Loading...
Welcome to Chinese Journal of Applied Ecology! Today is Share:

Table of Content

    18 February 2018, Volume 29 Issue 2
    Special Features for the Changbai Mountains Forum
    Species, functional, structural diversity of typical plant communities and their responses to environmental factors in Miao Archipelago, China.
    ZHENG Li-ting, SU Tian, LIU Xiang-yu, YIN Fang, GUO Chao, TUO Bin, YAN En-rong
    2018, 29(2):  343-351.  doi:10.13287/j.1001-9332.201802.037
    Asbtract ( 516 )   PDF (686KB) ( 29 )  
    Island vegetation plays an important role in biodiversity research across the world. The study of plant diversity in island is helpful for understanding the mechanism of plant diversity maintenance under land-sea interaction. Here, four typical plant communities (Quercus acutissima community, Robinia pseudoacacia community, Pinus thunbergii community and Vitex negundo community) in Miao Archipelago were selected to examine the species, functional and structural diversities and their responses to environmental factors at the community scale by using species diversity indices, functional diversity indices, as well as structural diversity indices. The results showed that the species richness and Rao index of P. thunbergii community was higher than that of Q. acutissima community and R. pseudoacacia community, but the structural diversity was lower. The species diversity and structural diversity of V. Negundo shrub were lower than that of forest community, but the functional diversity was higher than some forest communities. The relationship between the diversity of typical plant communities in island area illustrated a significant positive correlation between species richness with Rao index and tree height diversity, however the correlation with functional evenness was significantly negative. The structural diversity and functional evenness were determined by slope with negative and positive relationships, respectively. Functional heterogeneity, functional divergence and species diversity were affected largely by soil physical and chemical properties, displaying the positive relationship with soil bulk density and soil total carbon content, and a negative relationship with soil water content. In conclusion, diversity pattern of plant community in Miao Archipelago reflected not only the characteristics in mainland vegetation but also the special nature of the sea island.
    Divergence between ring- and diffuse-porous wood types in broadleaf trees of Changbai Mountains results in substantial differences in hydraulic traits.
    YIN Xiao-han, HAO Guang-you
    2018, 29(2):  352-360.  doi:10.13287/j.1001-9332.201802.035
    Asbtract ( 466 )   PDF (1708KB) ( 64 )  
    Hydraulic characteristics of trees are strongly influenced by their xylem structures. The divergence in wood type between ring-porous and diffuse-porous species is expected to lead to significantly different hydraulic architecture between these two functional groups. However, there is a lack of comprehensive comparative studies in hydraulic traits between the two groups, in that no study has compared the whole-shoot level hydraulic conductance and detailed pit-level xylem anatomy has not been reported yet. In the present study, detailed hydraulic related traits were stu-died in three ring-porous and four diffuse-porous tree species commonly found in the broadleaf tree species of the Changbai Mountains, including whole-shoot hydraulic conductance (Kshoot), resis-tance to drought-induced embolism (P50), and detailed tissue- and pit-level anatomical characteristics. Our results showed that: 1) consistent with the differences in stem hydraulic conductivity, ring-porous species showed significantly higher Kshoot but significantly lower resistance to drought-induced embolism, i.e., higher P50, indicating a trade-off between hydraulic efficiency and safety in those two functional groups; 2) consistent with their significant divergence in hydraulic functions, the two functional groups showed significant differences in a suite of xylem anatomical characteristics at both the tissue and pit levels, such as maximum vessel length, vessel diameter, pit aperture area and aperture fraction; 3) significant correlations were identified between xylem structural characteristics and between structure and functions across both functional groups, indicating that differences in hydraulic functions were underlain by divergences in a suite structural traits. The competing structural requirements between different hydraulic traits, such as between shoot hydraulic conductance and resistance to drought-induced embolism, reflected the biophysical constraints of xylem design that could not fulfill multiple requirements of xylem functioning at the same time.
    Population structure and regeneration strategy of relict deciduous broadleaved trees on Mount Tianmu, Zhejiang Province, China.
    SHANG Kan-kan, CHEN Bo, DA Liang-jun
    2018, 29(2):  361-368.  doi:10.13287/j.1001-9332.201802.031
    Asbtract ( 421 )   PDF (744KB) ( 23 )  
    The population structure, regeneration ways and spatial relationships of six relict deci-duous broadleaved trees were examined based on community investigation on Mount Tianmu, East China. The results showed that relict deciduous broadleaved trees had a strong ability of vegetative reproduction and their population structure was generally belonged to intermittent type. Some relict species such as Cyclocarya paliurus and Liquidamb aracalycina regenerated discontinuously at appropriate sites via long-distance diffusion. Some species such as Emmenoptery henryi and Euptelea pleiospermum regenerated discontinuously around mature trees due to habitat limitation and frequent disturbance. After occupying forest gaps by seedling regeneration, C. paliurus, L. acalycina, Nyssasinensis and Liquidambar formosana could recruit and form multi-stemmed individuals by their inherent sprouting ability at relatively stable sites such as crest slope and side slope. At riverbed, valley slope and head hollow, recognized as unstable habitats, Emmenopterys henryi, E. pleiospermum, and L. formosana could also recruit by strong sprouting ability due to sparse seedlings and individual loss incurred by disturbance. Therefore, the relict deciduous broadleaved trees could be classified into two ecological species groups (repairment species for forest gap and supplement species for special habitat) based on spatial distribution and strategy of regeneration and competition. We suggested that the protection of special habitats of their communities should be strengthened.
    Spatial distribution patterns and associations of typical tree species in different regions.
    YAN Hai-bing, MA Hui-jing, FENG Fan, LIANG Nan, SHI Chan, YANG Xiu-qing, HAN You-zhi
    2018, 29(2):  369-379.  doi:10.13287/j.1001-9332.201802.040
    Asbtract ( 377 )   PDF (993KB) ( 37 )  
    Based on the monitoring data from the plots of Changbai Mountains in the temperate zone (CBS), Guandi Mountain in the warm temperate zone (GDS), Heishiding Mountain in the subtropical zone (HSD), we analyzed the spatial distribution of tree species from three families (Pinaceae, Fagaceae, Rosaceae) and their correlation using paired correlation function g(r). The results showed that the individual number and size class structural characteristics of the trees from the three families varied among different regions. Pinaceae had high population density and a bimodal size-class structure in GDS plot but a small number and skewed normal size-class structure in CBS and HSD plots. Fagaceae had low abundance and a bimodal, skewed normal size-class structure respectively in CBS and GDS plots but a large number and an inverted J-type diameter distribution in HSD plot. Rosaceae had high abundance and a L-type size structure in GDS plot but relatively low abundance and a L-inverted and J-type size class distribution respectively in HSD and CBS plots. The trees from those three families showed different spatial distribution patterns in three different forest plots. The large size class individuals of Pinaceae were regularly distributed at small scale in CBS and GDS plots but aggregated in HSD plot, the middle and small size class ones were consis-tently aggregated in three plots. Fagaceae trees were mainly characterized by large size class and approximately distributed at random in CBS plot, but mainly characterized by middle or small size class and aggregated in GDS and HSD plots. The trees of Rosaceae were aggregated in three plots. The aggregation degree of trees from three families decreased with the increases of spatial scales. The large size class individuals of Fagaceae were negatively associated at small scale or uncorrelated with Pinaceae trees in CBS and HSD plots. The middle or small size class individuals of Fagaceae were negatively associated with Pinaceae ones in CBS and GDS plots but positively associated with Pinaceae ones in HSD plot. Trees from Pinaceae were negatively correlated with trees from Rosaceae in three plots. The middle or small size class individuals of Fagaceae were positively correlated with individuals of Rosaceae in CBS and GDS plots but negatively correlated with trees of Rosaceae in HSD plot. In conclusion, the spatial distribution patterns and associations of the trees from three families changed with the size class, research scale and had different patterns among three plots.
    Carbon, nitrogen and phosphorus stoichiometry of five common herbaceous species across islands in the Yellow Sea and the East China Sea.
