Table of Content

07 February 2015, Volume 34 Issue 2

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Effects of  changes in solar radiation on net ecosystem exchange of carbon dioxide of planted subtropical coniferous forest in Qianyanzhou.

WANG Meng-meng1, ZHANG Mi1，2，3**, WANG Hui-min4, ZHANG Lei-ming4, YANG Shen-bin1，3

2015, 34(2):  303-311. 

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Solar radiation drives photosynthesis of vegetation. Changes in solar radiation received by ground surface affect the net ecosystem exchange of carbon dioxide (NEE) of forest ecosystem. In this study, we obtained 30min flux data and routine meteorological data at a planted subtropical coniferous forest in Qianyanzhou station. The clearness index was used to quantify the change in sky condition. Based on these data and index, the effects of changes in solar radiation received by ground surface on NEE were analyzed in midgrowing season (June to August) from 2003 to 2010. The results showed that NEE reached its maximum when the clearness index was 0.4-0.6 (a middle intensity of solar radiation). Compared with clear sky condition, the increase of diffuse radiation and the decrease of air temperature and vapor press deficit (VPD) under cloudy sky condition led to the increase of NEE. The NEE with clearness index of 0.4-0.5 and 0.5-0.6 was significantly higher than that with clearness index of 0.7-0.8. Clearness index with values of 0.6-0.7 and 0-0.1 occurred more frequently, suggesting that the sky condition and solar radiation received by ground surface under this condition were not optimal for the net carbon uptake of this forest ecosystem.

 

Dynamics of recovery process of understory vegetation of Betula platyphylla-Larix gmelinii forest in Daxing’an Mountains after fire disturbance.

HAN Feng-lin1,2, BU Ren-cang1**, CHANG Yu1, HU Yuan-man1, MA Jun1,2, NIE Zhi-wen1,2

2015, 34(2):  312-318. 

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Forest fire plays a vital role in the succession of forest ecosystems, and determines species composition, structure stability and species diversity in the forest ecosystems. In this study, we investigated the understory vegetation of Larix gmelinii-Betula platyphylla forests in Daxing’anling Mountains, and analyzed the recovery process of burned areas with the method of spatial pattern instead of time series. The results showed that the community composition changed from xerophytes to mesophytes and hygrophytes in the shrub and herb layers, while species diversity did not show an increasing trend with the community succession. In the herb layer, species richness index showed an increasing trend at beginning and then decreased after 5-8 years on the burned areas. Similarly, species diversity index reached the maximum value 5 years after the fire and tended to be relatively stable value 20 years after. Species evenness index reached its lowest value about 5 years after the fire, then presented an increase and then tended to be stable finally. The temporal trend of species diversity index in the shrub layer was similar to that of herbaceous species but there was a lag of 3-5 years. Understory biomass increased exponentially with restoration age, reaching 10.5 t·hm^-2 at 25 years after the fire.

 

Temporal variation and controlling factors of photochemical efficiency and non-photochemical quenching in Artemisia ordosica.

WU Ya-juan1，2, ZHA Tian-shan1，2, JIA Xin1，2**, QIN Shu-gao1，2, LI Yuan1，2, WANG Ben1，2

2015, 34(2):  319-325. 

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Knowledge on the dynamics and environmental controls of leaf chlorophyll fluorescence is important in understanding how plant physiological processes respond to abiotic stresses such as drought, strong radiation and extreme temperature in arid and semiarid ecosystems. Therefore, chlorophyll fluorescence measurements are an effective tool for exploring plant adaptive strategies. We conducted in situ field measurements of chlorophyll fluorescence on Artemisia ordosica in Yanchi, Northwest China from June to October in 2012. The objectives were to explore seasonal and diurnal variations of chlorophyll fluorescence parameters, and to examine the relationships between chlorophyll fluorescence parameters and environmental factors. The results showed that the photochemical efficiency (Φ) decreased with increasing photosynthetically active radiation (PAR) and air temperature (T_a), but increased with relative humidity (RH). Therefore, PAR was likely the primary factor driving the changes in chlorophyll fluorescence parameters. Both Φ and the nonphotochemical quenching (NPQ) of A. ordosica varied with PAR on a diurnal basis. The diurnal trends of both T_a and RH, however, lagged the chlorophyll fluorescence parameters by 3-4 h. Given the same PAR, Φ in the early growing season was greater than that in the late growing season, and NPQ was higher in the midgrowing season period than at the late stage of the growing season.

Fractal properties of spatial pattern of Pinus tabuliformis population in Qiliyu, Shanxi.

TIAN Hui-xia, YAN Ming**

2015, 34(2):  326-332. 

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Pinus tabuliformis is a dominant species in the most widely distributed temperate coniferous forest community in northern China. The species is resistant to low temperature, dry conditions and poor soil nutrient status. It is also one of the most important tree species for forestation in large parts of northern China. In order to study the spatial distribution pattern of P. tabuliformis community, a 100 m ×100 m plot of natural P. tabuliformis stand was established in Qiliyu Forest Farm in July 2013. All trees in the plot were tagged, mapped and measured. The measurements included the diameter at breast height, total tree height and two crown diameters (eastwest and northsouth directions). The fractal properties of the spatial pattern of P. tabuliformis in the plot were studied by using the boxcounting dimension, information dimension and correlation dimension of fractal theory. The results showed that the high box-counting dimension (1.785) and correlation dimension (1.826) reflected a relatively high degree of individual spatial relatedness, sharp intraspecific competition and powerful spatial occupying of P. tabuliformis population. Information dimension of population pattern (0.262) and the scale variation degree of pattern intensities were low and the individuals were evenly distributed in space. Three fractal dimensions complement and influence each other. These results have important significance for more comprehensive and accurate interpretation of spatial pattern of P. tabuliformis population.

Carbon densities of major tree species in forests in southern Lüliang Mountains of Shanxi Province, China.

WANG Yan1, WANG Meng-ben1**, ZHU Shi-zhong2, ZHAO Tian-liang2

2015, 34(2):  333-340. 

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Forest plays an important role in regional and global carbon cycle. Accurate estimation of biomass and carbon densities of various forest types is important to assess their contributions to total carbon storage in a region. In this study, based on the national forest inventory data in 2005 and 2010, the biomass of main tree species of the forests in the southern Lüliang Mountains was estimated by using both the weighted biomass regression model (WBRM) and the continuous function for biomass expansion factor (CFBEF). The results showed that the estimates from the WBRM were significantly higher than those from the CFBEF (P<0.01), and the WBRM was better for biomass estimation at the medium to small scales compared with the CFBEF. On the basis of 28 × 112 (species × plots) carbon density matrix obtained by WBRM, the classification and ordination of forest communities were carried out using the methods of TWINSPAN, DCA and CCA, respectively. Meanwhile, oneway ANOVA was used to test the significance of difference in carbon density among different forest formations, and Pearson correlation analysis was used to assess the correlation of carbon density with the environmental factors (elevation, slope, aspect and position). The results showed that the forest communities in the southern Lüliang Mountains were classified into 8 forest formations, and a significant difference in carbon density was found among these formations (P<0.01). Form. Quercus wutaishanica + Acer mono and Form. Q.utaishanica + Pinus tabuliformis had significantly higher carbon densities than others, and the carbon density of Form. Pinus bungeana + Platycladus orientalis was the lowest among the eight formations. The carbon density in 2010 was significantly higher than that in 2005. The total carbon density increased with an average value of 1.54 t·hm^-2·a^-1. The impacts of the environmental factors on the formations were in order of elevation > slope > aspect > position. There were significant correlations between the carbon density and elevation, and slope. The carbon density was first increased with the increase of elevation/slope, and then decreased. The forest carbon density was higher on shady and halfshady slopes (north and east) than on sunny and halfsunny slopes (south and eastsouth), and was lowest on steep slopes. In addition to tending management, tree species with stronger adaptability to environmental conditions should be selected for reforestation in order to enhance forest carbon density.

