Table of Content

10 December 2016, Volume 35 Issue 12

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Provenance zone allocation and validation for reconstruction of historical forest landscape in Changbai Mountains.

ZHOU Sheng-nan1,2, LIANG Yu1*, HE Hong-shi3,4, WU Zhi-wei1

2016, 35(12):  3137-3147. 

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For the sake of studying the formation mechanism of forest distribution and succession process differences among four terrestrial aspects of Changbai Mountains, the forest succession dynamics after the volcano super eruption occurred 800 years ago was to be reconstructed. Especially, the role of seed dispersal in the forest succession on tephra bare land was emphasized. Provenance zone was an intact and primeval forest ecological system after the volcano eruption, of which the forest composition, stand structure and succession dynamics can keep stable in long term regardless of any interference, and it provided sufficient seeds for the vegetation recovery on tephra bare land. This study defined the distribution range of tephra bare land after Changbai volcano erupted by integrating previous research results and a 15km extension outside the tephra bare land as provenance zone. In order to prove that provenance zone is a stable forest ecosystem and pave the way for the forest landscape reconstruction on tephra bare land, a spatially explicit forest landscape model LANDIS PRO 7.0 was used to simulate the 800 years long dynamic changes of forest aboveground biomass and species distribution area in provenance zone. Moreover, the simulation results were calibrated and validated using inventory data and data derived from published papers. The results showed that forest aboveground biomass in provenance zone kept relatively stable either in broadleaved Korean pine forest belt, sprucefir forest belt or at the whole landscape scale. Both the initialization biomass of major species in broadleaved Korean pine forest belt, sprucefir forest belt and the longterm results simulated at landscape scale were in the range of field survey and previous researches. The goodness of fit test value 〖AKe-〗 (%), MAE (%), RMSE (%) and ME were less than 10. Little differences were found between model initialization biomass, longterm simulation results and field survey or previous researches. A reasonable provenance zone allocation, calibration and validation for the simulation results and an effective stability analysis for the forest ecosystem in provenance zone were beneficial to enhancing the veracity of forest succession simulation on tephra bare land. It is of significance to explain the present differences of forest distribution regulations and succession processes among different aspects of Changbai Mountains as well as to predict its future forest succession dynamics.

 

Effects of canopy structure on understory vegetation in shelterbelt forests along the middle and upper reaches of Pearl River.

TAN Yi-bo1,2,3, HE Qin-fei1,2,3, ZHENG Wei1,2,3, PENG Yu-hua1,2,3, HOU Yuan-rui1,2,3, HE Feng1,2,3, SHEN Wen-hui1,2,3*

2016, 35(12):  3148-3156. 

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Understory vegetation of shelterbelt forest is important for water conservation, soil retention and ecosystem service enhancement. Five types of shelterbelts along the middle and upper reaches of Pearl River in Du’an, Guangxi were observed, including Eucalyptus robusta forest, Zenia insignis forest, Pinus massoniana forest, Pinus massoniana + Schima superba mixed forest and Cyclobalanopsis glauca forest, to study the effect of canopy structure and understory light on vascular species composition and regeneration. We used DMCLX5 and external Nikon FC-E8 fisheye lens to record canopy openness (CO), leaf area index (LAI), transmitted direct solar radiation, transmitted diffuse solar radiation and transmitted total solar radiation, and investigated relations among the indexes and their effects on the understory vegetation. The results showed that: 1) P. massoniana + S. superba mixed forest was more conducive to maintaining shrub layer diversity than other pure forests; 2) The canopy structure indexes (CO and LAI) were significantly correlated with understory light indicators (P<0.001), and canopy structure had a greater effect on transmitted diffuse solar radiation than on transmitted direct solar radiation; 3) CO and understory light were significantly negatively correlated to shrub layer species richness (S) and Shannon index (H) (P<0.001), suggesting that higher light in understory did not facilitate the maintenance of the shrub layer diversity. We concluded that canopy structure was a key factor affecting the shrub diversity and regeneration, and the interspecific competition between shrub layer and herb layer might be another important factor. To improve ecosystem services of the forests, we recommend planting associated tree species to increase canopy density, promoting the development of shrub layer species. For herb layer improvement, single dominant herb species should be moderately reduced in coverage to provide space for other species’ regeneration.

Response of photosynthetic rate of Salix gordejevii and Caragana microphylla to light intensity and CO₂ concentration in the dune-meadow transitional area of Horqin sandy land.

LU Yang, LIU Ting-xi*, YAN Xue, DUAN Li-min, ZHANG Sheng-wei, HAN Chun-xue

2016, 35(12):  3157-3164. 

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The light response curves and CO₂ response curves of Caragana microphylla and Salix gordejevii in the dunemeadow transitional area of Horqin sandy land were measured using a Li-6400XT portable photosynthesis system. The measured data were fitted using a rectangular hyperbola model, a nonrectangular hyperbola model, and a modified rectangular hyperbola model of the photosynthetic response to light and intercellular CO₂ concentration, respectively. The results showed that the modified rectangular hyperbola model could better fit the light response and CO₂ response curves. However, there were significant differences in photosynthetic characteristic parameters between the two plants, due to the effects of the desert environment. C. microphylla showed a lower light compensation point and CO₂ compensation point, but a higher light saturation point than S. gordejevii. This suggested that C. microphylla had a stronger ability to adapt to the environment. The apparent quantum yield of S. gordejevii was greater than that of C. microphylla, which indicated that S. gordejevii had a high conversion efficiency of light energy. In addition, C. microphylla presented a lower rate of dark respiration than that of S. gordejevii. When the CO₂ concentration reached saturation, the maximum net photosynthetic rates of C. microphylla and S. gordejevii were 44.5 and 29.7 μmol·m^-2·s^-1 respectively, which were 3.98 and 1.87 times of those under saturation light. A habitat with highCO₂ concentration promoted the growth of S. gordejevii, while C. microphylla formed the accumulation of organic matter at a lower CO₂ concentration. At the same time, C. microphylla had high efficiency of carboxylation and a strong ability of CO₂ assimilation.

Changing characteristics of main structural indexes of community during the expansion of moso bamboo forests.

LIU Xi-zhen, FAN Shao-hui*, LIU Guang-lu*, PENG Chao

2016, 35(12):  3165-3171. 

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To clarify the changes of main structural indexes of community during the expansion of moso bamboo forests (Phyllostachys edulis), the interfaces of bamboobroadleaved forest, bambooChinese fir forest and bambooabandoned land were selected by setting transects. The results indicated that with the expansion of bamboo forests to broadleaved forests, diameter at breast height (DBH), biomass, leaf area index (LAI), litterfall amount, carbon (C), nitrogen (N) and phosphorus (P) contents, C∶P and N∶P showed a decreasing trend. With the expansion of bamboo forests to Chinese fir forests, the DBH and biomass of forefront bamboos were low while they were high for bamboo in the middle of interface. LAI, litterfall amount and C and N contents decreased with the increasing indensity of bamboo to Chinese fir, while litterfall P content, litterfall C∶P and N∶P increased with the increasing proportion of bamboo to Chinese fir. With the expansion of bamboo forests to abandoned land, DBH, biomass, LAI, litterfall biomass, C∶P and N∶P increased with the increasing proportion of bamboo while the contents of C, N and P declined. Overall, with the expansion of bamboo forests to broadleaved forests, Chinese fir forests and abandoned land, DBH, LAI and the quantity and quality of litterfall were changed adaptively. Specifically, when bamboo expanded to broadleaved forests, the growth of bamboo was promoted by increasing the DBH, LAI and litterfall quantity in forefront interface, as well as higher contents of C, N and P. With the expansion of bamboo forests to Chinese fir forests, the limitation of P for bamboo growth was reduced by increasing the LAI, DBH and litterfall C∶P and N∶P. With the expansion to abandoned land, the body size and LAI of bamboo were reduced to accommodate a relatively extreme environmental condition; Litterfall amount, P content and N∶P increased with the increase of DBH.

Effects of soil fauna on the concentrations of dissolved organic carbon and total dissolved nitrogen in four types of foliar litters in different phenophases in Sichuan Basin.