    GUO Chao, TUO Bin, SU Tian, ZHENG Li-ting, LIU Xiang-yu, YIN Fang, HE Dong, YAN En-rong
    2018, 29(2):  380-388.  doi:10.13287/j.1001-9332.201802.034
    Asbtract ( 420 )   PDF (648KB) ( 50 )  
    Understanding variation of carbon (C), nitrogen (N) and phosphorus (P) stoichiometry in common plant species across islands along a latitude gradient is insightful to reveal the adaptation strategies of plant species to environmental changes. Five common herbaceous species including Artemisia argyi, Setaira viridis, Humulus japonicus, Ophiopog onjaponicus, and Oxalis corniculata were sampled in 125 plots across nine islands in Eastern China. C, N and P contents in leaves, stems, and roots of five plant species were measured, and their relationships with soil C, N and P contents as well as mean annual air temperature (MAT) and mean annual precipitation (MAP) were investigated. The results showed that the range of C, N and P contents in aboveground parts of five species across nine islands was 352.16-518.16, 10.81-34.43, 0.58-2.38 mg·g-1, while the range of C:N, N:P and C:P was 11.98-38.99, 4.67-27.47, 133.39-748.54, respectively. In terms of roots, the range of C, N and P contents of five species was 312.28-493.34, 9.26-23.27, 0.40-2.10 mg·g-1, while the range of C:N, N:P and C:P was 18.18-46.79, 8.53-37.38, 174.45-1120.40, respectively. With the increases of latitude, contents of N and P in aboveground parts increased, but N:P decreased. Relative to N content, P content showed higher variation and was largely dependent on environment. Climate factors explained 60% of the variation of N and P contents and N:P across nine islands. In contrast, N and P contents and N:P of roots were independent of latitude, with climatic factors only explained 6%-10% of their variations. The contribution of climatic factors and soil nutrients contributed to the variations of N and P contents differed between above ground parts and roots of five species. Soil N and P had significant effects on P content in roots. Soil P content was positively correlated to aboveground P content. Soil properties explained 37% of the variation in N and P contents of plant roots. Our results suggested that latitude-associated environment shifts were the main drivers of variation in N and P contents and N:P in aboveground parts, and soil nutrients especially affected variation in P in roots of five common plant species, when the effects of plant phylogeny was controlled.
    Biodiversity of subalpine meadow in Heyeping of Luya Mountain, China.
    BAI Jia-ye, LIU Wei-hua, ZHAO Bing-qing, ZHANG Qing, GUO Dong-gang
    2018, 29(2):  389-396.  doi:10.13287/j.1001-9332.201802.038
    Asbtract ( 434 )   PDF (651KB) ( 37 )  
    In this study, investigation on plant community was conducted in Heyeping subalpine meadow of Luya Mountain in Shanxi Province of China. The importance values of 36 herbaceous species, α diversity index, phylogenetic diversity index, as well as their correlations were investigated. The results showed that the species diversity of the subalpine meadow was uniformly distributed. Species richness was higher in marginal areas, indicating an ‘edge effect’. The phylogenetic structure of four plots was convergent and that of 12 plots was dispersive. The phylogenetic diversity index (PD) was positively correlated with the Petrick index, Simpson index and Shannon index, while there was no significant correlation of either the net relatedness index (NRI) or the nearest taxon index (NTI) to the α diversity indices.
    Clonal diversity and genetic structure of Enhalus acoroides populations along Hainan Island, China.
    JIANG Kai, GAO Hui, CHEN Xiao-yong
    2018, 29(2):  397-402.  doi:10.13287/j.1001-9332.201802.039
    Asbtract ( 449 )   PDF (557KB) ( 44 )  
    Seagrasses are monocotyledons that grow in intertidal and subtidal zones. Seagrass beds are among ecosystems with the highest ecosystem service value. However, seagrass beds are rapidly decline due to anthropogenic disturbances and global climate change. Enhalus acoroides, a monoecious perennial species, is the largest seagrass in stature. It distributes in tropical regions, with Hainan Island as its northern limits. Clonal diversity and genetic structure of E. acoroides populations in Hainan Island were studied to facilitate its conservation and restoration. We used four polymorphic microsatellites to genotype samples collected from four extant populations. We found low clonal and genetic diversities within populations, consistent with the expectations of genetic structure in edge populations. A large range of genetic differentiation was found between these four populations, probably due to the large range of geographic distances between them and genetic drift by local extinction and recolonization. We found no sign of recent bottlenecks in all the populations, probably due to the within-population genetic diversity being too low to show obvious reduction even after bottlenecks. We proposed suggestions on population conservation for those with high priority. Given that seagrass bed had experienced rapid decline in recent years, strengthened conservation and ecological restoration are urgently needed.
    Structure and ecological functions of soil micro-food web.
    DU Xiao-fang, LI Ying-bin, LIU Fang, SU Xiao-lin, LI Qi
    2018, 29(2):  403-411.  doi:10.13287/j.1001-9332.201802.033
    Asbtract ( 681 )   PDF (780KB) ( 178 )  
    Soil micro-food web, as a part of the detritus food webs, directly or indirectly participates in nutrient cycling by feeding on substrate and microorganisms and consequently influences the functions of terrestrial ecosystems. Here, we reviewed the research progress of soil micro-food web in recent years by focusing on its composition, structure and ecological function in soil ecosystem. The important roles of soil micro-food web in driving carbon (C) and nitrogen (N) transformation, organic matter decomposition and plant growth were reviewed through the description of energy channel and trophic cascade effects of soil micro-food web. At last, the research perspectives were put forward. Future researches should be combined with high-throughput sequencing and stable isotope techniques for better understanding the belowground ecological process and their feedback mechanisms to plant growth through modeling analysis.
    Original Articles
    Dynamic change of Pinus tabuliformis forest productivity and its response to future climate change in Shaanxi Province, China.
    HUO Xiao-ying, PENG Shou-zhang, REN Jing-yu, CAO Yang, CHEN Yun-ming
    2018, 29(2):  412-420.  doi:10.13287/j.1001-9332.201802.006
    Asbtract ( 465 )   PDF (1411KB) ( 29 )  
    This study analyzed the dynamics of net primary productivity (NPP) of Pinus tabuliformis forest under future climate scenarios in Shaanxi Province during 2015-2100, using a dynamic vegetation model (LPJ-GUESS). The results showed that in the 2015-2100 period, annual mean temperature of this region would significantly increase by 0.12, 0.23 and 0.54 ℃·10 a-1 under RCP2.6, RCP4.5 and RCP8.5 scenarios, respectively, while the annual precipitation would have no significant change under climate scenarios except RCP4.5, under which it would significantly increase by 14.36 mm·10 a-1. Compared with the NPP of P. tabuliformis forest in the historical period (1961-1990), it would increase by 1.6%-29.6% in the future period, and the enhancement could reach 45.4% at the end of this century (2071-2100) under RCP8.5 scenario. The NPP under the RCP8.5 scenario was the highest, followed by the RCP4.5 and RCP2.6 scenarios. During 2015-2100, the NPP in the northern Shaanxi region would significantly decrease with the rate of 41.00 and 21.00 g C·m-2·10 a-1 under the RCP2.6 and RCP4.5 scenarios, respectively, implying that this area has the potentiality to be carbon source.
    Multi-temporal scale analysis of impacts of extreme high temperature on net carbon uptake in subtropical coniferous plantation.
    ZHANG Mi, WEN Xue-fa, ZHANG Lei-ming, WANG Hui-min, GUO Yi-wen, YU Gui-rui
    2018, 29(2):  421-432.  doi:10.13287/j.1001-9332.201802.015
    Asbtract ( 476 )   PDF (3357KB) ( 37 )  
    Extreme high temperature is one of important extreme weathers that impact forest ecosystem carbon cycle. In this study, applying CO2 flux and routine meteorological data measured during 2003-2012, we examined the impacts of extreme high temperature and extreme high temperature event on net carbon uptake of subtropical coniferous plantation in Qianyanzhou. Combining with wavelet analysis, we analyzed environmental controls on net carbon uptake at different temporal scales, when the extreme high temperature and extreme high temperature event happened. The results showed that mean daily cumulative NEE decreased by 51% in the days with daily maximum air temperature range between 35 ℃ and 40 ℃, compared with that in the days with the range between 30 ℃ and 34 ℃. The effects of the extreme high temperature and extreme high temperature event on monthly NEE and annual NEE related to the strength and duration of extreme high tempe-rature event. In 2003, when strong extreme high temperature event happened, the sum of monthly cumulative NEE in July and August was only -11.64 g C·m-2·(2 month)-1. The value decreased by 90%, compared with multi-year average value. At the same time, the relative variation of annual NEE reached -6.7%. In July and August, when the extreme high temperature and extreme high temperature event occurred, air temperature (Ta) and vapor press deficit (VPD) were the dominant controller for the daily variation of NEE. The coherency between NEE & Ta and NEE & VPD was 0.97 and 0.95, respectively. At 8-, 16-, and 32-day periods, Ta, VPD, soil water content at 5 cm depth (SWC), and precipitation (P) controlled NEE. The coherency between NEE & SWC and NEE & P was higher than 0.8 at monthly scale. The results indicated that atmospheric water deficit impacted NEE at short temporal scale, when the extreme high temperature and extreme high temperature event occurred, both of atmospheric water deficit and soil drought stress impacted NEE at long temporal scales in this ecosystem.
    Effects of temperature on soil organic carbon mineralization rate and enzyme kinetic para-meters in temperate and subtropical forests.
