Table of Content

18 September 2012, Volume 23 Issue 09

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Articles

Effects of forest floor litter and nitrogen addition on soil microbial biomass C and N and microbial activity in a mixed Pinus tabulaeformis and Quercus liaotungensis forest stand in Shanxi Province of China.

TU Yu1, YOU Ye-ming1, SUN Jian-xin1,2

2012, 23(09):  2325-2331. 

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From September 2010 to October 2011, a field experiment with randomized block design was conducted in a mixed Pinus tabulaeformis and Quercus liaotungensis forest stand in Lingkong Mountain of Shanxi Province to study the effects of forest floor litter and nitrogen addition on the soil microbial carbon (MBC) and nitrogen (MBN) and microbial activity (MR). The litter treatments included complete litter removal, doubling of leaf litter (L), doubling of woody litter (B), and doubling of mixed leaf and woody litter (LB), and the nitrogen addition rates were 0 (N₀), 5 g·m^-2·yr^-1 (N₁), and 10 g·m^-2·yr^-1 (N₂). Except that the treatment of complete litter removal without nitrogen addition decreased the soil organic carbon content significantly, all the other treatments had no significant differences in the effects on soil organic carbon. The soil MBC, MBN, and MR varied in the ranges of 262.42-873.16 mg·kg^-1, 73.55-173.85 mg·kg^-1, and 2.38-3.68 mg·kg^-1·d^-1, respectively, and the MBC and MBN had significant positive correlations with the MR. Nitrogen addition did not show any effect on the MBC, MBN, and MR, whereas litter treatments affected the MR significantly, with the highest MR in treatment LB, followed by  treatments L and B, and the lowest in treatment of complete litter removal. There were no interactive effects between litter and nitrogen addition treatments on any of the variables studied. It was suggested that shortterm nitrogen addition and forest floor litter change could have limited effects on soil microbial processes.  

Population structure and understory species diversity of different aged Pinus sylvestrisvar. mongolica plantations in Nenjiang Sandy Land of Northeast China.

MENG Xiang-nan1,2, ZHAO Yu-sen1, ZHENG Lei3, XIN Ying1

2012, 23(09):  2332-2338. 

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Taking the Pinus sylvestris var. mongolica sandfixing plantations at different development stages (24-, 29-, 39-, and 43 years old) in Nenjiang Sandy Land as test objects, this paper studied their population structure, understory species composition, and species diversity. No  regenerated seedlings were found in all the four P. sylvestris var. mongolica plantations. The mean individual height and DBH of the populations differed significantly with development stage. With the increasing age of the plantations, the proportion of small-sized individuals decreased obviously, while that of large-sized individuals increased, population tended to mature, and the diameter structure except 43 years old plantation was in normal distribution. A total of 33 understory plant species were recorded, belonging to 28 genera and 15 families. Setaria viridis was the dominant species, but its dominance decreased gradually with increasing age of the plantations. With the increase of plantation age, the proportion of annual plants decreased, while that of perennial plants increased. The Simpson index and Pielou index had no significant differences among the different aged plantations, but the richness index, Shannon index, and Alatalo index of 39 years old plantation were significantly higher than those of 24 years old stands, suggesting that the species diversity of the community improved with time.

Root architecture and phosphorus efficiency of different provenance Pinus massoniana under low phosphorous stress.

YANG Qing1, ZHANG Yi1, ZHOU Zhi-chun1, FENG Zhong-ping2

2012, 23(09):  2339-2345. 

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Taking four representative provenances of Pinus massoniana from Chun’an of Zhejiang, Wuping of Fujian, Cenxi of Guangxi, and Xinyi of Guangdong in East and South China as test materials, a pot experiment was conducted to study their variations in root architecture and phosphorus (P) efficiency under eterogeneous and homogeneous low P stress. Large variations were detected in the major growth traits and the indices of P efficiency among the P. massoniana provenances under both heterogeneous and homogeneous low P stress. Under heterogeneous low P stress, the provenances from Xinyi of Guangdong and Wuping of Fujian exhibited higher P efficiency and greater dry matter accumulation, and their root architecture presented large adaptive changes, with the values of root parameters in Prich soil surface layer being significantly higher than those of the P inefficient provenances from Chun’an of Zhejiang and Cenxi of Guangxi, which should be responsible for the higher P absorption efficiency and high P efficiency of the provenances from Xinyi and Wuping under heterogeneous low P condition. The root architecture parameters in Prich soil surface layer and the plant dry matter accumulation of different provenance P. massoniana under heterogeneous low P stress had a correlation coefficient >0.95. Under homogeneous low P stress, the provenances with higher P efficiency had a significantly higher P uptake efficiency than the provenances with lower P efficiency, but the root parametres of the provenances with higher P efficiency had no significant correlation with the P efficiency of the provenances. There existed differences in the adaptive mechanism for the heterogeneous and homogeneous low P stress among the the P. massoniana provenances, and thus, different strategies should be adopted in the selection of Pefficient provenances for different forest stands.

Fine root production and turnover in Pinus massoniana plantation in Three Gorges Reservoir Area of China.

WANG Rui-li1, CHENG Rui-mei1, XIAO Wen-fa1, FENG Xiao-hui1,2, LIU Ze-bin1, GE Xiao-gai1, WANG Xiao-rong1,3, ZHANG Wei-yin1

2012, 23(09):  2346-2352. 

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By the methods of sequential soil cores and buried bags,  an investigation was conducted to study the seasonal dynamics of fine roots in a 20-year-old Pinus massoniana plantation in Three Gorges Reservoir Area from March to December 2011, with the annual production and turnover rate of the fine roots calculated. In the plantation, the annual mean biomass of <2 mm fine roots was 146.98 g·m^-2·a^-1, in which, the living root biomass (102.92 g·m^-2·a^-1) was far greater than that of the dead root biomass (44.06 g·m^-2·a^-1). Among the fine roots with different sizes, <1 mm fine roots had an obvious seasonal dynamics in their biomass, showing a unimodal curve in the sampling period. The annual production and turnover rate of <2 mm fine roots were 104.12 g·m^-2·a^-1 and 1.05 a^-1, respectively, in which, the annual production of <1 mm and 1-2 mm fine roots was 58.35 and 45.77 g·m^-2·a^-1, and the turnover rate was 1.41  and 0.69 a^-1, respectively.   

Root system spatial distribution of different aged Armeniaca vulgaris cv. Luntaibaixing in arid oasis under irrigation.

WANG Shi-wei, PAN Cun-de

2012, 23(09):  2353-2360. 

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By the methods of layered digging and image scanning analysis, this paper studied the root system spatial distribution of different aged Armeniaca vulgaris  cv. Luntaibaixing in arid oasis under irrigation. The root system of  A. vulgaris cv. Luntaibaixing was mainly constituted by fine roots (d≤1 mm), while medium roots (1＜d≤2 mm) and thick roots (d＞2 mm) only had a small proportion. For the trees aged 5-year old, 10-year old, and 15-year old, the percentage of fine root length in the total root length was 90.9%, 88.4%, and 79.9% respectively, the root length density increased with tree age, and the length density of the roots with different diameter classes was 15-year old＞10-year old＞5-year old. In vertical direction, the root length density decreased after an initial decrease, and the root dry mass density had a significant difference between soil layers. The intensive distribution region of the root biomass density for the trees aged 5-year old, 10-year old, and 15-year old was 30-80 cm, 30-100 cm, and 30-100 cm soil depth within the 200 cm range from the trees, respectively.
 In horizontal direction, the root dry mass density at different distances from the trees had significant difference, i.e., the farther the distance from the tree trunk, the smaller the root dry mass density. In order to decrease the overlap between the tree line and to reduce water and nutrient competition, the row ledge of  A. vulgaris cv. Luntaibaixing in arid oasis under irrigation should not be less than 6 m.