LIAO Shu1,2, YANG Wan-qin1,2, PENG Yan1,2, LI Jun1,2, TAN Yu1,2, TAN Bo1,2, WU Fu-zhong1,2*

2016, 35(12):  3172-3182. 

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A field litterbag experiment using four dominant types of foliar litters (Cinnamomum longepaniculatum, Pinus massoniana, Quercus acutissima and Cryptomeria fortune) in the Sichuan Basin was conducted at two subtropical forests from November 2013 to October 2014. Airdrying foliar litters were placed in nylon litterbags (20 cm × 20 cm in size, 10 g per litterbag) with mesh sizes of 0.04 mm on the bottom and 0.04 mm (to exclude soil fauna) or 3.00 mm (to permit soil fauna in) on the top. Samples were harvested in different phenophases (litter falling, budding, expanding, maturing and senescing periods) and were used to determine the concentrations of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) in these foliar litters. After one year of decomposition, the DOC concentrations in the four foliar litters tended to decrease, whereas TDN concentrations tended to increase. Compared with the no soil fauna treatment, the DOC concentrations in foliar litters significantly decreased but the TDN concentrations significantly increased in the treatment with soil fauna, and the decrease of DOC concentration and the increase of TDN concentration were more obvious in the C. longepaniculatum and C. fortune litter, respectively. The effects of soil fauna on DOC and TDN concentrations were stronger in the leaf senescing and leaf falling periods, respectively. These results indicated that soil fauna significantly affects the decomposition of dissolved carbon and nitrogen in foliar litter, supporting the phenomenon of nitrogen sequestration during litter decomposition. Furthermore, the decomposed nitrogen in foliar litter promoted by soil fauna during the growing season is favorable for the requirement of nutrients for plant growth.

Soil microbial properties in Larix principisrupprechtii plantations of different ages in Mt. Taiyue, Shanxi, China.

WU Ran, KANG Feng-feng, HAN Hai-rong*, CHENG Xiao-qin, ZHOU Wen-song, WANG Luo-xin, CHEN Jing, TIAN Ping

2016, 35(12):  3183-3190. 

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Soil microorganisms play an important role in carbon and nitrogen cycling. Changes in litterfall and soil properties due to stand age can have important implications to soil carbon (C) and nutrient cycling via microbial pathway. Soil degradation has widely occurred in Larix principisrupprechtii plantation because of its simple forest structure; however, little is known about how soil nutrients are related to soil microbial properties. Here we determined soil microbial responses to different aged L. principisrupprechtii plantations (18-, 35-, and 51-year-old) in Taiyue Mountain of Shanxi Province. The results showed that soil microbial biomass C and the proportion of microbial biomass C to the sum of microbial biomass C and dissolved organic C increased with the increase of stand age. Soil microbial biomass C/N ratio in the 51-year-old L. principisrupprechtii plantation was the highest (13), being 60% higher than that in the 18- and 35-year-old L. principisrupprechtii plantations. The microbial carbon entropy ranged from 1.5% in the 35-year-old L. principisrupprechtii plantation to 2.8% in the 18-year-old L. principisrupprechtii plantation. Soil microbial biomass N, fungal Shannon diversity, soil and litter C/N ratios decreased in the following order: 35yearold > 18yearold > 51-year-old plantations. Fungal community structure diversity had a direct effect on soil microbial biomass C, while litter C/N had a significant effect on soil microbial biomass N, and soil and microbial biomass C/N ratios were the direct factors regulating soil fungal community structure diversity. In general, the active organic C content in the 35-year-old L. principisrupprechtii plantation was lower than those in the other two plantations, and its carbon pool was more stable and nutrient situation was better.

Characteristics of soil dissolved organic carbon and microbial biomass carbon in different urban forest communities.

TAO Xiao, FAN Wei, YANG Chun, WANG Ze-fu, XU Xiao-niu*

2016, 35(12):  3191-3196. 

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Soil dissolved organic carbon (DOC) and microbial biomass carbon (MBC) play an important role in ecosystem carbon cycle. In order to better understand the characteristics of soil DOC contents and MBC  and their controlling factors in urban forest, three forest types including Metasequoia glyptostroboides, Cinnamomum camphora, and Cedrus deodara were selected in Hefei City. The results showed that soil DOC contents were significantly influenced by forest type (P<0.05). The annual averages of soil DOC contents at the depth of 0-30 cm in M. glyptostroboides, C. deodara and C. camphora forests were 80.35, 60.13, and 43.36 mg·kg-1 respectively, and decreased with the increase of soil depth in general. The DOC contents in M. glyptostroboides and C. deodara forest soils were higher in summer and autumn than in winter, while a minimum DOC value was observed in C. camphora forest soil in June. The annual average values of MBC at the depth of 0-30 cm were in the order of M. glyptostroboides (412.84 mg·kg^-1) > C. deodara (358.85 mg·kg^-1) > C. camphora (283.40 mg·kg^-1). The soil MBC was significantly influenced by soil layer (P < 0.05), and generally decreased as the soil depth increased. The MBC values of different forest types were higher in summer and autumn than in winter. The correlation analysis showed that DOC contents and MBC were significantly positively correlated with the contents of soil organic carbon in M. glyptostroboides and C. camphora forests (P<0.01), while significantly positively correlated with root biomass in C. deodara forest (P<0.01), which suggested that exudates and decomposition of roots might be important sources of soil carbon for C. deodara forest.

Effects of shrubs on the growth of saplings of Pinus tabuliformis plantations on the Loess Plateau.

HAN Bing-bing, WANG Xiao-an*, LI Jing, WANG Li-juan, YUAN Zhi-jian

2016, 35(12):  3197-3204. 

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In order to explore the effects of shrubs on the growth of 9-year-old saplings of Pinus tabuliformis on the Loess Plateau, the saplings were planted in 3 types of habitats: the edge of shrubs, the central of shrubs and shrubcutting release area. The characteristics of crown shapes and the growth conditions of currentyear trunk, branch and leaf of samplings were compared. The results showed that the tree height was not significantly different among the 3 habitats. The crown width, living crown ratio, the duration years of green leaves in the branch, basal diameter of the saplings all changed with the same pattern across the three habitats, being ranked as the edge of shrubs>shrubcutting release area>the central of shrubs; however, the height under branch showed an opposite pattern among habitats. The crown shapes did not differ between the central of shrubs and shrubcutting release area. The growth of the currentyear trunk, branch and leaf of P. tabuliformis was affected by shrubs only when the saplings were lower than the shrubs. The negative effects of shrubs on the growth of such saplings were alleviated by forest tending measures in the shrubcutting release area. The saplings changed their crown shape by selfpruning. They would take some bionomic strategies to adapt to the environment when they were shaded by the shrubs, such as allocating more biomass to the growth of length than to the growth of diameter in currentyear trunk and branch, increasing leaf biomass proportion at the branch level, and increasing specific leaf area.

Herbaceous plant biodiversity in Songnen grassland: Species diversity and functional group diversity.

FAN Gao-hua1,2, SHEN Xiang-jin1, LI Qiang1, SONG Yan-tao3, ZHOU Dao-wei1, HUANG Ying-xin1*

2016, 35(12):  3205-3214. 

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Biodiversity has significant impacts on ecosystem function. As important aspects of biodiversity, species diversity and functional group diversity have caused wide concern of ecologists. However, comprehensive and systematic studies are lacking on Songnen grassland biodiversity. In this study, we investigated 42 communities (including 427 species) and studied biodiversity of herbaceous plants in Songnen grassland. The species in Songnen grassland were dominated by families of Gramineae, Asteraceae, and Leguminosae. The aboveground biomass of the dominant species had absolute advantage, and was significantly positively related with the aboveground biomass of the community (R²=0.904). The species diversity indexes had significant differences between different communities in Songnen grassland. Among all the 42 communities, species richness index of Leymus chinensis dominated community (the most important community) was the lowest (2.6). The diversity indexes of different functional groups also had obvious differences. The functional group diversity of C₄ grasses dominated community was higher than that of C₃ grasses dominated community. There was a significant positive relationship between functional group diversity and species diversity (P<0.01), indicating that functional group diversity may be able to denote the biodiversity of ecosystem to some extent in Songnen grassland.