    LIU Shuang, ZHANG Xin-yu, YANG Yang, TANG Yu-qian, WANG Zhong-qiang
    2018, 29(2):  433-440.  doi:10.13287/j.1001-9332.201802.001
    Asbtract ( 447 )   PDF (967KB) ( 38 )  
    We examined the effects of temperature on SOC mineralization rate (Cmin) and enzyme kinetic parameters in soils of two different latitudinal forests, i.e., broad-leaved Korean pine forest in Changbai Mountain at higher latitude and evergreen broad-leaved forest in Dinghu Mountain at lower latitude. The results showed that the soil Cmin increased with temperature, and the Cmin and Q10(Cmin) of the Changbai Mountain forest soil were higher than those of the Dinghu Mountain forest soil. The maximal rates of velocity (Vmax) and the half-saturation constant (Km) of the Changbai Mountain forest soil were higher relative to the Dinghu Mountain soil for both soil β-glucosidase (βG) and N-acetyl-β-D-glucosaminidase (NAG), but being opposite for catalytic efficiency (Vmax/Km). Both Vmax and Vmax/Km of βG and NAG increased with the increase of incubation temperature, while Km decreased, i.e., the affinity of enzymes to the substrate were increased. Inconsistent with the soil Q10 (Cmin), Q10(Vmax) and Q10(Km) of the soil βG were higher in Dinghu Mountain forest soil than those in the Changbai Mountain forest soil. The mechanisms underlying the effects of temperate variation on Cmin and the enzyme kinetic parameters were different, and thus the temperature sensitivity of Cmin and enzyme kinetic parameters should be considered differentially in the models of soil biochemical process.
    Effects of selective cutting on soil phosphorus forms and availability in Korean pine broad-leaved forest in Xiaoxing’an Mountains of China.
    ZHANG Xin, GU Hui-yan, CHEN Xiang-wei
    2018, 29(2):  441-448.  doi:10.13287/j.1001-9332.201802.009
    Asbtract ( 422 )   PDF (479KB) ( 23 )  
    In order to clarify the effects of selective cutting on soil phosphorus availability in Korean pine broad-leaved forest, surface soil (0-10 cm) samples from original Korean pine broad-leaved forest and natural forests with mild, medium and intensive cutting disturbances were collected. The Sui modified Hedley phosphorus fractionation method was used to continuously extract soil samples and analyzed the differences and changes of soil phosphorus fractions from different experimental stands. The results showed that the soil total phosphorus content of Korean pine broad-leaved forest varied from 1.09 to 1.66 g·kg-1, with the original stand and intensive cutting disturbance stand being the maximum and minimum one, respectively. The differences of soil total phosphorus content among cutting disturbance levels were significant. The Olsen phosphorus and phosphorus activation coefficients changed with an amplitude of 7.26-17.79 mg·kg-1 and 0.67%-1.07%, respectively. Both of them significantly decreased with the increase of selective cutting disturbance level. The concentrations of all P fractions except HCl-Po, i.e., H2O-Pi, NaHCO3-P, NaOH-P, HCl-Pi, Residual-P, decreased with increasing cutting disturbance levels compared with original forest. The correlation coefficient between H2O-Pi and soil Olsen phosphorus was the highest (0.98), though it only accounted for 1.5%-2.2% of the total phosphorus. NaOH-P content contributed to more than 48.0% of the total phosphorus, acknowledged as the potential source of soil phosphorus. In conclusion, selective cutting disturbance could constrain phosphorus storage and soil phosphorus availabi-lity of the Korean pine broad-leaved forests by significantly reducing the content of soil inorganic phosphorus and NaOH-Po, and such trends were positively dependent on the intensity of selective cutting.
    Relationships between leaf functional traits of Machilus pauhoi understory seedlings from different provenances and geographical environmental factors.
    YU Hua, ZHONG Quan-lin, HUANG Yun-bo, CHENG Dong-liang, PEI Pan, ZHANG Zhong-rui, XU Chao-bin, ZHENG Wen-ting
    2018, 29(2):  449-458.  doi:10.13287/j.1001-9332.201802.008
    Asbtract ( 344 )   PDF (600KB) ( 78 )  
    To understand the adaptation mechanism of Machilus pauhoi seedlings to environmental changes, leaf functional traits of M. pauhoi seedlings from nine provenances, as well as relationships between leaf traits and environmental factors were analyzed. The results showed that leaf functional traits of M. pauhoi seedlings from different provenances showed significant intraspecific variations, with the coefficient of variation ranging from 8.8% to 28.2%. Specific leaf area, leaf relative water content, leaf tissue density and leaf thickness differed significantly among seedlings from different provenances, implying high leaf morphological plasticity. Moreover, leaf tissue density was positively correlated to leaf dry matter content and leaf relative water content, but negatively correlated to specific leaf area and leaf thickness. Specific leaf area showed significantly negative correlations with leaf dry matter content and leaf area. The covariation among those traits examined here indicated that M. pauhoi seedlings could adjust and balance the combination of leaf traits in response to environmental changes. Longitude, latitude, >10 ℃ annual accumulated temperature and mean annual temperature contributed largely to the variation of leaf functional traits of M. pauhoi seedlings. Leaf thickness decreased with the increase of longitude, while leaf dry matter content and leaf relative water content increased with the increase of longitude. Leaf tissue density was positively correlated with longitude and mean annual temperature, suggesting that longitude rather than mean annual temperature had greater effects on it. Leaf area was positively correlated with >10 ℃ annual accumulated temperature and longitude, indicating that annual accumulated temperature rather than longitude had greater effects on the variation of leaf area.
    Effects of alien species Robinia pseudoacacia on plant community functional structure in hilly-gully region of Loess Plateau, China.
    ZHU Duo-ju, WEN Zhong-ming, ZHANG Jing, TAO Yu, ZENG Hong-wen, TANG Yang
    2018, 29(2):  459-466.  doi:10.13287/j.1001-9332.201802.007
    Asbtract ( 399 )   PDF (758KB) ( 39 )  
    To investigate the effects of the introduction of Robinia pseudoacacia on the functional structure of plant communities, we selected paired-plots of R. pseudoacacia communities and native plant communities across different vegetation zones, i.e., steppe zone, forest-steppe zone, forest zone in hilly-gully region of Loess Plateau, China. We measured several functional characteristics and then compared the functional structures of R. pseudoacacia and native plant communities in different vegetation zones. The results showed that the variation of the functional traits across different vegetation zones were consistent in R. pseudoacacia community and native plant community, including leaf carbon concentration, leaf nitrogen concentration, leaf phosphorus concentration, specific leaf area, and leaf tissue density. The leaf carbon concentration, leaf nitrogen concentration, and specific leaf area of the R. pseudoacacia community were significantly higher than those of the native plant community. The trend of change that the functional diversity indices, i.e., FRic, FEve, FDiv, FDis, Rao of the R. pseudoacacia community and the native plant community with vegetation zones were different. The introduction of R. pseudoacacia enhanced the plant community functional diversity in the forest zone but reduced community functional diversity in the steppe zone.
    Effects of nitrogen deposition and management intensity on stoichiometry of leaf litter in Moso bamboo forest.
    YAO Jun-neng, LYU Jian-hua, YU Wei-liang, ZHANG Jun-bo, LEI Zhao-feng, LI Quan, SONG Xin-zhang
    2018, 29(2):  467-473.  doi:10.13287/j.1001-9332.201802.003
    Asbtract ( 379 )   PDF (593KB) ( 27 )  
    In this study, a field experiment was conducted to estimate the effects of simulated nitrogen (N) deposition (low-N: 30 kg N·hm-2·a-1, moderate-N: 60 kg N·hm-2·a-1, high-N: 90 kg N·hm-2·a-1) on ecological stoichiometry of leaf litter in Moso bamboo forest under conventional management (CM) and intensive management (IM) practices. The results showed that compared with CM, IM significantly increased C, N and P concentrations of leaf litter by 9.3%, 32.4% and 22.7%, respectively, but significantly decreased C:N, C:P and N:P ratios by 17.4%, 54.3% and 44.6%, respectively. In CM Moso bamboo plots, low- and moderate-N deposition significantly increased C, N and P concentrations of leaf litter but decreased C:N, C:P and N:P, high-N deposition significantly increased C, N concentrations, C:P and N:P, but decreased P concentration. In IM Moso bamboo plots, low-N deposition significantly increased P concentration but decreased C concentrations, C:P and N:P, moderate-N deposition significantly increased N and P concentrations but decreased C concentration, C:N, C:P and N:P, high-N deposition significantly increased C:N, C:P and N:P but decreased P concentration. The interaction of management intensity and N deposition significantly influenced stoichiometry of leaf litter, except for C:N. The P concentration of leaf litter was significantly correlated with P concentration in soils.