Spatial heterogeneity of soil properties and its relationships with terrain factors in broadleaved forest in Tiantong of Zhejiang Province, East China.

ZHANG Na1,2, WANG Xi-hua1,2, ZHENG Ze-mei1,2, MA Zun-ping1,2, YANG Qing-song1,2, FANG Xiao-feng1,2, XIE Yu-bin1,2

2012, 23(09):  2361-2369. 

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By using geostatistical methods, this paper studied the spatial heterogeneity and distribution patterns of soil pH, total carbon, total nitrogen, and total phosphorus in an evergreen broadleaved forest in Tiantong of Zhejiang Province, and the effects of terrain factors (elevation, convexity, and slope) on the soil properties were quantified based on RDA ordination and partial regression analysis. The coefficient of variation for the soil pH, total carbon, total nitrogen, and total phosphorus was 5.18%, 42.98%, 36.55%, and 46.27%, respectively, and the spatial dependence of the soil properties was at a scale of 81.6-54.5 m. The soil pH, total carbon, and total nitrogen had moderate spatial autocorrelation, while the soil total phosphorus had a strong spatial autocorrelation. The soil pH, total carbon, and total nitrogen showed scattered spatial distribution, while the soil total phosphorus presented banded type. Among the terrain factors, convexity had the strongest effects on the soil pH and total phosphorus, both of which had negative correlation with convexity, and the convexity could explain 21.24% and 14.62% of the spatial variability of soil pH and total phosphorus, respectively. Elevation had the most powerful effects on the soil total carbon and total nitrogen, both of which had positive correlation with elevation, and the elevation could explain 10.54% and 10.60% of the spatial variability of soil total carbon and total nitrogen, respectively. There existed differences in the effects of different terrain factors on the spatial variability of the soil properties, which was related to the effects of terrain factors on the distribution of acidic rainfall in the region and on the local soil moisture content and air temperature.

Water physiological characteristics and leaf traits of different  aged Salix cheilophila on alpine sandy land.

LIU Hai-tao1,2, JIA Zhi-qing1,2，ZHU Ya-juan1,.2, YU Yang1,2, LI Qing-xue1,2

2012, 23(09):  2370-2376. 

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Taking  4-, 11-, 25-, and 37- year old Salix cheilophila stands on the alpine sandy land of Gonghe basin in Qinghai of West China as test objects, a laboratory test was conducted on their relative water  deficit, water holding ability, specific leaf area (SLA), leaf massbased nitrogen concentration (N_mass) and phosphorous concentration (P_mass), and N_mass/P_mass, aimed to understand the variation patterns of the water physiological characteristics and leaf traits of different  aged S. cheilophila on alpine sandy land. No significant difference was observed in the relative water deficit of the four stands. The daily mean value of water potential of the 37-year old stand was significantly lower, as compared with that of the other three stands, and the 4- and 11-year old stands had a significantly lower daily mean water potential than the 25-year old stand. The water loss rate of the 4-year old stand was significantly lower than that of the other three stands, and the 25-year old S. cheilophila stand had a significantly lower water loss rate than the 11-year old stand. The 4year old stand also had a significantly lower SLA than the other three stands, implying its higher water use efficiency. The N_mass of the 11-year old stand was significantly higher than that of the other three stands, and the 25-year old stand had a significantly higher N_mass than the 37-year old stand, implying that the 11 and 25-year old stands had a higher photosynthetic capacity. The P_mass of the 11-year old stand was significantly higher than that of the 25- and 37-year old stands, and the 4-year old stand had a significantly higher P_mass than the 25-year old stand. The N_mass/P_mass of the four stands was 5.16-6.28, and the 25-year old stand had a significantly higher N_mass/P_mass than the 4- and 11-year old stands. The N_mass of the four stands was significantly positively correlated with P_mass, the P_mass was highly significantly negatively correlated with N_mass/P_mass and significantly negatively correlated with stand age, and the N_mass/P_mass was significantly positively correlated with stand age. It was suggested that S. cheilophila at its different developmental stages could have different ecological adaptive strategies.

Effects of thinning on Calligonumarborescens growth and soil watersalt distribution in Tarim Desert Highway shelterbelt, Xinjiang of Northwest China.

ZHANG Jian-guo1,2, LI Ying-gang2,3, XU Xin-wen2, LEI Jia-qiang2, LI Sheng-yu2

2012, 23(09):  2377-2382. 

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In order to understand the effects of thinning on the growth of Calligonum arborescens and the soil watersalt distribution in Tarim Desert Highway shelterbelt, a thinning experiment was conducted on an aged and declined C. arborescens woodland in a demonstration section of the shelterbelt, with the growth of C. arborescens and the soil watersalt distribution monitored. Thinning had no effects on the phenophase of  C. arborescens, but after thinning, the growth of the current year plant height, crown width, ground diameter, and new branch length of reserved trees was larger than that of the control, and the increment was in the order of planting space 2 m×1 m > 1 m×1 m > the control, with significant differences among the treatments. The assimilation branch surface area in treatments 2 m×1 m and 1 m×1 m were 5.97 m² and 5.22 m² per plant, respectively, being significantly larger than the control (3.1 m² per plant). The soil moisture content in 0-160 cm layer was significantly higher in treatments 2 m×1 m and 1 m×1 m than in the control, and increased obviously with thinning intensity. The soil salt content was in the order of control > planting space 1 m×1 m > 2 m×1 m, and the differences among the treatments were significant. It was suggested that the best reserved plant density after thinning was planting space 2 m×1 m.

Characteristics of rainfall interception by Caragana korshinskii and Hippophae rhamnoides in Loess Plateau of Northwest China.

JIAN Sheng-qi, ZHAO Chuan-yan, FANG Shu-min, YU Kai, WANG Yang, LIU Yi-yue, ZHENG Xiang-lin, PENG Shou-zhang

2012, 23(09):  2383-2389. 

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From May to October 2011, an investigation was conducted on the effects of rainfall and its intensity on the canopy interception, throughfall, and stemflow of Caragana korshinskii and Hippophae rhamnoides, the main shrub species commonly planted to stabilize soil and water in the Anjiagou catchment of Loess Plateau. A total of 47 rainfall events were observed, most of which were featured with low intensity, and the total amount and average intensity of the rainfalls were 208.9 mm and 2.82 mm·h^-1, respectively. As a whole, the rainfall events of 2-10 mm and 0.1-2 mm·h^-1 had the highest frequency. The canopy interception, throughfall, and stemflow of C. korshinski were 58.5 mm (28%), 124.7 mm (59.7%), and 25.7 mm (12.3%), while those of H. rhamnoides were 17.6 mm (8.4%), 153.1 mm (73.3%), and 38.2 mm (18.3%), respectively. Regression analysis showed that the canopy interception, throughfall, and stemflow of the two shrub species all had significant positive correlations with the rainfall amount, and had exponent or power correlations with the rainfall amount and the maximum rainfall intensity in 10 minutes.

Dynamic change of Yulania sap flow before dormancy in response to environmental factors.

ZHU Zhong-long, JIA Zhong-kui, MA Lu-yi, WANG Xiao-ling, DUAN Jie

2012, 23(09):  2390-2396. 

