Table of Content

10 May 2009, Volume 28 Issue 05

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Articles

Changes in carbon budget of Northeast China forest ecosystems under future climatic scenario.

ZHAO Jun-fang¹;YAN Xiao-dong²;JIA Gen-suo²

2009, 28(05):  781-787 . 

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In this paper, the possible changes in carbon budget of forest ecosystems in Northeast China under the future climatic scenario were simulated by using the forest carbon budget model for China (FORCCHN) driven by the simulated future output data from FGOALS model. The results showed that under A1B (balanced development scenario) and in 2003〖KG-*2〗-〖KG-*7〗2049, the net primary productivity (NPP) and soil respiration rate of Northeast China forest ecosystems had an increasing trend, and the increment of soil respiration rate would be far higher than that of NPP (13443% vs. 1084%). The forest ecosystems in Northeast China would still be an obvious carbon sink, but their carbon-absorbing capability would be decreasing. Nevertheless, the total mount of absorbed carbon dioxide would be still increasing. All of these illustrated that from 2003 to 2049, the forest ecosystems in Northeast China would play an active role in reducing greenhouse gases concentration and in mitigating the impact of climatic change.

Spatial patterns of species diversity of the communities within which Arabidopsis thaliana survived in Northern Tianshan Mountains.

TAO Ye;XU Yan-yan;LIU Tong;WANG Dan;JIANG Cheng-guo;CUI Yun-he;YAN Ping

2009, 28(05):  795-803 . 

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Based on the survey of Arabidopsis thaliana distribution in Northern Tianshan Mountains in Xinjiang, this paper studied the characteristics of species diversity in 13 A. thaliana plots (the communities within which A. thaliana survived), and the effects of environmental factors on the spatial patterns of the diversity. The results showed that the species diversity indices differed largely with the plots, being the highest in Yili region at Borohoro Mountain, followed by in Emin region at Taerbahatai Mountain. The diversity indices of 8 A. thaliana plots in mid-Tianshan Mountains were low and changed largely, and those in Aletai region at Altay Mountain were at medium level. As a whole, the species diversity patterns appeared evident spatial heterogeneity. The kind and amount of A. thaliana and its adjacent species in each plot were different, with the highest in mid-Tianshan Mountains. The species diversity patterns fitted well with precipitation, and the diversity indices generally increased with increasing precipitation. The DCCA ordination of diversity indices indicated that in addition to precipitation, the micro-environmental factors such as slope aspect, soil available potassium, and soil electrical conductivity were also the important factors affecting the species diversity patterns.

Seasonal variation of nitrogen and phosphorus concentration and accumulation of Cyperus malaccensis in Minjiang River estuary.

ZENG Cong-sheng^1,2,3,4;ZHANG Lin-hai^1,2;TONG Chuan^1,2,3,4

2009, 28(05):  788-794 . 

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A one-year investigation on the N and P concentration and accumulation of Cyperus malaccensis in the wetlands of Minjiang River estuary showed that the N and P concentration of C. malaccensis aboveground parts was in the order of flower > leave> stem, being higher in living plants than in dead standings, and in spring and winter than in autumn and summer; while the N and P accumulation was in the order of stem>leave>flower. The N and P concentration and accumulation of C. malaccensis below ground parts were 0〖KG-*2〗-〖KG-*7〗15 cm>15〖KG-*2〗-〖KG-*7〗30 cm>30〖KG-*2〗-〖KG-*7〗60 cm. The average N concentration and the N and P accumulation of aboveground parts were higher than those of belowground parts, while the average P concentration fluctuated throughout the year. The N accumulation reached the peak (429 g·m-2) in autumn, while P accumulation had its peak (73 g·m-2) in summer. The P concentration and accumulation were significantly lower than N (P<001). From the viewpoint of N/P ratio, N was a key element limiting the primary productivity of C. malaccensis.

Natural selection of phenotypic characteristics of Arabidopsis thaliana growing in northern piedmont of Tianshan Mountains.

WANG Dan¹;LIU Tong¹;JIANG Cheng-guo¹;WEI Peng¹;DENG Xin-na²

2009, 28(05):  804-810 . 

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This paper studied the natural adaptation of photo-physiological, morphological, and developmental characteristics of Arabidopsis thaliana growing in arid and humid soil environments in northern piedmont of Tianshan Mountains. The results showed that the branch number, plant height, relative fitness (cornu-fruit mass), and rosette leaf area of A. thaliana in these two soil environments were significantly different. Root mass was positively correlated to relative fitness, rosette leaf area, water use efficiency, and photosynthesis rate, while intercellular carbon concentration was negatively correlated to photosynthesis rate and water use efficiency. The analysis of selection gradient indicated that plant height, branch number, and rosette leaf area were belonged to directional selection in arid and humid soil environments. Principal component analysis showed that the photo-physiological characteristics among treatments were conformed regularly, indicating that A. thaliana species would turn up homogeneous reaction when confronting environmental response. Path analysis suggested that the water use efficiency, branch mass, plant height, and cornu-fruit number were of direct path in the statistical model because of their strong effects on relative fitness, while rosette leaf area had effects on relative fitness via the indirect path of branch number, florescence, and cornu-fruit number.

Population genetic diversity and structure of Schisandra sphenanthera, a medicinal plant in China.