    The relative contributions of plant quality, simulated rising temperature, and habitat to litter decomposition.
    WANG Hang, YAN Peng-fei, ZHAN Peng-fei, ZHANG Xiao-ning, LIU Zhen-ya, GUO Yu-jing, XIAO De-rong
    2018, 29(2):  474-482.  doi:10.13287/j.1001-9332.201802.002
    Asbtract ( 355 )   PDF (1036KB) ( 37 )  
    With litter bag methods, we examined mass loss rates and different chemical fractions of litters from two wetland plant species, Zizania caduciflora and Hippuris vulgaris. Those two species examined here varied significantly in their initial litter chemical traits. Experiment was performed under simulated rising temperature (1.5-2.0 ℃), and under three different habitats (air, air-water interface and water-soil interface). The results showed that, during one-year decomposition period, the mass resi-dual rates exhibited distinct seasonal dynamics, and there were strong interactive effects between seasonal dynamics and environmental factors. Different factors contributed differently for the variation of litter decomposition, 28.8% of which being explained by litter quality, 6.3% of which being explained by rising temperature, and 34.9% being explained by habitat. Along with the decomposition, the contents of different chemical fractions (easy or hard to decompose) varied greatly. Among them, nitrogen contents in H. vulgaris decreased by 53.1%, while the lignin contents increased by 45.4%. Overall, habitat was the most important factor driving litter decomposition, the second was litter quality, and rising temperature had minor effect.
    Capacity of Caragana microphylla shrub on counteracting snow movement and its influence on snow morphology in the Xilinhot Steppe, China.
    YAN Min, ZUO He-jun, DONG Zhi, LIU Bao-he, WANG Yan-jiao, WEI Xiang-hong, LI Gang-tie
    2018, 29(2):  483-491.  doi:10.13287/j.1001-9332.201802.012
    Asbtract ( 322 )   PDF (1822KB) ( 31 )  
    The aim of this study was to examine the impacts of characteristics of the shrub (shrub height, shrub width on the windward side, shrub length on the downwind side) on the snow morphology (snow height, snow width, and snow tail length) in the typical steppe of Xilinhot, China. The relationship between shrub height and parameters of snow morphology showed significant quadratic polynomial regression. The relationship between shrub width on the windward side, length on the downwind side and parameters of snow morphology showed significant power function (exponent was less than 1). The morphology and development characteristics of shrub snow were affected by the shrub characteristic parameters. Shrub height had the greatest influence on snow height. Shrub width at the windward side had the greatest influence on snow width and snow tail length. The snow morphology developed faster when the shrub was small, and then tended to be stable. The two-dimensional snow retention range model of shrub directly reflected the disturbance range of shrub to wind and the potential range of snow, indirectly reflected the capacity of shrub to retard snow movement. The three-dimensional snow blocking volume model of shrub snow directly reflected the snow resistance capacity of shrub under certain snow sources and wind conditions. Both models established here would provide a theoretical basis for estimating snow resources and preventing snow disaster in the wind blown snow area of typical steppe.
    Interspecific relationships of dominant species in the grassland community of moderately degraded tiankeng of Yunnan, China.
    JIAN Xiao-mei, SHUI Wei, CHEN Yi-ping, JIANG Cong, HU Ying, WANG Qian-feng, HUANG Meng-yuan
    2018, 29(2):  492-500.  doi:10.13287/j.1001-9332.201802.005
    Asbtract ( 355 )   PDF (1147KB) ( 26 )  
    Karst tiankeng is a special grand negative landform. The environment of tiankeng inside are independent of that outside, showing a unique characteristics of plant community. Taking a moderately degraded tiankeng with good accessibility, Bajiaxiantang as the focus, the dominant species with importance value >1 were selected to clarify the interspecific association of 11 dominant species by the multi-disciplinary approach including the variance ratio (VR) of overall association, χ2 test, association coefficient (AC) and Spearman rank correlation coefficient. The results showed that VR of overall association in this grassland community was 1.377 (which was larger than 1), indicating that this community had overall significantly positive interspecific association. Given the great difference between the positive and negative association and significantly negative correlation between heliophiles and sciophiles, the community had independent distribution. The number of positive pairs of species (26) was less than that with negative correlation (29) in Spearman correlation analysis. Combined with the difference of tiankeng’s micro-environment, dominant plant species of degraded tiankeng could be divided into three ecological groups. The grassland community in tiankeng showed circle distribution pattern.
    Responses of underground clonal storage to mowing of the alien clonal weed species Oxalis articulata.
    WANG Lu-yao, JIN Fang-mei, JIN Yi-jing, XU Jia-qing, WEN Wen, CHEN Jian-hua, YE Duo
    2018, 29(2):  501-506.  doi:10.13287/j.1001-9332.201802.004
    Asbtract ( 405 )   PDF (818KB) ( 41 )  
    Oxalis articulata, an alien clonal plant species, is widely cultivated in China as an ornamental species, and has escaped and became naturalized. Belowground storage in tubers of O. articulata may play a key role for the potential invasion. In this study, we investigated the responses of its clonal resource storage strategy to mowing, aiming to uncover the mechanism underlying their invasion from a perspective of clonal storage. We examined the changes of biomass in different organs, biomass allocation, and several functional traits of roots, tubers and leaves in O. articulata by conducting a greenhouse experiment. The results showed that significant main and interactive effects of mowing intensity and mowing frequency on some functional traits of leaves and roots were found. In contrast, tuber biomass and total biomass did not vary under different mowing treatments. The frequent mowing significantly increased the biomass allocation to tubers. These findings demonstrated that clonal storage, to some extent, could enhance the resistance of O. articulata to environmental disturbance, which might promote its invasiveness.
    Responses of stem hydraulic traits in Salix psammophila and Caragana korshinskii to manipulated precipitation variation.
    CHEN Li-ru, LI Yang-yang
    2018, 29(2):  507-514.  doi:10.13287/j.1001-9332.201802.017
    Asbtract ( 449 )   PDF (676KB) ( 50 )  
    With a precipitation manipulation experiment (Control, +45% and -50%), the responses of stem hydraulic traits in two dominant shrubs (Salix psammophila and Caragana korshinskii) of water-wind erosion crisscross region of the Loess Plateau to projected precipitation variation were examined to elucidate their adaptability to future precipitation changes. Results showed that the specific hydraulic conductivity (Ks), leaf specific conductivity (Kl) and Huber value in S. psammophila increased significantly by irrigation but showed no responses to drought. The predawn and midday leaf water potential and water transport efficiency (Ks and Kl) in C. korshinskii decreased significantly by drought, and showed no responses to irrigation. The embolism resistance across different treatments did not differ in the two shrubs. The midday native embolisms across treatments in S. psammophila were almost the same. Drought increased midday native embolism in C. korshinskii. Irrigation increased conduit diameter and conduit area per stem sap area while drought increased the vessel density and decreased the hydraulic diameter in S. psammophila. Irrigation had no effect on xylem anatomy, whereas drought increased the vessel density and wood density in C. korshinskii. These results indicated that irrigation promoted stem hydraulic function in S. psammophila, and drought decreased stem hydraulic function in C. korshinskii. C. korshinskii may be less resistant to future dry climate than S. psammophila.
    Effects of inorganic carbon supplies and light on photosynthetic functions of Pyropia haitanensis.
    JIANG Heng, ZOU Ding-hui, LOU Wen-yong
    2018, 29(2):  515-521.  doi:10.13287/j.1001-9332.201802.010
    Asbtract ( 368 )   PDF (614KB) ( 24 )  
    The increasing stocking density of algal often results in lowered carbon and light levels. In this study, Pyropia haitanensis were cultured under four different conditions, i.e., 390 μL·L-1 (ambient carbon supply) + ambient sunlight, 20 μL·L-1(decreased carbon supply) + ambient sunlight, 390 μL·L-1 + decreased sunlight (20% of ambient sunlight), 20 μL·L-1 + decreased sunlight. The activity of carbonic anhydrase (CA), photosynthetic rate and quantum efficiency of open photosynthetic system Ⅱ (Fv′/Fm′) of the algae under different temperatures were measured to investigate the effects of decreased carbon supply and lowered light on photosynthetic functions of P. haitanensis. The results showed the CA activities of the algae at decreased carbon supply and lowered sunlight was increased. The maximum Ci-saturated photosynthetic rates (Vmax) were elevated under the low sunlight compared with that under the ambient sunlight. The Vmax of the algae at low carbon seawater was lower than that at ambient carbon seawater under lowered sunlight. Under ambient sunlight, the Vmax of the decreased carbon-grown algae was higher than that of ambient carbon-grown algae. The Fv′/Fm′ values of the algae grown at lowered carbon supply and decreased sunlight conditions showed no variation at low temperature (10 ℃) and high temperature (30 ℃), whereas it was decreased by about 76.4% when cultured at 390 μL·L-1 + ambient sunlight at 200 min than that at 40 min under 30 ℃. These results suggested that decreased carbon supply and lowered sunlight intensity would improve in the capacity of HCO3- utilization and resistance to short-term temperature change in P. haitaneisis. The effects of low carbon on photosynthetic rate of the algae were dependent on light context.