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From September 26 to November 5, 2011, the sap flow of Yulania wufengensis trees including cold-resistance type (HK) and non cold-resistance type (HF), Y. ‘Sunspire’ (HY), and Yulania × soulangeana (EQ) which were introduced into Beijing four years before was monitored by Flow32 stem heat balance sensor, and, in combining with the environmental factors monitored synchronically, the changes of the sap flow before dormancy and the environmental factors were analyzed, with the responses of the sap flow to the environmental factors investigated at the scales of 0.5 h and 1 day. The sap flow of the Yulanias trees before dormancy displayed an obvious trend of declining day by day. The environmental factors affecting the sap flow could be divided into two categories, i.e., meteorological index (MI) and soil index (SI). The sap flow of the Yulanias trees had a synchronous variation rhythm with MI, and declined in parallel to SI. The combined effect of MI and SI on the diurnal changes of the sap flow was 69%-73%. At both 0.5 h and 1 day scales, the sap flow showed significantly correlations with total radiation (R_s), air vapor pressure deficit (D), air relative humidity (RH), air temperature (T_a), and wind speed (w). The sap flow showed no significant correlations with soil temperature (T_s) and soil water content (SWC) at 0.5 h scale, but had significant correlations with T_s, SWC, and day length (Z) at 1 day scale (the correlation efficient was about 0.8). Only R_s, Z, and D were included into the model at 1 day scale, but almost all environmental factors (except SWC and T_s) were included in the model at 0.5 h scale. Except for HF type, the regression coefficients of the model for the Yulanias trees at 1 day scale (0.92-0.96) were larger than those at 0.5 h scale (0.77-0.87), and the correlations between the dynamic changes of sap flow and the environmental factor were consistent, which was in accord with the fact that the HF could not overwinter in Beijing but the others could.  

Effects of site conditions and tree age on Robinia pseudoacacia and Populus simonii leaf hydraulic traits and drought resistance.

LI Jun-hui1,3, LI Yang-yang1,2, ZHAO Li-min4, ZUO Li-xiang4

2012, 23(09):  2397-2403. 

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In order to elucidate the hydrophysiological mechanisms of the formation of ‘dwarf and aged’ trees, two typical  tree species Robinia pseudoacacia and Populus simonii on the Loess Plateau were chosen as the test objects to study their leaf hydraulic traits and drought resistance under effects of site conditions (gully bottom tableland and inter-gully slopeland) and tree age. For both R. pseudoacacia and P. simonii, the trees growing on the wet tableland had higher leaf maximum hydraulic conductance (K_max) and hydraulic vulnerability (P₅₀), and the K_max decreased with tree age but the P₅₀ had less difference, as compared with the trees growing on the dry slopeland. The trees growing on the tableland also had higher leaf epidermal conductance and PV curve parameters (including relative water content at turgor pressure loss point RWC_tlp, water potential at turgor pressure loss point ψ_tlp, and osmotic potential at saturated water content ψ_sat), and the leaf epidermal conductance decreased significantly with tree age whereas the PV curve parameters had definite decrease. The K_max was significantly positively correlated with ψ_tlp, and the P₅₀ had definite correlations with PV curve parameters, suggesting that there existed a tradeoff relationship between K_max and drought resistance, and P₅₀was an important drought-resistant trait for the two tree species.  

Litter decomposition and its main affecting factors in tidal marshes of Minjiang Riverestuary, East China.

ZHANG Lin-hai1,3, ZENG Cong-sheng1,2,3, ZHANG Wen-juan1, WANG Tian-e1, TONG Chuan1,2,3

2012, 23(09):  2404-2410. 

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By using litterbag method, this paper studied the decomposition of the leaf and flower litters of two emergent macrophytes, native species Phragmites australis and invasive species Spartina alterniflora, and related affecting factors in the Minjiang River estuary of East China. In the decomposition process of the litters, the decay of standing litter (0-90 days) was an important period, and the loss rate of the flower and leaf litters dry mass of P. australis and S. alterniflora was 15.0±3.5% and 13.3±1.1%, and 31.9±1.1% and 20.8±1.4%, respectively. During lodging decay period (91-210 days), the loss rate of the flower and leaf litters dry mass of P. australis and S. alterniflora was 69.5±0.6% and 71.5±2.5%, and 76.8±1.9% and 67.5±2.1%, respectively. In standing decay period, the decomposition rate of the two plants litters was positively correlated with the litters C/N but negatively correlated to the litters N/P, and the litters P was an important factor limiting the litters decay. In lodging decay period,  the effects of the litters C/N, C/P, and N/P decreased, while the
environment factors (climate, soil moisture, soil acidity and salinity, and sediment properties) acted more important roles. The differences in the factors affecting the decay of the litters in different decomposition periods were mainly related to the micro-environment and tidal process for the two plant communities.

Impact of fire on carbon dynamics of Larix gmelinii forest in Daxing’an Mountains of Northeast China: A simulation with CENTURY model.

FANG Dong-ming1,2, ZHOU Guang-sheng1, JIANG Yan-ling1, JIA Bing-rui1, XU Zhen-zhu1, SUI Xing-hua1,2

2012, 23(09):  2411-2421. 

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Fire is one of the important natural disturbances to forest ecosystem, giving strong impact on the ecosystem carbon dynamics. By using CENTURY model, this paper simulated the responses of the carbon budget of Larix gmelinii forest in Huzhong area of Daxing’an Mountains to different intensities of fire. The results indicated that after the fires happened, the soil total carbon pool of the forest had a slight increase in the first few years and then recovered gradually, while the stand biomass carbon pool increased after an initial decrease, with the recovery rate of carbon pool  of the stand fine components  being faster than that of the coarse components. The fluctuation of the carbon pools increased with the increase of fire intensity. After the fires, both the net primary productivity (NPP) of forest vegetation and the soil heterotrophic respiration increased after an initial decrease, but the recovery rate of the NPP was faster than that of soil heterotrophic respiration, resulting in the alternation of the stand functioned as a carbon source or sink. After light fire, the forest still functioned as a weak carbon sink, and quickly recovered as a carbon sink to the level before the fire happened. After other intensities fire, the forest functioned as a carbon source within 9-12 years, and then turned back to a carbon sink again. It was suggested that lower intensity forest fire could promote the regeneration of L. gmelinii forest, reduce the combustibles, and have no strong impact on the stand carbon budget, while higher intensity forest fire would lead to the serious loss of soil and tree carbon sequestration, retard the recovery of the forest, and thereby, the forest would be a carbon source in a longer term.

Transferability of remote sensing-based models for estimating moso bamboo forest aboveground biomass.

YU Chao-lin1,2, DU Hua-qiang1,2, ZHOU Guo-mo1,2, XU Xiao-jun1,2, GUI Zu-yun3

2012, 23(09):  2422-2428. 

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Taking the moso bamboo production areas Lin’an, Anji, and Longquan in Zhejiang Province of East China as study areas, and based on the integration of field survey data and Landsat 5 Thematic Mappr images, five models for estimating the moso bamboo (Phyllostachys heterocycla var. pubescens) forest biomass were constructed by using linear, nonlinear, stepwise regression, multiple regression, and ErfBP neural network, and the models were evaluated. The models with higher precision were then transferred to the study areas for examining the model’s transferability. The results indicated that for the three moso bamboo production areas, Erf-BP neural network model presented the highest precision, followed by stepwise regression and nonlinear models. The Erf-BP neural network model had the best transferability. Model type and independent variables had relatively high effects on the transferability of statistical-based models.

Effects of vegetation cover and normalized difference moisture index on thermal landscape pattern: A case study of Guangzhou, South China.

WANG Gang1,2, GUAN Dong-sheng1,2

2012, 23(09):  2429-2436. 

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By using Landsat5 TM images, the land surface temperature (LST), vegetation cover, and normalized difference moisture index (NDMI) in different areas of Guangzhou were extracted, and the effects of vegetation cover and NDMI on the land surface temperature of the City were studied, based on the landscape ecological methodologies. There existed good linear correlations among the vegetation cover, land surface temperature, and NDMI, but the correlation coefficients for any two of the three items differed obviously with different areas. If the vegetation cover in different areas of Guangzhou was improved to the same level, urban center had the best cooling effect, followed by the suburbs in the north edge of urban center. The forest parks in different areas of the City also had different cooling effect on the surrounding environment. The difference of the average temperature between the 960-1080 m buffer zone and the inner park were 4.69 ℃ in Baiyun Mountain, 1.27 ℃ in Mazaishan, and 0.41 ℃ in Liuxihe. High vegetation cover could increase the thermal landscape heterogeneity and the aggregation among different landscapes, and promote the energy exchange between the lower temperature patches and higher temperature patches, playing an important role in controlling hot island effect. NDMI and vegetation cover had the same effects on the formation of thermal landscape pattern.