 

Characterization of caloric values in 14 plant species in Hunshandake Sandy Land.

GAO Kai1**, HAN Guo-dong1,2, YU Yong-qi1, ZHANG Li-juan1

2015, 34(2):  341-346. 

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Wild plants can be served as potential sources of bio-fuel production. We determined the caloric values, ash contents, concentrations of C, N and mineral elements of 14 plant species in Hunshadake Sandy Land of Inner Mongolia. We also examined the relationship between caloric value and ash content and the contents of other mineral elements. The results showed that the caloric value ranged from 16.18 to 20.23 MJ·kg^-1 across all species, with a mean value of 18.80 MJ·kg^-1, which is higher than that of worldwide terrestrial plants. The caloric values of the 14 species were in order of Caragana microphylla>Artemisia desertorum>Cynanchum thesioides>Artemisia sievrsiana>Hedysarum fruticosum>Trigonella ruthenica>Cleistogenes squarrosa>Psammochloa villosa>Agropyron mongolicum>Polygonum divaricatum>Agropyron cristatum>Iris tenuifolia>Kochia prostrate> Salsola collina. The ash contents of the 14 species ranged from 3.98% to 12.18%, with the order of S. collina>K. prostrate>C. thesioides>I. tenuifolia>P. divaricatum>C. microphylla>A. desertorum>A. cristatum>T. ruthenica>A. mongolicum>A. sievrsiana>H. fruticosum>C. squarrosa>P. villosa. Across the 14 species, the caloric value was negatively correlated with ash content (P<0.01) and positively correlated with both C and N concentrations (all P<0.01). Moreover, the caloric value was negatively correlated with the concentrations of metal elements, and positively correlated with the concentrations of nonmetal elements (P>0.05). Our results indicated that these wild plants could be served as an important source of bio-energy, as their caloric values were much higher than that of the commonly used biomass for bio-energy (such as switch grass, corn stalk and king grass) in this region.

The response of soil temperature to experimental warming in a subtropical evergreen broad-leaved forest in Ailao Mountains, Yunnan, SW China.

ZHANG Yi-ping1,2**, WU Chuan-sheng2,4, LIANG Nai-shen3, SHA Li-qing1,2, LUO Xin2, LIU Yu-hong1,2

2015, 34(2):  347-351. 

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To improve our understanding of responses of soil temperature to global warming in forests, we conducted a soil warming experiment in a subtropical evergreen broadleaved forest in Ailao Mountains, Yunnan, SW China. Based on measurements from 2011 to 2013, we examined warming effects on seasonal and diurnal patterns of soil temperature. The results showed that warming effects in dry season were greater than in rainy season, showing seasonal variations, but not diurnal variations. Soilsurface temperatures increased between January and April, with a 3 ℃ maximum in February. Warming increased soil temperature by 2 ℃ at the soil depth of 5 cm. The warming effect decreased exponentially with soil depth. Based on a 0.5 ℃ temperature increase, soil warming could reach the depth of 3.82 m in the dry season, 12.04 m in the rainy season, with an annual mean of 6.58 m.

Soil microbial properties under different vegetation types in Shiwan Mountain, Guangxi Province.

SUN Ying-jie, HE Cheng-xin, XU Guang-ping, MO Ling, GU Da-xing, YAO Yue-feng, HUANG Yu-qing**

2015, 34(2):  352-359. 

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To investigate soil microbial properties and their correlation with soil nutrients under different tropical vegetation types in Shiwan Dashan Mountain, Guangxi, China, the soil physicochemical properties, microbial quantity and microbial biomass carbon, nitrogen and phosphorus of secondary broadleaved forest, masson pine forest, shrubgrassland and abandoned land were comparatively analyzed. The results indicated that the number of total microbes in the same soil layer followed the order of secondary broadleaved forest > masson pine forest > shrubgrassland > abandoned land, and it decreased with the increasing soil depth. Soil microbial biomass carbon, nitrogen and phosphorus decreased with the increasing soil depth, and significant differences existed among the different vegetation types. Soil microbial biomass showed significant relationships with soil nutrients in secondary broadleaved forest, masson pine forest and shrubgrassland. Such relationships in the abandoned land were obviously lower than in the other three vegetation types. Moreover, soil microbial biomass phosphorus had no correlation with total nitrogen, available nitrogen and potassium in the abandoned land. Therefore, the number of soil microbes and soil microbial biomass can be used as indicators to evaluate soil fertility of forest ecosystem in Shiwan Mountain, Guangxi. Revegetation should be adopted to facilitate the development of soil microbial communities and improve soil characteristics, so as to promote the rehabilitation of the degraded ecosystems.

Effects of elevated nitrogen deposition on microbial community structure in poplar plantation.

ZHAO Chao1, ZHANG Wen-wen1, RUAN Hong-hua1**, XU Chang-bai2, CAO Guo-hua2

2015, 34(2):  360-366. 

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Soil microbial communities may respond to anthropogenic increases in ecosystem nitrogen (N) availability, and the microbial response may ultimately feed back on ecosystem carbon and N dynamics. We examined the effects of nitrogen deposition on soil microbial community structure composition in a Chinese poplar plantation subject to simulated nitrogen deposition for two years at Dongtai Forest Farm of Jiangsu Province, China. Nitrogen loadings were designed at 5 levels as N0 (control), lowN (50 kg·hm^-2·a^-1), mdeiumN (100 kg·hm^-2·a^-1), highN (150 kg·hm^-2·a^-1), ultra highN (300 kg·hm^-2·a^-1), respectively. Nitrogen addition was carried out within the forest monthly during May and August in 2012-2013. Soil samples were collected at 0-10 cm depths in October 2013. Soil microbial community structure composition was measured using phospholipid fatty acid (PLFA) analysis. Nitrogen additions did not change the total content of PLFAs but increased the amount of bacterial and grampositive bacterial PLFAs. The content of fungal PLFAs did not change significantly, except under the medium level N addition. Nitrogen additions of medium, high, ultrahigh levels decreased the amount of arbuscular mycorrhizal fungal and protistic PLFAs. Principal component analysis (PCA) of microbial PLFA data showed that microbial community structure were changed in all Nadded plots except the lowN trreatment. Our findings indicated that soil community structure can be influenced by shortterm N additions in the poplar plantation.