Niche characteristics of dominant herbaceous species under different land reclamation patterns in Antaibao Opencast Coal Mine.

YUAN Ye1, ZHAO Zhong-qiu1,2*, BAI Zhong-ke1,2, WANG Huai-quan1, XU Zhi-guo1, NIU Shu-ye1

2016, 35(12):  3215-3222. 

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Reclamation is a key measure to restore the damaged ecosystems in opencast coal mines, and the herbaceous communities differ among reclamation patterns in reclaimed areas. Three permanent plots with different reclamation patterns, WⅠ (Picea meyeri + Picea wilsonii + Hippophae rhamnoides), SⅠ (Robinia pseudoacacia + Pinus tabuliformis) and SⅢ (R. pseudoacacia + Ulmus pumila + Ailanthus altissima), were established to investigate niche breadth and niche overlap of dominant herb species, based on the analysis of herbaceous community composition and diversity in Antaibao Opencast Coal Mine. The results showed that Asteraceae, Poaceae and Leguminosae were the dominant herb families,  and WⅠ had the highest species diversity. As for community succession, the herbs tended to develop from annual to perennial and xerophyte to semixerophyte. Roegneria kamoji, Artemisia sieversiana, and Agrostis matsumurae had the widest niche breadth, being the most important dominant species. Niche breadth was positively related to importance value (IV); however, niche breadth and IV differed among the three plots, due to differences in reclamation patterns, site conditions and physiological properties of herb species. In addition, niche overlap value was larger between species with wider niche breadth values. On the contrary, species with narrower niche breadth values had smaller niche overlap value.

Temporal-spatial dynamics of natural regeneration of species in ecological reclamation of Antaibao Opencast Coal Mine.

ZHANG Qing1, BI Run-cheng1, WU Zhao-fei2, ZHAO Bing-qing2, BAI Zhong-ke3,4, GUO Dong-gang2*

2016, 35(12):  3223-3232. 

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A 1hm² permanent plot from the ecoreclamation area in Antaibao Opencast Coal Mine of China Coal Pingshuo Coal Company Limited was established after reforestation of a mixed plantation of “locust (Robinia pseudoacacia) + elm (Ulmus pumila) + ailanthus (Ailanthus altissima)”. Based on the 2010 and 2015 survey data, quantitative characters of major regenerated species during vegetation restoration process were analyzed, to provide a scientific basis for revealing natural regeneration of artificial vegetation and sustainable management. The results showed that during 2010-2015, the number of seedling individuals in the plot increased from 4216 to 11177, and that of sapling individuals increased from 687 to 727. The increased numbers of seedlings and saplings were mainly contributed by elm and ailanthus. The survival rate of seedlings was in the order of elm > ailanthus > locust, and that of saplings was in the order of elm > locust > ailanthus. Seedlings in the plot showed an aggregated distribution on the scale of 0-20 m, and the degree of aggregation decreased with the increase of scale. Saplings showed an aggregated distribution on smallscale (0-5 m), and a random distribution on the other scales. Whether at community level or species level, the heights of seedling and sapling and biological factors jointly affected the survival of seedlings and saplings. There was a significant densitydependent effect in the natural regeneration process of ecoreclamation area in Antaibao Opencast Coal Mine.

Response of soil water and soil fertility to vegetation restoration in an opencast coal-mine in a loess area.

GU Yu1,WANG Jin-man1,2*, WANG Hong-dan1, LIU Peng1, GAO Zhen-huan1, LI Bo1

2016, 35(12):  3233-3241. 

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There is a complex interaction between reclaimed vegetation and soil environment in mining area. In particular, soil fertility and soil moisture are closely related to vegetation restoration. How to realize the coordinated development among reclaimed vegetation, soil moisture and fertility to promote the improvement of ecological system is the core issue of ecological restoration in mining areas. Therefore, the Antaibao Opencast Coal-mine dumps in Shanxi Pingshuo mining area were selected to analyze the relationship between the characteristics of soil water or fertility and the vegetation restoration by the plot investigation method, and the coupled coordination degree model was used to quantify the influence of soil quality on vegetation growth and assess the coordination degree of soil water or soil fertility and reclaimed vegetation. The results showed that the soil water content increased with increasing soil depth in the 0-40 cm soil layer, and the change trend of soil organic matter and total nitrogen was opposite to that of soil water content. The effect of soil fertility characteristics on the growth of reclaimed vegetation was greater than that of soil water; the coupling relationship between soil water or fertility and reclaimed vegetation was basically coordinated. In the loess area, the soil nutrient condition is poor, the ecological environment is harsh, and thus the key of ecological reconstruction is to improve the soil fertility condition, select the appropriate vegetation reclamation model and control the density of vegetation. This study can provide a reference for land reclamation and ecological restoration in the dumps of opencast coal-mine in the loess area.

Bark’s adsorption capacity of atmospheric particulate matter.

XU Xiao-wu1, BAO Le1, MO Li2, XU Yan-sen3, YU Xin-xiao1*

2016, 35(12):  3242-3249. 

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Leaves of plants have a great effect on the removal of atmospheric particulate matter (PM). Likewise, the barks of plants have the similar function. In addition, previous research has already proved that particles deposited on the bark surface have a relatively slight influence on biological regulating function. This study investigated the adsorption capacity of barks of ten common plant species in Beijing. The PM adsorption mass per unit area of each species’ bark in different seasons was measured. Three fractions of PM were thus collected: 10-100 μm (large), 2.5-10 μm (coarse) and 0.2-2.5 μm (fine). Furthermore, the barks were classified according to adsorption capacity. The results showed that barks generally had great adsorption capacity of particulate matter with an average of 2182.07 μg·cm^-2. The mass of large particles accounted for 88% of the total, and the fine particles and coarse particles accounted for 6% respectively. The mass of large particles deposited on the barks changed significantly under different meteorological and pollution conditions, while the mass of small particles did not. In general, bark’s adsorption mass was high in the season with heavy haze and less rain or wind. However, adsorption mass was low in the windy and rainy season. For particles deposited on the bark, some of them would be suspended once again, some of them would be removed by rainfall, and the rest would continue to accumulate on the bark surface. In the same particle size range, bark’s adsorption capacity of particulate matter differed with species, affected by the surface structure and properties of the bark. They were divided into four categories: (1) rough bark with strong adsorption ability and low moisture and lipid; (2) smooth bark with weak adsorption capacity and high moisture and lipid; (3) bark with medium adsorption capacity and shallow or longitudinal crack; (4) split bark with differential adsorption capacity of different sized particles. This study proved the effect of bark on removing atmospheric particulate matter and provided theoretical foundation for urban green space planning system, which would decrease human exposure to atmospheric pollutants in the future.

Effects of biochar application on the growth of Robinia pseudoacacia L. seedlings and soil properties in limestone soil in a karst mountain site.

SUN Jia-man1,2, BU Xiao-li1,2, WU Yong-bo1,2, XUE Jian-hui1,2*

2016, 35(12):  3250-3257. 

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Biochar is a carbonrich solid material produced by heating biomass in an oxygenlimited environment, which has been widely concerned as a soil conditioner, fertilizer release carrier and carbon (C) storage agent in recent years. In this study, a pot experiment was conducted to investigate the effects of three kinds of biochar (rice husk biochar, RHB; cotton straw biochar, CSB; woodchip biochar, WCB) amended with 1%, 2.5%, 5%, 10% (dry mass basis) on pH, capillary capacity, organic matter and available nutrient concentrations of limestone soil, and the growth traits, root characteristics of Robinia pseudoacacia L. seedlings (45 days old) at a karst site. The results showed that biochar application improved root characteristics and promoted the growth of R. pseudoacacia. Compared with CK, RHB_2.5 significantly accelerated total root length, total root surface area and the root length of 0-0.6, 0.6-1.2, 1.2-1.8 mm in diameter of R. pseudoacacia by 198%, 125%, 287%, 209% and 146%, respectively. RHB₅ and WCB_2.5 significantly increased the root activity by 36% and 32%, respectively. CSB₁₀ increased seedling height, basal diameter, aboveground biomass, and total biomass by Symbol`@@30%, 6%, 147% and 118%, respectively. Root/shoot ratio was decreased significantly by 57% after CSB₅ application. Moreover, biochar application remarkably improved soil water and nutrient availability, and the effects increased with the increase of application rate. Compared with the CK, RHB₁₀, CSB₁₀ and WCB₁₀ increased soil organic matter by 25%, 195% and 68%, available N by 49%, 105% and 45%, available P by 114%, 766% and 115%, and available K by 170%, 27% and 89%, respectively. RHB₁ and WCB_10 increased soil pH by 1.22% and 1.48%, respectively. Therefore, biochar application can improve quality of limestone soil in karst area, and promote root development and growth of R. pseudoacacia seedlings, which is of importance to the improvement of limestone soil and revegetation in karst area.