Estimation of leaf area index of three forest types in Xiaoxing’an Mountains of Northeast China.

LIU Zhi-li, JIN Guang-ze

2012, 23(09):  2437-2444. 

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From early July to early November 2009, the effective leaf area index (LAI_e) of secondary Betula platyphylla forest, spruce-fir valley forest, and mixed broadleaved-Korean pine forest in Xiaoxing’an Mountains were measured with Winscanopy2006 Plant Canopy Analyzer, and the LAI_e measured in early November and calibrated with the woodytototal ratio as well as the clumping index (for clumping beyond the shoots) and the needletoshoot area ratio (for clumping within the shoots) was derived as the true leaf area index (LAI_t). In combining with litterfall method, the LAI_t and its seasonal dynamics of the three forest types were estimated. The LAI_e of the secondary B. platyphylla forest reached its peak in July, with a value of 2.21, and that of the spruce-fir valley forest and mixed broadleaved-Korean pine forest peaked in August, with the values of 2.57 and 2.68, respectively. All the three forest types had the highest LAI_t in July, with the values of 3.44, 3.86, and 6.93 for the secondary B. platyphylla forest, sprucefir valley forest, and mixed broadleavedKorean pine forest, respectively. In comparison with the method proposed in thisstudy, the peak time LAI_e of the secondary B. platyphylla forest, spruce-fir valley forest, and mixed broadleaved-Korean pine forest obtained by the optical instrument method was underestimated by 33.1%, 32.9% and 66.0%, respectively, and the LAI_e of the three forest types in the entire study period was underestimated averagely by -13.2%, 22.8%, and 56.5%, correspondingly.

Current distribution of Schisandra chinensis in China and its predicted responses to climate change.

HU Li-le2, ZHANG Hai-ying1, QIN Ling1, YAN Bo-qian1

2012, 23(09):  2445-2450. 

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With integration of literature data, specimens records, and field surveys, the current distribution map of Schisandra chinensis in China was drawn, and, based on this map and considering 21 environmental factors, the future distribution of S. chinensis in China in the 2050s and 2080s under the IPCC A2 and A1B climate change scenarios was predicted by using Maxent software. Currently, the S. chinensis in China occurred in 15 provinces, involving 151 counties, and its distribution area decreased with decreasing latitude and longitude. The main distribution area included Heilongjiang, Liaoning, Inner Mongolia, and Jilin. The potential distribution area of S. chinensis in China was 145.12×10⁴ km², 48.6% of which were the favorable habitat area, mainly distributed in Changbai Mountains, Xiaoxing’anling Mountains, Daxing’anling Mountains, and the regions between Hebei and Liaoning provinces. The most favorable habitat area only accounted for 0.3%, and was mainly in the Kuandian Manchu Autonomous County, Benxi Manchu Autonomous County, and Huanren Manchu Autonomous County of Liaoning Province, the Antu County and Helong County of Jilin Province, and the Yakeshi City of Inner Mongolia. U〖JP2〗nder the two climate change scenarios, the potential future distribution area of S. chinensis in China would have a gradual decrease, and the decrement would be larger under A2 than under A1B scenario. By 2050, the distribution area of the S. chinensis under A1B and A2 scenarios would be moderately decreased to 84.0% and 81.5% of the current distribution area, respectively; by 2080, the distribution of S. chinensis under A2 scenario would be dramatically decreased to only 0.5% of the current range, and that under A1B scenario would be decreased to 1/2 of the current range.

Retrieval of forest topsoil organic matter’s spatial pattern based on LiDAR data.

LI Chao1, LIU Zhao-gang1, YUE Shu-feng1, LI Feng-ri1, DONG Ling-bo1, BI Meng2

2012, 23(09):  2451-2458. 

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Forest soil is one of the main carbon pools in terrestrial ecosystem. Its organic matter content can provide basic information for estimating soil carbon storage, and also, is an important index for evaluating the function of soil carbon sink. Based on the LiDAR data and the topsoil organic matter contents in 55 permanent plots at Liangshui National Nature Reserve, Heilongjiang Province of Northeast China in August 2009, and by using partial least squares (PLS) method, this paper retrieved the forest topsoil organic matter’s spatial pattern in the Reserve, extracted and screened the variables related to the distribution of the topsoil organic matter (e.g., intensity, counts, elevation, slope, and aspect), and analyzed and defined the correlations between the screened variables and topsoil organic matter content, with the prediction model of forest soil organic matter content established and validated. In the Reserve, the forest topsoil organic matter content was significantly and positively correlated with three variables (intensity, r=0.765; counts, r=0.423; and elevation r=0.475; all P<0.001). The model prediction on the topsoil organic matter content was reliable (precision=83.3%, R²=0.725, RMSE=1.955). In the areas of forest edge and of low canopy stands, the topsoil organic matter content was less than 100 g·kg^-1. The majority of the study area had a topsoil organic matter content of 100-150 g·kg^-1, while a few areas had the topsoil organic matter content as high as 150-318.4 g·kg^-1.

Characteristics of soil macrofaunal community structure in secondary forest and forest plantations in western Qinling Mountains of Northwest China.

LIU Ji-liang1, CAO Jing2, LI Shi-jie2, PAN Chun-lin3, PAN Cheng-chen1

2012, 23(09):  2459-2466. 

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Long-term disturbance of human beings on secondary forest ecosystem would have profound impacts on belowground ecological processes, whereas the community structure and functional diversity of soil fauna would be sensitive to the changes of belowground ecological processes, with significance as an indicator of the changes. In this study, the method of handsorting was adopted to investigate the density of soil macrofaunal community in a secondary forest and the Pinus tabulaeformis, Larix kaempferi, Picea abie, and Picea asperata plantations of nearly 30 years old in Xiaolongshan forest area of western Qinling Mountains, and the PCA ordination and oneway ANOVA analysis were applied to analyze the community structure and trophic group composition of soil macrofauna in the five forest types. In the P. tabulaeformis and L. kaempferi plantations, the density of soil macrofaunal community was 3.0 and 2.1 times of that in the secondary forest, respectively, and the consumers/decomposers ratio of the community was obviously higher than that in the secondary forest. Among the plantations, P. tabulaeformis and L. kaempferi plantations had a significantly higher consumers/decomposers ratio of soil macrofaunal community than P. abies and P. asperata plantations. There was an obvious difference in community structure of soil macrofauna among the four plantations. The density of soil macrofaunal community in P. tabulaeformis and L. kaempferi plantations was 3.5 and 2.1 times higher than that in P. asperata plantation, respectively, whereas the group richness of soil macrofaunal community in P. tabulaeformis plantation was 1.5 times of that in P. abies and P. asperata plantations.

Characteristics and adaption of seasonal drought  in southern China under the background of global climate change. Ⅱ. Spatiotemporal characteristics of drought for wintering grain and oil crops based on crop water deficit index.

SUI Yue1,2, HUANG Wan-hua1,3, YANG Xiao-guang1, LI Mao-song4

2012, 23(09):  2467-2476. 

