Table of Content

10 November 2015, Volume 34 Issue 11

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Characteristics of N∶P stoichiometry and the adaptation strategies for different coastal wetland communities in the Yellow River Delta.

ZHANG Sen1, LIU Fu-de1**, LIU Qing2,3, LIU Yu-hong4, LI De-sheng1

2015, 34(11):  2983-2989. 

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In order to study the spatial distribution patterns of nitrogen (N) and phosphorus (P) and the stoichiometric characteristics of three typical plant communities (Suaeda salsa, Phragmites australis and Tamarix chinensis) of coastal wetlands in the Yellow River Delta, soil and plant samples were collected. The results showed that the contents of aboveground N and underground N and P of S. salsa were lower than those of P. australis and T. chinensis, while the aboveground P content and N/P ratio of T. chinensis were higher than those of P. australis and S. salsa. For the three wetland communities, the N content of aboveground biomass was significantly higher than that of underground biomass, indicating that N tended to be allocated to the aboveground photosynthetic organ in the Nlimited habitat. However, an opposite trend existed for the P contents of above and underground biomass of T. chinensis and S. salsa, which revealed that species in different successional status would adopt different strategies to adapt to various environments. Unlike the woody species T. chinensis, the aboveground biomass of P. australis and S. salsa had higher N/P ratios than the underground biomass, and this was possibly related to the high relative growth rate of the aboveground organs of herbaceous species. The soil N content and N/P ratio decreased with  the soil depth increasing, while no obvious changes of soil P were found along the vertical soil profile. The weak correlations
 between the top soil (source) and the plant organs (pool) suggested that physiological accommodation of coastal wetland plants played some roles in N/P stoichiometric regulation besides soil conditions.

Effect of light radiation on litter decomposition in alpine meadow of the Tibetan Plateau.

WU Jie, YU Qin, LIANG De-fei, ZHANG Jing-ran, LI Zhun, ZHANG Shi-ting

2015, 34(11):  2990-2994. 

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Light radiation plays an important role in litter decomposition in arid and semiarid ecosystems. Yet, whether light radiation significantly affects litter decomposition in Tibetan alpine meadow remains unclear. In present study, we measured leaf litter decomposition of ten common species (Thermopsis lanceolata, Polygonum viviparum, Kobresia capillifolia, Anemone rivularis, Scirpus pumilus, Gentiana straminea, Artemisia sieversiana, Saussurea nigrescens, Elymus nutans and Ligularia virgaurea) abundant in Tibetan alpine meadows under shading and control treatments. The results showed that species differed significantly in litter lignin content, with highest in P. viviparum (29.44%) and lowest in L. virgaurea (4.91%). In general, shading decreased litter mass loss, while the decrease extent depended on species. Litter mass loss significantly negatively correlated with lignin content either in shading or in control treatments. Shading decreased the litter lignin mass loss, and the decrease extent varied with species. This study suggests that light radiation promotes litter decomposition through accelerating photodegration of lignin in Tibetan alpine meadow.

Effects of land-use types on plant species diversity in Jinzhong Basin.

WANG Ying-gang**, LIANG Wei, ZHANG Ting, SU Shang-jun, ZHU Zhen-hua, LIU Bin

2015, 34(11):  2995-3001. 

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Regional land development and utilization can influence plant species diversity, and analyzing the mechanisms and patterns of such influence is of great importance. In this study, six land-use types, including woodland, inland beach, orchard, cemetery, farmland furrows and highway land in Jinzhong Basin were chosen to investigate the species composition of plant community. The plant diversity indices (such as the Jaccard similarity index and Gleason richness index) of these six land-use types were calculated. The result showed that the highest Jaccard similarity index (0.552) was found between farmland furrows and cemetery land, while the lowest one (0.216) was found between orchard and highway land. The arithmetic averages of Gleason richness index were ranked as cemetery > furrow > inland beach > woodland > orchard > highway land. The ttest of independent samples revealed the significant differences in Gleason richness index between most pairs of land-use types except for woodland vs. river, woodland vs. orchard, woodland vs. cemetery, river vs. orchards, and cemetery vs. furrow. Moreover, it was found that human disturbance was the principal factor responsible for the difference of plant species diversity among all land-use types. The results provide referential data to improve the rationality and effectiveness in land use and protection of biological diversity in future.

Plant species diversity changes along altitudinal gradient on the northwest slope of Huanggang Mountain of Jiangxi Wuyi Mountain.

GUO Ying-rong, LEI Ping**, YAN Yu-hong, YUAN Rong-bin, WU Shu-yu, LI Jian-ping

2015, 34(11):  3002-3008. 

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Wuyi Mountain is the key region of highest biodiversity in southeast China, and its peak Huanggang Mountain has a typical altitudinal belt of subtropical vegetation on the northwestern slope. In order to better understand the variations in plant species diversity along the altitudinal gradient, five altitudinal ranges with distinct vegetation types were selected on the northwest slope of Huanggang Mountain (900-2000 m, and denoted by gradients 1, 2, 3, 4 and 5 from low to high altitudes), and α and β diversity indices were used to quantify plant species diversity. The results showed that the mean richness of families, genera, and species in communities as well as the mean individuals and species of trees followed a decreasing trend with the increase of  the elevation, and gradient 1 showed significant differences with gradients 3, 4 and 5 (P<0.05). α diversity index also showed a decreasing trend with the increase of altitude. Gleason richness index of gradient 1 showed significant differences with gradients 3, 4 and 5 (P<0.05), but Shannon diversity index of gradient 1 only showed a significant difference with that of the gradient 5 (P<0.05), while Pielou evenness index did not show significant difference (P>0.05). However, β diversity index and mean species density followed a V-typed trend (firstly decrease, and then increase) in the different gradients. Diversity indices of trees didn’t show the same trend as the communities, but the difference of Pielou index showed the same results in the different gradients. Taken together, the results indicated that the communities in low altitudinal gradient were characterized by high plant diversity, while that in middle altitudinal gradient showed lowest density.

Species diversity of forest community in Macaca mulatta habitat in Lishan National Nature Reserve, Shanxi.

TIE Jun1,2**, LI Yan-fen3, WANG Xia3, BAI Feng-lin1, CUI Fang-tian1, JIN Shan1,2

2015, 34(11):  3009-3015. 

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Based on the numerical classification of forest communities in Macaca mulatta habitat in Lishan National Nature Reserve, species diversity of these forest communities in the reserve was evaluated by species richness index, species diversity index and evenness index. Furthermore, the correlation between diversity indices among different synusiae of forest communities was analyzed. The results indicated that: (1) The variation patterns of the diversity of the twelve associations could be well represented by species richness index, species diversity index and evenness index. (2) The variation tendencies of Patrick richness index (R), Shannon diversity index (H), Hill diversity index (N₁ and N₂), Alatalo evenness index and Pielou evenness index were similar for all forest communities, while the tendency of Simpson diversity index (λ) was opposite to that of H index. (3) Changes of the richness, diversity, and evenness indexes of the forest communities presented a tendency of diversification. The richness index and diversity index in various synusiae were in order of herb layer > arbor layer > shrub layer. However, differences of evenness index in each synusia existed among the different forest communities. Greater difference of evenness index was observed in shrub layer among different communities, while lesser difference of evenness index was in arbor layer and herb layer.