YAN Bo-qian^1,2,4;WANG Ting¹;HU Li-le³

2009, 28(05):  811-819 . 

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Schisandra sphenanthera has been used as a traditional medicinal plant, possessing a tremendous potential for commercial development. Population genetic information on S. sphenanthera will be helpful for its evaluation, utilization and conservation. Genetic diversity and structure in ten natural populations of the species were analysed by using nine SSR markers developed by the authors. A total of 58 alleles were detected, and the mean expected heterozygosity (HE) and observed heterozygosity (HO) were 0528 and 0519, respectively. Large continuous populations maintained relatively high degree of genetic diversity, whereas small populations exhibited low genetic diversity. In S. sphenanthera, the estimated level of inbreeding was significant with the FIS of 0042. The population genetic differentiation was 0108. Across all populations, each pairwise comparison of genetic differentiation as meaured by FST was significant. Bayesian clustering analysis revealed two genetic clusters: south and north populations drew by the Yangtse River. The special natural barrier and subsequent recolonization play a role in the formation of population genetic structure in S. sphenanthera.

Phenological characteristics in Minqin desert area and their relationships with air temperature.

CHANG Zhao-feng^1,2;HAN Fu-gui^1,2;ZHONG Sheng-nian^1,2

2009, 28(05):  820-826 . 

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The analysis on the phenological characteristics in Minqin desert area based on 34 years phenological observation data showed that there were 2 phenological types in bourgeon period, 4 phenological types in leaf expansion period, 4 phenological types in flowering period, and 2 phenological types in fruit ripeness period. Sin〖JP2〗ce 1974, the mean annual air temperature and the mean monthly air temperature of February, March, and June in the area had a significant warming trend, and the phenology of plants in spring also had an evident advance trend. The bud expanding period of the phenological type ‘low temperature-short sunshine-early budded’ advanced 97 days. From bourgeon period to leaf expansion period, to flowering period, and to fruit ripeness period, the magnitude of phenological advance reduced gradually. The advance of phenology was related with the rising temperature of current month. Two phenological types in bourgeon period and 4 phenological types in leaf expansion period were the differentiation of the adaptation of plants to the air temperature in spring and late fall, while four phenological types in flowering period and 2 phenological types in fruit ripening period were the adaptive responses of the diversities of plant’s flowering period and fruit-ripening period to the local drought environment.

Salt distribution patterns in rhizosphere system of desert halophytes.

YI Liang-peng¹;MA Jian²;LI Yan²

2009, 28(05):  827-832 . 

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With saline soil and non-saline soil (cotton soil) as test soils, four types of desert halophytes were planted in pots by using horizontal root-mat method. Stratified soil samples at different distance from rhizoplane were collected by slicing the frozen thin soil layer, and their pH value and the contents of total salt, Cl-, SO42-, Na+, K+, Ca2+ and Mg2+ were determined. The results indicated that in saline soils, the pH value at different distance from rhizoplane presented a regular gradient distribution, i.e., the nearer the distance from the rhizoplane, the lower the pH was; while in cotton soil, the pH had no significant variation. There was a relatively great salt-deficit area in rhizosphere, with the highest deficit rate appeared at 0〖KG-*2〗-〖KG-*7〗4 mm from rhizoplane. In saline soil, an enrichment of Cl-, SO42-, Na+, K+ and Mg2+ was observed in the rhizosphere of all test plants except Phragmites communis; and in cotton soil, the ions except K+ also showed a high concentration in rhizosphere, but lower than that in saline soil. Additionally, in cotton soil, K+ was in deficit, while Ca2+ was rich. All test plants, especially succulent halophytes and salt-secreting halophytes, had higher contents of Cl-, Na+, Ca2+ and K+ in their aboveground part than in their underground part. Cl- and Na+ had the highest content in rhizosphere, and showed the largest accumulation in aboveground part of plants.

Effects of Angelica sinensis rhizosphere soil on A. sinensis seed germination and seedling growth.

ZHU Hui¹;MA Rui-jun¹;WU Shuang-tao²;LIN Jin-zhe¹;LIAO Yi-ying¹

2009, 28(05):  833-838 . 

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To investigate the autotoxicity of continuous cropping obstacle of Angelica sinensis, the allelopathic effects of the aqueous extract of A. sinensis rhizosphere soil on A. sinensis seed germination, seedling growth, and physiological indices were determined by applying allelopathic effect index (RI), integrated allelopathic effect index (M), and variance analysis. It was shown that the aqueous extracts of A. sinensis rhizosphere and nonrhizosphere soils had significant inhibitory effects on the seed germination, seedling growth, and enzyme activities of A. sinensis, compared with distilled water and unplanted soil aqueous extract. The integrated allelopathic effects of A. sinensis rhizosphere soil extract increased with its increasing mass concentration, and had significant differences (P<005) between various mass concentrations (0125〖KG-*2〗-〖KG-*7〗1000 g·ml-1). At the same mass concentrations, the effects of rhizosphere soil extract were more distinct than those of nonrhizosphere soil extract. The rhizosphere and nonrhizosphere soil extracts at the mass concentration of 0500 g·ml-1 inhibited the SOD, POD, CAT and NR activities of A. sinensis seedlings significantly, and there was a significant difference (P<005) in the inhibitory effects between the two soil extracts. The inhibitory effect of the aqueous extracts of rhizosphere-, nonrhizosphere- and unplanted soils on the seed germination, seedling growth, and enzymatic activities of A. sinensis was in the order of rhizosphere soil>nonrhizosphere soil>unplanted soil, indicating that autotoxicity could be one of the reasons of continuous cropping obstacle of A. sinensis.