Responses of growth and photosynthetic characteristics of Acer truncatum seedlings to hardening pavements.

CHEN Yuan-yuan1,2, JIANG Bo3, WANG Xiao-ke1*, LI Li1,2

2016, 35(12):  3258-3265. 

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In this paper we investigated the ecophysiological characteristics and growth of Acer truncatum seedlings under different land pavements in a field experiment in a suburb of Beijing. A. truncatum seedlings were planted in different plots: paved with pervious bricks, paved with impervious brick, and nonpaved (the control). The results showed that pavement induced decreases in net photosynthesis (P_n), stomatal conductance (g_s), transpiration rate (T_r, leaf photosynthetic pigment contents, photochemical effective quantum yield of photosystem II (F_v′/F_m′), actual photochemical efficiency (Ф_PSII), electron transport rate (ETR), photochemical quenching (q_p), maximum net photosynthesis rate (P_max), apparent quantum yield (AQY) and light saturation point (LSP), and enhanced MDA content. We also found that plant height and basal diameter of A. truncatum seedlings under pavements were reduced. Both pavements had significantly higher surface temperatures than the control, which resulted in heat stress on A. truncatum seedlings. The heat stress seriously hurt the photosystem II and limited the ETR, thus reducing leaf photosynthesis and suppressing plant growth. Furthermore, pervious pavement had higher surface temperatures because it had higher roughness and heat storage capacity than impervious pavement. The ecophysiology and growth of A. truncatum seedlings would suffer more severe stresses under pervious pavement than under impervious pavement. This study highlights the importance of urban greening for lowering surface temperatures of paved lands to alleviate heat stress due to pavements, especially pervious pavement.

Regulation effects of exogenous spermine on morphology and physiology of Toona ciliata seedlings under drought stress.

LIU Qiu1,2*, LI Zhi-hui1, WU Ji-you2, YANG Shuo-zhi2, WU Zhi-hua3, LI Yan1

2016, 35(12):  3266-3272. 

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To understand the morphological and physiological regulation effects of exogenous spermine (Spm) on Toona ciliata Roem. seedlings under drought stress, twoyearold potted seedlings of T. cilliate were adopted as experimental materials, and a drought stress and exogenous Spm regulation experiment was carried out under rain shelter by combining persistent drought stress with soil moisture measurement. The experiment contained 4 drought stress treatments: control (relative soil water content 45%-50%, watering  to saturation state of soil moisture every day, CK), mild (relative soil water content 30%-38%, persistent drought for 7 days), moderate (relative soil water content 25%-30%, persistent drought for 14 days), and severe (relative soil water content 20%-25%, persistent drought for 21 days). Afterwards, spraying Spm (1 mmol·L^-1) was applied to the seedlings after the mild, moderate, and severe drought treatments for 3 consecutive days, then the seedlings were normally managed for 5 days. The repair effect of exogenous Spm on morphological damage in plants under severe drought stress was much lower than those under mild and moderate drought stress. There were extremely significant differences in leaf relative water content and leaf chlorophyll content among CK, droughtstress treatment (either mild, moderate or severe) and Spm regulation treatment (P<0.01). There was extremely significant difference in leaf relative conductance among CK, moderatedroughtstress treatment (or severedroughtstress treatment) and Spm regulation treatment (P<0.01). Differences in leaf MDA content and POD content were significant (P<0.05) among CK, milddroughtstress treatment and Spm regulation treatment and they were extremely significant among CK, severedroughtstress treatment and Spm regulation treatment (P<0.01). The proline content was extremely significantly different among CK, severedroughtstress treatment and Spm regulation treatment (P<0.01). Therefore, we could conclude that 1 mmol·L^-1 exogenous Spm treatment could repair the morphological and physiological damages of T. ciliata seedlings under drought stress and promote the drought resistance ability, and such effects were more obvious in plants under mild and moderate drought stress.

Effects of waterlogging on the growth and antioxidant enzyme activity of Carex cinerascens seedlings.

CAO Yun1*, ZHENG Xiang2, YANG Yang3, CHEN Bing-xiang1, GUO Zhi-chang1, WU Hai-ying1

2016, 35(12):  3273-3278. 

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Waterlogging is an important factor influencing wetland plant growth, reproduction and population distribution. To clarify the influence of waterlogging on plant growth and physiological characteristics, we set up four treatments: normal watering (control), completely submerged group, 1/2 immersed group and 1/4 immersed group with Carex cinerascens seedlings as the research object, and determined the morphological indicators (plant height, germination) and physiological indicators (SPAD, MDA, SOD, POD and CAT) under different flooding conditions. The results showed that waterlogging stress inhibited the growth of C. cinerascens seedlings, decreased plant height, and the edges of leaves were damaged and yellow. Waterlogging also affected rhizomatic germination of C. cinerascens, and moderate waterlogging would improve its germination. Waterlogging decreased the leaf relative chlorophyll content, inhibiting the photosynthesis of plant leaves. Waterlogging stress aggravated leaf membrane lipid peroxidation, prompted the MDA levels and increased the activities of corresponding antioxidant enzymes POD, CAT and SOD, indicating that the dynamic balance between the scavenging system and the generation of reactive oxygen species was destroyed. Our study suggests that waterlogging stress would aggravate the membrane lipid peroxidation, inhibit the normal growth of C. cinerascens seedlings, and accelerate the production of antioxidant enzymes to counter the adverse effects of waterlogging stress at the same time.

Effects of water and nitrogen interaction on photosynthetic physiology of Isatis indigotica and quality of medicinal material.

ZHANG Ke, WANG Yi-rong, ZHAO Yu-long, TANG Xiao-qing*, WANG Yu

2016, 35(12):  3279-3285. 

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In order to provide a theoretical basis for good quality cultivation of Isatis indigotica, a twofactor split plot experiment was designed to explore the effects of water (no waterlogging, W0; slight waterlogging, W1; moderate waterlogging, W2) and nitrogen \[0 mmol·L^-1 (N0); 5 mmol·L^-1 (N1, low N level); 15 mmol·^-1 (N2, moderate N level); and 25 mmol·L^-1 (N3, high N level)\] interaction on photosynthetic physiology of I. indigotica and quality of medicinal material with chlorophyll content, photosynthetic parameters, indigo and indirubin contents in leaves, and protein, polysaccharide and epigoitrin in roots as indexes by using pot experiments sheltering from rain. The results showed that water and nitrogen interaction significantly affected photosynthetic physiology of I. indigotica and quality of medicinal material. The chlorophyll content under treatment W2N3, the net photosynthetic rate (P_n) and stomatal conductance (G_s) under treatment W0N2, the intercellular carbon dioxide concentration (C_i) under treatment W0N1 and the transpiration rate (T_r) under treatment W1N2, were the highest among all treatments, respectively, which indicated that photosynthesis and transpiration of leaves were strengthened under N2 level. The epigoitrin content under treatment W2N3, the polysaccharide content under treatment W1N2, the protein content and total nitrogen content under treatment W2N0 in roots, the total nitrogen content, indigo and indirubin content in leaves under treatment W2N0, were the highest among all treatments, respectively. These results illustrate that the secondary metabolism is activated by moderate flooding in short time, and thus the active ingredient contents in leaves and roots would increase.

Effects of high temperature and humidity stress on the physiological characters of spring soybean seeds and the expression of seed deteriorationrelated gene GmSbh1 at the physiological maturity stage.

SHU Ying-jie1,2, ZHOU Yu-li1, TAO Yuan2, HU Neng-bing1, HUANG Shou-cheng1, HE Qing-yuan1, SHI Xia-qing1*

2016, 35(12):  3286-3292. 