Diversity of culturable actinomycetes in saline-alkali soil in Jiuquan region of Hexi Corridor.

LI Hai-yun1, HU Lei1,2, NIU Shi-quan1**, KONG Wei-bao1, DA Wen-yan1, HAN Cai-hong1, YAN Wei-ru1, GENG Hui1

2015, 34(2):  367-372. 

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In order to reveal the population diversity of culturable actinomycetes in saline-alkali soil in Jiuquan region of Hexi Corridor, Gansu, four soil samples were analyzed using dilution plate coating method, and phylogenetic analysis was conducted based on 16S rRNA gene sequencing. The results showed that total 63 strains of culturable actinomycetes were isolated according to their phenotypes, belonging to 24 genera, 11 families and 7 suborders, among which, 24 strains belonging to genus Streptomyces were the dominant populations, accounting for 38.1% of total number of actinomycetes strains. In addition, there were 22 strains of actinomyces with sequence similarity less than 98% compared with the known strains in GenBank, accounting for 34.9% of total number of actinomycetes strains. These results indicate that actinomycetes resources are abundant with high diversity in the saline-alkali soil in Jiuquan region of Hexi Corridor.

Spatial variability of soil total nitrogen, available phosphorus and available potassium in Huanghuadianzi watershed.

LI Long, YAO Yun-feng**, QIN Fu-cang

2015, 34(2):  373-379. 

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The spatial autocorrelation, semi-variograms and Kriging interpolation were used to study the spatial variations of total nitrogen, available phosphorus and available potassium in Huanghuadianzi watershed in Aohan Chifeng, Inner Mongolia based on the field sampling. The results showed that total nitrogen, available phosphorus and available potassium were in island distribution on the whole. Total nitrogen and available phosphorus showed a scattered “fertile islands” distribution, while available potassium showed an obvious island distribution. The spatial autocorrelation of nutrients increased with the decrease of lag distance. There were positively and negatively correlated regions, corresponding to the spatial clustering and spatial isolation, respectively. The C₀/(C+C₀) value of available phosphorus was 17.21%, belonging to a strong spatial correlation. Such values for total nitrogen and available potassium were 27.03% and 44.99%, respectively, belonging to a moderate spatial correlation. Both spatial autocorrelation distance and range were in order of total nitrogen < available phosphorus < available potassium. The nutrient contents under different landuse types were in order of cropland > forestland > grassland. Human activity was the main factor influencing the spatial variability of nutrients in the study area.

The niches of dominant species in different resource dimensions in the lower reaches of Fenhe River, Shanxi Province of China.

PANG Chun-hua1**, FAN Xiao1, ZHANG Feng2, NI Rui-jun1, FENG Xiao-jia1, MA Xiao-bo1

2015, 34(2):  380-386. 

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A field plot sampling method was employed to investigate niches of dominant species in different resource dimensions in the lower reaches of Fenhe River, Shanxi Province of China. Niche breaths and overlaps of 20 main wetland plant species along soil pH, soil SOM, total P, total N and total K were analyzed using Shannon and Pianka formulae. The differences in niche breadth of each species in different resource dimensions show that different species have different abilities to use resources, so they have different ecological adaptability. The dominant species in the region are Rorippa globosa, Phragmites australis, Rumex dentatus, and Scirpus planiculmis, and they have higher niche breadth and adaptability to environment. Polygonum hydropiper, Artemisia lavandulaefolia, Capsella bursapastoris and Iris lactea var. chinensis have lower niche breadth. The niche overlaps of P. australis, S. planiculmis, R. globosa, R. dentatus with others were relatively larger, which illustrates that these plants make a similar use of natural resources and that there is certain competition among them.

Effect of re-vegetation on herbage plant species diversity of dumping site in an open pit coal mine.

ZHAO Yang, ZHANG Peng, HU Yi-gang**, HUANG Lei, SU Jie-qiong

2015, 34(2):  387-392. 

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A quantitative survey of plant species was carried at the northern dumping site in the Heidaigou open pit coal mine in August and September of 2012. A total of five revegetation types were selected for the plant species composition and diversity survey: tree, tree + shrub, tree + herbage (Gramineae), tree + herbage (Leguminosae) and abandoned farmland. The results showed that species abundance of the abandoned farmland was 181.00±12.52, being higher than that of the other re-vegetation types. Species richness of the abandoned farmland and tree + herbage (Leguminosae) (4.50±0.95 and 4.78±0.87, respectively) was higher than that of the other re-vegetation types. Species abundance and richness showed positive relationships with soil organic matter and total nitrogen content, but negative relationships with soil phosphorus content. Increasing soil organic matter and total nitrogen contents in shallow layer is an efficient way to promote plant diversity restoration at the dumping site. Also, we suggest that nitrogenfixing plants should be given a preference for re-vegetation.

Microclimate characteristics of apple orchard at different growth stages on the Loess Plateau.

QU Zhen-jiang1**, ZHANG Yong1, WANG Jing-hong1, ZHANG Tao1, YANG Fang2, GAO Feng1

2015, 34(2):  399-405. 

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An automatic measurement system of microclimate gradients was employed to observe photosynthetically active radiation (PAR), air temperature, tree body temperature, relative humidity at different heights of 6, 3 and 1.5 meters, and total radiation atop the canopy and soil temperature and humidity from 10 to 60 cm with intervals of 10 cm in an apple orchard on the Loess Plateau from January 2011 to December 2013. The microclimate characteristics of the apple orchard at different growth stages were investigated. The results showed that the total radiation, PAR, air temperature and tree body temperature all presented an obvious diurnal variation with one peak. The total radiation and PAR peaked at 12:50, air temperature and tree body temperature peaked around 16:00. The total radiation and PAR reached maximum at vigorous growth stage and second at initial growth stage. The air temperature, tree body temperature and soil temperature reached maximum at vigorous growth stage, and came second at initial growth stage. PAR atop the canopy was greater than that beneath the canopy at vigorous growth and dormant stages. The vertical variation of air temperature was greatest at dormant stage, and next at vigorous growth stage. Except at the surface, soil temperatures increased with the depth, accompanying a smaller diurnal variation. Humidity was maximum at vigorous growth stage, and next at dormant stage, and its maximum daily difference occurred at initial growth stage and came second at vigorous period. Humidity was higher beneath canopy than atop canopy during night, especially at vigorous growth stage. Soil moisture was highest at initial growth stage and next at vigorous growth stage. It was lower in the surface and deep layers, and reached maximum at 20 cm depth with a great variation.

Suitable temperature indices of double-cropping super early rice at tillering stage.

LU Kui-dong1**, LI Han-mao2, HUANG Wan-hua1, LI Ying-chun3

2015, 34(2):  406-412. 