Effects of elevated CO₂ concentration on anti-oxidative enzyme activities of urban Pinus tabulaeformis.

RUAN Ya-nan^1,2;HE Xing-yuan²;CHEN Wei²;CHEN Zhen-ju²;SUN Yu²

2009, 28(05):  839-844 . 

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Open-topped chamber method was used to study the effects of elevated CO2 concentration (700 μmol mol-1) on the superoxide anion (O〖SX(B-*3〗-〖〗·〖SX）〗2) generation rate, hydrogen peroxide (H2O2) content, and activities of superoxide dismutase (SOD) and crucial enzymes in AsA-GSH cycles in the needles of Pinus tabulaeformis in Shenyang urban area. After a short period (2 months) exposure to the elevated CO2, the superoxide anion generation rate and H2O2 content in P. tabulaeformis needles decreased and the SOD, APX, MDAR, DHAR and GR activities increased, being helpful to the enhancement of P. tabulaeformis anti-oxidative capability. However, a longer period (> 60 days) of exposure might have reverse effects.

Effects of Ageratina adenophora- invaded soil and its extract on upland rice Oryza sativa seed germination and seedling growth.

YAN Qi;LIU Wan-xue;LI Hui-na;WAN Fang-hao

2009, 28(05):  879-883 . 

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A laboratory test was conducted to study the effects of Ageratina adenophora- invaded soil and its methanol extract on the seed germination and seedling growth of upland rice Oryza sativa. The results showed that both the invaded soil and its methanol extract had different degrees of inhibitory effects on the seed germination and seedling growth of upland rice. The heavier the A. adenophora invaded, stronger the inhibitory effects of invaded soil and its extract were. It was speculated that some allelopatic chemicals released by A. adenophora could accumulate in soil, and had negative effects on the growth of native plants.

Photosynthetic characteristics of Pinus koraiensis seedlings under different light regimes.

SUN Yi-rong;ZHU Jiao-jun;YU Li-zhong;YAN Qiao-ling;WANG Kai

2009, 28(05):  850-857 . 

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Pinus koraiensis is an ecologically important tree species in Northeast China. To explore its light adaptation characteristics and related eco-physiological mechanisms, the 3-, 5-, and 7-year old P. koraiensis seedlings were transplanted under the conditions of 100%, 60%, 30%, and 15% of full sunlight (marked as FI, II, LI, and WI, respectively), and sampled from forest gap, understory, and edge (marked as G, U and E, respectively) under actual light. The study on the changes of net photosynthetic rate (Pn), chlorophyll (Chl) content per unit leaf area, and specific leaf mass (LMA) showed that the Pn of 3- and 5-year old P. koraiensis in treatments II and LI was similar, and higher than that in treatment FI. 7 years old P. koraiensis had the highest Pn in treatment FI. In all treatments, P. koraiensis had a mono-peak change of Pn, with the peak at 13:00. The dark respiration rate (Rd) and maximum photosynthetic rates (Amax) of 3- and 5-year old P. koraiensis were higher in treatment LI than in treatment FI. The LMA decreased with decreasing light intensity, suggesting that P. koraiensis could effectively adapt to the changes of light condition in this way. No significant differences were observed in the photosynthetic characteristics of 3- and 5-year old P. koraiensis between treatments II and U, and between treatments LI, WI, and E, which suggested that the simulated light conditions matched well with the actual one. The plasticity index of eco-physiological parameters of 3 years old P. koraiensis was the highest. It was concluded that 1) the light requirement of P. koraiensis increased with its increasing age, 2) the optimal light condition for 3- and 5-year old P. koraiensis was 30%〖KG-*2〗-〖KG-*7〗60% of full sunlight, and that for 7 years old P. koraiensis was full sunlight, and 3) the favorable age of P. koraiensis seedlings for transplanting was 3 years old.

Characteristics of canopy and air temperature in tropical seasonal rainforests in Xishuangbanna.

YANG Zhen^1,3;ZHANG Yi-ping¹;YU Gui-rui²;ZHAO Shuang-ju⁴;SONG Qing-hai¹;GAO Ju-ming^1,3

2009, 28(05):  845-849 . 

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Based on the observation data in 2005, this paper analyzed the seasonal variations of the canopy temperature and the air temperature above and below the canopy in a tropical seasonal rainforest in Xishuangbanna of Southwest China. The results showed that at the same layers, the canopy temperature was higher than the air temperature except at nights of foggy-cool season. At most time of foggy-cool and dry-heat seasons, the air temperature above the canopy was higher than that below the canopy, while there was an opposite trend at noon time. In the rain season with higher mean air temperature, the air temperature above the canopy was all along higher than that below the canopy. The differences in the variations of the air temperature above and below the canopy presented the feedback effect of the seasonal tropical rainforest canopy to the microclimate in the forest. At the night time of foggy-cool season, the canopy temperature and air temperature differed with those at other time, suggesting that the low temperature at the nights of foggy-cool season was the key limiting factor for the existence of tropical seasonal rainforests in Xishuangbanna.