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Preharvest seed deteriorationresistant soybean cultivar Xiangdou No. 3 and deteriorationsensitive cultivar Ningzhen No. 1 were used as experimental materials and the influences of high temperature and humidity (HTH) stress \[treatment group, (40±2) ℃/(30±2) ℃, RH (95±5)%/(70±5)%, 10 h/14 h (day/night); control group, 30±2 ℃/20±2 ℃, RH 75±5%/70±5%, 10 h/14 h (day/night)\] on seed germination, membrane lipid peroxidation, osmotic adjustment, protective enzyme activities and the expression of seed deteriorationrelated gene GmSbh1 in spring soybean seeds were studied at the physiological maturity stage for 1, 5, 10, 16, 24, 48, 96 and 168 h. HTH stress was found to cause decline of germination potential and germination percentage, especially after 24 hours stress, with the seed deteriorationresistant cultivar having a lower degree of the decline than the deteriorationsensitive one. HTH stress also led to the increase of membrane permeability and membrane lipid peroxidation, and showed more intensified peroxidation after more than 5 hours stress. The increased level of membrane lipid peroxidation in Xiangdou No. 3 was lower than that in Ningzhen No. 1 under the same stress treatment. The contents of proline and soluble sugar of the seeds significantly increased under HTH stress in both cultivars. In addition, the extent of proline content increase in Xiangdou No. 3 was significantly greater than that in Ningzhen No. 1, but the two cultivars showed no obvious difference in the increment of soluble sugar contents. The activities of protective enzymes including superoxide dismutase, peroxides and catalase increased initially then decreased in the treatment group with extended treatment time, but a slight change was observed in the control group, with the treatments presenting higher activities of the protective enzymes than the control. The amount increase of protective enzymes activities in Xiangdou No. 3 was greater than that in Ningzhen No. 1 under HTH stress compared with the control. More importantly, under HTH stress, Xiangdou No. 3 maintained highlevel enzyme activities after stress, while enzyme activities in Ningzhen No. 1 had a rapid decrease after an initial increase. Under HTH stress, expression of GmSbh1 showed an upregulated trend in Ningzhen No. 1 but a downregulated trend in Xiangdou No. 3. Hence, the main physiological and molecular mechanisms for preharvest seed deterioration of spring soybean seeds were closely related to increased membrane permeability, intensified osmo-tic adjustment, enhanced lipid peroxidation, decreased activities of protective enzymes and differential expression of GmSbh1 gene under HTH stress.

Cloning and expression of a Cdtransport related gene GmNramp1 in soybean.

LI Nan1,2, GAO Zhen-rui1,2, ZHANG Xiao-na1,2, CUI Min-long1*

2016, 35(12):  3293-3298. 

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Heavy metal cadmium (Cd), a member of the main pollutants in the soil, has been listed as one of the priority pollutants and human carcinogens. Cd can affect the crop’s growth and development and enter the body to affect human health through the food chain. Existing research shows that the Nramp protein family has played a key role in the regulation process of Cd absorption and transport in the model plant Arabidopsis and rice. However, the Nramp genes involved in the Cd absorption and transport have rarely been reported in the soybean. Through the analysis of soybean database, we found a member of Nramp family, named GmNramp1 (Glyma07g02680). Analysis of the RT-PCR results shows that the 75 μmol·L^-1 CdCl₂ treatment of soybean root, cotyledon, hypocotyl, and leaves for different time decreases the expression of the GmNramp1 gene. And the transcriptome sequencing result of soybean root treated with Cd also supports the same conclusion of Nramp gene function. The results show that GmNramp1 gene may participate in the absorption and transport process of Cd in soybean. This study provides a theore-tical basis and genetic resources for breeding soybean resistant to heavy metals.

Kin selection of Arabidopsis thaliana under different densities.

LI Jie1,2,3, WANG Jing3, XU Xing-liang1, LIANG Tao1，2*

2016, 35(12):  3299-3305. 

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Kin selection theory predicts that kin individuals could cooperate to increase their fitness through kin recognition. Previous studies confirmed that kin selection occurred in some plant species, and kin responses differed among species. However, the tested species were still seldom, and the influences of environmental factors were not considered. In order to verify kin selection in different ecotypes of Arabidopsis thaliana, our study selected three Arabidopsis ecotypes of Columbia (Col), Landsbergerecta (Ler) and Wassileskijia (Ws) as the research objects, to explore the influence of density on kin selection through measuring differences in plant phenotypic traits (plant height, rosette area, leaf area and seed number, etc.) and biomass (root, stem, leaf and seed biomass) between kin groups and nokin groups under three simulated densities. Our study showed significant differences in aboveground traits, but no differences in root distribution between kin and stranger groups of each ecotype. Kin response differed among the three ecotypes: Col and Ws ecotypes mainly responded to kin recognition in reproduction tissue (seeds), while Ler mainly in vegetable tissues (leaf and stem). Which phenotypic and biomass traits and how the traits of same ecotypes responded to kin recognition mainly relied on planting density, suggesting that density was an important factor in plant kin selection.

Arthropod community characteristics and stability in summer maize fields with different planting environments.

CHAI Zheng-qun1,2, KE Sheng-jie1, HUANG Ji1, HUANG Yu-miao1, JIA Yong-chao1,3, TAO Mei1, LI Qiang1, CHEN Guo-hua1*

2016, 35(12):  3306-3314. 

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An investigation was conducted on arthropod community in summer maize fields with different planting environments in Puer, Yunnan Province. The community characteristic index, community stability and principal component analysis were applied to analyze the arthropod community in summer maize fields with different planting environments. The results showed that a total of 10174 arthropod individuals were collected, which belonged to 2 classes, 15 orders, 100 families, and 261 species. In summer maize field with monoculture planting environment, 5604 arthropod individuals were found, belonging to 2 classes, 13 orders, 84 families and 168 species. In summer maize field with mixed planting environment, 4570 arthropod individuals belonging to 2 classes 15 orders 90 families and 209 species were found. Compared with summer maize field with monoculture planting environment, the number of species, diversity, evenness, abundance index of arthropod community, the number of species and individuals of natural enemies in summer maize field with mixed planting environment were higher, while the individuals and proportion of phytophagous insects, the dominant concentration index and dominance index were lower. In summer maize field with mixed planting environment, the community was more stable, and diversity, evenness and richness index of community had smaller fluctuation with time. In summer maize field with monoculture planting environment, the individual number of piercing sucking insects and species number of leaffeeding insects were the dominant factors affecting arthropod community, while in summer maize field with mixed planting environment, the individual number of parasitic insects, species number of predatory insects and the individual number of piercing sucking insects were the dominant factors determining the change of arthropod community.

Roles of PRDM16 and BMP7 gene expressions in body mass regulation in Tupaia belangeri.

GAO Wen-rong1,2, WANG Zheng-kun1, HOU Dong-min1, ZHU Wan-long1*

2016, 35(12):  3315-3322. 

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In order to clarify the adjustment roles of PR domaincontaining 16 (PRDM16) and bone morphogenetic proteins 7 (BMP7) genes expressions in the physiological adaptation of tree shrew (Tupaia belangeri) to seasonal environment changes, the indexes of tree shrew’s body mass, resting metabolic rate (RMR), nonshivering thermogenesis (NST), food intake, brown adipose tissue (BAT) mass, white adipose tissue (WAT) mass, PRDM16 and BMP7 genes expressions were measured under different seasons and cold acclimatization. The results showed that, with the seasonal changes, tree shrew’s body mass, BAT mass, WAT mass, RMR, NST and food intake in winter were significantly higher than that in summer; its PRDM16 and BMP7 genes expressions showed significant differences in different seasons. Seasonal variation tendency of PRDM16 gene expression was in order of winter>autumn>spring> summer, and the seasonal variation tendency of BMP7 gene expression was in order of winter>autumn>summer>spring. Cold acclimatization increased its body mass, BAT mass, WAT mass, RMR, NST and food intake. PRDM16 and BMP7 genes expressions were also increased under cold acclimation. The results suggested that the gene expression levels of PRDM16 and BMP7 of the tree shrews were increased in winter or with cold exposure, which promoted the formation of brown fat cells to increase the thermogenesis to adapt to the cold condition in winter. Moreover, PRDM16 and BMP7 genes play important roles in the seasonal thermogenic regulation and energy metabolism in the tree shrews.