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High and stable yield of doublecropping super rice has become an important part for national food security since 2006 when it has been promoted. However, only few studies have focused on the relationship between its ecological characteristics or production structure formation and meteorological factors. In this paper, the suitable temperature indices were studied based on the data of temperature controlled by the artificial climate chamber and field cultivation observation, in combination with analysis of the correlations between temperature and tillering rate, leaf area, biomass, grain number per spike, seed setting rate, sterile grain rate and theoretical yield in Nanchang, Jiangxi Province during 2012 to 2013. The results showed that the suitable temperature at active tillering stage ranged from 26 ℃ to 28 ℃ with the optimum value of 27 ℃; for the later tillering stage, the suitable temperature ranged from 25 ℃ to 27 ℃ with the optimum value of 26 ℃. For tillering period, unsuitable low temperature index was 18.5 ℃, while unsuitable high temperature index was 35.8 ℃. Temperature indices from this study would provide reference for reasonably arranging sowing dates so as to avoid chilling damage.

Effects of shading on the growth and photosynthesis of Macropanax rosthornii seedlings.

Wenbin1, NIE Dong-ling2, WU Si-zheng2**, BAI Wen-fu2, SHEN Su-zhen1

2015, 34(2):  413-419. 

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The effects of shading treatments (full sunlight intensity, 70% sunlight intensity, 40% sunlight intensity) on chlorophyll content, photosynthetic characteristics and growth of Macropanax rosthornii seedlings were examined in a pot-culture experiment. The results showed that shading treatments enhanced the growth performance of the individuals of M. rosthornii with dark green leaves. Both canopy size and the number of compound leaves under shading were significantly greater than those under full sunlight  (P<0.05). The contents of total chlorophyll, chlorophyll a and chlorophyll b in leaves under shading were significantly higher than under full sunlight. The chlorophyll contents increased with the enhanced intensity of shading. On the contrary, the chlorophyll a/b showed a decreasing trend. Under shading, the apparent quantum yield (AQY) and the maximum net photosynthetic rate (P_max) increased, and the light saturation point (LSP) and light compensation point (LCP) distinctly decreased. The efficiency of primary lightenergy conversion (F_v/F_m) and potential activity (F₀/F_m) of PSⅡ were increased by shading, in particular, F_v/F_m and F₀/F_m were significantly  higher under 40% sunlight than under full sunlight (P<0.05). The nonphotochemical quenching coefficients (NPQ) were significantly  lower under shading treatments than under full sunlight (P<0.05), and NPQ further decreased with increasing the shading intensity in which heat dissipation was reduced to increase the efficiency of lightenergy conversion of PSⅡ. Meanwhile, the photochemical quenching coefficient (q_P) was rarely influenced by shading. Thus, as a shaderequiring plant, M. rosthornii had a rather strong ability to utilize low-intensity light and grew well under appropriate shading.

Responses of seed germination of five Asteraceae species to temperature and their invasivity.

CHEN Wen1, WANG Ju-hong2**, CHEN Dan-sheng2, ZHU Hui2

2015, 34(2):  420-424. 

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Seed germinations of five Asteraceae  species including Bidens pilosa, Mikania micrantha, Wedelia trilobata, Ageratum conyzoides and Eclipta prostrata (a native species) from eastern Guangdong were studied following wetstorage at 15 ℃ for 30 days and then incubation at 25 ℃ or 25/15 ℃ for 30 days, to reveal the response of germination to temperature. The result showed that B. pilosa, E. prostrate, A. conyzoides, M. micrantha and W. trilobata seeds germinated to 100%, 98%, 62%-78%, 44%-52%, 2% (at 25 ℃)-86% (at 25/15 ℃) after seed dispersal, respectively. At the first stage (at 15 ℃ under wet condition), the germination percentages of five Composite plants were 82%-91% (B. pilosa), 19%-26% (W. trilobata), 8.7%-12% (E. prostrata), 0-1% (W. trilobata), 0% (A. conyzoides). At the second stage (at 25 ℃ and 25/15 ℃), seeds of A. conyzoides germinated to 35% and 49%, E. prostrate to 58%-68%, W. trilobata to 4% (at 25 ℃) and 55% (at 25/15 ℃). Quick germination, high germination percentages, and broad temperature adaptation of germination may be important characters of these alien invasive plants.

Behavioral responses of Frankliniella occidentalis to kidney bean plants and their volatiles under different treatments.

ZHANG Jun, ZHI Jun-rui**, YANG Guang-ming

2015, 34(2):  425-430. 

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By using the Ytube olfactometer in the laboratory, the behavioral responses of Frankliniella occidentalis female adults were studied to kidney bean plants and 8 typical volatile chemicals induced by healthy plants (CK)， mechanical damage (MD), thrip nymph feeding (DFNF), thrip adult feeding (DFAF), exogenous jasmonic acid (JA) and methyl salicylate (MeSA). The results showed that F. occidentalis had different responses to kidney bean plants with different treatments. Compared to clean air (A), the kidney bean plant induced by JA and MeSA had stronger repellency to F. occidentalis, while F. occidentalis didn’〖KG-*9〗t show significant response to other treatments. F. occidentalis responded more significantlyto healthy plants (CK) and MD than to other treated plants, but the preference of F. occidentalis had no significant difference between CK and MD. Kidney bean plants induced by JA and MeSA had stronger repellency to F. occidentalis than other treated plants, and the effect of JA was less than MeSA. Among 8 standard chemical samples tested, (Z)3-Hexenol always showed a strong attraction to F. occidentalis at 5 concentration levels. α-Tetpinolene, 1-Octen-3-ol, (Z)-3-Hexenyl acetate and Isopentanol showed strong attractions to F. occidentalis just at certain concentrations. However, (Z)-3-Hexenal, Cyclopentanol and 3-methylButanal displayed repellency to F. occidentalis at 10^-1-10^-3, 10^-1-10^-4, 10^-4 μL·μL^-1 concentrations, respectively.

Allelopathy of Panax notoginseng on wheat

WANG Qing-ling, DONG Tao, ZHANG Zi-long**

2015, 34(2):  431-437. 

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With three wheat varieties (99-1, Chuanmai 45 and Wenmai No. 8) grown in Panax notoginsengproducing region as receptor materials, the allelopathic effects of different concentrations of stem and leaf aqueous extracts, root aqueous extracts, hair root and hair root rotted liquids from P. notoginseng were measured. The results showed that: (1) Stem and leaf aqueous extracts had obvious inhibition on the germination potential, germination rate, germination index, mean germination days, seedling height, root number, the length of longest root, shoot dry weight, root dry weight, ratio of root to shoot, and total dry weight of the tested wheat varieties, while root aqueous extracts inhibited only the length of longest roots. (2) Hair root showed significant inhibitory effects on the wheat cultivars. With the increase of concentration, the inhibition effects increased. (3) With the increase of concentration, hair root rotted liquids showed bidirectional effects of “promotion at low concentration and suppression at high concentration” on Chuanmai 45 and Wenmai No. 8, and inhibitory effects on variety 991. (4) The allelopathic sensitivity of 99-1 and Wenmai No. 8 to P. notoginseng was stronger compared with Chuanmai 45, and thus the latter would be more suitable for rotation with P. notoginseng.