Variation in community characteristics and its influencing factors of alpine grasslands along an elevation gradient.

CUI Hai-jun, WANG Gen-xu**, YANG Yan, YANG Yang

2015, 34(11):  3016-3023. 

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To explore the evolvement pattern of grasslands in humid Tibetan Plateau region and its responses to ongoing climate change, we selected the alpine grasslands with different altitudes along the sunny slope of Yajiageng mountain in the eastern Tibetan Plateau, and studied the variation in smallscale characteristics of grassland communities along the elevation gradient, and analyzed the effects of climate and soil variables on community characteristics. Our results showed that aboveground biomass decreased significantly with  the altitude increasing, while the underground biomass and the rootshoot ratios of community increased significantly. Community diversity indexes showed significant change between lower altitude sites, but did not change significantly between higher altitude sites. Overall community diversity and evenness increased with
 the altitude increasing. The variation in community characteristics of different altitudes was mainly controlled by climatic factors, and the temperature played a leading role. The interpretation of the variance from soil factors could be ignored.  Community diversity indexes showed negative correlations with aboveground biomass along the elevation gradient, which supports root competition hypothesis and light competition hypothesis.

Understory biodiversity of plantations on karst mountains in Guangxi and its relation to environmental factors.

HUANG Xiao-rong**, HE Feng, PANG Shi-long, HOU Yuan-rui, LU Guo-dao

2015, 34(11):  3024-3033. 

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Plantations of broadleaf species on karst mountains were investigated in Pingguo, Guangxi, to evaluate their understory biodiversity and community composition in relation to 9 habitat variables and 1 standtype factor by TWINSPAN classification, redundancy analysis (RDA) and canonical correspondence analysis (CCA). The results showed that slope position of plantations was the main factor dominating understory species composition, while rock exposure and site steepness contributed most to the distribution of harmful species. Effects of habitat factors were higher than that of standtype factor, and the former explained 23%-55% of variance in species composition, while stand type approximated 11%-17% of the variance. There were more harmful herb species on terraces than on slope lands, but fewer harmful shrub species on terraces. However, many harmful species flourishing in compulsively conserved karst mountains in Guangxi were absent in the plantations.

Spatial patterns of woody species in Rhododendron simsii shrubland at Daweishan, Hunan Province.

ZHANG Xu1, LI Jia-xiang1,2**, YU Xun-lin1, XIE Zong-qiang2, XUN Yuan3

2015, 34(11):  3034-3039. 

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Based on the data collected from 6 plots (15 m×15 m) of Rhododendron simsii shrubland at Daweishan, Hunan Province, this study analyzed the distribution patterns and aggregate intensity of 14 common woody species in R. simsii shrubland by variance/mean ratio, ttest, negative binomial parameter, clustered index, mean crowding index, poly block index, diffusion index, Green’s index and Cassic index. The results showed that 85.7% of 14 woody species (e.g. R. simsii, Symplocos hunanensis, Ilex szechwanensis) were distributed aggregately in R. simsii shrubland and their aggregate intensity decreased with their population density. The aggregate intensity of nondominant species (e.g. Viburnum foetidum var. rectangulatum, Weigela japonica var. sinica and Rhododendron latoucheae) was larger than that of dominant species (e.g. R. simsii and Symplocos hunanensis). The adaptability of species to mild, humid climate at the top of the mountain, biological characteristics (e.g. seed dispersal, sprouting abilities and shadetolerance) and disturbance were the main driving factors of spatial distribution patterns of woody species in R. simsii shrubland.

Population structure and spatial distribution characteristics of Phellodendron amurense in Beijing.

SONG Chao1, YU Qi-yin1, YU Meng-fan1, XING Shao-hua1**, LIU Run-ze2, QU Hong2, HUANG San-xiang2

2015, 34(11):  3040-3049. 

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Phellodendron amurense is listed as a secondgrade national key protected wild plant in China. In Beijing, it often scatters in broad-leaved forest. In order to understand the structure and spatial distribution of P. amurense population in Beijing, a total of twelve 20 m × 20 m plots in Baihua Mountain, Songshan and Wuling nature reserves were established, and the population characteristics including diameter classes and static life table, and spatial distribution of P. amurense were analyzed. The results showed that: 1) The individual amount of juvenile P. amurense was the highest, and that of adult P. amurense was in the middle rank, and old P. amurense had few individuals. Inverted “J” diameter class structure indicated a growing population of P. amurense. But in some local small populations, there were differences in the diameter class structures of the whole population. 2) There were three mortality peaks in the whole growth stage of P. amurense, with the first one from sapling stage to small tree stage, the second one from small tree to big tree stage, holding the highest mortality, and the third at the end of big tree stage. 3) The spatial distribution of P. amurense followed an aggregated pattern, while its distribution pattern would be different at different growth stages, due to its biological and ecological characteristics and the influence of intraspecific and interspecific relationship of P. amurense populations. Thus, it is critical for increasing P. amurense population to adjust diameter class composition in local population and facilitate aggregate distribution of young P. amurense.

Phenotypic diversity in artificial sapling populations of Pinus tabuliformis in Ziwuling Mountain.

WANG Xian, WANG Xiao-an**, ZHU Yun-yun, DENG Mei-jiao

2015, 34(11):  3050-3056. 

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The phenotypic traits of needles and branches from four artificial sapling populations of Pinus tabuliformis were investigated in Ziwuling Mountain of Shaanxi Province, China. The saplings were planted in grassland, shrub land, under Betula platyphylla stand and Quercus wutaishanica stand. Remarkably significant differences existed in seven studied phenotypic traits (i.e. needle length, needle width, needle thickness, the length/width ratio of needles, length and diameter of currentyear branches, and the number of needles) both within and among populations. As suggested by the phenotypic differentiation coefficient (V_ST), the majority of phenotypic variation occurred among populations (72.88%) rather than within populations (27.12%), implying that this pattern of phenotypic variation could be largely explained by the environmental factors. There occurred a moderate dispersion degree of phenotypic traits with the mean variation coefficient (CV) of 19.74%. Significant associations were detected between any two of the phenotypic traits, except for the association between needle length and width. According to the cluster analysis, the four artificial sapling populations of P. tabuliformis could be divided into three groups.

 

The influence of groundwater depth on aboveground herbaceous characteristics in the lower reaches of Tarim River.

WANG Xi-yi1, XU Hai-liang2**, PAN Cun-de1, LING Hong-bo2

2015, 34(11):  3057-3064. 

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Based on the investigation from 30 plant sampling plots on 5 sections and the corresponding groundwater data in the lower reaches of Tarim River in 2014, the relationship between groundwater depth and the aboveground ecological characteristics of herbaceous plants was analyzed. The results showed that: (1) With the increase of distance from river channel, the groundwater depth increased while the biodiversity and the vegetation coverage declined and the structure of plant community became simple. Herbaceous plants were rare when the groundwater depth was 6-7 m. (2) A significant correlation between groundwater depth and aboveground biomass showed that, as the groundwater depth increased, the aboveground biomass and the moisture content decreased, whereas the relationship between groundwater depth and net primary productivity was inconspicuous. (3) The groundwater level rose obviously nearby the river due to the project of ecological water conveyance and the expansion of the influenced region of ecological water conveyance; the response of vegetation was remarkable, i.e. the growth vigor improved, and the biodiversity and coverage increased obviously.