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In recent years, seasonal drought occurs frequently in southern China, giving severe impact on the production of local wintering crops. Based on the 1959-2009 meteorological data from 268 meteorological stations in southern China, and by using crop water deficit index (CWDI) as agricultural drought index, this paper analyzed the spatiotemporal characteristics of drought for winter wheat and rapeseed. The results showed that in southern China, drought happened more frequently in Southwest China, north Huaihe basin, and parts of South China during the developmental stages of wintering crops. In the mid-lower Yangtze basin, the intensity and extent of drought increased during the mid-late developmental stages of winter wheat, and became much heavier at its later developmental stages. For rapeseed, the intensity and extent of drought increased during the developmental stage before winter and the late developmental stages. In southwest part, the intensity and extent of drought increased significantly during the developmental stage before winter for winter wheat and rapeseed. Since the early 1990s, the intensity and extent of drought in southern China increased during the mid-late developmental stages of wintering crops.

Effects of high temperature stress on photosynthetic parameters and chlorophyll fluorescence characteristics of Xinjiang hybrid hazels.

SHI Yan-jiang1, LUO Qing-hong1, SONG Feng-hui1,2, YU Tao1, KOU Yun-ling1,2

2012, 23(09):  2477-2482. 

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With five temperature gradient treatments, this paper studied the effects of high temperature stress on the photosynthetic parameters and chlorophyll fluorescence characteristics of four Xinjiang hybrid hazels. When the temperature gradually raised from 25 ℃ to 45 ℃, the net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, water use efficiency and light use efficiency of the hybrid hazels decreased gradually, and the decrement was the largest at 35 ℃-45 ℃. The actual photochemical efficiency of photosystem II, electron transport rate, and photochemical quenching coefficient increased slowly with increasing temperature, but decreased sharply when the temperature was raised to >35 ℃. The water consumption for transpiration and the heat dissipation also increased with increasing temperature. Among the four hybrid hazels, Xinzhen No.3 had higher tolerance against high temperature in photosynthesis, belonging to heat-resistant cultivar.  

Responses of spring corn growth and yield in a cold area of China to field warming at nighttime during preanthesis stage.

QIAN Chun-rong1,2, YU Yang2, ZHAO Yang2, GONG Xiu-jie2, JIANG Yu-bo2, WANG Jun-he2, YANG Zhong-liang3, ZHANG Weijian1,4

2012, 23(09):  2483-2488. 

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By using the facility for increasing free air temperature, a field experiment was conducted in a cold area of Northeast China to study the responses of the growth and yield of rain-fed spring corn to the field warming at nighttime during pre-anthesis stage. Under the field warming at nighttime, the nighttime temperature in 0-10 cm soil layer increased by 1.7 ℃, and the soil moisture content had a slight decrease. Nighttime warming advanced the spring corn phenophases obviously, shorted the pre-anthesis phase by 1 day, and prolonged the post-anthesis phase by 1 day. Nighttime warming also promoted the corn seedlings growth and the root length. Comparing with those in un-warming treatment,  green leaf area and threeear-leave area in nighttime warming treatment increased by 13.5% and 14.6%, and the aboveground biomass, grain yield, and 100-grain mass increased significantly by 8.2%, 9.3%, and 7.1%, respectively. It was suggested that the climate warming (especially the nighttime warming) in Northeast China could improve spring corn growth, and directly affect the corn yield.

Effects of field border length for irrigation on the water consumption characteristics and grain yield of wheat.

MA Shang-yu, YU Zhen-wen, WANG Dong, ZHANG Yong-li, SHI Yu

2012, 23(09):  2489-2496. 

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In the wheat growth seasons of 2009-2010 and 2010-2011, six border lengths of 10, 20, 40, 60, 80 and 100 m were installed in a wheat field to study the effects of different border lengths for irrigation on the water consumption characteristics and grain yield of wheat. The results showed that with the increasing border length from 10 to 80 m, the irrigation amount and the proportion of irrigation amount to total water consumption amount, the water content in 0-200 cm soillayers and the soil water supply capacity at anthesis stage, as well as the wheat grain yield and water use efficiency increased, while the soil water consumption amount and the water consumption amount of wheat from jointing to anthesis stages as well as the total water consumption amount decreased. At the border length of <80 m, the irrigation amount was smaller, and the water content in upper soil layers was lower, as compared with those at the border length of 80 m, which led to the wheat to absorb more water from deeper soil layers, and thus, the total water consumption increased. At the border length of 100 m, the irrigation amount, soil water consumption amount, and total water consumption amount all increased, and, due to the excessive irrigation amount and the uneven distribution of irrigation water when irrigated once, the 1000-grain mass, grain yield, and water use efficiency decreased significantly, which was not conductive to the water-saving and high-yield cultivation.

Effects of nitrogen regulators on fertilizer nitrogen transformation in meadow cinnamon soil and on pakchoi growth.

SUN Zhi-mei, ZHANG Kuo, LIU Jian-tao, SI Huan-sen, Wang Yan-qun

2012, 23(09):  2497-2503. 

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Soil incubation test and pot experiment were conducted to investigate the effects of dicyandiamide (DCD) and its combination with nano-carbon on the transformation of fertilizers (urea and ammonium bicarbonate) nitrogen (N) in meadow cinnamon soil, a typical soil type in North China Plain, and on the growth of pakchoi (Brassica chinensis). In the first two weeks after applying urea and ammonium bicarbonate, the soil NH₄⁺-N and NO₃^--N contents varied greatly, but little variation was observed since then. The effects of the applied fertilizer N on the pakchoi growth and its N use efficiency differed significantly at early growth stages, but had little difference at harvesting stage. The DCD inhibited the transformation of the fertilizer N (especially ammonium bicarbonate N) into nitrate markedly, and this effect increased with increasing DCD dose. Under the conditions of our experiment, the optimal application rate of DCD was 1.0-1.5% of applied fertilize N, which could increase the pakchoi yield significantly, improve the leaf color, decrease the plant nitrate contents, and increase the fertilizer N use efficiency. The combination of DCD and nano-carbon exerted a synergistic effect on inhibiting soil ammonium oxidation, and also, promoted the pakchoi growth and N utilization at early growth stages significantly and decreased the plant nitrate level at harvesting stage.

Effects of high temperature and hydrogen cyanamide on dormant nectarine’s floral bud respiratory metabolism.

TAN Yue1,2, LENG Chuan-yuan1,2, LI Ling1,2, XU Chen-shan3, CHEN Xiu-de1,2, GAO Dong-sheng1,2

2012, 23(09):  2504-2508. 

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Taking 3-year old potted ‘Shuguang’ nectarine (Prunus persicavar. nectarianacv. Shuguang) as test material, this paper studied the effects of high temperature (50 ℃, HT) and hydrogen cyanamide (HC) on the floral bud respiratory metabolism of the tree during its natural dormancy. Both HT and HC could break the natural dormancy of the tree, and lead to a significant decrease in the respiratory metabolism of floral buds for several hours. The main respiratory pathways, tricarboxylic acid cycle (TCA) and pentose phosphate pathway (PPP), were affected. For the buds not received dormancy-breaking treatments, both the TCA and the PPP decreased, while treating with HT and HC induced a rapid recovery of PPP after the early respiratory attenuation. HT also induced the recovery of TCA, but HC did not show this effect in 96 hours. Therefore, respiratory attenuation and the following PPP activation could be the important part in the floral bud respiratory mechanism of HT- and HC-induced dormancy release.

Effects of the volatiles from different tomato varieties on host selection behavior of B-biotype Bemisia tabaci.

ZHAO Yan-qun1, ZHAO Jin-rui1 , MAO Li-juan2, SHI Zu-hua1

2012, 23(09):  2509-2514. 