Effects of light and water availability on the morphology and allelopathy of the native outbreak species Merremia boisiana (Gagnep.) Oostr.

HUANG Qiao-qiao1, SHEN Yi-de1, LI Xiao-xia1, ZHANG Guo-liang2, HUANG Dong-dong1, FAN Zhi-wei1**

2015, 34(2):  438-444. 

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Merremia boisiana is a native species in Hainan Province of China, and its population quantity has been rapidly increasing in recent two decades, which poses a heavy threat to many secondary forests, planted forests and shrublands. There are different light and water quantity conditions in habitats where populations of M. boisiana have broken out, and outbreak species usually adapt to diverse environmental conditions through high phenotypic plasticity. To reveal the ecophysiological mechanisms underlying the adaptation of the outbreak species M. boisiana to diverse environmental conditions, this study assessed the effects of different light and water availability on the growth, morphological traits and their plasticity, and allelopathy of M. boisiana through a greenhouse pot experiment. Biomass of M. boisiana decreased under high light intensity and drought. Low light increased total stem length, specific stem length, and specific leaf area, and decreased the root/shoot ratio of M. boisiana. The mean phenotypic plasticity index of these morphological traits was 0.36. Under high light and drought, aqueous leachates from dry leaves of M. boisiana were least inhibitory to seed germination and seedling shoot growth of Lactuca sativa var. ramosa, possibly because M. boisiana decreased its resource allocation to competition (allelopathy) under stress conditions. Plasticity in morphology might facilitate M. boisiana to better capture light as well as grow to the canopy at a faster rate under low light availability in the forest understory, while plasticity in allelopathy indicates that M. boisiana might adjust its resource allocation to competition (allelopathy) to adapt to various water conditions. We conclude that plasticity of M. boisiana in morphological traits and allelopathy might be one of the ecophysiological mechanisms of M. boisiana adapting to various environmental conditions and causing outbreak.

Influences of chemical components of water extracts from submerged macrophyte leaves on the growth of three common epiphytic algae.

JI Hai-ting1,2, XIE Dong1, ZHOU Heng-jie1, AN Shu-qing1**

2015, 34(2):  445-453. 

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This study analyzed the chemical components of leaf waterextracts of typical submerged macrophytes (native species: Hydrilla verticillata and Myriophyllum spicatum; exotic species: Elodea nuttallii and Cabomba caroliniana) from lakes in the middle and lower reaches of Yangtze River. The selected chemical components were 2Naphthalenamine,N-phenyl (produced by all of the four submerged macrophytes), 1-Propanone,1-phenyl (only produced by E. nuttallii), and Benzobfuran,2,3-dihydro (only produced by C. caroliniana). Then we used relative growth rate, algal cell concentration and chlorophyll content as algae growth indicators to explore the influences of different dosages of the three chemical components on the growth of epiphytic algae (Chlorella vulgaris, Scenedesmus obliqnus and S. quadricanda). Our results showed that the three chemical components significantly reduced algal cell concentration and chlorophyll content of S. obliqnus and C. vulgaris, however, their inhibitory effects on S. quadricanda were weaker. There were significant differences in the responses of these three epiphytic algae to different dosages and processing time. The lower dose of chemical components could promote the growth of epiphytic algae, while the higher dose showed inhibition effects, and the algae showed obvious and steady growth with the extension of processing time. Overall, 1-Propanone,1-phenyl-showed the strongest inhibiting effect, followed by Benzobfuran,2,3-dihydro, and the weakest was 2-Naphthalenamine,N-phenyl, suggesting that the chemical components from the exotic submerged macrophytes (E. nuttallii and C. caroliniana) have stronger inhibiting effects on epiphytic algae.

Effects of temperature, light intensity and salinity on the growth, total lipid and fatty acid of Phaeodactylum tricornutum mutant.

YE Li, JIANG Xia-min**, MAO Xin-xin, GAO Xiu-zhi, ZHANG Ze-ling

2015, 34(2):  454-462. 

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To obtain a better culture conditions for microalgae, singlefactor test was performed to reveal the effects of ecological factors on Phaeodactylum tricornutum mutant MP-2, including temperature (10, 15, 20, 25, 30 ℃), light intensity (20, 40, 60, 80, 100, 120 μmol·m^-2·s^-1) and salinity (5, 10, 15, 20, 25, 30, 35, 40). The results showed that all these ecological factors exerted significant effects on the growth, total lipid content and fatty acid composition of MP-2. This strain would get a better growth and higher lipid content at 10-25 ℃, and the optimal temperature is 20 ℃. The highest contents of EPA and PUFA appeared at 15 ℃, because low temperature was favorable to their accumulation. The suitable light intensity for growth was defined at 20-120 μmol·m^-2·s^-1, with the optimum at 40 μmol·m^-2·s^-1. Low light intensity benefits the accumulation of total lipid, with highest total lipid content at 20-40 μmol·m^-2·s^-1. The light intensity also had a significant effect on the accumulation of EPA and PUFA (P<0.05), with highest contents of EPA (29.15%) and PUFA (40.22%-40.56%) at 100 μmol·m^-2·s^-1 and 80-100 μmol·m^-2·s^-1, respectively. This strain would grow well at salinities 10-40, with optimum at 25. High salinity would be beneficial to total lipid content, whilst low salinity would be beneficial to the accumulations of EPA and PUFA. The highest total lipid content would be obtained at salinities 30-35, while EPA and PUFA at salinities 10-15 and 15, respectively.

Spatial-temporal characteristics and affecting factors of eutrophication in Sanbanxi Reservoir, Guizhou Province.

ZHANG Lei1, LI Qiu-hua1**, WU Di1, ZHOU Qian-lan2, HUANG Guo-jia1, OU Teng1

2015, 34(2):  463-470. 

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In order to reveal the spatial and temporal characteristics of eutrophication in Sanbanxi Reservoir, a large and deep reservoir, and its influencing factors, the eutrophic index and related environmental factors were investigated in November (dry period) 2012, April (normal period) and July (wet period) 2013. The results indicated that the eutrophication characteristics of Sanbanxi Reservoir showed obvious spatial and temporal variations. The trophic level index (TLI) was 33.39-39.20 in the dry period and the eutrophication status kept at mesotropher. The TLI was 39.70-59.44 in the normal period and 39.19-56.27 in the wet period. The upper layer was at light eutropher, and the middle and lower layer kept at mesotropher. The eutrophication status decreased at first and then increased with the increasing depth. Nitrogen and phosphorus were the main factors causing the eutrophication status of Sanbanxi Reservoir, especially phosphorus made the greatest contribution to the eutrophication status. Reducing the discharge of phosphorus can effectively control the trend of eutrophication.

The biological characteristics and growth patterns of Mytilus coruscus in the waters of Zhongjieshan Islands.