    Effects of nitrate nitrogen supply on the growth, photosynthetic characteristics and 15N absorption, utilization of Malus hupehensis seedlings.
    PENG Ling, LIU Jing-jing, WANG Fen, GE Shun-feng, JIANG Yuan-mao
    2018, 29(2):  522-530.  doi:10.13287/j.1001-9332.201802.026
    Asbtract ( 319 )   PDF (751KB) ( 25 )  
    To explore the effects of different nitrate nitrogen levels (N0, N1, N2, N3 and N4 were equivalent to 0, 2.5, 5, 10, 20 mmol·L-1 15NO3- -N, respectively) on the growth, photosynthetic characteristics and 15N absorption, utilization and distribution, Malus hupehensis seedlings were grown in cultural liquid Hoagland by using the 15N-labeled tracer method. The results showed that the leaf chlorophyll content, leaf area and dry mass in different organs were the highest in N2 treatment. With the increase of 15NO3- -N application rates, the leaf net photosynthetic rate (Pn)significantly increased but tended to decease when the 15NO3--N concentration exceeded N2 treatment. In the 20th day after treatment, the root activity, root length, root surface area and number of tips of seedlings in N2 treatment were significantly higher than those in the other treatments. The distribution ratio of 15N in different organs was significantly different among those treatments. The relatively balanced distribution ratio of 15N appeared in N2 treatment, which the 15N utilization rate also reached relatively higher level. The total N content and 15N absorption of seedlings increased at low 15NO3--N concentration, reached the highest value in N2 treatment with 103.77 and 21.57 mg, and then deceased at high 15NO3--N concentration. At the 12th day after treatment, the leaf nitrate reductase (NR) activity was the highest in N2 treatment and the lowest in N4 treatment. The leaf nitrate reductase (NR) activity deceased by 84.9% in N4 treatment compared with N2 treatment at the 16th day after treatment. Our findings indicated that the photosynthesis and absorption of nitrate nitrogen were inhibited under low 15NO3--N stress, and the assimilation of nitrate nitrogen and root growth were restrained under too much higher 15NO3--N level, which was not good for the growth, nitrogen absorption and utilization of apple seedlings. The appropriate nitrogen level could promote plant growth, enhance the photosynthesis and also increase the absorption, utilization and distribution of nitrogen.
    Effects of nitrogen application rate on light interception and dry matter distribution at diffe-rent layers in wheat canopy under supplemental irrigation based on measuring soil moisture.
    ZHENG Xue-jiao, YU Zhen-wen, ZHANG Yong-li, SHI Yu
    2018, 29(2):  531-537.  doi:10.13287/j.1001-9332.201802.024
    Asbtract ( 383 )   PDF (459KB) ( 22 )  
    With the large-spike wheat cultivar Shannong 23 as test material,a field experiment was conducted by increasing the relative soil moisture content to 70% and 65% at jointing and anthesis stages. Four nitrogen levels,0 (N0), 180 (N1), 240 (N2) and 300 kg·hm-2(N3), were designed to examine the effects of nitrogen application rates on the interception of photosynthetic active radiation (PAR) and dry matter distribution of wheat at different canopy layers. The results showed that the total stem number of wheat population at anthesis stage, the leaf area index at 10, 20 and 30 days after anthesis, PAR capture ratio at upper and middle layers and total PAR capture ratio in wheat canopy on day 20 after anthesis of treatment N2 were significantly higher than those in the treatments of both N0 and N1. Those indexes showed no significant increase when the application rate increased to 300 kg·hm-2(N3). The vegetative organ dry matter accumulation of all layers at maturity stage of treatment N2 were significantly higher than N0 and N1. Compared with treatment N0 and N1, N2 increased the grain and total dry matter accumulation by 36.7% and 35.4%, 9.5% and 10.2%, respectively, but had no significant difference with treatment N3. The vegetative organ dry matter accumulation at all layers, grain and total dry matter accumulation were significantly and positively correlated with PAR capture ratio at upper and middle layers, and had no significant correlation with that at lower layer. The vegetative organ dry matter accumulation at all layers was significantly and positively correlated with grain dry matter accumulation. The application rate at 240 kg·hm-2(N2) would be the optimum treatment under the present experimental condition.
    Structure characteristics of soil and canopy and their relationships in wheat field under different tillage and application of organic fertilizer.
    ZHANG Dai-jing, ZHANG Yan-yan, WANG Yan-jie, CHEN Qian-qing, YANG Hui-li, MA Jian-hui, LI Chun-xi
    2018, 29(2):  538-546.  doi:10.13287/j.1001-9332.201802.029
    Asbtract ( 400 )   PDF (1019KB) ( 31 )  
    With the aim to optimize the structural characteristics of wheat canopy by improving topsoil structure, we examined the effects of three different tillage treatments, deep tillage (DT), shallow tillage (ST), no-tillage (NT) alone, and with application of organic fertilizer, DTF, STF and NTF, on the soil structure and wheat canopy characteristics for five years. Under the same tillage treatment, application of organic fertilizer decreased soil bulk density, the content of soil aggregates with diameter > 5 mm, the mean mass diameter (MWD), and geometric mean diameter (GMD) values of the soil aggregates with diameter >0.25 mm. Soil porosity and the content of soil aggregates with diameters of 2-5 mm and 0.25-2 mm at 20-40 cm soil layer were increased. Compared with other treatments, NTF was better in improving soil bulk density and increased soil porosity at 0-20 cm soil layer. DTF decreased the soil bulk density and the stability of mechanical aggregate with diameter > 0.25 mm at 40-60 cm soil layer, and increased soil permeability. Application of organic fertilizer decreased leaf angle index and increased leaf area index (LAI) and the net photosynthetic rate (Pn) of the flag leaf at post-anthesis stage. The lowest angle index and the highest Pn were detected in STF and DTF treatment, respectively. Results from path analysis showed that the direct path coefficients were significant from the independent variables (soil bulk density, soil porosity, R0.25 and MWD) to the dependent variables (angle index, LAI and Pn). At 0-20 cm soil layer, the increased MWD value was beneficial to the improvement of Pn and LAI. At 20-40 cm soil layer, the increased soil bulk density would optimize the leaf angle and further improve canopy light penetration. At 40-60 cm soil layer, high soil bulk density and low porosity negatively affected the value of LAI and Pn. We concluded that deep tillage or shallow tillage with application of organic fertilizer would be beneficial for improving soil structure, increasing soil permeability, optimizing wheat canopy structure, increasing canopy light harvesting rate, leaf area index and photosynthetic rate, with positive consequences on wheat yield.
    Effects of elevated ozone concentrations on enzyme activities and organic acids content in wheat rhizospheric soil.
    YIN Wei-qin, JING Hao-qi, WANG Ya-bo, WEI Si-yu, SUN Yue, WANG Sheng-sen, WANG Xiao-zhisup>1,2*
    2018, 29(2):  547-553.  doi:10.13287/j.1001-9332.201802.022
    Asbtract ( 424 )   PDF (672KB) ( 19 )  
    The elevated concentration of tropospheric ozone (O3) is an important global climate change driver, with adverse impacts on soil ecological environment and crop growth. In this study, a pot experiment was carried out in an open top chamber (OTC), to investigate the effects of elevated ozone concentration on soil enzyme activities (catalase, polyphenol oxidase, dehydrogenase and invertase), organic acids contents (oxalic acid, citric acid and malic acid) at different growth stages (tillering, jointing, heading and ripening stages) of wheat, and combined with the rhizospheric soil physicochemical properties and plant root characteristics to analyze the underlying reasons. The results showed that, elevated ozone concentration increased soil catalase, polyphenol oxidase, dehydrogenase and invertase activities at wheat ripening period to different degrees, with the effects on the activities of catalase and polyphenol oxidase being statistically significant. At the heading stage, activities of dehydrogenase and invertase were significantly increased by up to 76.7%. At the ripening stage, elevated ozone concentration significantly increased the content of citric acid and malic acid and redox potential (Eh) in rhizospheric soil, but reduced soil pH, electrical conductivity, total carbon and nitrogen. For root characteristics, elevated ozone concentrations significantly reduced the wheat root biomass, total root length and root surface area but increased the average root diameter.
    Physiological and biochemical mechanism of spermidine improving drought resistance in maize seedlings under drought stress.