Relationships between diameter at breast height and cone/seed character of Pinus thunbergii population in Yantai coastal protection forest.

WANG Guang-mei;HAN Guang-xuan;MAO Pei-li;LIU Su-jing;ZHANG Zhi-dong;LI Qiu-yan;XUE Qin-zhao

2009, 28(05):  858-863 . 

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To understand the seed production dynamics of Pinus thunbergii population in Yantai coastal protection forest, the relationships between the diameter at breast height (DBH) and cone/seed characters of the population were studied, with the DBH as the measurement of age and size. According to the DBH size and its distribution proportion, the population was divided into 5 diameter classes (35〖KG-*2〗-〖KG-*7〗65, 65〖KG-*2〗-〖KG-*7〗95, 95〖KG-*2〗-〖KG-*7〗125, 125〖KG-*2〗-〖KG-*7〗155, and 155〖KG-*2〗-〖KG-*7〗19 cm), with 5, 8, 11, 14, and 17 cm as the measurement of each diameter class, respectively. Multiple comparison and regression analysis were conducted for the cone/seed character of each diameter class. The results showed that DBH had significant influence on the fecundity of P. thunbergii. With increasing DBH, the fecundity increased first, but began to decrease when the DBH reached 17 cm. The seed size and 100-seed mass had a decreasing trend when the DBH increased, whereas the seed wing size was in adverse. This phenomenon might be a tradeoff in P. thunbergii seed production, i.e., to decrease seed size and mass to increase seed dispersal ability. For all DBH classes, the number of fertile scales was the most effective prediction variable of seed number and seed mass per cone, but could not better predict the other characters of cone, such as cone length, cone width, cone dry mass, and total number of scales, illustrating that the seed production of P. thunbergii was controlled by many factors.

Allelopathy of Salix babylonica leaf extracts on Chlorella pyrenoidosa.

LI Qing-hua;GUO Pei-yong;TIAN Mei-yan;JIANG Zhong-yang

2009, 28(05):  884-888 . 

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The allelopathic effects of Salix babylonica leaf extracts on the growth and morphology of Chlorella pyrenoidosa were investigated by measuring the cell density of treated algae. It was shown that the leaf extracts of S. babylonica had definite allelopathic effects on C. pyrenoidosa, depending on their concentration. The EC50, 96 h value of the extracts was 1182 g·L-1. Lower concentrations (10 and 20 g·L-1) of the extracts inhibited the algal growth first and promoted it then, while higher concentration (30 g·L-1) of the extracts showed inhibitory effect all the time. The maximum inhibitory rate of the extracts at concentrations of 10, 20, and 30 g·L-1 was 375%, 393%, and 565%, respectively. After treated with the extracts, part of C. pyrenoidosa cells aggregated, expanded, turned transparent, and finally lysed. The amount of the aggregated cells increased with increasing concentration of the extracts. When treated with 30 g·L-1 of the extracts, C. pyrenoidosa cells largely aggregated, and precipitated as cell pellets to the bottom of the container.

Effects of different phosphorous fertilization rate on crop yield and soil phosphorous potential fertility at lower reaches of Liaohe River Plain.

YU Wan-tai¹;ZHU Xian-jin^1,2;ZHOU Hua¹;MA Qiang¹;JIANG Zi-shao¹

2009, 28(05):  864-871 . 

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A six years field experiment was conducted at the lower reaches of Liaohe River Plain to study the effects of different application rate of phosphorous (P) fertilizer on the use efficiency of applied fertilizer P, establishment of soil P pool, and the release rate of soil P. The results showed that P fertilization increased crop yield, and the yield increment of soybean was greater than that of maize. However, when the P application rate exceeded 25 kg·hm-2 per year, the yield-increasing effect was not significant. Phosphorous fertilization also increased the P uptake by crops, and the increment was higher than yield increment. When the P application rate was 25 kg·hm-2 per year, the fertilizer P use efficiency was about 30%. With the increase of P application rate, the use efficiency of fertilizer P decreased, but the proportion of soil available P transformed from residual fertilizer P increased. After the P fertilization, the transformation rate of residual fertilizer P into soil less-available P reached as high as 80%, and the proportion of the transformed soil less-available P increased with increasing P application rate, which was of significance in the establishment of soil P pool.

Effects of phosphorous fertilization on the dynamic changes of Olsen-P and CaCl₂-P in different texture soils.

WEN Lin-qin^1,2;ZHAO Mu-qiu^1,3;NIU Ming-fen²;CHEN Xin¹;LU Cai-yan¹

2009, 28(05):  872-878 . 