LIANG Jun, YU Bao-cun, BI Yuan-xin, WANG Wei-ding**

2015, 34(2):  471-476. 

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Mytilus coruscus is an economic mollusc and good object for artificial propagation and culture, but there are very few reports about its biological characteristics so far. Based on the data of tracking survey of one-year-old M. coruscus from April 2013 to February 2014 and of sampling survey of two-year-old M. coruscus during August to December 2013, Taylor formula, linear function and Von Bertalanffy growth equation were used to analyze their biological characteristics and growth patterns in the waters of Zhongjieshan Islands. The result showed that there were no obvious differences in shell length, shell height, shell width, body weight, shell weight and wet weight of soft tissues between male and female individuals. There were significant positive linear correlations between shell length and shell height and shell width. Moreover, there were significant power function relationships between shell length and body weight, shell weight, and wet weight of soft tissues. The growth equations of shell length and body weight were as follows: L_t=87.48(1-e^-0.348(t+0.913)) and W_t=79.51(1-e^-0.348(t+0.913)) 3-respectively. The period between August and October was considered to be the rapid growth season, and inflection point of sexual maturity of M. coruscus was in late August. It was proposed that midOctober was the best harvest season for spring seeding.

Annual dynamics of cladocera community structure in swine wastewater recycling system.

DONG Xu-feng1,2, SONG Xiang-fu1,2**, LIU Ya-qin2, ZHOU Wen-zong2, CHEN Gui-fa2

2015, 34(2):  477-482. 

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From June 2012 to May 2013, a monthly investigation was conducted to understand the annual variation of cladocera community structure (including species composition and standing crop) and related main affecting factors in the swine wastewater recycling system of Shanghai Agricultural Academy of Sciences. The results showed that a total of 22 species in 10 genera of 5 families were identified through the year. There were 7 dominant species, including Daphnia pulex, Moina macrocopa, and Ceriodaphnia cornuta. The mean annual density and biomass of the cladocera were 135.02 ind·L^-1 and 11.14 mg·L^-1, with peaking values in June and April and minimum values in January and July, respectively. The Shannon index, Pielou index, and Margalef index were higher in autumn and winter than in summer and spring. The Pearson correlation analysis showed that pH, dissolved oxygen, total nitrogen, total phosphorus and ammonia nitrogen were the main factors affecting the community structure of cladocera in the system.

Differences between two amaranth cultivars in accumulations of Cd and main osmotic adjustment substances under salt stress.

XU Zhi-min1,2, HE Bao-yan1,2**, LI Qu-sheng1,2, LEI Yong-kang1,2, MEI Xiu-qin1,2, CAO Gang1,2, ZHOU Li-zhen1,2, CHEN Yan-fang1,2

2015, 34(2):  483-490. 

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A pot experiment was conducted in sewageirrigated garden soil (2.28 mg·kg^-1 Cd) pretreated with different concentrations of NaCl. The differences between two amaranth cultivars (BRLA and ARW) in accumulations of Cd and main osmotic adjustment substances under salt stress were investigated. Under salt stress, the contents of Cd and Na⁺ in roots and leaves of cultivars BRLA and ARW significantly increased compared with the control (P<0.05), and the Cd content was obviously higher in ARW than in BRLA. BRLA had stronger Na⁺ retention capacity in roots than ARW, decreasing the transportation of Na⁺ from root to leaf. In 0.4% NaCl treatment, the K⁺/Na⁺ ratio decreased by 39.2% in leaves of BRLA, and by 56.9% in leaves of ARW. Mg²⁺ content increased in roots and leaves of BRLA and decreased in roots of ARW. More proline accumulated in roots and leaves of both cultivars under salt stress compared with the control (P<0.05) and BRLA exhibited greater proline synthetic ability than ARW. Contents of soluble protein and free amino acids in roots and leaves of both cultivars decreased with the increase of soil salinity, while soluble sugar in roots of both cultivars increased with the increase of soil salinity. These results suggested that BRLA had lower Cd uptake, higher salt tolerance and stronger osmotic adjustment ability than ARW. Our study provided some useful information for screening and breeding of salt tolerant cultivars with low Cd accumulation.

Short-term effects of nutrient additions and snow increase in winter on nitrogen utilization rate of Kobresia humilis meadow.

WEI Qing1,2, ZHOU Hua-kun1**, YAO Bu-qing1, WANG Wen-ying2, LIU Ze-hua2, ZHAO Xin-quan1

2015, 34(2):  491-496. 

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The effects of nutrient and water additions on nitrogen utilization rate of alpine plants were investigated using the ¹⁵N labeling technique in a Kobresia humilis meadow over a short term period. Four treatments were set up as follows: increased snow in winter (W), N fertilization (N), P fertilization (P), and control (CK). About one month after the labeling, the ¹⁵N absolute abundance of belowground of plants was the highest. More added N was recovered in the soil. This indicates that N was not fully used by plants in the short term, and less N was transferred into litter. The N utilization rates for plants under different treatments were in order of P treatments > N treatments > W treatments > CK. This reflects that nutrient and moisture modify N utilization rate of alpine plants in K. humilis meadows, and the nutrient is more important.

Spatial distribution patterns of specific root lengths of Avena sativa L. and Vicia villosa Roth in mixedsowing grassland under density dependence in northern slope of Qilian Mountains.

SONG Qing-hua, ZHAO Cheng-zhang**, SHI Yuan-chun, DU Jing

2015, 34(2):  497-503. 

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The specific root length (SRL) reflects the feature of plants’ adaptation to different environments. In this study, the mixedsowing grassland of gramineous grass Avena sativa and leguminous grass Vicia vilosa with the density ratio of CK₁ (1∶0), A₁ (8∶2), A₂ (6∶4), A₃ (5∶5), A₄ (4∶6), A₅ (2∶8) and CK₂ (0∶1) was established in the upper reaches of Qilian Mountains, Gansu Province, Northwest China in 2013, aimed to study the spatial distribution patterns of SRLs of the two mixedsowing grasses. The results showed that the total root length and SRL of all mixed sowing groups of A. sativa were greater than those of V. villosa (P<0.05), but both species had no significant difference in underground biomass. With the decrease of A. sativa density and the increase of V. vilosa density in mixedsowing grassland, the root lengths of both grasses increased gradually (P<0.05), the root biomass decreased first and then increased (P<0.05), the SRLs increased first and then decreased (P<0.05). The SRLs of both species in the five mixed sowing groups gradually decreased with soil layers, and the superficial degree in fine roots of A. sativa was higher than that of V. villosa. The layering distribution of roots of currentyear grass changed the resource allocation strategy, gradually optimized the utilization structure of resources, and maximized the utilization of soil resources.

Species diversity of butterflies in Fanjing Mountain National Nature Reserve of Guizhou.

MEI Jie1,2, RAN Hui1,2**, YANG Tian-you1,2, XU Qin-zhi1,2

2015, 34(2):  504-509. 