Difference in biomass allocation pattern among different branch orders in Reaumuria soongorica with slope aspects.

ZHENG Hui-ling, ZHAO Cheng-zhang**, FENG Wei, HAN Ling, XU Ting, DUAN Bei-bei

2015, 34(11):  3065-3071. 

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Biomass allocation pattern affects the gaining recources and competition ability of plant. Elucidation of the biomass allocation patterns among different root branch orders is important for understanding the phenotypic plasticity of plants under different habitats. In this study, we aimed to study the biomass allocation patterns of the first three root branch orders for Reaumuria soongorica in response to slope aspect change in a desert grassland on the northern slope of Qilian Mountains, Northwest China with the method of whole root system excavation and with ArcGIS to construct the digital elevation model for the study sites. The results showed that the coverage, density, height, species richness, aboveground biomass and soil moisture content of the plant community exhibited different variation tendencies in different slope aspects (P<0.05). The change patterns among the density, height, rootshoot ratio of R. soongorica varied with slope aspects (P<0.05). With the slope aspect turning from south to west, east and north, the proportion of the firstorder branch biomass of R. soongorica gradually increased (P<0.05), while the proportion of the secondorder and thirdorder branch biomass decreased (P<0.05). An isometric relationship was found between secondorder branch biomass and thirdorder branch biomass in plots within each slope, whereas the growth speed of firstorder branch biomass was greater than that of secondorder and thirdorder branch biomass. The root resource allocation mode by reasonable tradeoff among different branch orders with changes in slope aspect of the habitat reflected the adaptation mechanism of plant populations to environment under conditions of multiple competition for resources.

Regulating effect of row spacing on the population of late-sowing winter wheat.

XUE Ying-wen1,2, WANG Zhi-min1, ZHANG Ying-hua1**

2015, 34(11):  3073-3078. 

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In order to investigate the effect of row spacing on the population of late-sowing winter wheat, a widely planted cultivar, Jimai 22, was sown with row spacing at 12, 20, and 30 cm (denoted as J12, J20 and J30, respectively) during 2011-2013. Canopy structure and environmental factors under the canopy, individual plant traits and their variations, yield and yield components were analyzed. The results showed that the population’s leaf area index in treatment J12 increased significantly during the late growth stage, the light intercept increased significantly and the loss of light leakage decreased apparently. Compared with J20 and J30 treatments, within J12 population the maximum temperature decreased by 0.9 and 2.5 ℃, and the relative humidity increased by 0.3% and 0.9%, respectively. The variation of individual plant traits in J12 treatment decreased, spike length and spikelet number increased significantly, and the variation of grain yield per spike decreased, which increased the stability of the population yield, and increased the grain yield by 7.8%-24.5%, compared with J20 and J30. It was concluded that narrow row spacing (12 cm) benefited the grain yield of late-sowing winter wheat in the areas with water shortage in the North China Plain.

Effects of long-term fertilization on weed community and early rice yield of reddish paddy field.

DONG Chun-hua1,2, ZENG Xi-bai3**, WEN Shi-lin2, GAO Ju-sheng2

2015, 34(11):  3079-3085. 

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An investigation was made at a doublerice reddish paddy field established in 1982 to study the growth and development and grain yield of early rice and species and biomass of weeds after 30-year application of organic fertilizer, chemical fertilizer, organic and inorganic fertilizer at the same application rates of nitrogen (N), phosphorus (P), and potassium (K) contained in chemical fertilizer and organic fertilizer. The results showed that fertilization promoted the growth and significantly increased the yield of early rice. To some extent, increasing amount of fertilizers and balancing types of fertilizers and nutrients promoted the growth and yield of early rice. On the basis of applying organic fertilizer, applying nitrogen fertilizer in priority, followed by applying phosphate fertilizer, could increase early rice yield in reddish paddy soil. Among all the fertilization treatments, singleorganic fertilizer application had the best effect in increasing the density and promoting the growth of weeds; among all combined application of organic and inorganic fertilizer treatments, balanced combined application had the best effect in promoting the growth of weeds, in particular, suppressing the reproduction of malignant weeds. Compared with organic fertilizer or chemical fertilizer application alone, combined application of organic and inorganic fertilizers generally reduced the diversity, dominance and evenness of weed community in early rice field. Long-term application of chemical fertilizer, especially nitrogen fertilizer played a decisive role in the diversity, dominance and evenness of weed community on the basis of applying organic fertilizer. The weed biomass at the active tillering stage of early rice could represent early rice grain yield to a certain extent.

Effects of milk vetch application on double cropping rice yield and yield stability.

TANG Shan1, WANG Yun-qing1**, ZHAO Jue-jian2, ZHANG Zhi3, WU Li-meng3, CAO Wei-dong4

2015, 34(11):  3086-3093. 

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Based on the double cropping rice yield and soil nutrient situation in a sitespecific experiment during 2008 and 2013, we studied the effect of yearly milk vetch application on rice yield and its stability, and discussed the correlation between rice yield with soil nutrient variation. The results showed that milk vetch application significantly improved both early and late rice yields. Milk vetch application to early rice reduced the interannual variation of double cropping rice yield, and thus made the overall rice yield more stable. Increased soil fertility by milk vetch application was the decisive factor for increment of overall rice yield and yield stability. Further analysis showed that N released from milk vetch improved soil organic matter and total nitrogen more significantly than commensurate application of chemical fertilizer N. The application of milk vetch not only improved the productivity of paddy soil, but also made the productivity of paddy soil ecosystem more stable by raising its soil fertility. We conclude that using milk vetch as green manure can provide available nutrients in current season and improve soil fertility over a long period of time.

Diversity and growth promotion of endophytic bacteria isolated from Oryza officinalis in Guangxi.

YANG Jie, QIN Ying-xi, WANG Xiao-tian, YIN Kun, JIANG Yuan, YUAN Tao, TAN Zhi-yuan**

2015, 34(11):  3094-3100. 

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The endophytic bacteria isolated from Oryza officinalis growing in Guangxi were screened by two nitrogenfree media and grouped by IS-PCR DNA fingerprinting. The representative strains of each group were further studied by physiological and biochemical tests, and 16S rRNA gene analysis. The possible plant growth promotion of the endophytic diazotrophs was tested in the rice. The results showed that a total of 69 endophytic bacteria including 26 endophytic diazotrophs were obtained from O. officinalis. The nitrogenase activity of the endophytic diazotrophs ranged from 0.60 to 46.71 μmol C₂H₄·mL^-1·h^-1. The 69 endophytic bacteria were assigned to 11 groups and 1 ungrouped strain by analysis of IS-PCR DNA fingerprinting. 16S rRNA gene sequencing analysis of representative strains of each group showed that the endophytic diazotrophs were closely related to Ideonella spp., Enterobacter asburiae, Azospirillum largimobile, and the other endophytic bacteria were closely related to Bacillus pumilus, B. cereus, Rhizobium daejeonense, B. safensis, Lysinibacillus fusiformis, Microbacterium paraoxydans, Paenibacillus barcinonensis, and Serratia marcescens, which indicated the high diversity of endophytic bacteria colonized in the host plants of O. officinalis. All of the representative strains of the endophytic bacteria have the ability to release phosphate and potassium. Among these endophytic bacteria, strain yy34 has a great ability of phosphate releasing and strains yy19, yy26 and yy29 have a great ability of potassium releasing. Seven strains (yy05, yy16, yy19, yy25, yy29, yy34 and yy49) can secrete indole3-acetic acid. The representative strains of the endophytic diazotrophs inoculated with rice significantly promoted the rice growth. The leaf length of inoculated rice increased by 23.0%-45.2%, the root length increased by 19.8%-36.2%, the tiller number increased by 59.9%-119.8%, the fresh weight of rice increased by 101.4%-257.0%, the dry weight of rice increased by 68.4%-101.7%, and the root weight increased by 122.2%-188.9% compared with noninoculated rice.