 

The diversity of arbuscular mycorrhizal fungi in the rhizosphere of Spiraea pubescens in the Daqingshan Mountain, Inner Mongolia, China.

ZHAO Min1, ZHENG Rong2, BAI Shu-lan1*, ZHU Yan-yu1

2016, 35(12):  3323-3328. 

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To evaluate the diversity of arbuscular mycorrhizal fungi in the rhizosphere of Spiraea pubescens in the Daqingshan Mountain of Inner Mongolia, China, soil samples were collected from three sites Shuimocun, Xiaojinggou and Baishitougou. AMF spores were separated by wetsieving and decanting procedure and centrifugation using sucrose and identified by the morphological methods. The results showed that 48 AMF species were isolated from all soil samples, belonging to 11 genera, and 2 were unidentified species. Glomus was the dominant genus in the three sites. Spore density in soil from Shuimocun was significantly higher than those from Xiaojinggou and Baishitougou. However, the Simpson index and Pielou index in Shuimocun and Xiaojinggou were higher than in Baishitougou. Redundancy analysis of the relationship between soil factors and AMF diversity showed that AMF richness was significantly positively correlated with pH, soil organic carbon and available potassium, and pH was the driving factor influencing AMF richness. Available nitrogen and available phosphorus were significantly negatively correlated with AMF richness and Simpson index.

Effect of vermicompost on soil fungi community structure under tomato continuous cropping in greenhouse.

ZHAO Feng-yan1, WU Pan-pan1, LI Tian-lai2, XIONG Xiao-nan1, YANG Li-juan1*

2016, 35(12):  3329-3334. 

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A pot experiment was conducted in greenhouse to explore the effect of vermicompost on soil fungal community structure of tomato continuous cropping. Four treatments were employed: vermicompost + chemical fertilizer (EM), chicken manure + chemical fertilizer (CM), chemical fertilizers (CF), and no fertilizer application as control (CK). The results showed that: (1) application of organic fertilizer significantly increased the pH value of continuous cropping soil; CM and EM treatments increased to 6.80 and 6.84, respectively, with an increment of 0.34 and 0.38 compared with CK, and a decrement of 0.37 and 0.41 compared with CF, respectively. Compared with the other three fertilizer treatments, EM treatment significantly increased the contents of soil organic matter, total carbon and total nitrogen. Organic matter content in EM increased by 2.41%, 7.86% and 9.60% compared to those in CM, CF and CK, total carbon content in EM increased by 5.09%, 7.67% and 7.13%, and total nitrogen increased by 7.14%, 21.43% and 18.57%, respectively. (2) The relative abundance of predominant fungi at phylum level was significantly decreased after vermicompost application. For example, the relative abundance of Basidiomycota in EM was 18% lower than that in CK, 14% lower than that in CF, and slightly lower than that in CM. (3) Redundancy analysis results showed that pH value had greatest influence on fungal community structure of different treatments, followed by total nitrogen, organic matter, carbon/nitrogen ratio, available nitrogen, available potassium, total carbon and conductivity, while soil moisture and available phosphorus had no significant effects on fungal community structure. Therefore, applying vermicompost in tomato continuous cropping soil can improve soil nutrient contents and reduce the relative abundance of dominant fungi, relieving the tomato continuous cropping obstacle.

Variations of climate resources and their impacts on wine grape quality at the east foot of Ningxia Helan Mountain during harvest of wine grapes.

ZHENG Guang-fen1,2, WANG Su-yan1,2*, YANG Jian-ling1, LI Jian-ping1, ZHANG Xiao-yu1, MA Li-wen1, LI Xin1,2

2016, 35(12):  3335-3343. 

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Using meteorological data from the east foot of Ningxia Helan Mountain during 1981 to 2015, and combing thresholds of some key climate resources of premium wine grapes from previous research results, we analyzed the change characteristics of precipitation, rainy days, diurnal range of temperature, waterheat coefficient and sunshine duration during harvest of wine grapes and their possible influences on wine grape quality. The results showed that the key climate resources had changed significantly in recent 35 years and an abrupt climate change occurred at the end of 1990s. After the abrupt climate change, the precipitation increased by 88%, and the possibility of precipitation ≥30 mm in September was 44%-71%, being 2.8-4.2 times as much as before. The possibility of precipitation ≥10 mm in the first ten days of September was 47%-65%, being 1.4-1.7 times as much as before. The rainy days increased by 55%-76%, and the frequency of lasting rain process (≥3 days) increased. The diurnal range of temperature decreased by 1.4 ℃, and the possibility of diurnal range of temperature ≤7.6 ℃ was 17%-22%, being 1.6 to 2.2 times as much as before. At the same time, waterheat coefficient increased by 0.26-0.37, with an increase rate of 60%-100%, and the possibilities ≥0.57 and ≥0.63  were 2.1-4.2 and 2.7-4.2 times as much as before, respectively. The sunshine duration decreased by 16%. The days of sunshine duration <6.5 h increased by 3.9-5.3 d, with an increase rate of 53%-78%. Therefore, the changes of key climate resources can decrease sugar content and increase acid content of wine grapes, thus decreasing the sugar/acid ratio and the content of tannins. In addition, these changes create favorable conditions for the occurrence of downy mildew and white rot of wine grapes.

Bird diversity and bird strike risk at Zhalantun Genghis Khan Airport.

ZHAO Huan-le, WANG Tong, YANG Fan, YANG Gui-sheng*

2016, 35(12):  3344-3352. 

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The investigation of bird diversity at and around the airport is important to carry out bird strike prevention for the newly built airport. Using line transect method and a fixed radius point count method, we investigated the bird diversity in the region of Genghis Khan Airport of Zhalantun and its surrounding area (with a radius of 8 km) in Inner Mongolia from January to December 2015. According to the survey, 82 bird species were recorded, belonging to 31 families and 15 orders. The analysis of bird community structure showed that the highest bird diversity index (0.740) and evenness index (0.819) were found in spring within the airport boundary, the highest dominance indexes (0.683) in winter and the highest average density (2.83 ind·hm^-2) in summer. For the area outside the boundary, the diversity index (1.576) and the average density (28.60 ind·hm^-2) were both highest in summer of the wetland, the evenness index (0.902) was highest in winter of the grassland, and the dominance index (2.113) was highest in winter of residential area. We reassigned the risk value of bird species, and integrated 7 factors to calculate the hazard index based on the previous studies, including the volume and quantity of birds, the number of occurrences, flight height, the distance from the airport, the number of transect occurrence and clustering. The results indicated that there were 14 serious threat species, such as Common Cormorant (Phalacrocorax carbo), Tree Sparrow (Passer montanus), Ruddy Shelduck (Tadorna ferruginea) and so on. Accordingly, we proposed advices and control measures for avoiding bird strikes of different seasons, areas and species, which provided scientific basis for future bird strike prevention at Zhalantun Genghis Khan Airport.

An investigation of pollinators and niche analysis in Xiangyun Basin during winter.

HU Zong-wen, ZHANG Xue-wen*, YANG Juan, WANG Yan-hui, HUANG Xin-qiu, XUN Li-jie, MIAO Chun-hui

2016, 35(12):  3353-3359. 