    LI Li-jie, GU Wan-rong, MENG Yao, WANG Yue-li, MU Jun-yi, LI Jing, WEI Shi
    2018, 29(2):  554-564.  doi:10.13287/j.1001-9332.201802.021
    Asbtract ( 504 )   PDF (1875KB) ( 47 )  
    To explore the role of exogenous spermidine (Spd) in enhancing the resistance of maize to drought stress, 15% polyethylene glycol (PEG-6000) was used to simulate drought stress and with ‘Xianyu 335’ (drought-insensitive) and ‘Fenghe 1’ (drought sensitive) as the experiment materials, the effects of Spd (0.1 mmol·L-1) on the growth, photosynthetic characteristics, chlorophyll content, osmotic adjustment substance, membrane lipid peroxidation and root activity of maize seedlings were investigated. The results showed that the application of Spd significantly promoted the growth of maize seedlings under drought stress, increased chlorophyll content, net photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr) and water use efficiency (WUE), and decreased the enhancement of intercellular carbon dioxide concentration (Ci) in ‘Fenghe 1’. Moreover, the stomatal and non-stomatal limitations of photosynthetic ability caused by drought stress in ‘Fenghe 1’ were effectively reduced by exogenous Spd. The application of Spd increased the content of proline and soluble sugar, decreased theO2 generation rate, contents of H2O2 and MDA and cell membrane permeability, enhanced the root activity. The changes of drought-sensitive ‘Fenghe 1’ were greater than drought-tolerant ‘Xianyu 335’. These results indicated that exogenous Spd had positive effects on the seedlings to capture and converse solar energy, thus promoting photosynthesis and the growth of maize seedlings. It would also enhance the adaptability of seedlings to drought stress by reducing the production of reactive oxygen species (ROS), increasing the accumulation of osmotic adjustment substances to stabilize the cell membrane system and improving the root vigor. The positive effects of Spd was more obvious for drought-sensitive variety ‘Fenghe 1’.
    Effects of short-term granulated straw incorporation on grain yield and soil respiration in a winter wheat-summer maize cropping system.
    ZHANG Li, WANG Jing, PANG Huan-cheng, ZHANG Jun-tong, GUO Jian-jun, DONG Guo-hao
    2018, 29(2):  565-572.  doi:10.13287/j.1001-9332.201802.030
    Asbtract ( 436 )   PDF (720KB) ( 26 )  
    Direct straw return to soils often leads to poor combination between soil and straw, decreases straw decomposition and suppresses crop growth. Those problems hamper crop yield and its stability. Granulated straw with high bulk density and small volume improves the straw quality and the soil-straw combination. It remains unknown how does the practice influence soil carbon emission and grain yield. A micro-field experiment was carried out to investigate the responses of wheat and maize yields, soil respiration and soil carbon use efficiency. There are three treatments: No straw incorporation (CK), conventionally chopped straw incorporation (CCSI), and granulated straw incorporation (GSI). The results showed that the GSI treatment increased grain yield. Compared with the CK and CCSI treatments, the total yield of wheat and maize was significantly increased by 14.0% and 5.8%, respectively. Meanwhile, the GSI treatment promoted soil carbon emission. The average rate of soil respiration and the cumulative carbon emission during growing season were significantly higher than that in the CK treatment. Compared with the CCSI treatment, the rate and the cumulative amount of soil carbon emission during the wheat growing season were significantly elevated by 15.2% and 8.9%, but there was no significant difference during the maize growing season. The GSI treatment decreased the sensitivity of soil respiration to temperature and increased soil carbon use efficiency. Compared with the CK and CCSI treatments, the sensitivity of the GSI treatment was significantly decreased by 22.6% and 10.1%, and the efficiency was increased by 2.3% and 1.9%. Although granulated straw incorporation promoted soil carbon emissions, it had higher soil carbon use efficiency than conventionally chopped straw incorporation due to the higher yield. The application of granulated straw incorporation could serve as a new option of straw return to soil in Huang-Huai-Hai region. Further research was needed to understand the long-term effects of granulated straw incorporation on soil carbon emission.
    Effects of different tillage patterns on soil properties, maize yield and water use efficiency in Weibei Highland, China.
    LIU Dan, ZHANG Xia, LI Jun, WANG Xu-dong
    2018, 29(2):  573-582.  doi:10.13287/j.1001-9332.201802.023
    Asbtract ( 394 )   PDF (601KB) ( 31 )  
    An eight-year field experiment of straw returning was conducted on dark loessial soil in Weibei Highland to investigate the effects of tillage patterns on soil aggregate, soil organic carbon (SOC), corn yield and soil water use efficiency (WUE). There were six tillage patterns, including conventional tillage (CT/CT), no-tillage (NT/NT), subsoiling tillage (ST/ST), no-tillage/subsoiling tillage (NT/ST), conventional tillage/no-tillage (CT/NT) and conventional tillage/subsoiling tillage (CT/ST). The results showed that compared with CT/CT, the patterns of NT/NT, ST/ST and the rotational tillage patterns (NT/ST, CT/NT and CT/ST) decreased the mean mass diameter of soil mechanical stable aggregate. The patterns of NT/NT, ST/ST and NT/ST increased the content of soil water-stable aggregate with the particle size >0.25 mm (WR0.25) and their mean mass diameter, especially in the depth of 20-50 cm. These patterns reduced the proportion of aggregate destruction (PAD). Compared with CT/CT, the patterns of NT/ST, CT/NT, NT/NT and ST/ST increased the content of SOC in 0-10 cm soil layer. The content of SOC decreased as the increases of soil depth for all tillage patterns, but the decrease in SOC of three single tillage patterns (ST/ST, NT/NT and CT/CT) was larger than that of three rotational tillage patterns. Compared with CT/CT, the other five tillage patterns increased soil water storage in 0-200 cm soil profile, crop yield and WUE in maize. The yield and WUE in NT/ST pattern were significantly increased by 15.1% and 27.5%, respectively. Both corn yield and WUE were significantly and positively correlated with soil water storage in 0-200 cm soil profile in field during the cropping and fallow periods. Moreover, soil water storage during the cropping period was positively correlated with WR0.25, but negatively correlated with PAD in 0-50 cm soil layer. Particularly, maize yield, WUE and soil water storage during the cropping period were closely related to WR0.25 in 20-50 cm soil layer and PAD. Both WUE and soil water storage during the cropping period was correlated with the SOC content in 0-10 cm soil layer. With respect to the soil properties, crop yield and WUE, the tillage pattern of NT/ST was the best stratety in dark loessial soil for spring maize growth in Weibei Highland.
    Photosynthetic physio-ecological characteristics in soybean leaves at different CO2 concentrations.
    YE Zi-piao, KANG Hua-jing, DUAN Shi-hua, WANG Yi-juan
    2018, 29(2):  583-591.  doi:10.13287/j.1001-9332.201802.025
    Asbtract ( 473 )   PDF (796KB) ( 41 )  
    The availability of CO2, a substrate for photosynthesis, affects the photosynthesis process and photosynthate production. Using the Li-6400-40B, we measured the photosynthetic electron transport rate and the photosynthetic light-response curves of soybean (Glycine max) leaves at different CO2 concentrations (300, 400, 500 and 600 μmol·mol-1). By fitting these parameters with a mechanistic model characterizing the light response of photosynthesis, we obtained aseries of photosynthetic parameters, eco-physiological parameters, as well as the physical parameters of photosynthetic pigments. The results showed that the electronic use efficiency, maximum electron transport rate, and maximum net photosynthetic rate increased with the increase of CO2 concentration. The light compensation point and dark respiration rate decreased with the increase of CO2 concentration. In addition, the light-use efficiency and intrinsic (instantaneous) water-use efficiency increased with the increase of CO2 concentration, and their values differed significantly among different CO2 concentrations. There was no significant difference on the maximum carboxylation efficiency among different CO2 concentrations. Those results suggested that CO2 concentration could affect the primary light reaction of photosynthesis in soybean leaves, and thus higher CO2 concentration could decrease the minimum average lifespan of excitons at the lowest excited state, which would enhance the velocity of light energy transport and the use efficiency of photosynthetic electron flow.
    Phosphorus application effects and input threshold of Chinese cabbage in the oasis irrigation region.