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By the methods of headspace solid-phase micro extraction and gas chromatography-mass spectrometry, and using Y-type olfactometer, this paper identified the volatiles from six tomato varieties (Zheza 809, Zheza 203, Hezuo 903, Kate No.1, Huangtuoyan, and Jinfei), and bio-assayed the olfactory responses of female B-biotype Bemisia tabaci to the tomato plants and their released volatiles. Thirteen kinds of compounds in the volatiles collected from the six tomato varieties were identified, among which, terpenoids were the main components. However, the compositions and contents of the volatiles differed with tomato varieties. (+)-3-carene and β-caryophyllene showed stronger repellency than other terpenoids to B-type B. tabaci. B-type B. tabaci showed the lowest preference to the tomato varieties such as Zheza 809 and Zheza 203 which contained more kinds of terpenoids and had higher proportion of terpenoids in the volatiles, and showed the greatest preference to the varieties like Huangtuoyan and Jinfei which contained fewer kinds of terpenoids and had lower proportion of terpenoids in the volatiles.

Effects of fluctuating thermal regime on cold tolerance of parasitoid wasp Aphidius gifuensis.

SONG Xiu-chao1, CUI Ning-ning1, ZHENG Fang-qiang1, MO Tie-lu1, LIU Tong-xian2, XU Yong-yu1

2012, 23(09):  2515-2520. 

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In order to understand the effects of fluctuating thermal regime (FTR) on the cold tolerance of female and male Aphidius gifuensis adults in the mummies of Schizaphis graminum and to explore the variation patterns of the biochemical substances in the adult body, this paper determined the supercooling point (SCP), freezing point (FP), and the water, fat, protein, and carbohydrate contents of the adults after FTR treatments. Compared with that at constant temperature (20 ℃), the cold tolerance of the adults at 4 ℃ 22 h/20 ℃ 2 h and 4 ℃ 46 h/20 ℃ 2 h after 1 week enhanced significantly. The SCP and FP after FTR presented a downtrend, being the lowest (-26.38 ℃ and -25.51 ℃, respectively) for the female adults after 1 week of 4 ℃ 22 h/20 ℃ and the lowest (-26.82 ℃ and -26.38 ℃, respectively) for the male adults after 1 week of 4 ℃ 46 h/20 ℃ 2 h. After FTR, the carbohydrate and protein contents of the female and male adults increased while the fat and water contents were in adverse, with distinct changes after 1 week of 4 ℃ 22 h/20 ℃ 2 h and 4 ℃ 46 h/20 ℃ 2 h. The results indicated that FTR could enhance the cold tolerance of A. gifuensis adults, which was closely related to the variations of the biochemical substances in the adult body, and the treatments 4 ℃ 22 h/20 ℃ 2 h and 4 ℃ 46 h/20 ℃ 2 h for 1 week were most advantageous to the survival and practical application of A. gifuensis.

Effects of calcium fertilizer on the development, survival, and feeding of B-biotype Bemisia tabaci on Euphorbia pulcherrima.  

HUANG Jun1, ZHANG Juan2, YU Yong-ming1, LIU Jian-xin1, LI Ming-jiang1, ZHU Kai-yuan1

2012, 23(09):  2521-2528. 

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This paper studied the development, survival, and feeding of B-biotype Bemisia tabaci on Euphorbia pulcherrima under the conditions of 26±1 ℃ and 60%-80% relative humidity after applying calcium fertilizer, taking applying fresh water as the control. There existed significant differences in the developmental duration of B. tabaci between treatment applying calcium fertilizer and the control. After applying calcium fertilizer, the egg stage of B. tabaci shortened significantly, and the development from egg to adult took 20.18 days (for the control, it took 18.72 days). However, there were no significant differences in the survival rates of B. tabaci at different development stages between the two treatments. The feeding of B. tabaci on E. pulcherrima induced the plant leaf chlorophyll fluorescence parameters changed, i.e., the photochemical efficiency (F_v/F_m), photochemical quenching coefficient (q_P), light use efficiency (a), maximum photosynthesis rate (rETR_max), and tolerance to light (I_k) decreased significantly, while the non-photochemical quenching coefficient (NPQ) had a significant increase. After applying calcium fertilizer, the plant leaf photoinhibition parameter (β), rETR_max, and I_k had less difference with the control. The nail polish blot observation on the lower epidermis structure of plant leaf showed that calcium fertilizer could effectively compensate the decrease in the photosynthesis of E. pulcherrima damaged by B-biotype B. tabaci.

Identification of endophytic actinomycete St24 tomato plants from and its application in bio-control of gray mold disease.

WANG Mei-qin1, MA Lin2, HAN Ju-cai1, LIU Hui-ping1， HE Yun-chun1

2012, 23(09):  2529-2535. 

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An endophytic actinomycete strain St24 with acaricidal activity was isolated from the root-stem junction of tomato plants, with the taxonomic position of the strain and its control effect against gray mold disease investigated. The St24 was identified as Streptomyces vinaceus, and its broth’s petroleum ether extracts could inhibit a variety of pathogens. The inhibitory effect of the extracts on Botrytis cinerea was the strongest, with the EC₅₀ of inhibiting B. cinerea mycelia growth being 11.78 mg·L^-1. After treated with the extracts, the amount of the mycelia decreased, and the mycelia became crenate or broken, with the protoplast extravasated and the tuberculate malformation appeared. The B. cinerea culture treated with the extracts showed the maximum absorption at 260 nm, which was absent in the control, indicating that the St24 extracts increased the pathogens cell membrane permeability. Pot experiment showed that the extracts could protect tomato plants against B. cinerea. Foliar spraying the extracts at 100 mg·L^-1 had the best protective effect, with the controlling effect reached 94.3% after 24 h and 85.4% after 120 h.

Sequence polymorphism and mapping of wheat Ca²⁺binding proteinTaCRT-A gene

WANG Ji-ping1,2, MAO Xin-guo1, LI Run-zhi2, JING Rui-lian1

2012, 23(09):  2536-2542. 

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Taking thirty-seven hexaploid wheat (AABBDD) accessions with different drought resistance at seedling stage, three wheat species with A genome (AA), and three tetraploid wheat species (AABB) as test materials, and by direct sequencing the single nucleotide polymorphism (SNP) in TaCRT-A, this paper analyzed the relationships of the SNP with the drought resistance of wheat (Triticum aestivum) at its seedling stage, and mapped the TaCRT-A on the chromosome of wheat. The full-length sequence of the TaCRT-A genomic DNA was 3887 bp. A total of 202 nucleotide variant loci were observed in the full length sequence of 167141 bp, among which, 165 SNP and 37 InDel with the frequencies of 1 SNP/1013 bp and 1 InDel/4517 bp were detected, respectively. The nucleotide diversity (π) in coding region of TaCRT-A was lower than that in non-coding region, suggesting that the selection pressure in coding region was stronger than that in noncoding region. The 43 accessions could be classified as 14 haplotypes (H1-H14) by haploid analysis, among which, H1, H2, and H13 all contained one accession which was the donor species of A genome in common wheat, H6 and H7 had one high droughtresistant accession, H8 comprised tetraploid wheat, droughtresistant accessions, and droughtsensitive accessions, whereas H11 included the wheat accessions with droughtresistance and mediumdrought resistance. Though the expression of TaCRT was induced by water stress, no significant relationship was identified between TaCRT-A polymorphism and drought resistance. Using a population of recombinant inbred lines derived from a cross of Opata 85×W7984, the TaCRT-A was mapped between SSR markers Xmwg30 and Xmwg570 on chromosome 3A, and the genetic distances were 10.5 cM and 49.6 cM from the flanking markers, respectively.

Dynamic evaluation on landscape connectivity of ecological land: A case study of Shenzhen, Guangdong Province of South China.

WU Jian-sheng, LIU Hong-meng, HUANG Xiu-lan, FENG Zhe

2012, 23(09):  2543-2549. 