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Aquic brown soil samples from the Agro-Ecological Experimental Station of Chinese Academy of Sciences in Luancheng of Hebei Province and light chernozem samples from Baicheng of Jilin Province were applied with different doses of phosphorous fertilizer, and aerobically incubated at 25 ℃ for 1, 3, 10, 30, and 60 days. The dynamic changes of Olsen-P and CaCl2-P in the soil samples during incubation were studied, aimed to approach the possibility of agricultural phosphorus non-point source pollution from these soils caused by phosphorous fertilization. In the meantime, Heckrath segmented regression model was used for fitting the Olsen-P and CaCl2-P contents in the two soils after incubated for 60 days to obtain the Olsen-P content corresponding to the environmental sensitive point of soil phosphorus, which would be regarded as the proof of soil phosphorus-fixation capacity. The results indicated that when the phosphorous fertilization rate exceeded 400 kg·hm-2, the Olsen-P and CaCl2-P contents in the two soils increased significantly, and under the same incubation conditions, the quantitative changes of Olsen-P and CaCl2-P in the same phosphorous fertilization treatments were different, illustrating that a phosphorous fertilization rate of > 400 kg·hm-2 increased the possibility of phosphorus loss from the soils, and the phosphorus loss capacity was different between the two soils. After incubated for 60 days, the Olsen-P content corresponding to the environmental sensitive point of soil phosphorus in Luancheng and Baicheng was 889 and 1425 mg·kg-1, respectively, suggesting that the soil from Baicheng had an obviously higher phosphorus fixation capability than that from Luancheng.

Responses of vegetation index (NDVI) in typical ecological areas of Shanxi Province to climate change.

WU Yong-li;LI Zhi-cai;WANG Yun-feng;LUAN Qing;TIAN Guo-zhen

2009, 28(05):  925-932 . 

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By using the 1982〖KG-*2〗-〖KG-*7〗2006 NASA/GIMMS half-monthly composite NDVI data of 8 km resolution and related climate data, and based on the investigations of terrain, land use, and vegetation, this paper classified Shanxi Province into 9 typical ecological areas, and analyzed the dynamic changes of annual, decadal, and monthly NDVI as well as the responses of the NDVI to precipitation, air temperature, and PSDI in the areas. The results indicated that in recent 25 years, the NDVI in the Province had an increasing trend, and exhibited an obvious annual variation. The NDVI was higher in southern part than in northern part, and in eastern part than in western part. For different ecological areas, forested area had the highest NDVI, followed by agricultural area, and pasturing area. The vegetation index in forested area increased obviously in spring, and that in most ecological areas except southern agricultural area represented single apex type. The NDVI in forested area related well with air temperature, and the correlation of NDVI with PDSI was more closely than with precipitation or air temperature. The responses of vegetation index to climate change had an obvious lag effect, and the annual variation of precipitation, especially the accumulative effect of precipitation, affected vegetation index significantly.

Distribution and source of polycyclic aromatic hydrocarbons (PAHs) in soils of Baiyangdian area.

ZHAO Jian;ZHOU Huai-dong;LU Jin;WANG Yu-chun;HU Chun-hong;YUAN Hao

2009, 28(05):  901-906 . 

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Surface (0〖KG-*2〗-〖KG-*7〗20 cm) and subsurface (20〖KG-*2〗-〖KG-*7〗30 or 30〖KG-*2〗-〖KG-*7〗40 cm) soil samples in Baiyangdian area were collected, and their 16 polycyclic aromatic hydrocarbons (PAHs) contents were determined by GC/MS. The total PAHs contents in surface soils varied from 1460 to 6459 ng·g-1, with an average of 4174 ng·g-1, and those in subsurface soils varied from 430 to 3945 ng·g-1, with an average of 1524 ng·g-1. The PAHs contents in surface soils had less correlation with soil total organic carbon (TOC) content, while those in subsurface soils were in adverse, indicating the increasing binding degree of PAHs to TOC in the processes of soil burial and reconstruction, and the differences in the environmental behaviors of different PAHs. In general, low ring (2〖KG-*2〗-〖KG-*7〗3 rings) PAHs such as Nap and Phe transferred from top soil to bottom soil more easily than high ring (≥4 rings) PAHs. The values of PAHs isomer ratios suggested that biomass and coal combustion were the major sources of PAHs in surface soils of Baiyangdian area, which could be related with the human activities such as straw combustion.

Phylogenetic diversity of bacteria associated with dinoflagellate Alexandrium catenella.

LIU Bing¹;LI Yu²;YE Qian²;LI Tai-wu¹;SU Xiu-rong¹;LI Deng-feng¹;CHEN Yan¹;SHI Xi-zhi¹

2009, 28(05):  889-894 . 

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The phylogenetic diversity of bacteria associated with Alexandrium catenella was studied by 16S rDNA gene sequences. With culture-independent approach, the total bacterial DNA was extracted from A. catenella. 16S rDNA genes were amplified by PCR, and a 16S rDNA clone library was constructed. The phylogenetic diversity of the bacteria was determined by RFLP-16S rDNA sequencing of cloned DNA fragments. A total of 84 cloned 16S rDNA fragments were digested with restriction endonucleases HaeⅢ, and 30 different PFLP types were obtained. Fifty cloned partial sequences were acquired, most of which were related to Proteobacter, and mainly attributed to α-Proteobacteria and Bacteroidetes in the phylogenetic tree. In α-Proteobacteria, Roseobacter sp. was the dominant clade. This study demonstrated the prolific bacterial diversity of A. catenella.

Arsenic concentration, distribution, and forms in the waters and sediments of Jinzhou Bay and its adjacent estuaries.

WANG Shu-ying^1,2;JIA Yong-feng¹;WANG Shao-feng¹;WANG Xin¹;WANG He^1,2;ZHU Hui-jie^1,2;ZHAO Zhi-xi^1,2;LIU Bing-zhu³

2009, 28(05):  895-900 . 