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In order to clarify the species and ecological niche of flowervisiting insects in Xiangyun Basin in winter, we investigated the pollinators who visited oilseed rape (Brassica chinensis), cabbage mustard (Brassica alboglabra), and broad bean (Vicia faba) on the field during December 2015 to January 2016. We recorded pollinator species, headage, visiting frequency and settling time at intervals of 30 min in one day per week, and analyzed the pollinator composition and niche characteristics (niche breadth and niche overlap). The results showed that the pollinators were mainly from Hymenoptera and Diptera, and honeybees (including Apis mellifera and Apis cerana) and flies (Musca domestica and Eristalis tenax) were the dominant species. The peak visiting time had interspecific difference, and most species visited flowers during 11:00-15:30 on the day. The pollinators also made interspecific difference in settling time (F_2,862=13.43, P<0.01), with the longest for M. domestica (32.80±2.56 s), and the shortest for A. mellifera (9.91±0.40 s). The pollinators had the maximum visiting time on oilseed rape (16.50±0.82 s), and the minimum on broad bean (10.31±1.14 s). There was a difference in niche breadth among pollinators, with the greatest for A. mellifera (Levins’ niche (Bi)=0.8345, Hurlbert’s niche (Ba)=0.3074). Moreover, niche overlap was higher in intraspecies but smaller in interspecies, being 0.8451 between A. cerana and A. mellifera, and 0.0928 between A. cerana and M. domestica. We conclude that the different peak visiting time of pollinators can decrease the competition of collecting limited food resource in winter. The honeybees have higher niche breadth on pollination and thus are the dominant pollinators; however, the niche overlaps are higher in the intraspecies, which makes a stronger competition pressure. Higher niche overlaps between honeybees may explain the disappearance phenomenon of native bee A. cerana after the introduction of exotic bee A. mellifera.

Survey on butterfly diversity in Sanya City.

LI Qi-lin*, LIN Chi-xian, FU Fang-yi

2016, 35(12):  3360-3363. 

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We conducted a survey on butterfly diversity in four districts from Sanya City: Yazhou, Tianya, Jiyang and Haitang District, from 2013 to 2014. A total of 78 species were recorded, which belong to 9 families, 49 genera. The number of species in each family was in order of Pieridae > Nymphalidae > Satyridae > Satyridae > Lycaenidae = Papilionidae > Danaidae > Amathusiidae = Acraeidae = Hesperiidae, while Pieridae butterflies accounted for 23.08% of the total number. In the four kinds of habitats, the forest in Yazhou District had the highest Shannon diversity index H and dominance index D. The largest similarity coefficient was found between residential area and farmland (0.200), followed between woodland and water area (0.172). Our results indicated that butterfly diversity was mainly related to habitat type in Sanya City.

Relationship between zoobenthos biodiversity and environmental factors in Nanla River.

LI Zheng-fei1,2, WANG Jun1,2, XIE Zhi-cai1, DING Cheng-zhi3, JIANG Xiao-ming1*

2016, 35(12):  3364-3373. 

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The tropical Asian river systems support a high array of aquatic biodiversity, especially its endemism. We choose the Nanla River in Xishuangbanna, one primary tributary of the Lancang River, as a case study to examine longitudinal patterns of macrobenthic biodiversity in July 2015. This river harbored a total of 96 taxa belonging to 5 phyla, 7 classes and 50 families. Among them, Insecta was the speciesrichest group (74 taxa), followed by Mollusca (8), Oligochaeta (9), Leech (3) and 2 others (Turbellaria and Nematoda). The dominant taxa across the whole watershed were Limnodrilus hoffmeisteri (accounting for 16.76% of total abundance), Cheumatopsyche sp. (10.60%), Polypedilum scalaenum (10.27%), Corbicula fluminea (5.01%), Bellamya aeruginosa (4.74%) and Choroterpides sp. (4.26%). Species richness, density, Margalef and Shannon diversity indices significantly decreased along the longitudinal gradient (from the upper to the lower reaches). The abundance of Oligochaeta, Chironomidae and Mollusca increased downstream at the expense of Ephemeroptera and Trichoptera. CCA analysis showed that four environmental factors (water depth and three types of substrate) and six spatial factors (PCNM14, PCNM10 and PCNM14) were the key drivers structuring the macrobenthic communities. Variance partitioning analysis indicated that the spatial factors had a stronger controlling effect on macrobenthic communities than environmental ones. This study provides useful information for the conservation of benthic biodiversity in tropical Asian rivers.

Reduction of arsenic in arsenic bearing minerals by a Bacillus strain.

DENG Bo-huan1,2, XU Li-ying1*, WANG Yu-long1,2, WANG Xin1, JIA Yong-feng1

2016, 35(12):  3374-3381. 

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In natural environment, arsenic is usually adsorbed on iron oxide, aluminum oxide and other oxide minerals, or formed co-precipitation with these oxide minerals. Microorganisms can reduce arsenate directly or reduce Asbearing iron oxides and other arsenic bearing minerals under anaerobic condition, which could influence the transformation of arsenic. In this study, a bacteria strain was screened and identified as Bacillus sp. (strain DX04), and the reduction behavior and pathway of the strain on different speciations of the arsenic was studied. Under anaerobic conditions, reduction rate of arsenate with the strain DX-04 was highest in 12-24 h. Arsenate in the medium promoted the growth of the strain DX-04. In the liquid medium inoculated with strain DX-04 and FeAs coprecipitation, the concentration of dissolved As(III) showed the trend of increase at first and decrease several hours later. Arsenic reduction and release occurred, and then the second precipitation was formed. Under the reduction of the strain DX-04, the As(V) adsorbed on aluminum hydroxide minerals released into the liquid phase, and then the dissolved As(V) was reduced. The role of microorganisms can cause the release of arsenic from arsenic bearing minerals into water and sediment environment, which becomes a potential threat to human health.

Assessment on agricultural non-point source pollution in a drinking water source using remote sensing images.

LI Jia-wei1, GUAN Xu2, WANG Guo-qiang1, JIANG Hong3*

2016, 35(12):  3382-3392. 

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Ever-increasing water environmental pollution, caused by non-point source (NPS) pollution, has seriously affected the safety of drinking water, which has drawn much more concern in recent years. Here, the secondary drinking water source protection of Chaihe Reservoir was selected. With a questionnaire survey, we proposed a new mechanistic method to assess the pollution sources of agricultural NPS pollution (e.g., agricultural planting, livestock farming and rural life) in this study. The dynamic equilibrium equation N_P=N_AP+(1-α)N_RF+(1-β)N_1F, was used to analyze dynamic change of nitrogen and phosphorus and estimate the total load of NPS pollution. The livestock farming and rural life pollution loads were assessed by export coefficient method. Additionally, the agricultural planting pollution load was mostly due to fertilizer application. Decision tree classification method was used to classify and extract the information of crop. The crop type was identified by land use, which was determined by remote sensing data and the theory of phenology. The amount of fertilizer application was calculated by cropyield evaluating model, which was based on the relationship between NDVI and measured cropyield. The results showed that crop type was sensitive to remote sensing data. Both nitrogen and phosphorus pollution from agricultural planting contributed the maximum loads, being 205.9 and 61.61 t·a^-1, respectively, which indicated that agricultural planting was the main source of NPS load in the study area. Our results can help the management of this drinking water source protection area, decreasing in NPS loads into downstream water bodies and consequently restoring the ecological environment.

Landscape pattern optimization based on the granularity inverse method and MCR model in Dongfang City, Hainan Province.

TANG Li1*, LUO Yi-yin2, LUO Gai-gai3, LI Jun1, LIU Qin-chu1, LI Jin-zhao1

2016, 35(12):  3393-3403. 

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Landscape pattern optimization is an important safeguard measure to realize sound development of ecosystem health and ecological security. Using granularity inverse method with minimal cumulative resistance model from an angle of enhancing the overall connectivity of ecosystem, a study was carried out to optimize the landscape pattern in Dongfang City, Hainan Pro-vince. Then, specific optimization measures were put forward, so as to provide scientific reference for the construction of the ecological environment in the area. The results showed that 1800 m granularity landscape component is regarded as the optimal structure for Dongfang City. There are 12 ecological sources aggregately, and 32 new ecological landscape patches are needed to increase. Besides, the distribution trend of ecological sources is characterized by a large quantity but small scale in the northwest and small quantity but large scale in the southeast, which is mainly influenced by human disturbance. Ecological resistance surface is constructed by considering the landscape type, ecological resistance and slope gradient synthetically to better express the actual situation of ecological resistance. However, there are obvious differences between dominant ecological resistance and recessive ecological resistance, reflecting the weak ecological area to a certain extent. The district has 23 ecological corridors and 30 ecological nodes. According to the landscape base and functions, this paper classified the corridors and nodes and put forward the corresponding construction mea〖HJ*6〗sures. This study carries out risk assessment of ecological corridors and hot spot analysis of ecological nods in an ecological security perspective for the first time, which determines the key and order of ecological construction. Landscape pattern optimization will enhance the overall connectivity of ecosystem in Dongfang City remarkably, and the optimization results could provide scientific basis for ecological environment construction.