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Ecological land is the most crucial and sensitive land use type in rapidly urbanizing areas. Landscape connectivity can help us to better understand the interactions between landscape structure and landscape function. By using the land use data of Shenzhen from 1996 to 2008 and the graph theory based integral index of connectivity (IIC), probability index of connectivity (PC), and importance value of patches (dPC), a dynamic evaluation on the landscape connectivity of ecological land in the City was conducted, and a spatial assessment was made to identify the most important patches for maintaining overall landscape connectivity. In combining with the basic ecological controlling line in Shenzhen, the variations of the landscape connectivity of the ecological land inside and outside the basic ecological controlling line were evaluated. From 1996 to 2008, the overall landscape connectivity of the ecological land in Shenzhen displayed a downward trend, the importance and the spatial distribution of the important patches for maintaining the overall landscape connectivity changed, and the basic ecological controlling line played definite roles in maintaining the landscape connectivity of ecological land inside the line.

Niche analysis of phytoplankton’s dominant species in Dianshan Lake of East China.

XU Chun-yan1, YU Qiu-jia1, XU Feng-jie1, HU Xue-qin1, YOU Wen-hui2

2012, 23(09):  2550-2558. 

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By using modified Levins and Petraitis formulae, this paper determined the niche breadth and niche overlap of the phytoplankton’s dominant species in Dianshan Lake of East China, and analyzed the relationships between the niche breadth and niche overlap and the density and dominance of the dominant species. The niche breadth and niche overlap of the dominant species differed in different periods, and different dominant species had different adaptive capacity to the environmental factors. Based on their niche breadth in different seasons, the dominant species in the Lake could be classified into four groups, among which, Chroomonas acuta and Chlorella vulgaris had broader niche, more quantity, wider distribution, and better use of environmental resources. During cyanobacterial blooms, the niche overlap among Cyanophyta species was comparatively higher, Microcystis aeruginosa had broader niche breadth, but other species showed lower niche breadth. Correlation analysis showed that the dominance of the dominant species in different seasons had significant correlation with their niche breadth, and the dominant species density had significant correlation with their niche overlap.

Dynamic changes of phytoplankton’s community structure in Beixi of Jiulongjiang River, Fujian Province of East China and related affecting factors.

TIAN Yong-qiang, YU Chao-chao, WANG Lei, HUANG Bang-qin

2012, 23(09):  2559-2565. 

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An investigation was conducted on the phytoplankton’s community composition, abundance, and their relations with environmental factors in Beixi of Jiulongjiang River, Fujian Province in February (dry season), May (wet season), and October (normal season), 2011. A total of 107 phytoplankton species were identified, belonging to 64 genera and 7 phyla. The dominant species changed with seasons. Campylomonas marssoni and Cyclotella meneghiniana dominated in dry season, Scenedesmus quadricauda and Crucigenia tetrapedia dominated in wet season, and Merismopedia tenuissima dominated in normal season. The phytoplankton’s abundance was the highest in dry season (averaged 154.77×10⁴ cells·L^-1), followed by in normal season (76.40×10⁴ cells·L^-1), and in wet season (45.40×10⁴ cells·L^-1). The abundance in dry and normal seasons was significantly positively correlated with water ammonium nitrogen concentration (P<0.05), while that in wet season was significantly positively correlated with water temperature (P<0.01). Canonical correspondence analysis (CCA) showed that water temperature was the most important factor affecting the phytoplankton’s community structure, and dissolved phosphorous concentration also played important role for the community structure. The CCA ordination plots could well display the phytoplankton’s community structure and its relationships with environmental factors.  

Relationships between spatial distribution of two dominant small-sized fishes and submerged macrophyte cover in Niushan Lake of China.

YE Shao-wen, ZHANG Tang-lin, LI Zhong-jie, LIU Jia-shou

2012, 23(09):  2566-2572. 

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By using a set of pelagic gillnets with eight mesh sizes, an investigation was made on the spatial distribution of small fishes in submerged macrophyte habitats in a shallow macrophytic lake (Niushan Lake) in the middle reach of Yangtze River in summer, 2005. The fish composition, abundance, and size structure were examined along a biomass gradient of the most dominant submerged macrophyte Potamogeton maackianus. A total of 1124 individuals from 13 fish species were caught during the study period. According to the abundance and occurrence, sharpbelly Hemiculter leucisculus and redfin culter Cultrichthys erythropterus were identified as the two dominant small pelagic fishes in the lake. There existed domelike relationships between the fish species richness and Shannon diversity index and the submerged macrophyte biomass within its observed range. For the two dominant small fishes, their abundance was significantly positively correlated with macrophyte biomass, and the average sizes of the individuals of H. leucisculus and C. erythropterus were larger in unvegetated habitat but smaller in heavily vegetated habitats, indicating that the young individuals tended to live in dense submerged macrophyte covers. Other two habitat factors, i.e., water depth and distance to shore, had little effects on the spatial distribution of the two fish species. It was inferred that P. maackianus cover should be the important refuge habitat for the two dominant smallsized fishes in Niushan Lake, and it would be necessary to protect or restore the submerged macrophyte covers including P. maackianus.

Community structure of phycophyta and evaluation of water quality in Sichuan section of Jialing River.

MA Yong-hong, ZENG Yu, REN Li-ping, ZHOU Cai-quan

2012, 23(09):  2573-2579. 

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In order to understand the characteristics of the phycophyta community structure and water quality in Sichuan section of Jialing River, water samples were collected from 12 sites along the section in dry season (January) and rainy season (September), with the phycophyta species composition, Shannon diversity index (H′'), Pielou evenness index (E), and Margalef richness index (d) analyzed. A total of 171 phycophyta species (including variety) were collected, belonging to 8 phyla, 42 families, and 95 genera, among which, Bacillariophyta, Chlorophyta, and Cyanophyta were the dominant groups. In dry season, the mean cell density of the phycophyta was 14.71×10⁴ind·L^-1, being the highest at sites JX (28.33.4×10⁴ ind·L^-1) and HYZ (25.40×10⁴ ind·L^-1), and diatom species had a higher richness than the others. In rainy season, the mean cell density was only 10.78×10⁴ ind·L^-1, being the lowest (3.31×10⁴ ind·L^-1) at site QJ, and the species richness of chlorophyta and cyanobateria had somewhat increase. In the whole section, the mean d, H′, and E of the phycophyta were 2.35, 1.60, and 0.31 in dry season, and 2.57, 2.09, and 0.39 in rainy season, respectively. Our results indicated that there were significant differences in the spatiotemporal distribution patterns of the community structure, cell density, diversity index, and evenness index of phycophyta in Sichuan section of Jialing River. The water quality of this section was overall belonged to mesosaprobic, being better at sites JX and SX (belonged to oligosaprobic or βmesosaprobic), but worse at sites CX, HYZ, XZ, and QJ (belonged to αmesosaprobic).

Bioremediation of river water quality by consecutively adjustable submerged vegetation net. 

WU Hai-long1,2, HUO Yuan-zi1,2, SHAO Liu1,2, WANG Yang-yang1,2, YU Ke-feng1,2, HE Pei-min1,2, WEN Wen-ke1,2

2012, 23(09):  2580-2586. 

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A series of consecutively adjustable submerged vegetation nets were constructed in a polluted shallow river with a length of about 200 m and nearby the water resource protection area of Taihu Lake in East China, forming an aquatic vegetation consisted of submerged plant species Cabomba caroliniana, Vallisneria natans, Elodea nuttallii, Hydrilla verticillata, and Potamogeton crispus. The water quality indices including total nitrogen (TN), ammonium nitrogen (NH₄⁺-N), nitrite nitrogen (NO₂^--N), nitrate nitrogen (NO^₃--N), total phosphorus (TP), and phosphate (PO₄^3--P) were monitored, and the bioremediation effect of the vegetation nets was evaluated. After setting up the vegetation nets, the Secchi depth (SD) of the river changed from 0.5 m to 1.7-1.8 m, and the TN and TP concentrations 15 and 20 days after the nets constructed decreased by 35.6% and 66.3%, and 29.4% and 63.2%, respectively. After five months, the concentrations of NH₄⁺-N, NO₂^--N, NO₃^--N, TN, TP, and PO₄^3--P decreased by 92.4%, 76.8%, 72.7%, 739%, 905%, and 92.0%, respectively. This study showed that consecutively adjustable submerged vegetation net could be a potential approach for treating polluted river waters, particularly for the bioremediation of polluted small landscape shallow water bodies.