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Sediment and water samples were collected from Jinzhou Bay and three rivers of Huludao to investigate their arsenic concentration, distribution, and forms. The arsenic concentration in the sediments and waters of Lianshan River and Wuli River, and in the sediments of the downstream of Cishan River adjacent to zinc refining plant was lower than 10 mg·kg-1 and 10 μg·L-1, and reached to 752 mg·kg-1, respectively, indicating that the former two rivers did not suffer significant arsenic pollution, while the downstream of Cishan River was arsenic-polluted to a certain degree. Wuli Estuary was very seriously arsenic-polluted. In the effluent of zinc refining plant at Wuli Estuary, the arsenic concentration was as high as 31761 mg·kg-1, being 158 times higher than the national sediment guideline. Because of the release of effluent and slag from the zinc refining plant, Jinzhou Bay was also very seriously polluted, with the highest concentration of arsenic reached to 5695 mg·kg-1. There was a similar vertical distribution pattern of arsenic concentration in the sediments and pore-water, suggesting that the arsenic concentration in pore-water was mainly controlled by that in sediments. The results of sequential extraction showed that exchangeable arsenic was the dominant form, followed by residual arsenic, and amorphous Fe oxides-arsenic, illustrating that the arsenic in the sediments was very active and easily released to the above waters, possessing a chronic and serious threat on the ecosystems of Huludao and Jinzhou Bay. The influence of Fe oxides on the behaviors of arsenic in the sediments was not significant.

Effects of Miscanthus floridulus natural inhabitation on heavy metals forms and microbial parameters in mine tailings.

YANG Jing-dan;CHEN You-jing;ZHANG Chong-bang;WANG Jiang

2009, 28(05):  907-914 . 

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Selecting four sites with different degrees of Miscanthus floridulus natural inhabitation and one bare site in Sanmen mine tailings of Zhejiang Province as test objectives, this paper studied the effects of M. floridulus inhabitation on the heavy metals (Pb, Zn, Cu, and Cd) form transformation, microbial parameters, and their relationships in the mine tailings. The results indicated that M. floridulus natural inhabitation increased the fractions of carbonates-bound and sulphides-organic matter- bound heavy metals (P<0.05), but decreased those of exchangeable, iron-manganese oxides- bound, and residual heavy metals (P<0.05). Except the decrease of microbial respiration quotient (P<0.05) and no regular change of microbial biomass carbon quotient, the other microbial parameters increased with increasing natural inhabitation of M. floridulus (P<0.05). Canonical correlation analysis (CCA) showed that the overall changes of microbial parameters had significant positive correlations with the fractions of carbonates-bound and sulphides-organic matter- bound heavy metals (R2=09874, 09939), and significant negative correlations with exchangeable, iron-manganese oxides- bound, and residual heavy metals (R2=09972, 09964, 09949).

Climate warming and its effects on agricultural production in Dalian.

HOU Guo-cheng; WANG Xiu-ping

2009, 28(05):  933-937 . 

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By using the 1961〖KG-*2〗-〖KG-*7〗2007 observation data of monthly mean temperature, monthly mean maximum and minimum temperature, accumulative temperature of < 0 ℃, ≥ 0 ℃ and ≥10 ℃, and frost-free period from 7 meteorological stations in Dalian, the variation characteristics of these climate indices in last 47 years were analyzed, and the responses of Dalian thermal resources to climate warming as well as the effects of climate warming on the agricultural production in Dalian were studied. In 1988〖KG-*2〗-〖KG-*7〗2007, the monthly mean temperature, monthly mean maximum and minimum temperature, and accumulative temperature of ≥0 ℃ and ≥10 ℃ in Dalian increased markedly, compared with those in 1961〖KG-*2〗-〖KG-*7〗1987. The monthly mean minimum temperature had the largest increment, and the increment was larger in winter than in summer. Therefore, the climate warming in Dalian mainly came from the contribution of the increase of the minimum temperature in winter. The absolute value of accumulative temperature of <0℃ decreased obviously, the first frost date postponed, while the last frost date advanced, resulting an obvious increase of the days of frost-free period. Since the late 1980s, especially in the early 21st century, abnormally warming events more frequently occurred in Dalian, the thermal resources being increased, which would be favorable to the facility agricultural. On the other hand, the survival rates of overwintering diseases and pests increased. Consequently, there would be both advantages and disadvantages of climate warming to the agricultural production in Dalian.

Roles of composite marine microbial preparation in improving soil quality of Eucalyptus plantation.

HU Zhi-gang^1,2;HU Jiang-chun¹;LIU Li¹; WANG Si-long¹;SU Zhen-fei³;WANG Shu-jin¹

2009, 28(05):  915-920 . 

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To maintain and improve soil quality is a crucial issue in agriculture and forestry. In this paper, a composite preparation of marine Bacillus subtilis 3728, marine B. subtilis 3512, marine Trichoderma TF4, and white clover (Trrifolium repens) was developed, and applied to the soil in a one-year-old Eucalyptus plantation to examine its improvement effects on soil quality. The results showed that this preparation played a regulation role on the soil microbial populations and communities. The individuals of Aspergillius, Trichoderma, Mucor, and other cellulose-decomposing fungi in the soil increased, while those of Fusarium decreased, compared with the control. In the meanwhile, the total number of soil bacteria increased 10 fold, among which, Bacillus subtilis and B. cereus increased 202 and 118 folds, respectively, and the total number of soil actinomyces increased 03 folds. This preparation increased the contents of soil organic matter, ammonia nitrogen, and available phosphorous, and stimulated the activities of soil sucrase, protease, and urease significantly. After applied the preparation into soil for 180 days, the average tree height of Eucalyptus was 126% greater than that of the control, suggesting the promotion effects of the preparation on Eucalyptu growth.

