions of extreme climatic events and research methods in literature, we synthesize the effects of extreme rainfall events and extreme droughts on soil water and nutrient availability, individual plant development and physiological characteristics, community structure, ecosystem productivity and carbon cycling. In addition, we put forward five scientific questions on research concerning the impacts of extreme climatic events and identify two key issues on manipulative precipitation experiments to help with understanding the mechanisms on how grassland ecosystems respond to extreme climatic events in the context of global change.

    Ecological implications of hydraulic redistribution in nutrient cycling of soil-plant system
    SU Hua,LIU Wei,LI Yong-Geng
    Chin J Plant Ecol. 2014, 38 (9):  1019-1028.  doi:10.3724/SP.J.1258.2014.00096
    Abstract ( 1255 )   Full Text ( 70 )   PDF (97512KB) ( 1552 )   Save
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    Hydraulic redistribution (HR), one of the common bio-physical processes, plays key roles in mediating plant drought stress, regulating plant interspecific relations and community composition, as well as in influencing water and carbon balance of ecosystems. Great improvements have been achieved in HR research with fast development of isotopic labelling and tracing technologies. This paper summarizes the effects of HR on nutrient cycling of soil-plant system, based on studies over the past decade. HR increases soil water content in dry soil layers, thus helping to prevent embolism in roots, increasing the survival rate and the growth rate of fine roots and improving microbial activities. Such effects improve plant nutrient uptake, i.e., hydraulic lift promotes nitrogen uptake from upper soil layers and hydraulic descent promotes phosphorus uptake from deep soil layers. HR may facilitate nutrient exchange between upper and lower soil nutrient pools, improve nutrient flows and regulate the N:P ratio in both plants and soil. These effects may ultimately affect global ecosystems. Under the global change scenarios (e.g. nitrogen deposition), it is necessary to further explore the effects of HR on biogeochemical cycles. HR should be taken into account when using ecosystem models for future predictions.


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