Sediment heavy metals quality criteria for fresh waters based on biological effect database approach.

ZHANG Ting, ZHONG Wen-jue, ZENG Yi, ZHU Ling-yan

2012, 23(09):  2587-2594. 

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Heavy metals are the important pollutants in sediments, which can cause serious damage to benthonic organisms and aquatic ecology, while biological effect database approach (BEDA) is a widely used method for assessing sediment quality in developed countries or regions. This paper introduced the concrete steps of this approach, and built the sediment quality criteria of five heavy metals (Cu, Zn, Cd, Pb, and Ni) for  fresh waters. The comparability, reliability, and predictability of the criteria were also tested. It was shown that the threshold effect level (TEL) of the Cd, Ni, Pb, Zn, and Cu was 3.0, 31.4, 47.3, 74.9, and 45.5 mg·kg^-1 dry mass, and the probable effect level (PEL) of the Cd, Ni, Pb, Zn, and Cu was 19, 76.9, 204.1, 403.6, and 181.1 mg·kg^-1 dry mass basis, respectively. Except for Zn, the TEL and PEL for the Cu, Cd, Pb, and Ni were consistent with the definitional biological effect of the heavy metals, being accordance with the demands of sediment quality criteria for protecting benthic organisms and having high reliability, and thus, could be used as the proposed sediment quality criteria for  fresh waters in China.

Effects of Cd²⁺ on antioxidant system in hepatopancreas of Procambarus clarkii.

TAN Shu-hua, YUAN Zhi-dong, LIU Yu-fang, YANG Ya-nan

2012, 23(09):  2595-2601. 

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By the method of toxicity bioassay, this paper studied the effects of different concentration (1.72, 3.44, 6.89, 13.77, and 27.55 mg·L^-1) Cd²⁺ on the activities of antioxidative enzymes (SOD, CAT, and GSH-PX) and the antioxidation substances (GSH and Vc) in hepatopancreas of freshwater crayfish Procambarus clarkii. The results showed that the SOD activity was induced at the lowest concentration (1.72 mg·L^-1) Cd²⁺ but inhibited at all other test concentrations Cd²⁺, and the inhibition degree was positively correlated with the Cd²⁺ concentration. Under all test concentrations Cd²⁺, the CAT activity decreased after an initial increase, with a peak 3 days after exposure. The CAT activity was sensitive to lower concentrations (≤6.89 mg·L^-1) Cd²⁺, but had no significant difference at higher concentrations (>6.89 mg·L^-1) Cd²⁺. When the Cd²⁺concentration was ≤6.89 mg·L^-1, the GSHPX activity showed a trend of increasing first and then decreased; when the Cd²⁺ concentration was 13.77 or 27.55 mg·L^-1, the GSH-PX activity was depressed during the first day of exposure. When the Cd²⁺ concentration was ≤6.89 mg·L^-1, the GSH content reached the highest value on the first day of exposure, and maintained at a higher level than the control group. However, when the Cd²⁺ concentration was ≥13.77 mg·L^-1, the GSH content had no significant difference with the control. The Vc content was very sensitive to all test concentrations Cd²⁺. It decreased significantly on the first day of exposure, with the decrement positively correlated to Cd²⁺concentration, but showed a recovering trend with exposure time. The results indicated that both the antioxidative enzymes and the antioxidation substances in the hepatopancreas of P. clarkii played important roles in coping with Cd²⁺ stress, and in most cases, showed a time and dosedependent relationship with Cd²⁺ concentration. The GSH-PX activity and Vc content of P. clarkii could be used as the potential bioindicators in evaluating Cd²⁺ contamination.

Facilitation and limitation on plant recruitment by animal dispersers.

LI Ning, WANG Zheng, PAN Yang, BAI Bing, LU Chang-hu

2012, 23(09):  2602-2608. 

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In plant-animal network, seed dispersers play both facilitation and limitation roles on plant recruitment. This paper summarized the effects of the dispersers foraging and spatial utilization behaviors on plant recruitment at population level, and analyzed the dispersal effectiveness of the dispersers in the facilitation and limitation on plant recruitment at community level. Different food-treating behaviors of animal dispersers have decisive role on the fate of seeds, and the seed fate has interspecific difference. The role of plants in animal dietary also determines the plants recruitment fate. When preferred by animal dispersers, the seeds can escape the impact of forest fragmentation. The spatial behavior of the dispersers can cause seed fate change. Whether the dispersers’ movement distance can escape the distance limitation of conspecific adults determines the seed recruitment. The spatial concordance between the animal suitable habitat and the plant recruitment habitat directly affects the dispersal efficiency. The non-redundancy of effective dispersers not only leads the seed dispersal network to be more stable, but also benefits plant recruitment. Ineffective dispersal of the dispersers limits plant recruitment, but supplies suitable chance for other plants olonization. Future researches should incorporate the animal behavior in plant recruitment researches, and to explore the roles of animal dispersers in vegetation recovery from the aspect of ecosystem service should be the focus in the study of restoration ecology.

Applications of archaeal membrane lipids in investigating archaeal community composition and its responses to environmental factors.

CAO Peng1,2, SHEN Ju-pei1, HE Ji-zheng1

2012, 23(09):  2609-2616. 

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Archaea, as the third life form distinct from bacteria and eukaryota, widely distribute in various kinds of habitats, and play important roles in the biogeochemical cycles of carbon and nitrogen and in ecosystem functioning. As the biomarker of archaea, archaeal membrane lipids can be used to investigate the archaeal community composition and its responses to the environment. This paper introduced the structural characteristics of archaeal membrane lipids and the differences in the membrane lipids composition among different archaeal communities, and discussed the feasibility of using archeal membrane lipids in depicting archaeal community composition. The abundance of archaeal membrane lipids in the environment could be used to characterize the biomass of archaea, and the related results could complement and ascertain each other with the DNAbased biomolecular approaches on the accuracy, analysis efficiency, and cost. Based on the description of the difficulties and importance of using archaeal membrane lipids to analyze the composition and abundance of archaeal communities, and by linking to the environmental factors such as temperature and pH that affected the archaeal community composition, the relationships between archaea and their habitats were further expatiated, and the evolution process of archaeal communities and its application prospects in the studies of geochemistry and geological events were analyzed.

Applications of diatom in river health assessment: A review.

LI Guo-chen1,2, LIU Lu-san1, WANG Xing1, LI Li1

2012, 23(09):  2617-2624. 

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Diatom, as a kind of autotrophic photosynthetic eukaryotic algae, is an important primary producer in aquatic ecosystem, and can reflect the average status of water environment. As the bio-indicators of the environment, Nitzschia communis, Navicula minuscula, and Gomphonema parvulum can indicate the eutrophication of waters, whereas Gomphonema angustum, Epithemia adnata, and Diatoma moniliformis can indicate the oligotrophication of waters. Cyclotella bodanica, Neidium affine, and Eunotia exigua are all the eosinophilic species that can indicate waters acidity, Aminutissimum nodusa can indicate water’s Cu concentration, and Synedra ulna can indicate the Zn concentration in waters. Some other diatoms can also indicate water’s contamination. This paper reviewed the research progress on the applications of diatom and diatom indices in river health assessment, pointed out the related existing problems, and put forward some future research directions, e.g., further perfect the classification and identification of diatoms, broadly carry out the researches of diatom indices upon different areas and conditions, pay more attention to the screening of diatom biointegrality indices, and establish a benchmark which suits for the assessment of water quality.