Effects of temperature on the development of Bactrocera dorsalis (Diptera: Tephritidae) population.

LUO Zhi-xin¹;REN Li-li¹;QI Li-yan²;ZHOU Shu-dong³;DAI Hua-guo¹

2009, 28(05):  921-924 . 

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By the method of artificial breeding in laboratory, this paper studied the effects of temperature on the development of invasive alien species Bactrocera dorsalis in Wuxi of Jiangsu, China. The results indicated that the development rate of B. dorsalis at its each development stage increased from 17 ℃ to 33 ℃. By using linear regression model and direct optimal method, the development threshold temperature (DTT) was determined, which was 99 ℃ for the developmental period from egg to adult, and was 105 ℃, 96 ℃, and 103 ℃ for the egg, larva, and pupa stages, respectively. The effective accumulation temperature (EAT) was 3810 day-degree for the developmental period from egg to adult, and was 241, 1786, and 1767 day-degree for egg, larva, and pupa stages, respectively. Temperature also affected the survival rate of B. dorsalis at its each developmental stage. The survival rate for egg stage was the highest at 25 ℃, and that for pupa stage was the lowest at 17 ℃. In addition, temperature had definite effects on the sex ratio of B. dorsalis. At 25 ℃, the proportion of the females was the highest.

Ecological pressure in eco-city construction of Shenyang.

GU Xiao-wei;WANG Qing;FENG Min;YU Hong-min;ZHANG Bo;WANG Zhong-xin

2009, 28(05):  943-949 . 

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Ecological footprint （EF） method was used to measure the ecological pressure in Shenyang City in 1991〖KG-*2〗-〖KG-*7〗2005, and the EF of the City in 2006〖KG-*2〗-〖KG-*7〗2010 was predicted. The results showed that in 1991〖KG-*2〗-〖KG-*7〗2005, the per-capita EF of the City was 175 hm2, while the per-capita bio-capacity was 041 hm2, resulting in a per-capita ecological deficit of 134 hm2. The per-capita EF demand was 324 times more than the bio-capacity. The cropland and energy footprints accounted for more than 85% of the total EF, and thus, the changes in these two components had substantial effects on the total EF. According to the prediction, the EF of Shenyang City would grow at a high rate after 2005, and would reach 511 hm2 per capita in 2010, being 350, 332, and 196 times of that in 1991, 2000, and 2005, respectively. Based on the outcome of this study, some suggestions were proposed for the ecological and sustainable development in Shenyang.

Ecological invasion of Gambusia affinis: A review.

YAN Yun-zhi¹;CHEN Yi-feng²;TAO Juan¹

2009, 28(05):  950-958 . 

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Gambusia affinis is originated from Middle and North America, and was introduced into different countries for controlling mosquito larvae in the early 20th century, becoming an alien invasive species distributed globally. Although it is still a disputation about whether G. affinis can control mosquito, this invasive species has brought tremendous impacts on the native species (including invertebrates, fishes, and amphibians), ecosystems, and water environments. In this paper, the biological traits, invasion mechanisms, efficiency in mosquito control, and ecological effects of G. affinis were summarized, and the strategies and measures for its management and control were brought forward, aimed to offer basic information for the studies on the alien invasive species and their management and control in China.

Dynamic changes of composite drought indiex in Liaoning Province in recent 50 years.

LIU Xiao-mei¹;LI Jing¹;Lü Zhi-hong²;LIU Ming³;XING Wan-ru³

2009, 28(05):  938-942 . 

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By using the daily precipitation and daily mean air temperature data from 37 observation stations in Liaoning Province, the daily composite drought index (CI) in 1958〖KG-*2〗-〖KG-*7〗2007 was calculated. Based on this calculation, the drought process in the Province was diagnosed, and its spatiotemporal variations were analyzed. The results showed that in the Province, drought event occurred everywhere, and its frequency was most great in west part. The drought frequency was greater in May and June in whole Liaoning, and also, greater in autumn in west Liaoning. The drought days both in a year and in the growth season were increasing.

Research progress on ecology of natural wetland zoobenthos in China.

HU Zhi-yuan;BAO Yi-xin;CHENG Hong-yi;ZHANG Long-long;GE Bao-ming

2009, 28(05):  959-968 . 

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Zoobenthos is an important part in wetland ecosystem, and plays a connection link in energy flow and matter cycling. Its community structure can reflect the abiotic factors (e.g., bottom sediment condition, water quality, and water temperature) and biotic factors (e.g., vegetation, interactions between species, and predation pressure). This paper introduced the concept, life forms, and functional groups of zoobenthos, and discussed the features of the study on the ecology of zoobenthos as well as the related key research areas and important achievements in China, with the focus on the spatiotemporal difference in the distribution of zoobenthos community, relationships between zoobenthos and environmental factors, and indicative significance of zoobenthos as bio-indicator in water health. The future research directions on the ecology of zoobenthos in China were prospected.