Endophytic bacterial community structure and function of Stipa roots from different types of steppes in northern China.

XU Ting1,2, YANG Li-qiang1,2, SONG Yu3, LI Xin-yu1, ZHANG Hui-wen1**

2015, 34(11):  3101-3110. 

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In order to study the diversity and function of endophytic bacteria, the roots of Stipa sp. were collected from six types of steppes (subalpine meadow, alpine meadow, Gobi desert, desert steppe, typical steppe, and meadow steppe in northern China) across Xinjiang, Gansu and Inner Mongolia. By strict surface disinfection and streak plate method, 200 endophytic bacteria that belonged to 28 genera, 7 classes, 4 phyla were isolated from the roots of Stipa sp. Half of the isolates were identified as Bacillus, which was the most dominant genus in the roots of Stipa sp. Pseudomonas and Bacillus were the most dominant genera in the samples of Gobi desert and the other five steppes, respectively. Subalpine meadow had the highest Shannon index, and typical steppe and meadow steppe had relatively higher Margalef index and evenness index. Alpine meadow which contained the lowest genus number showed the lowest Shannon index, Margalef index and evenness index. The similarity coefficients varied from 0.25-0.61 between the six steppes. Alpine meadow had relatively lower similarity coefficients (0.25-0.33) with the other steppes, followed by the similarity coefficients between Gobi desert and desert steppe. Furthermore, out of 200 isolates, 73 strains showed IAA-producing activity, 35 isolates turned out to have phosphatesolubilizing activity, 23 isolates were confirmed to have antifungal activity, 20 strains were proved to be diazotrophic bacteria, and 6 strains showed potassiumsolubilizing activity. Isolates producing IAA all ranked the first in abundance in each of the six steppes, especially in alpine meadow, subalpine meadows and desert steppe. Isolates with phosphatesolubilizing activity had a relatively larger proportion in alpine meadow, and the same to the isolates with antagonistic activity strains in subalpine meadow and nitrogenfixing bacteria in the desert steppe. However, the isolates with potassiumsolubilizing activity were in relatively lower abundance in all six steppes. The functional endophytic bacteria belonged to 25 genera, so their diversity was high. In addition, the isolates from Bacillus and Pseudomonas had more detected functions and high abundance, suggesting that endophytic bacteria belonging to Bacillus and Pseudomonas were important in the roots of Stipa. The study also collected 14 bacteria with high activity for detected function, which had great applied potential.

Responses of summer maize leaf water content and photosynthetic characteristics to consecutive drought with different intensities.

WANG Qiu-ling1, ZHOU Guang-sheng1**, MA Xue-yan1,2

2015, 34(11):  3111-3117. 

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The effects of occurrence and development of consecutive drought with different intensities on leaf water content and photosynthetic characteristics of summer maize were studied based on the summer maize drought manipulation experiment from 7leaf stage. The results indicated that the leaf water content decreased linearly during growing season and it was significantly correlated with relative soil moisture (P<0.005), implying that the leaf water content may be used as an index of crop drought. The photosynthetic rate, transpiration rate and stomatal conductance of maize leaf during growing season decreased significantly with the decrease of relative soil moisture. The difference of all these parameters among different water treatments declined with the development of consecutive drought. The water use efficiency showed a rising trend and its difference among different water treatments was small at earlier stage, but enlarged at later stage with the aggravation of consecutive drought. There was a conversion from stomatal limitation to nonstomatal limitation for photosynthesis during growing season, respectively occurring 46, 38, 30, and 35 days after water controlling for W1 to W4 water treatments. The conversion occurrence time was negatively related with drought intensity and consecutive time.

Effects of light intensity on photosynthetic physiology and chlorophyll fluorescence characteristics of hybrid Paulownia.

WANG Nan, LI Fang-dong, YE Jin-shan**

2015, 34(11):  3118-3124. 

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The purpose of this experiment was to compare the differences of leaf photosynthetic capacity and chlorophyll fluorescence characteristics between Paulownia backcross optimal plants (including BC-1(194) and BC-1(192)) and their parent TF33. Three light levels \[100% (L₀), 50% (L₁) and 25% (L₂) of natural sunlight\] were conducted to simulate the light conditions of forest opening, forest gap and understory, respectively. The results showed that: (1) The diurnal variation of net photosynthetic rate (P_n) changed from bimodal pattern to unimodal type curve after shading, and the average daily P_n decreased significantly with increase of shade degrees (P<0.05). P_n of BC-1(194) and BC-1(192) showed no significant advantage under L₀. But the P_n transgressive heterosis of BC-1(192) and BC-1(194) were respectively 2.23% and 3.67% under L₁. BC-1(192) had no remarkable advantage in P_n compared to TF33, while BC-1(194) showed hybrid weakness under L₂. (2) TF33 had the highest maximum net photosynthetic rate (P_max) and light saturation point (LSP), but the lowest light compensation point (LCP) and dark respiration rate (R_d) under L₀ among three clones. Under the condition of L₁, P_max, LSP and apparent quantum yield value (AQY) of BC-1(192) were the highest, while LCP and R_d were the lowest. Although P_max of BC-1(194) and BC-1(192) in L₂ were lower than that of TF33, LCP and R_d were lower, too. (3) The differences in fluorescence parameters were not significant among TF33, BC-1(194) and BC-1(192) under L₀. qP and qN were significantly different among three clones and BC-1(192) had the weakest heat dissipation but strongest photosynthetic capacity under L₁. BC-1(192) had no significant difference in qP with TF33, while BC-1(194) had significant difference with TF33 under L₂. At the same time, BC-1(192) had significant difference in F_v/F_m, F₀, ETR with BC-1(194) and TF33 (P<0.05). Our results indicated that TF33, BC-1(194) and BC-1(192) had internal regulatory mechanisms for responding to weak light to a certain extent, but it is most appropriate for growth under full light and their photosynthetic capacity decreased with the increase of shading degree. Inadequate light could become a decisive limiting factor for the growth of hybrid Paulownia. BC-1(194) and BC-1(192) had photosynthetic superiority compared with their parent TF33 in the low light condition of L₁.

Stem sap flow dynamics of Hippophae rhamnoides L. subsp. sinensis Rousi in relation to environmental factors in Ulan Buh Desert during fruit stage.

HUANG Ya-ru1,2, XIN Zhi-ming1,2, LUO Hong-mei1, LUO Feng-min1,2, MA Ying-bin1,2, GE Gen-batu1,2, LI Xin-le1,2, SUN Fei1, HAO Yu-guang1,2**

2015, 34(11):  3125-3131. 