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Based on the investigation of butterfly resource in Fanjing Mountain and its surrounding area from November 2010 to November 2012, 446 specimens were collected. These samples belong to 10 families, 60 genera and 86 species. Papilionidae and Nymphalidae accounted for 164 and 132 specimens, respectively, being larger than any other families. The species diversity index of Nymphalidae was highest (2.654), followed by Papilionidae (2.377), and Acraeidae being the lowest. The genus diversity index of Nymphalidae was the highest (2.338), followed by Lycaenidae (1.906), and Acraeidae being the lowest. In the five different habitat types (shrubland, forest edge, forest, slope grassland, and cropland), both the species richness and the hierarchical diversity indexes decreased in order, and the numbers of species were 56, 39, 12, 8 and 8, respectively. As for species composition, the similarity between shrubland and forest edge was the largest with a coefficient being 0.218; followed by that between slope grassland and shrubland, and that between cropland and other habitat types were lower.

Pollution characteristics and affecting factors of mercury in particulates PM_2.5 in Guiyang City.

LIANG Long-chao1,2, QIU Guang-le2, CHEN Zhuo1,3**

2015, 34(2):  510-515. 

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A total of 367 twentyfour hour composited particulate matter (PM_2.5) samples were continuously collected in Guiyang City from June 2013 to May 2014. Meteorological data were simultaneously recorded by HOBO U30. Mercury (Hg) concentrations in PM_2.5 samples were measured by using Lumex with a Zeeman atomic absorption spectrometer (ZAAS). Results showed that the daily concentrations of Hg in PM_2.5 ranged from 11 to 2560 pg·m^-3 with an average of 104±85 pg·m^-3. The highest concentrations of Hg in PM_2.5 were found in December and January and the lowest in July. An obvious seasonal variation was observed as: summer < autumn < spring < winter. The anthropogenic sources from northeastern wind as well as the scarcity of precipitations resulted in high levels of Hg in PM_2.5 in winter. Compared with the investigated results in China’s other cities, the present study shows a lower level of particulate Hg pollution in Guiyang.

River habitat quality assessment, water quality analysis and their response relation of Puhe River Basin

WANG Qiong1,2, FAN Zhi-ping1**, LI Fa-yun1， JU Wen-peng3

2015, 34(2):  516-523. 

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River habitat is an important factor to maintain ecological integrity and river health. According to environmental characteristics of Puhe River Basin, a comprehensive river habitat assessment index system was established by using analytic hierarchy process. Habitat quality status of 25 sections of Puhe River Basin was evaluated. Correlation between the habitat quality indicators and water quality parameters were further evaluated. The results showed that: (1) Significant differences in habitat quality were found among the different sections. One section achieved the preferable level, 5 good, 16 fair, and 3 poor; (2) The comprehensive river habitat assessment index was negatively correlated with TP, NH₄⁺-N, COD_Cr, and other habitat quality indices were also correlated with the water quality index. It was indicated that habitat quality was a major factor impacting the water quality.

Water footprint in Beijing.

SUN Yan-zhi1,2, LU Chun-xia1**, XIE Gao-di1, LI Na1

2015, 34(2):  524-531. 

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Water shortage and water pollution have become a restrictive factor of sustainable development in Beijing, and water resource utilization has aroused much attention. Water footprint study links the production and consumption to the use of water resources, and can reveal the comprehensive utilization of water resources. Based on the water footprint, this study assessed the water resource utilization of Beijing, and the results showed that: (1) In 2012, the water footprint in Beijing was 35.26 billion m³, and the per capita water footprint was 1704 m³, far beyond the total water volume of 3.59 billion m³ and per capita consumption of 193.3 m³ in the statistics. Thus, the water resources were under enormous pressure. (2) The virtual water consumption of urban and rural regions was different. Except the animal products, the rural residents’ virtual water consumption of food was relatively high, with 103.5 m³ per year per capita, while urban per capita annual was 72.5 m³, lower than the dried and fresh fruits of 92.4 m³. (3) Animal products accounted for the largest proportion of the virtual water consumption, which illustrated the relatively high consumption of animal products of Beijing residents and the high virtualwater content of animal products per unit. For this reason, it may be appropriate to increase imported animal products to replace local animal products in the virtual water trade, reducing the consumption of water resources.

Water-soil resources optimization based on accumulative cost resistance model in Shiyang River basin.

WEI Wei1**, LEI Li2, FAN Wen1, ZHOU Jun-ju1, SHI Wei1, XIE Bin-bin3

2015, 34(2):  532-540. 

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Taking the optimization of water-soil resources as an objective, the energy exchange and transfer resistance, and cost resistance spatial distribution of the watersoil resources in Shiyang River basin were analyzed according to the minimum accumulative resistance surface, the accumulative cost resistance model and the surface dissipative technology. The results showed that the ecological core sources of watersoil resources were river net, other water areas, croplands and construction lands. The maximum value of accumulative cost resistance was found in construction lands which had the biggest resistance to energy flow and transfer of ecosystems. In contrast, the river net had the minimum cost resistance. According to the configuration methods and division principles of water-soil resources, Shiyang River basin was divided into five types, i.e., the key areas to be optimized, areas waiting for configuration optimization, the importantly concerned areas, concerned areas, and ecological improvement and conservation areas. The key areas to be optimized are mainly distributed in Minqin and Wuwei oases that carry more than 85% of towns and population. Some measures should be taken to improve the ability of water conservation and to reduce ecological risk, for example, increasing oasis area in fringe, afforestation in the transition zone of oasis and desert and reducing planting waterintensively consuming crops.

Chinese translation for the scientific term “Ecological Restoration”. 

ZHANG Yi-ping1,2**, WANG Guo-yi1,2, WANG Yu-hang1,2

2015, 34(2):  541-549. 

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The scientific term “ecological restoration” was originated in Western world in the early 1980s and introduced to China later on by some Chinese ecologists. The faithful and expressive Chinese translation for the term, however, has been still argued about both inside and outside the scientific fields of ecology in China from the beginning till now. To reach a more precise translation for the term, this paper has made three thorough comparisons about the term itself and its different Chinese translations. The comparisons included: one among the definitions and their evolutions from different sources and various periods in Western countries, one among the connotational explanations for its keyword “restoration” (or the verb form “to restore”) in retrospect with etymological viewpoints in traditional and contemporary dictionaries, with EnglishEnglish or EnglishChinese explanations, and the other among some expressions of the term excerpted from governmental websites, newspapers and authoritative speeches. Through those comparisons, it could be concluded that whether from the evolution towards the term itself or its connotational contents in the keyword restoration, and from the pure and applied scientific meanings or ecological engineering practices, the term “ecological restoration” should be translated as “sheng tai xiu fu” in Chinese. We believed that this translation for the term could not only satisfy the basic principles of faithfulness, expressiveness and elegance in translation and interpretation, but also be conducive to promoting and guiding the current actions and engineering implementation of ecological restoration practices in China.

Research progress on adaptive responses of anatomical structure of plant roots to stress.

WANG Pan1,2, CHEN Nai-lian1,2, ZOU Xian-hua1,2, MA Xiang-qing1,2, WU Peng-fei1,2**

2015, 34(2):  550-556. 