Effects of urban greenbelt structure on air negative ions concentration.

MU Dan;LIANG Ying-hui

2009, 28(05):  988-991 . 

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Choosing representative greenbelts in Jiamusi City, Heilongjiang Province as the objectives, this paper studied the effects of different greenbelt structures on the air negative ions concentration. The results indicated that air negative ions concentration differed significantly with greenbelt structure. Multilayer structure tree-shrub-grass had the highest air negative ions concentration and the best air quality, followed by tree-grass, shrub-grass, and grass.

Characteristics of plankton community structure in Maqu section at upper reaches of Yellow River in spring.

ZHANG Jun-yan¹;ZHANG Jian-jun²;YANG Xing-zhong¹;LI Ke-she²;SHNEG Hong-bao²;FENG Hui¹;LI Fang¹

2009, 28(05):  983-987 . 

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In order to understand the status of water quality in Maqu section at the upper reaches of Yellow River, the plankton community composition was investigated from April to May 2006. Twenty three species (genera) and 5 phylum of phytoplankton were observed in the whole section. The density of the phytoplankton was 32 ×104〖KG-*2〗-〖KG-*7〗54×104 cells·L-1, averaging 197×104 cells·L-1, and the biomass of the phytoplankton was 0069〖KG-*2〗-〖KG-*7〗0464 mg·L-1, averaging 0228 mg·L-1. The highest density was in Qihama, and the highest biomass was in Maqu Bridge. At the same time, 10 species (genera) and 2 phylum of zooplankton were observed. The density of the zooplankton was 670〖KG-*2〗-〖KG-*7〗1273 cells·L-1, averaging 88156 cells·L-1, and the biomass of the zooplankton was 0044〖KG-*2〗-〖KG-*7〗0089 mg·L-1, averaging 0064 mg·L-1. The composition of plankton in Maqu section was mainly of cold-water type, and the phytoplankton diversity index ranged from 2 to 3. These results suggested that in Maqu section, the water quality was of slightly polluted, the richness and evenness of plankton were lower, and the composition and structure of plankton community were instable, being easily disturbed by external environment.

Regional ecological risk assessment: Its research progress and prospect.

YIN He^1,2;WANG Yang-lin¹;CAI Jia-liang³;LÜ Xiao-fang^1,2;LIU Xiao-qian^1,2

2009, 28(05):  969-975 . 

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Ecological risk assessment is a key measure of ecological environment management. To assess the ecological risk at regional scale is of practical significance in strengthening ecosystem management and regional ecological safety. This paper reviewed the concept, definition, main contents, and development process of regional ecological risk assessment, and discussed the key issues in related researches, e.g., region, scale, model, and uncertainty. In the meanwhile, the further research directions on regional ecological risk assessment were prospected.

Evaluation of response extent of forests to disturbances.

YU Li-zhong¹;ZHU Jiao-jun¹;ZHANG Yan-hong²;ZHAO Feng-jun²; ZHOU Yong-tian³

2009, 28(05):  976-982 . 

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Disturbance is one of the driving forces of forest community succession, and of significance in forest ecosystems. The impact extent of disturbances on forest ecosystems was mostly depended on the frequency, intensity, and spatial scale of the disturbances, and, excessive and frequent disturbances may lead to the destruction of forest ecosystems. The response of forest ecosystems to disturbances represents in many aspects, and the internal relationships among these aspects are quite complicated. Therefore, it is difficult to define the response of forest ecosystems to the disturbances from one or several phenomena in a forest ecosystem. Aiming to correctly evaluate the response extent of existing forest ecosystems to the disturbances, the authors considered that the response extent of forests to disturbances (REFD) could be related to the change degrees of forest ecosystem structure and function under the existence of disturbance, which only reflect the extent of the differences between existing forests and objective forests (zonal climax vegetation or original forest vegetation) after disturbances, but not the types of intensity and property of the disturbances. The concept and connotation of REFD were defined and explored, and the evaluation principles and methods of REFD were also summarized.

Recreational pressure of urban parks in Shenyang.

LI Xiao-ma¹;LIU Chang-fu¹;WU Wei²

2009, 28(05):  992-998 . 

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Supported by GIS, the recreational pressure of urban parks in Shenyang was studied by using distance decay model combined with Voronoi graph. The results showed that the total recreational pressure of urban parks in Shenyang did not display obvious difference between downtown and suburban area, but the total recreational pressure of urban parks in the northwestern part of the city was higher than that in its southeastern part. Zhongshan Park, Xinhua Park, Laodong Park, Shifu Square, and Wanliutang Park suffered from the highest total recreational pressure, while Xinhua Park, Shifu Square, Bayi Park, Shenhai Park, and Fenglu Park suffered more urban park area-weighted recreational pressure. An obvious difference in area-weighted recreational pressure was observed between the parks in downtown and suburban area. The combination of distance decay model and Voronoi graph could overcome the shortcomings of distance decay model or Voronoi graph alone, being able to effectively measure the intensity of the recreational disturbances of urban parks, and to evaluate the service pressure of other urban service facilities. The related information acquired in this study could provide references for optimizing the spatial distribution of urban parks in Shenyang and making effective management plans for the urban parks in the City.