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In this study, Dynamax sap flow measuring system and automatic meteorological station were used to estimate stem sap flow of Hippophae rhamnoides L. subsp. sinensis Rousi and its relationships with environmental factors during fruit stage in Ulan Buh Desert. The results showed that the stem sap flow of H. rthamnoides fluctuated significantly, with a singlepeak curve from day to night. The sap flow started at 8:00. The peak value of the sap flow appeared at about 10:00, being 227.94-307.86 g·h^-1. The minimum value of the sap flow appeared at about 21:30, being 11.04-26.29 g·h^-1. The sap flow was closely related to environmental factors. The sap flow rate and variation on clear days were generally higher than on cloudy and rainy days. Total radiation, air relative humidity, air temperature and wind speed were the major factors affecting the stem sap flow rate of H. rthamnoides. Moreover, the diurnal variation characteristics of transpiration rate was similar to the sap flow rate, but the peak value of the transpiration rate lagged about 3 hours compared to that of the sap flow.

Responses of roots and needles of Pinus sylvestris var. mongolica and Pinus tabuliformis to spring drought stress.

WANG Kai**, GUO Jing-jing, WANG Dong-qi, LIU Shuang, NI Pan-pan

2015, 34(11):  3132-3138. 

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In the present study, the effects of spring drought stress on morphology and physiological characteristics of needles and roots of mature Pinus sylvestris var. mongolica and P. tabuliformis trees were analyzed, and the damage extents of the two tree species were compared. The results showed that the water and proline contents, and POD and CAT activities in needles of P. sylvestris var. mongolica were significantly higher than those of P. tabuliformis (P<0.05). Meanwhile, the root activity, water, soluble protein and proline contents, and CAT activity, specific root length and specific root surface area of P. sylvestris var. mongolica were significantly higher than those of P. tabuliformis (P<0.05). The malondialdehyde content in needles was significantly lower in P. sylvestris var. mongolica than in P. tabuliformis (P<0.05), but the value in roots of P. sylvestris var. mongolica was significantly higher than that in P. tabuliformis (P<0.05). The soluble sugar and proline contents, and SOD activity in needles were significantly greater than those in roots (P<0.05). However, the soluble protein content and CAT activity in needles of P. sylvestris var. mongolica were significantly lower than those in roots (P<0.05). POD activity in needles of P. tabuliformis was significantly lower than that in roots (P<0.05). These results indicated that the responses of P. sylvestris var. mongolica were more sensitive than P. tabuliformis under spring drought stress. The responses of needles were inconsistent with that of roots. The damages of drought were more severe to the needles of P. tabuliformis and the roots of P. sylvestris var. mongolica.

 

Grade index of spring drought disaster for paprika in Hainan Province.

ZHANG Lei1,3, HUO Zhi-guo1,2**, CHEN Hui-lin4, WU Cui-ling4

2015, 34(11):  3139-3145. 

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Paprika (Capsicum annuum L.) is sensitive to not only waterlogging but also drought. Taking Haipao No. 1 as the test material in greenhouse, an experiment was conducted to study the effects of drought on physiological parameters and yield of paprika based on two factors \[continuous dry days (10-50 days) and irrigation (0-16 mm)\] with nine levels in a uniform design scheme. Through correlation and regression analyses, a grade index of spring drought disaster for paprika was constructed. The results showed that the rate of dead paprika seedlings was negatively correlated with the relative soil moisture at depth 20 cm (r=-0.73) and little correlated with irrigation. Continuous drought duration notably affected the rate of dead paprika seedlings, and thus was chosen as the drought index for paprika. Net photosynthetic rate, transpiration rate and stomatal conductance of paprika decreased and relative yield loss increased significantly with the increase of continuous drought duration. Considering the standard of meteorological drought and the regression model relating the rate of dead paprika seedlings with continuous dry days, the critical values of continuous dry days for mild, moderate and severe droughts were 27, 32 and 36 days, respectively. The drought disaster index for paprika fitted well with the actual drought disaster situation and could help provide strategies for monitoring and precaution against drought disaster for paprika.

 

Salinity suitability of Zostera marina seedlings.

XU Qiang, NIU Shu-na, ZHANG Pei-dong**, ZHANG Xiu-mei, FANG Chao

2015, 34(11):  3146-3150. 

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The effect of different salinities (5, 10, 15, 20, 25, 30 (control), 35, 40, and 45) on survival and growth of Zostera marina seedlings were examined under laboratory conditions, to determine their salinity suitability during a period of 30 days. The results showed that the seedlings exposed to salinities of 5 and 10 began to rot rapidly and all died during the first 10 days. Survival rate of seedlings under salinities of 20-45 ranged from 49% to 58%, which were significantly higher than those of seedlings under low salinities (5-15) (P<0.05). Seedling morphometrics and growth rate were greatest under salinity 20, in which sheath length, root length and root elongation rate of seedlings were significantly higher than those of seedlings attained in control and other salinity treatments (P<0.05). Total leaf area per shoot and leaf elongation rate under salinity 20 were not significantly different from those attained under control treatment (P>0.05) but significantly higher than those attained in salinities of 15, 35, 40 and 45 (P<0.05). Suitability analysis suggests that Z. marina  seedlings can survive in a salinity range from 15 to 45; however, the suitable salinity range for their growth is from 20 to 30.

Factors influencing endangered species richness in global Ramsar sites.

SHI Pei-wen1, LIU Mao-song1**, CHI Ting2, SHENG Sheng3, XU Chi1

2015, 34(11):  3151-3157. 

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Ramsar Wetlands of International Importance are significant for biodiversity protection as roosting, breeding or wintering sites of endangered species. The driving factors of wetland endangered species richness were analyzed by using the spatial autoregressive model at the scale of 300, 600 and 1200 km. The results indicated that human interruption hypothesis has the highest explanatory strength among all hypotheses for endangered species richness of Ramsar sites, followed by energy hypothesis and habitat heterogeneity hypothesis. The endangered species richness of Ramsar sites is significantly positively correlated with annual range of temperature and habitat size function, and significantly negatively correlated with GDP per capita. The results are helpful to deeply understanding the driving factors of endangered species richness on global scale as well as to endangered species protection of global Ramsar sites.

Spatial pattern of rural settlements in loess hilly area: A case study of Tianshui City, Gansu Province.

MA Li-bang1**, FAN Hao2, SHI Pei-ji1, GUO Xiao-dong2, MENG Xiao-nan1

2015, 34(11):  3158-3165. 

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Based on the second national land resource survey database of Tianshui City in 2013, the attribute data such as rural settlements, rivers and roads were extracted. The spatial distribution characteristics of rural settlements at county and city levels were analyzed by using landscape spatial pattern indexes and landscape pattern analysis model. The results showed that an obvious spatial differentiation in landscapes of rural settlements of Tianshui City was found at county level. The rural settlements of Qin’an County were in shape of small patches, but intensively distributed, with villages being relatively close to each other. However, the rural settlements of Qingshui County were totally opposite to those of Qin’an County. The settlement patches of Qingshui, Gangu and Qin’an counties were complex and irregular, and presented a fragmented, random distribution. However, the settlement patches of other counties were simpler, with a lower degree of fragmentation and a regular distribution. In addition, there were obvious spatial features in the size, shape and pattern of distribution of rural settlements at Tianshui City scale. The differences between patch size of township rural settlements and the city’s average patch size were not obvious, so the size of rural settlements had a high level of homoplasy due to similar architectures and terrain characteristics in adjacent regions. Meanwhile, the dense rural settlements were mainly distributed in the north of the city and along the middle Weihe River, while rural settlements in the south and east of the city were sparse, presenting clear directivity of environment. The distribution of patch number and patch density showed an obvious "U" shape in northsouth direction, and a pattern of ‘west high and east low’ in westeast direction. They also showed a decreasing trend from central area to the eastwest sides.