    LIAN Cai-yun, MA Zhong-ming
    2018, 29(2):  592-598.  doi:10.13287/j.1001-9332.201802.027
    Asbtract ( 329 )   PDF (657KB) ( 20 )  
    To resolve the problem of higher application and lower use efficiency of phosphorus fertilizer of Chinese cabbage (Brassica pekinensis), the yield, use efficiency of phosphate fertilizer and soil phosphate balance were examined by a located field trial in Zhangye Observation and Experiment Station of the Agro-ecological Environment in oasis irrigation region from 2011 to 2013. The results showed that the yield increased with the increase of phosphorus fertilization rate from 0 to 112.52 kg P·hm-2, beyond which there would be no further enhancement. The yield was 5489.1 kg·hm-2 at 112.52 kg P·hm-2 treatment. This treatment increased the yield by 13.3%-23.8%, under which the phosphorus use efficiency was 14.2%. Soil Olsen-P and CaCl2-P were positively correlated. For 111.1 kg P·hm-2 treatment, the content of soil Olsen-P was 24.22 mg·kg-1, with no phosphorus leaching and no pollution. At the rate of 60.17 kg P·hm-2, there was a balance between phosphorus input and output and the phosphate demand of Chinese cabbage being met. In conclusion, the optimal phosphorus threshold was 60.17-112.52 kg·hm-2 for Chinese cabbage, the amount at which could reduce the risk of phosphorus pollution.
    Differences of vegetation phenology monitoring by remote sensing based on different spectral vegetation indices.
    ZUO Lu, WANG Huan-jiong, LIU Rong-gao, LIU Yang, SHANG Rong
    2018, 29(2):  599-606.  doi:10.13287/j.1001-9332.201802.019
    Asbtract ( 496 )   PDF (2200KB) ( 52 )  
    Vegetation phenology is a comprehensive indictor for the responses of terrestrial ecosystem to climatic and environmental changes. Remote sensing spectrum has been widely used in the extraction of vegetation phenology information. However, there are many differences between phenology extracted by remote sensing and site observations, with their physical meaning remaining unclear. We selected one tile of MODIS data in northeastern China (2000-2014) to examine the SOS and EOS differences derived from the normalized difference vegetation index (NDVI) and the simple ratio vegetation index (SR) based on both the red and near-infrared bands. The results showed that there were significant differences between NDVI-phenology and SR-phenology. SOS derived from NDVI averaged 18.9 days earlier than that from SR. EOS derived from NDVI averaged 19.0 days later than from SR. NDVI-phenology had a longer growing season. There were significant differences in the inter-annual variation of phenology from NDVI and SR. More than 20% of the pixel SOS and EOS derived from NDVI and SR showed the opposite temporal trend. These results caused by the seasonal curve characteristics and noise resistance differences of NDVI and SR. The observed data source of NDVI and SR were completely consistent, only the mathematical expressions were different, but phenology results were significantly different. Our results indicated that vegetation phenology monitoring by remote sensing is highly dependent on the mathematical expression of vegetation index. How to establish a reliable method for extracting vegetation phenology by remote sensing needs further research.
    Spatial-temporal pattern of sustainable intensification of agricultural land-use in Shandong Province, China.
    NIU Shan-dong, LYU Xiao, SHI Yang-yang
    2018, 29(2):  607-616.  doi:10.13287/j.1001-9332.201802.020
    Asbtract ( 442 )   PDF (1767KB) ( 53 )  
    Under the theoretical framework of sustainable intensification of agricultural land-use (SIALU), We used material flow analysis (MFA) method to establish evaluation index system for SIALU by utilizing data in 2000, 2005, 2010 and 2015 to quantify the level of SIALU of 17 cities in Shandong Province, and analyzed the variation in input-output of resources factors of agricultural land, spatial distribution of resource productivity and environmental economic efficiency, in order to reveal spatial-temporal differentiation of SIALU. Results showed that the direct material input to agricultural lands decreased, whereas hidden flow, stock and pollutant emissions increased gradually from 2000 to 2015. The material productivity of all cities in the province showed that the coastal areas in the peninsula were relatively lower than the southern region, and the level of material productivity in the northwest region was relatively higher. Environmental economic efficiency was gradually enhanced, and the western region was relatively higher than coastal area of the peninsula. During the period examined here, the spatial pattern of SIALU of various cities showed clustered distribution change, with the western region tending to gradually increase and the eastern region tending to gradually reduce. The dynamics of SIALU among different regions were divided into six grades: Northwestern Shandong > Northern Shandong > Southwestern Shandong > Southern Shandong > Central Shandong > Coastal areas of Shandong Peninsula.
    Temporal characteristics of soil fertility of cropland requisition-compensation in the typical region of Yangtze River Delta, China.
    XU Zhi-chao, YU Dong-sheng, PAN Yue, WANG Xi-yang, HUANG Jing-jing, SUN Bo
    2018, 29(2):  617-625.  doi:10.13287/j.1001-9332.201802.014
    Asbtract ( 407 )   PDF (2260KB) ( 19 )  
    Based on the satellite image in 1984, 2000 and 2016, we analyzed the temporal and spatial variation of cropland requisition-compensation in Changshu City, Jiangsu Province. Based on ArcGIS and the data of soil samples, membership function with integrated fertility index were used to evaluate the soil fertility in 1984 and 2000, respectively. The overlay analysis had been used to reveal the characteristics of soil fertility of cropland requisition-compensation between the period of 1984 to 2000 and 2000 to 2016. Results showed that the cropland reduced by 1/3 from 1984 to 2016, which was occupied by water area (51.7%) and residential, industrial and mining land (41.4%) between 1984 to 2000, while between 2000 to 2016 cropland was occupied dominantly by residential, industrial and mining land (80.8%). The soil fertility of in 65.5% of the total area of Changshu increased while the decreasing part just accounted for 3.9% from 1984 to 2000. At the same time, soil fertility was higher in the south area of Changshu City than other area. The quantity and quality of cropland requisition-compensation were not balanced, with the serious status of occupying more cropland but replenishing less, occupying fertile cropland and replenishing poor one in former period, and occupying more cropland and replenishing less, occupying poor cropland and replenishing poor one in the later period. The trend of cropland shrinking had not been altered, and the cropland compensation in different places was epidemic. The quality of cropland compensation in different places and the temporal characteristic of soil fertility should be highlighted for the balance of cropland requisition-compensation.
    Characteristics of temporal-spatial differentiation in landscape pattern vulnerability in Nansihu Lake wetland, China.
    LIANG Jia-xin, LI Xin-ju
    2018, 29(2):  626-634.  doi:10.13287/j.1001-9332.201802.018
    Asbtract ( 538 )   PDF (1292KB) ( 24 )  
    With remote sensing images from 1985, 2000 Lantsat 5 TM and 2015 Lantsat 8 OLI as data sources, we tried to select the suitable research scale and examine the temporal-spatial diffe-rentiation with such scale in the Nansihu Lake wetland by using landscape pattern vulnerability index constructed by sensitivity index and adaptability index, and combined with space statistics such as semivariogram and spatial autocorrelation. The results showed that 1 km × 1 km equidistant grid was the suitable research scale, which could eliminate the influence of spatial heterogeneity induced by random factors. From 1985 to 2015, the landscape pattern vulnerability in the Nansihu Lake wetland deteriorated gradually. The high-risk area of landscape pattern vulnerability dramatically expanded with time. The spatial heterogeneity of landscape pattern vulnerability increased, and the influence of non-structural factors on landscape pattern vulnerability strengthened. Spatial variability affected by spatial autocorrelation slightly weakened. Landscape pattern vulnerability had strong general spatial positive correlation, with the significant form of spatial agglomeration. The positive spatial autocorrelation continued to increase and the phenomenon of spatial concentration was more and more obvious over time. The local autocorrelation mainly based on high-high accumulation zone and low-low accumulation zone had stronger spatial autocorrelation among neighboring space units. The high-high accumulation areas showed the strongest level of significance, and the significant level of low-low accumulation zone increased with time. Natural factors, such as temperature and precipitation, affected water-level and landscape distribution, and thus changed the landscape patterns vulnerability of Nansihu Lake wetland. The dominant driver for the deterioration of landscape patterns vulnerability was human activities, including social economy activity and policy system.
    Landscape pattern and its vulnerability of Nansihu Lake basin during 1980-2015.
    XU Yan, SUN Xiao-yin, ZHANG Da-zhi, SHAN Rui-feng, LIU Fei
    2018, 29(2):  635-642.  doi:10.13287/j.1001-9332.201802.013
    Asbtract ( 529 )   PDF (2258KB) ( 39 )  
    Landscape pattern and its vulnerability have direct impacts on ecological environment in the basin. In order to protect the ecological security in Nansihu Lake basin, we analyzed the changes of landscape pattern based on seven sets of land use data (1980-2015), with landscape adaptability index (LAI) and landscape sensitivity index (LSI) being used to build the landscape vulnerability index (LVI). The spatial distribution and changes of LVI were analyzed. Results showed that the percentage of arable land areas decreased by 4.6% and construction land areas increased by 39.7% from 1980 to 2015. Other land use types showed fluctuating changes. The areas of forest land, grassland, and unused land decreased while water area increased. The arable land was the dominant land use type from 1980 to 2015 in this area. The degree of fragmentation of arable land and water area in the basin increased, whereas other land use types decreased. The fragmentation of whole basin decreased, but connectivity among landscape types enhanced. The irregularity and complexity of landscape pattern decreased, but diversity and evenness of landscape pattern displayed an increasing trend. With respect to LVI in different periods, the eastern part of the basin was higher than the western part, while the northern part was higher than the southern part. The spatial distribution of LVI was related to topography, layout of landscape types and change of land use. The LVI of Nansihu Lake basin showed a decline trend during 1980-2015. In the eastern part of the basin, higher level of LVI gradually dispersed and was replaced by lower level. In the northwest, the recovery of LVI was obvious. In the south and southwest parts, LVI was consistently low.