Seasonal variation of the surface thermal environment in Changshu City based on landscape pattern.

WANG Fang1,2, NIU Zhen-guo1*, XU Pan-pan1

2016, 35(12):  3404-3412. 

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The phenomenon of urban heat island has attracted people’s attention widely, especially in mega cities, while little attention has paid to small and mediumsized cities. The area and spatial pattern of various landuse types have different impacts on urban island, but we have little knowledge about the quantitative relationship between them, and small cities usually have different landuse patterns from mega cities. Changshu City close to Shanghai was taken as a representative small city in our study to analyze the relationship between urban heat island and various landuse types by using landscape ecology approach. The timeseries HJ satellite images in 2013 were employed to map land use of Changshu, and multitemporal Landsat8 OLI images were used to inverse the seasonal surface temperature. The results indicated that the intensity of heat island of Changshu was the strongest in winter due to the “warm island” effect of paddy field and dryland, while the weakest in summer due to water body’s “cold island” effect. Therefore, Changshu had a relatively favorable surface thermal environment. Meanwhile, the results also showed that there existed a threshold, beyond which the influence of waters, wetlands, forests on the urban heat island was no longer significant. We analyzed the impact factors of the construction land surface temperature by using GeogDetector approach. The results showed that water body had the greatest impact on construction land surface temperature in summer, while dryland had the greatest impact in winter. Our results provide suggestions for urban planning to maintain a better ecoenvironment in Changshu.

Effects of rice root radial oxygen loss on soil microflora and organic nitrogen mineralization: A review.

SUN Kai, HU Li-yan, ZHANG Wei, MENG Mei-yao, DAI Chuan-chao*

2016, 35(12):  3413-3420. 

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Radial oxygen loss (ROL) is one of the most important mechanisms for rice to obtain nutrients from soil when living in waterlogging environment, being quite important for rice growth and development. Recently, ROL has been demonstrated to significantly affect the population and diversity of soil microbes, including anaerobic bacteria, aerobic bacteria and facultative anaerobic bacteria. Meanwhile, numerous studies have reported that rice ROL plays roles in the mineralization process of soil organic nitrogen. However, the internal interactions between the mineralization of soil organic nitrogen and soil microbial dynamics at rice rhizosphere regulated by ROL have been largely ignored. In this review, we summarized the ROL traits of rice root, as well as the effects of ROL on soil microbes and organic nitrogen mineralization. We then discussed the synergistic effects of soil organic nitrogen and soil microbial dynamics on rice nitrogen absorption and metabolism. Finally, we outlined the problems and the prospects of rice ROL for further research.

Using Terrestrial Biotic Ligand Model to predict metal bioavailability in the cultivated fields: A review.

LI Xiao-min1, HUANG Yi-zong2*, HU Ying1, LI Ji1

2016, 35(12):  3421-3427. 

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With mineral mining and smelting, industrial “three wastes” emissions and other reasons, heavy metal pollution is more and more serious in Chinese farmland soil. It has been one of the hot issues that how to predict and evaluate the bioavailability and toxicity of heavy metals in soil in recent years. The Terrestrial Biotic Ligand Model (t-BLM) is a mechanism model to predict the bioavailability of heavy metals. It assumes that heavy metals access to living organisms and bind to biological sites with formation of biotic ligands. If biotic ligands reach a certain concentration, they will produce toxicity to organisms, which can determine the bioavailability of heavy metals. This paper discusses the research methods predicting or evaluating bioavailability and toxicity of heavy metals, the basic principles of t-BLM, and research progresses of t-BLM predicting soil metal bioavailability/toxicity tested by plants, animals and microorganisms. Besides, some problems in t-BLM theory and application are presented.

 

Determination of irrigation scheduling of spring maize in different hydrological years in Fuxin, Liaoning Province based on CROPWAT model.

GUO Jin-lu1,2, YIN Guang-hua1*, GU Jian1,2, LIU Zuo-xin1

2016, 35(12):  3428-3434. 

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Based on meteorological data from Fuxin Mongolian Autonomous County weather station in the last 30 years, crop water requirements and irrigation scheduling of spring maize were determined with CROPWAT model in different hydrological years (wet, normal, dry and extremely dry). The results indicated that crop water requirement of spring maize peaked at midseason stage, slightly decreased at last stage, and reached the lowest value at initial stage. Crop water requirement during the whole growing cycle was found to be 479.5-593.7 mm and reached its peak from heading stage to milk ripening stage. The coupling degree between spring maize water requirement and effective precipitation in the wet year was the highest, followed by the normal year, and the lowest in the extremely dry year. The net irrigation quotas were 127.6, 175.8, 296.5 and 411.6 mm in wet, normal, dry and extremely dry years, and the corresponding irrigation frequencies 3, 4, 6 and 8, respectively. The obtained results provided a theoretical basis for proper utilizing agricultural water resources and irrigation scheduling of spring maize, and could be used as efficient guidelines for local farmers to apply suitable irrigation scheduling.

Sampling methods about species richness and aboveground biomass of Potentilla fruticosa shrub meadow on Tibetan Plateau.

MENG Fan-dong1,3, WANG Chang-shun1, ZHU Xiao-xue2,3, CUI Shu-juan1,3, WANG Qi1,3, ZHOU Yang1,3, WANG Shi-ping1,4*

2016, 35(12):  3435-3442. 

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Studying methods for monitoring the aboveground biomass and species richness is critical to understand the response of the structure and function of alpine shrub ecosystems to climate change and human activities. Four monitoring methods, i.e. standard tree, quadrat, line transect and nested quadrat methods, were chosen to compare the changes of aboveground biomass and species richness of the Potentilla fruticosa shrub meadow. Our results showed that the minimum sampling area of P. fruticosa shrub meadow was 1 m², and the least number of quadrats should be 10. Generally, 12 quadrats of 1 m² were needed when both of species richness and aboveground biomass of the shrub meadow were monitored simultaneously. In order to improve work efficiency and reduce the destruction of vegetation, we measured the canopy and height of 17 plants randomly and established a predictive regression model (y=740.46x_1.08, R²=0.89, P<0.001, y indicates aboveground biomass, x indicates product of canopy diameter and height) based on biomass and the product of its canopy diameter and height as independent variables. The model could predict the shrub aboveground biomass precisely and improve the efficiency of field investigations.

Spatial downscaling of land surface temperature based on MODIS data.

LI Xiao-jun1,2，3, JIANG Tao3*, XIN Xiao-zhou1, ZHANG Hai-long1, LIU Qin-huo1

2016, 35(12):  3443-3450. 

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Due to technical constrains of remotely sensed land surface temperature (LST) data, there is a tradeoff between spatial and temporal resolution, i.e., a high temporal resolution is associated with a low spatial resolution and vice versa. To solve this disadvantage, based on three different conversion models in TsHARP (an algorithm for sharpening thermal imagery) method, this study made improvements by introducing a new parameter, namely, land surface emissivity (ε), and a new conversion model was put forward by replacing the original NDVI with MSAVI. The aims of this study involved the following aspects: firstly, to improve the original low spatial resolution of MODIS LST image data (1 km) to 250 m resolution by applying four models; se-condly, to assess the accuracy of each downscaling model based on qualitative and quantitative analysis with synchronous Landsat 8 TIRS LST data. The results showed that both models could effectively enhance the spatial resolution while simultaneously preserve the characteristics and spatial distribution of the original 1 km MODIS LST image, and also eliminate the “mosaic” effect in the original 1 km image. Statistical results indicated that absolute mean basis error (MBE) in 250 m MODIS LST generated by the four models was less than 1 ℃. Thus, the results were very close to the true surface temperature, indicating that all of the four models were effective and applicable in our study area. Quantitative comparisons of the four downscaled 250 m MODIS LST images and TIRS LST showed that the new conversion model (i.e. model 4) had the lowest RMSE (1.252 ℃), while the original model 1 had the highest RMSE (2.375 ℃). In addition, model 4 had obvious advantages in the description of high temperature areas (i.e. urban area) and low temperature areas (i.e. water bodies).