Changes of desert riparian vegetation along the main stream of Tarim River, Xinjiang.

CHEN Hai-yan1,2, CHEN Ya-ning1**

2015, 34(11):  3166-3173. 

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Based on the Landsat datasets in five different periods during the past four decades in combination with the plot investigation data along the main stream of Tarim River, Xinjiang, this paper explored the dynamic change of desert riparian vegetation. The results showed that: (1) The mean vegetation coverage along the main stream of Tarim River was about 15%, with a significant spatial variation. The vegetation coverage was the highest (20%) in the upstream area, and the lowest (9%) in the downstream area, and re〖JP2〗ached up to 17% on the north side and 12% on the south side. In addition, vegetation zone width had the same distribution patterns as the vegetation coverage. (2) The vegetation coverage had an increased trend in the main stream area of Tarim River, with an average rising rate of 0.0038·10 a^-1. The vegetation coverage in the upstream and midstream areas increased at 0.0083·10 a^-1 and 0.0013·10 a^-1, respectively, while the vegetation coverage in the downstream had a decline trend, with a decline rate of -0.0003·10 a^-1. (3) The lowmedium vegetation coverage reflecting desert riparian forest was in a declined trend, while the high vegetation coverage reflecting farmland and artificial vegetation had a rising trend. (4) The expansion of the artificial oasis was the main factor for the rise of vegetation zone width and vegetation coverage in the upstream area, with the expense of sacrificing ecological environment in the downstream area.

Change in temperature in South China and its impact on the potential epidemic duration of dengue fever.

DU Yao-dong1**, WU Xiao-xuan2, WANG Hua1

2015, 34(11):  3174-3181. 

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Based on the daily temperature data of 110 meteorological stations from 1961 to 2012, and future projection by the RegCM4 regional climate model under RCP (representative concentration pathways) scenarios, change in temperature in South China and its impact on the potential transmission duration of dengue fever were studied by using the methods of RossMacdonald transmission dynamical model of diseases, linear regression, accumulative anomaly and ArcGIS. The results showed that 21 ℃ could be used as the minimum temperature suitable for dengue fever transmission. The annual mean air temperature had increased significantly by 0.14 ℃ per decade during the past 52 years, and an abrupt change in annual mean air temperature happened in 1997. Compared to the 30year average in the period of 1981-2010, annual mean temperatures in South China in the 2020s, 2050s and 2080s will likely increase by 0.8, 1.3 and 1.7 ℃ under RCP4.5 scenario, and 0.9, 1.7 and 2.9 ℃ under RCP8.5 scenario, respectively. The annual mean days suitable for dengue fever transmission and area of year-round epidemic zone increased by 10 days and 408 km² during the period of 1997-2012 compared to those during the period of 1961-1996. Compared to the average in the period of 1997-2012, the annual mean days suitable for dengue fever transmission in 2020s, 2050s and 2080s will likely increase by 10, 15 and 20 days under RCP4.5 scenario, and 15, 25 and 40 days under RCP8.5 scenario, respectively, and the areas of year-round epidemic zone will likely correspondingly increase by 3962, 5436 and 8260 km² under RCP4.5 scenario, and 4536, 8780 and 20680 km² under RCP8.5 scenario, respectively.

 

Waterbird’s flight resistance pattern and spatial management strategies for coastal wetlands: A case study of Shenzhen Bay.

LIN Yong-hong1, XU Peng1, LIAO Xing2, WANG Yong-jun3, LUAN Sheng-ji1**

2015, 34(11):  3182-3190. 

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The coastal wetlands in Shenzhen Bay are internationally important habitats for waterbirds. They are also areas with rapid economic development and land use change. However, intensive building and construction greatly affect waterbirds’ flight processes. This study focused on waterbirds’ flight resistance pattern and spatial management strategies by using minimum cumulative resistance (MCR) model and waterbirds’ foraging flight and avoidance behavior. Little Egret (Egretta garzetta) and Shoveler （Anas clypeata) were selected as indicator species, and resistance surfaces were established to simulate these two species’ horizontal movement across urban regions. Results revealed how urban lands and buildings influence waterbirds’ flight processes. In addition, a comprehensive flight resistance pattern was built by overlaying the resistance surfaces of the two indicator species, with low, medium and high resistance levels. Finally, relative management strategies were proposed to protect the flight processes of waterbirds. This study illustrated that the relationship between urbanizing areas and biological processes has a vital practical significance on sustainable development of city.

Spatial-temporal CPUE profiles of the albacore tuna (Thunnus alalunga) and their relations to marine environmental factors in the South Pacific Ocean.

YAN Min1,2, ZHANG Heng1**, FAN Wei1, JIN Shao-fei1,3, YANG Sheng-long1

2015, 34(11):  3191-3197. 

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Albacore tuna (Thunnus alalung) is one of the main catch fisheries for longline fishery in South Pacific. Based on the data of the catch of the albacore tuna longline fishery in the South Pacific Ocean and sea surface temperature (SST), chlorophyll a concentration (Chl-) and sea surface height anomaly (SSHA) by remote sensing, we analyzed the spatialtemporal distribution of catch per unit of fishing effort (CPUE) of albacore tuna and the relationships of CPUE with marine environmental factors during 2009-2012. The results showed that the fishery was mainly distributed in the sea area (4° S-28° S, 158° E-176° E) and the seasonal change of CPUE was obvious. From January to March, the CPUE value was low (<12.5 ind·1000 hooks^-1), then increased to the maximum (18.1 ind·1000 hooks^-1) in July, but the CPUE value was gradually reduced during August to December. The catch gravity center of albacore tuna in January located in the sea area (16° S, 168° E), then migrated to northwest from February to March. However, the catch gravity center of albacore tuna moved to southeast during March to July, and began to move to northwest after August, while during SeptemberDecember the changes of catch gravity center were relatively small. As a whole, the optimum SST of albacore tuna fishing center ranged from 27.0 to 30.5 ℃ and the second optimum SST ranged from 20 to 24 ℃. The optimum Chla range of this fishery was 0.02-0.08 mg·m^-3 and the SSHA range was 3-23 cm, respectively.

Effects of single and cotreatment of arsenic and antimony on the accumulation and transformation of the two elements in Boston fern.

WANG Xiao-li1,2, YANG Fen1,3, WEI Chao-yang1**, TU Shu-xin2, LIU Jin-xin1,3

2015, 34(11):  3198-3204. 