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This paper reviews the adaptive changes of main anatomical structures of root system including cortical tissue, casparian strip and vascular cylinder under stress conditions, and reveals the responses of the roots to different stress conditions by selfadjustment and even alternation of structure. It is suggested that future research should be conducted to investigate the plasticity of root anatomical structure under different stress conditions. In addition, index systems of screening stressresistant varieties should be established by combining morphological, anatomical and physiological metabolic parameters of plants.

Termite biodiversity and its ecological indication to environmental change.

LI Zhi-qiang1**, KE Yun-ling1, BAN Da-xiong2, ZHANG Shi-jun1, YANG Yue-ping1

2015, 34(2):  557-561. 

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Termites (Blattodea: Termitoidae) as the dominant invertebrate decomposers are important for ecosystem function in tropical and subtropical ecosystems. However, the studies and applications of termite biodiversity in ecological management are limited for lack of standardized rapid sampling protocols. In order to provide approaches and directions for further studies on termite biodiversity and ecological management based on termites, this article summarized the termite functional classifications, sampling protocols, the responses of termite biodiversity to habitat’s differences and anthropogenic disturbances and their ecological indications.

 

Review on three-dimensional expansion and its atmosphere environmental effects of urban landscape.

GONG Ji-ping1,2, HU Yuan-man1, LIU Miao1**, CHANG Yu1, BU Ren-cang1, XIONG Zai-ping1, LI Chun-lin1

2015, 34(2):  562-570. 

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Recently, China has entered into a developmental stage of rapid urbanization, and cities have been expanding rapidly with increasing number of skyscrapers. Consequently, the interactions between cities and their surrounding environments have become more complex. Thus, developing theory and method of threedimensional landscape pattern dynamics and processes is important for urban ecological security and health. In this review, the study progresses on urban landscape pattern and its atmosphere environmental effects were introduced from threedimensional perspectives. Atmospheric numerical models of urban landuse at different scales, and atmosphere environmental effects of urban landscape elements and pattern change were elucidated. The deficiencies of theoretical basis of three-dimensional landscape pattern and research methods on atmospheric numerical models were summarized. In future, quantitative analysis of three-dimensional pattern and its environmental effect will be a new research direction in urban landscape ecology. On the basis of three dimensional urban landscape theories, building pattern indexes which could reflect the relationship between landscape pattern and atmospheric environment, constructing multiscale models which combine dynamic mechanism of urban landscape pattern change with atmospheric environmental factors, and strengthening optimization study of threedimensional urban landscape pattern are considered as future directions of the study field.

Stand thinning based on species diversity and spatial patterns.

LONG Cheng1,2, YANG Xiao-bo2,3**, LONG Wen-xing2,3, LI Dong-hai2,3

2015, 34(2):  571-581. 

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In order to understand the factors influencing stand thinning in tropical natural secondary forests, aboveground biomass, species diversity and spatial patterns were quantitatively analyzed by using aboveground biomass model, diversity index and O ring statistics. Moreover, the effects of species diversity and spatial patterns on stand thinning were studied with thinning index calculated by Yoda selfthinning model. The results showed that stand aboveground biomass increased first, then decreased and increased finally with declining stand density. An inflection point of aboveground biomass change occurred at diameter class Ⅲ or Ⅳ, and this should be paid attention to during forest management. In general, there was no significant correlation between diversity index and stand thinning index. However, the medium value of species diversity index corresponded to the largest thinning index, suggesting that stand thinning was strongest with the medium species diversity. A significant negative linear correlation existed between largest aggregation intensity and thinning index as follows: α=-1.7873O₁₁(r)_max+2.3451 (R²=0.798, P=0.003). The results indicated that if plant population assembled excessively, stand thinning would be suppressed rather than promoted in the tropical evergreen monsoon elfin forest.

 

Comparison on simulation methods of maize root distribution.

CAI Fu1, MING Hui-qing2, ZHU Xin-yu3, MI Na1, ZHAO Xian-li1, XIE Yan-bing1, ZHANG Yu-shu1**

2015, 34(2):  582-588. 

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A satisfactory parameterization of root distribution, a key parameter for simulating root water uptake process, is important in improving simulation performance of land surface process models (LSMs) for simulating water and heat flux exchanges. Using observation data of maize root biomass in different growing periods in previous studies,
simulation performances  of three root distribution parameterization methods which established by Schenk, Zeng and Jackson and applied to the mainstream LSMs (defined as M1, M2 and M3, respectively)  were compared. The results showed that M1 could reproduce accurately root distribution profiles in every growing period while M2 and M3 had similar performances, with relatively high simulation precision only after corn tasseling stage. By analyzing the dynamic pattern of the simulated two parameters
(d₅₀ and d₉₅, the depths in which 50% and 95% of all roots were located) in different growing periods, we found that d₉₅ increased with maize growth and its variability was the biggest at jointing and maturity and the smallest at tasseling stage. But, d₅₀ only increased with maize growth before flare opening stage and was almost invariable after tasseling stage. With further investigating, a biggest gap for d₅₀ and d₉₅ could be found between the observed value and the set value in LSMs before flare opening stage, which is one of the important reasons for errormaking in land surface process simulating.

Effects of no-tillage with straw mulching on soil moisture and crop yield in soils with different textures.

LIU Lian-hua, CHEN Yuan-quan, YANG Jing, NIE Zi-jin, ZHANG Jian-sheng, SHI Yan-qin, SUI Peng**

2015, 34(2):  393-398. 

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Sandy soil (S), sandy loam soil (SL) and sandy clay loam soil (SCL) were transported using the spatial displacement method to Wuqiao Station of China Agricultural University, Hebei Province for studying soil moisture and crop yield under no-tillage with mulch and conventional tillage during 2010 to 2013. The results showed that compared with conventional tillage, no-tillage with mulch increased soil volumetric water content, and the effect was more obvious on SL than on S and SCL; the soil volumetric water content of 0-20 cm under no-tillage with mulch was lower than under conventional tillage in SCL, which is different from S and SL. However, crop water use efficiency (WUE) was not improved under no-tillage with mulch according to the first two years experiment. The variation trend of WUE was consistent for the three soils in wheat growing season. WUEs under no-tillage with mulch were 13.95%, 9.76% and 8.61% lower than under conventional tillage in S, SL and SCL, respectively. In maize growing season, differences in WUE were observed among different soil textures. WUE under no-tillage with mulch was 6.45% lower than under conventional tillage in S, while the WUE under no-tillage with mulch was 4.89% higher than under conventional tillage in SCL, but the differences were not significant. No-tillage with mulch did not show advantage in yield increase. The wheat yields were 7.09%, 4.26% and 0.39% lower under notillage with mulch than under conventional tillage, and the maize yield was 9.81%, 4.11% and 10.19% lower than under conventional tillage in S, SL and SCL, respectively. Under the experimental conditions, no-tillage with mulch has a better effect on water conservation, but cannot increase crop yield in short term.