    Simulation of rainfall and snowmelt runoff reduction in a northern city based on combination of green ecological strategies.
    HAN Jin-feng, LIU Shuo, DAI Jun, QIU Hao
    2018, 29(2):  643-650.  doi:10.13287/j.1001-9332.201802.016
    Asbtract ( 341 )   PDF (1401KB) ( 26 )  
    With the aim to control and reduce rainfall and snowmelt runoff in northern cities in China, the summer runoff and spring snowmelt runoff in the studied area were simulated with the establishment of storm water management model (SWMM). According to the climate characteristics and the situation of the studied area, the low impact development (LID) green ecological strategies suitable for the studied area were established. There were three kinds of management strategies being used, including extended green roof, snow and rainwater harvesting devices, and grass-swales or trenches. We examined the impacts of those integrated green ecological measures on the summer rainfall and spring snowmelt runoff and their mitigation effects on the drainage network pressure. The results showed that the maximum flow rates of the measured rainfall in May 24th, June 10th and July 18th 2016 were 2.7, 6.2 and 7.4 m3·s-1 respectively. The peak flow rates at different return periods of 1, 2, 5, 10 years were 2.39, 3.91, 6.24 and 7.85 m3·s-1, respectively. In the snowmelt period, the peak flow appeared at the beginning of March. The LID measures had positive effect on peak flow reduction, and thus delayed peak time and relieved drainage pressure. The flow reduction rate was as high as 70%. Moreover, the snow harvesting devices played a positive role in controlling snowmelt runoff in spring.
    Double-ambient CO2 concentration affects the growth, development and sucking behavior of non-target brown plant hopper Nilaparvata lugens fed on transgenic Bt rice.
    LU Yong-qing, DAI Yang, YU Xiu-ying, YU Fu-lan, JIANG Shou-lin, ZHOU Zong-yuan, CHEN Fa-jun
    2018, 29(2):  651-658.  doi:10.13287/j.1001-9332.201802.036
    Asbtract ( 358 )   PDF (937KB) ( 17 )  
    In recent years, the two issues of climate change including elevated CO2 etc., and resistance of transgenic Bt crops against non-target insect pests have received widespread attention. Elevated CO2 can affect the herbivorous insects. To date, there is no consensus about the effect of elevated CO2 on the suck-feeding insect pests (non-target insect pests of transgenic Bt crops). Its effects on the suck-feeding behavior have rarely been reported. In this study, CO2 levels were set up in artificial climate chamber to examined the effects of ambient (400 μL·L-1) and double-ambient (800 μL·L-1) CO2 levels on the suck-feeding behavior, growth, development, and reproduction of the non-target insect pest of transgenic Bt rice, brown planthopper, Nilaparvata lugens. The results showed that CO2 level significantly affected the egg and nymph duration, longevity and body mass of adults, and feeding behavior of the 4th and 5th instar nymphs, while had no effect on the fecundity of N. lugens. The duration of eggs and nymphs, and the longevity of female adults were significantly shortened by 4.0%, 4.2% and 6.6% respectively, the proportion of the macropterous adults was significantly increased by 11.6%, and the body mass of newly hatched female adults was significantly decreased by 2.2% by elevated CO2. In addition, elevated CO2 significantly enhanced the stylet puncturing efficiency of the 4th and 5th instar nymphs of N. lugens. The duration ofphloem ingestion of the N4b waveform was significantly prolonged by 60.0% and 50.1%, and the frequency significantly was increased by 230.0% and 155.9% for the 4th and 5th instar nymphs of N. lugens by elevated CO2, respectively. It was concluded that double-ambient CO2 could promote the growth and development of N. lugens through enhancing its suck-feeding, shorten the generation life-span and increase the macropertous adults’ proportion of N. lugens. Thus, it could result in the occurrence of non-target rice planthopper N. lugens and make the transgenic Bt crops face with harm risk due to migration and diffusion of N. lugens under elevated CO2.
    The role of white gene and its mechanism during the formation of curly wing in Drosophila melanogaster.
    WU Cheng-li, LIN Xin-da, JIANG Yan-yun, MENG Shuai-shuai
    2018, 29(2):  659-668.  doi:10.13287/j.1001-9332.201802.032
    Asbtract ( 461 )   PDF (1221KB) ( 30 )  
    Curly wing is one of the most frequently used genetic markers in Drosophila melanogaster, but its molecular mechanism is remained unclear. Previous results have showed that physicochemical stimulation would affect the formation of the cruly wing. Our recent study found that H2O2 could not only affect the eclosion rate of D. melanogaster, but also induce the formation of curly wing. Here, we aimed to uncover the specific factors influencing the formation of curly wing in D. melanogaster via changing the concentration of H2O2 and the temperature as well as the time of H2O2 treatment. We measured the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-PX), in order to examine the effects of H2O2 on antioxidative capacity of D. melanogaster. The results showed that the eclosion rate of D. melanogaster was inversely correlated with the concentration of H2O2. The change of temperature, H2O2 concentration and the period of H2O2 treatment affected the degree of the curl and the proportion of the curly wing. The white mutant flies responded most significantly to these three conditions, the mini-white (white gene reverse mutation) flies could rescue the curly phenotype, and responded similarly to the wild type OR. H2O2 had effects on the formation of the curly wing which contained the Cy mutation, leading to increased rate of the curly wing. D. melanogaster treated with H2O2 would reduce the antioxidative capacity. Results from real-time quantitative PCR showed that H2O2 treatment resulted in a change in gene expression. The formation of curly wing was a complicated process, and H2O2 might act as a signaling molecule or indirectly affect certain factors in the formation of curly wing in D. melano-gaster. This process might share the same signaling pathway with the Cy mutant, or might be regulated by different modulating patterns.
    Reviews
    Advances in the studies on topographic effects of vegetation indices.
    ZHANG Hui, LI Ping-heng, ZHOU Guo-mo, ZHOU Yu-feng
    2018, 29(2):  669-677.  doi:10.13287/j.1001-9332.201802.011
    Asbtract ( 422 )   PDF (1299KB) ( 95 )  
    Vegetation index is a key indicator for qualitative and quantitative assessment of green vegetation, which has been widely used in vegetation monitoring. Forests are often distributed in mountainous areas with complex topography, which is one of the main factors of accurate retrieval of forest vegetation information. Here, we analyzed the topographic effects on canopy reflectance using a geometric optical model. The responses of complete ratio vegetation indices [simple ratio index (SR), normalized difference vegetation index (NDVI) and moisture adjusted vegetation index (MAVI)], incomplete ratio vegetation indices [enhanced vegetation index (EVI) and soil adjusted vegetation index (SAVI)], non-ratio vegetation indices [reduced simple ratio (RSR), modified normalized difference vegetation index (MNDVI), greenness vegetation index (GVI)] and, topography adjusted vegetation index [topography adjusted vegetation index (TAVI)] to topography were discussed in detail, with the aim to provide reference for selecting vegetation index in complex terrain mountainous area. The shortcomings of current literatures about the topographic effects on vegetation indices were analyzed and the future research directions were prospected.
    Application of non-invasive microelectrode ion flux estimation technique in crop stress physiology.
    LIU Ke, ZHANG Bing-lin, ZHANG Wen-ying, ZHANG Yun-bo, TIAN Xiao-hai
    2018, 29(2):  678-686.  doi:10.13287/j.1001-9332.201802.028
    Asbtract ( 479 )   PDF (1012KB) ( 29 )  
    Non-invasive microsensing technique has been widely used in evaluating the adaptive responses of plant cells and tissues to abiotic stresses. One of the representative techniques is the microelectrode ion flux estimation (MIFE), which allows concurrent quantification of net fluxes with high spatial and temporal resolution. More importantly, this technique permits simultaneous recording of ion concentration and mobility with less intervention to the in situ physiological status. With the availability of such advanced technique, the last three decades have seen a significant progress towards the role of ion signaling in a variety of abiotic stresses including salinity, extreme temperature, osmotic stress, hypoxia, and drought. In this review, we gave a brief introduction of the MIFE working principles and focused on its applications in detecting ion responses to various abiotic stresses.