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This study was conducted to explore the single and interactive effects of arsenic (As) and antimony (Sb) on the accumulation and transformation of As and Sb in Boston fern (Nephrolepis exaltata L.) at tissue and sub-cellular levels.  The results indicated that both single and co-treatment of As and Sb decreased the biomass of Boston fern, while increased the concentrations of As and Sb in the fern plant, as compared with the control. Arsenic and Sb concentrations in fern tissues were in the order of roots > leafstalks > leaflets and roots > leaflets > leafstalks, respectively. The As or Sb concentrations in various tissues of Boston fern under co-treatments were lower than those under single treatments, suggesting the existence of antagonism between As and Sb in Boston fern. Subcellular distributions of both elements were also determined. Under co-treatments, As in roots could be impelled from cell wall to cytosol and organelle, while in both leaflets and leafstalks it was from cytosol to cell wall and organelle. Meanwhile, Sb in roots could be stimulated from organelle to cytosol and cell wall, while in leaflets and leafstalks it was from cell wall to cytosol and organelle. When only As(III) was added, As(V) dominated in the roots and DMA prevailed in the leaflets, while the co-addition of Sb(III) promoted more As(III) to be transformed to As(V) and DMA. When only Sb(III) was added, Sb(III) predominated in various tissues of Boston fern, while co-addition of As(III) intensively inhibited the transformation of Sb(III) in the roots and leafstalks, whereas in the leaflets As(III) promoted the transformation of Sb(III) to Sb(V).

Heavy metal pollution characteristics and ecological risk assessment of different vegetable soils of Baiyin, Gansu, China.

LI You-wen1, CAO Chun1,2**, JU Tian-zhen1, ZHAO Xu-tao1,3, MOU Rui-qiang1, LIU Si-qi1, DU Ming-zhuo1

2015, 34(11):  3205-3213. 

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Here we monitored levels of 8 metals (Cu, Ni, Zn, Cr, As, Cd, Hg and Pb) in 128 soil samples collected from Dongdagou and Xidagou vegetable farms of Baiyin, Gansu, China, and used the anthropogenic influence multiple, principal component analysis, geological accumulation index and potential ecological risk assessment method to evaluate the pollution characteristics and potential risks. The results showed that the soil Cu, Zn, As, Cd, Hg and Pb contents exceeded the background values of Gansu, and the soil Zn, As and Cd contents at Dongdagou and the soil As and Cd contents at Xidagou were higher than the level II of the China’s national soil standards. There were high variations in soil Cd and Hg contents at Dongdagou and in soil Hg and As contents at Xidagou, which were likely impacted by the anthropogenic pollution. Principal component analysis showed that soil Cu, Cd and Pb contents at Dongdagou and soil Zn and Cd contents at Xidagou were controlled by many factors. Geoaccumulation index showed that the soil Cd, As, Hg and Zn contents at vegetable farms of Baiyin were classified as moderate to heavy pollution, the soil Cd content of some samples at Dongdagou even as very heavy pollution, and soil Ni and Cr contents as “no pollution”. The potential ecological risk analysis showed that the single potential ecological risk parameters (E_i) and comprehensive potential ecological risk index (RI) all followed a pattern of Dongdagou>Xidagou, and the single potential ecological risks of Cd, Hg and As were relatively high. Overall, the pollution of heavy metals at Dongdagou was more severe than at Xidagou, and the pollution degree and ecological risk had fallen over the years.

Large-scale cultivation of Sargassum vachellianum in the coast of Gouqi Island and its effects on water environmental factors.

LIU Yuan-yuan, ZHANG Jian-wei, HAN Jun-jun, WEI Zhang-liang, WU Hai-long, HUO Yuan-zi, YU Ke-feng, HE Pei-min**

2015, 34(11):  3214-3220. 

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In this paper, large-scale cultivation of Sargassum vachellianum in sea field and its effects on water environmental factors were studied. The results showed that the suitable water depth for S. vachellianum growth was 1.5-2.5 m, and the optimal water depth was 2 m. The fronds of seaweeds grew faster in spring and autumn and declined in summer. In May 2014, the highest specific growth rate of cultivating fronds and wild fronds reached up to 6.8%·d^-1 and 5.9%·d^-1, respectively, and cultivating fronds grew faster and matured earlier than wild fronds. In 2014, the IN, IP, TN, TP, COD and Ch-a mass concentrations in all stations except the 1st and 7th stations decreased significantly compared with in 2013 (P<0.05). DO mass concentration and SD increased by 4.52% and 8.09% (P<0.05), and COD and Chl-a mass concentration decreased by 18.75% and 43.51%, respectively, and the highest mass concentration of Chla was about 1.55 μg·L^-1. The quality of the sea waters was improved significantly after S. vachellianum cultivation. This study provided a theoretical basis for cultivation of S. vachellianum and sea water quality environment bioremediation with seaweeds.

Growth characteristics of silver carp (Hypophthalmichthys molitrix) in Wudalianchi Lake and related impact factors.

WANG Ji-long1, LIU Wei1, TANG Fu-jiang1, ZHAN Pei-rong1, LI Pei-lun1，2, WANG Chen1,2

2015, 34(11):  3221-3227. 

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To study the growth characters of silver carp (Hypophthalmichthys molitrix) in Wudalianchi Lake, 248 individuals were sampled from August to October in 2013 and 2014 respectively. Age was determined through the scale annuli, and body length and body weight were backcalculated. Keys formula and Von Bertalanffy growth equation were fitted to analyze the growth of body length and body weight. Growth parameters of silver carp were compared between different years and areas. Results showed the growth formula of silver carp in Wudalianchi Lake as follows:L_t=52.992［1-e^-0.301(t_i-0.064)］,W_t=2621.649［1-e^-0.301(t_i-0.064)］^2.901. Growth rate curve of body length has no inflexion, i.e. growth rate of body length declined as age increased. Growth rate curve of body weight has an inflexion, and the age, body length and body weight corresponding to the inflexion were 3.602, 34.72 cm and 769.08 g, respectively. Compared with silver carp populations in other waters, the population in Wudalianchi Lake grew most slowly. The growth of silver carp in 2013-2014 was larger than in 2012-2013. The growth of silver carp might be affected by both biotic and abiotic factors such as genetic factors, water temperature, food organism density and pressure from intra and interspecific competition in Wudalianchi Lake.

 

Progress on researches of drought-induced tree mortality mechanisms.

DAI Yong-xin1, WANG Lin2, WAN Xian-chong1

2015, 34(11):  3228-3236. 

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Warming and drought will occur with increased frequency and intensity along with global climate change. In recent years, extensive tree mortality and forest declines have been reported in response to drought and rising temperature. Despite an enormous body of empirical evidence, the underlying physiological mechanisms of the changes still remain unclear. At present, the study on the drought-induced tree mortality mechanisms is still a hot spot. Three hypotheses concerning the physiological mechanisms leading to tree mortality during drought have been proposed: hydraulic failure hypothesis, proposing that low water potential due to drought impedes long-distance water transport within plants and results in dehydration of plant tissues; carbon starvation hypothesis, suggesting that a prolonged stomatal closure during drought constrains carbon uptake and leads to a depletion of available carbohydrats; and biotic attack hypothesis, considering that trees subjected to drought are prone to attacks by insects and pathogens. Each of the hypotheses can interpret certain phenomena of drought-induced tree mortality, but cannot universally interpret all phenomena of drought-induced tree mortality under whatever drought conditions. Lately more attention has been paid to the combined action or interaction of the different mortality mechanisms, especially the coupling of hydraulic failure and carbon starvation. This paper mainly reviewed experimental evidence and existing problems of the three hypotheses. Meanwhile, the limitations of current researches and possible research direction in the future in this field were also discussed.

Research progress on vegetation phenological changes.

ZHAI Jia1,2, YUAN Feng-hui1, WU Jia-bing1**

2015, 34(11):  3237-3243. 

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The response of vegetation phenology to climate warming has attracted increasing attention during the last few decades under the background of global change. In this paper, we summarized the response of vegetation phenology to meteorological factors (temperature, moisture, light), and their research methods were also introduced. In addition, the research progress on vegetation phonological changes in China over the past several decades were overviewed. With the global climate warming, the start of season is generally advanced in most regions of China, while this trend is not remarkable in some arid regions of Xinjiang. It is noteworthy that different observation methods at different research scales complicated the intercomparison or synthesis of phonological data at regional and global scale. Therefore, we recommended that a unified phenological observation network should be established based on the ChinaFLUX network and the widely distributed Chinese Ecological Research Network. Moreover, the method of deriving plant phenology information from the eddy covariance data should be improved. A uniform judging criterion for phenological change could standardize the research on the response of vegetation phenology to climate warming.

Research progress on the eutrophication of Wuliangsuhai wetland.

GUO Jia, WEI Wei, YU Yi-lei, SONG Xiang-jing, ZHANG Man-yin, LI Sheng-nan**

2015, 34(11):  3244-3252. 

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The research progress of Wuliangsuhai wetland eutrophication over recent 20 years was reviewed. The eutrophic status of Wuliangsuhai wetland was summarized as follows: (1) The average contents of nitrogen (N) and phosphorus (P) in waters exceeded the Ⅴ grade of China National Surface Water Quality. Overall, the N and P contents were spatially higher in north and lower in south, and higher in west and lower in east. Locally, the features of spatial distribution were related to plant distribution. The overall characteristics of temporal distribution were influenced by the influent from Hetao region and air temperature. (2) N and P were enriched in sediments. In horizontal direction, the N content in sediments was higher in north and lower in south, and higher in west and lower in east. But the P content did not show any pattern. (3) The temporal and spatial distributions of algae were similar to that of N and P. In recent years, the excessive reproduction of algae often resulted in the bloom of Huangtai algae. (4) The organic matter in waters was significantly enriched and positively correlated with the N content spatially. (5) The organic matter in the sediments was mainly derived from terrestrial inputs and aquatic organisms. It had significant homology with N, being consistent with N in spatial distribution. The organic matter in the sediments was enriched significantly and became an important source of endogenous pollution. In future, studies on the mechanisms of eutrophication of Wuliangsuhai wetland should be strengthened, which may provide theoretical basis and technical support for the restoration of Wuliangsuhai wetland.

Progress in research on ecological compensation in China from the perspective of positive externality of environmental protection.

WANG Na-na1, WU Yong-feng1, HU Bo1, CHEN Chong-juan1,2, LIU Hong-bin3, LUO Liang-guo1**

2015, 34(11):  3253-3260. 

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It has been widely accepted that the internalization of external cost of ecosystem caused by human activities can be achieved by policy devices, which is also beneficial to establishment of institutional arrangement in the practice of encouragement of environmental protection. To maintain the enthusiasm of environmentalists, it is necessary to compensate them for their extra payment or opportunity lost due to environmental protection. We review the literature describing achievement progress in the ecocompensation definition, theoretical basis, connotation and types of compensation mechanism, compensation standard and method, and evaluation of compensation performance in China. Recommendations regarding legislation, method standardization and diversification, and effect tracking in the practices of ecocompensation are proposed.

 

Research progress on technologies of phytoremediation of heavy metal contaminated soils.

AN Jing, GONG Xiao-shuang, WEI Shu-he**

2015, 34(11):  3261-3270. 

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Heavy metal contamination in soil has become a serious problem in China in recent years. It not only affects the food safety and human health, but also limits the sustainable development. Among numerous remediation techniques, phytoremediation with hyperaccumulator plants is a low cost, effective, easy to operate, safe, and environmentally friendly technology for remediating heavy metal contaminated soils, and has been considered as one of the most potential green remediation technologies. The history and development of the phytoremediation technique is reviewed, and the essential technical problems limiting the development of the technique on large scale in China, such as selection and identification of the hyperaccumulator, the mechanism of absorption and transport of heavy metals, strengthening measures, and safe disposal and utilization of hyperaccumulator, are elucidated in the present paper. The perspectives of the application of phytoremediation in future are also discussed.

Selection of native evergreen tree species to restore damaged forests after ice storm in Nanling Mountains.

WANG Xu**, HU Wen-qiang, ZHOU Guang-yi, YANG Jin-chang

2015, 34(11):  3271-3277. 

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In January-February 2008, southern China had been experienced freezing rain and snow disaster, which was so-called ice storm disaster. The ice storm disaster had caused great destruction of evergreen broad-leaved forests in Nanling Mountains. However, the disaster also provides a good chance for the selection of tree species for resisting ice storm disaster. In order to select tree and shrub species suitable for restoration of forests damaged by the ice storm in 2008, the Yangdongshan Shierdushui provincial nature reserve of Guangdong Province was selected as a typical ice storm disaster area and four plots in the reserve were set to investigate tree species. Multivalue theory was employed to establish tree species selection and evaluation model, with integrating the four quantitative factors involving damaged index, importance value, sprout proportion and abundance of seedlings. Based on the field survey data and the quantitative evaluation model, the single factor satisfaction of each tree species was calculated and the reasonable satisfaction degree was calculated by weighting method. On the basis of the estimated values, tree species Castanopsis eyrei, Cyclobalanopsis hui, Castanopsis carlesii and Michelia maudiae and shrub species Rhododendron kwangtungense, R. latoucheae and R. rivulare were screened as suitable species for the restoration of degraded forests damaged by ice storm disaster in Nanling Mountains.

Analysis of ISSR genetic polymorphism for Tibetan yak.

YAO Hui1, ZHONG Jin-cheng1, JI Qiu-mei2, ZHANG Cheng-fu2, XIN Jin-wei2, CHEN Zhi-hua1**, CHAI Zhi-xin1

2015, 34(11):  3278-3282. 

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In order to analyze the genetic diversity of Tibetan yaks, 10 pairs of primers were selected from ISSR primer library and used to analyze 17 groups (species), with a total number of 850 yaks, by PCR amplification. The obtained statistical data were also analyzed by Popgen 32 software. The results showed that 10 pairs of ISSR primers amplified a total of 134 bands including 132 polymorphic bands. The polymorphism ratio is 95% and the size of the amplified fragment ranges from 200 to 2000 bp. The average effective number of alleles of 17 yak groups is 1.498, the mean index of Nei’s genetic diversity is 0.294 and average Shannon diversity index is 0.449. Clustering results show that Tibetan yaks are roughly divided into three categories: The first group includes Cuona yak, Jiangda yak, Gongbujiangda yak, Kangbu yak, Baqing yak, Leiwuqi yak, Sangsang yak, Jiali yak, Sibu yak and Longzi yak; the second includes Dingqing yak, Nierong yak, Pali yak, Riduo yak, Sangri yak and Shenza yak; the third group only includes Zhongba yak. Cluster analysis results are basically consistent with the geographic distribution of yaks.