Table of Content

08 December 2010, Volume 29 Issue 12

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Articles

Variations of Quercus variabilis leaf traits in relation to climatic factors at regional scale.

2010, 29(12):  2309-2316. 

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Leaf is the plant organ which is sensitive to the environmental changes in the process of evolution, and may exhibit phenotypic plasticity as a response to climate change. Quercus variabilis (Oriental oak) is one of the most widely distributed tree species in Asia, stretching from temperate to subtropical zone. With the leaf samples collected from 25 natural Q. variabilis populations across east-central China, this paper quantitatively investigated the leaf physiognomy, including petiole length, leaf length, leaf width, leaf area, dry weight, specific leaf area (SLA), and leaf index (ratio of leaf length to width), and correlated it with geographical and climatic factors at regional scale. The results showed that the leaf traits of Q. variabilis varied significantly within and among the populations. The leaf area and leaf width were significantly positively correlated with latitude, and the leaf width was significantly negatively correlated with mean annual temperature, which suggested that leaf area and leaf width were more sensitive to climatic variables, compared with other leaf traits, and temperature might have effects on the variation pattern of leaf size at regional scale. This study provided an understanding how Q. variabilis adapts to the changes in climate at regional scale in the context of global change.

Responses of woody plants phenology to air temperature in Northeast China in 1980-2005.

2010, 29(12):  2317-2326. 

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Based on 25 years  phenological observation data, the spatiotemporal characteristics of woody plants phenology in Northeast China were analyzed, and the effects of regional climate warming on the plant phenology were explored. In 1980-2005, the initial stage of leaf-developing of the woody plants in Northeast China advanced 0.23 d·a^-1, but that of leaf-yellowing postponed 0.19 d·a^-1. Consequently, the growth season prolonged 0.30 d·a^-1. Spatially, the phenological characteristics of five widespread woody plants (Salix matsudana, Prunus armeniaca, Populus simonii, Ulmus pumila, and Syringa oblata) were significantly different, i.e., with an average increase of 1° of latitude, the initial stage of leaf-developing tended to be postponed 3 d, that of leaf-yellowing advanced 1.35 d, and the growth season tended to be shortened 4.41 d. The initial stage of leaf-developing of these plants was significantly negatively correlated with the air temperature in February, March, and April (P<0.05), and the air temperature in April had the greatest effect, with the initial stage of leaf-developing advanced 2.35 d·℃^-1 on average. On the contrary, the air temperature in February had the least effect, with the average tendency being 1.18 d·℃^-1.

Effects of nitrogen and phosphorus addition on leaf litter decomposition in a suburban slash pine plantation in red soil region of China.

2010, 29(12):  2327-2333. 

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Litter decomposition in urban forests may be influenced by the elevated nitrogen (N) deposition and phosphorus (P) enrichment during rapid urbanization. In this paper, nylon litter bag method was used to simulated  the effects of  N deposition (10 g N·m^-2·a^-1, ［N］), P enrichment (2.5 g P·m^-2·a^-1, ［P］), and their combination (10 g N·m^-2·a^-1+2.5 g P·m^-2·a^-1, ［N+P］) on the decomposition rate, nutrient contents, and nutrient stoichiometric ratios of the litters in a Pinus elliottii Engelm. plantation in the suburb of Nanchang City, China. Compared with CK (without N and P addition), treatments ［N］, ［P］, and ［N+P］ increased the decomposition rate of the litters at early stage (0-180 d), but decreased it at the middle (180-360 d) and late (360-540 d) stages. By the end of the experiment (540 d), the decomposition rate in treatments ［N］, ［P］, and CK had no significant difference, but was higher than that in treatment ［N+P］ (P<0.05). Treatment ［N］ increased the litter N content, with the N immobilized at early stage but released later. Treatment ［P］ increased the litter P content, resulting in an increasing enrichment of P. Treatment［N+P］ increased the litter N and P contents, which were immobilized at early stage but released later. In all treatments, the litter C content showed a releasing trend. The relationships between the decomposition rate and the stoichiometric ratios of C, N, and P depended on decomposition stage. Our results suggested that the additive effect of elevated N deposition and P enrichment induced by urbanization could limit litter decomposition in urban forests.

Dynamics of annual litter mass and nutrient return of different age Masson pine plantations.

2010, 29(12):  2334-2340. 

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By using chronosequence method, an investigation was conducted on the annual litter mass and nutrient return of Masson pine plantations at different ages. The litter mass of the plantations varied obviously with season, and affected by species characteristics and climate. There was a lag effect of climate on litter mass. The nutrient concentrations in each litter component had an obvious seasonal variation, with the difference reached more than one-fold. With increasing stand age, the K return through litterfall decreased, while the other nutrients return showed ‘V’ shape. The stand at age 51 had higher nutrient use efficiency. Litterfall played an important role in maintaining stand fertility. Litter output, especially for fallen needles, would cut the key link of biogeochemical cycle, aggravate the nutrient deficiency of soil, and lead to the decrease of stand productivity. Therefore, in the management of Masson pine plantation, litter output should be reduced as possible to maintain the long-term productivity of the site.

Water use efficiency of halophytes in Ebinur Lake Wetland Nature Reserve of Xinjiang.

2010, 29(12):  2341-2346. 

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This paper measured the leaf δ¹³C value and main physiological indices of three types of halophytes in Ebinur Lake Wetland Nature Reserve of Xinjiang. These three types of halophytes were all C₃ plants, and had no significant differences in the δ¹³C value and water use efficiency. Among the three types of halophytes, euhalophytes had the greatest capacity to suck and store water, while recretohalophytes had the greatest endurance against salt stress. Water shortage exerted negative effects on the leaf δ¹³C value, contents of protein, praline, soluble sugars, and nitrate, and activity of nitrate reductase. The salt condition in the Reserve did not cause stress on the recretohalophytes and pseudohalophytes, but had negative effects on the euhalophytes in their existence.

Heteromorphic leaf structural characteristics and their correlations with diameter at breast height of Populus euphratica. 

2010, 29(12):  2347-2352. 

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Five indices of leaf structural traits, i.e., thickness (TH), area (AR), specific leaf area (SLA), dry weight (DW), and dry matter content (DMC), of five plant types of Populus euphratica were measured, and the relationships between the leaf structural traits and diameter breast height (DBH) of P. euphratica as well as the correlations among the five indices were analyzed. The results showed that the leaf AR, TH, and DW were very significantly positively correlated with DBH (P<0.01), the DMC was significantly positively correlated with DBH (P<0.05), while the SLA was very significantly negatively correlated with DBH (P<0.01). It was suggested that along with the plant growth, the leaf AR, TH, DW, and DMC increased gradually, while the SLA decreased. The correlations among the indices of the leaf structural characteristics showed that the leaf AR, TH, DW, and DMC of P. euphratica were significantly positively correlated each other, while the SLA was significantly negatively correlated with any of the four indices.

Distribution characteristics of stable carbon isotope of Schisandra chinensis(Turcz.) Baill. in relation to environmental factors.

2010, 29(12):  2353-2357. 

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By using stable carbon isotope analysis technique, the distribution characteristics of stable carbon isotope composition (δ¹³C values) in the fruit, peduncle, and leaf of Schisandra chinensis from Liaoning Province were studied, and the correlations between fruit δ¹³C value and environmental
 factors were analyzed. It was found that the organ-specific difference in δ¹³C values was highly significant (P<0.01), with the sequence of fruit (-26.356‰±0.377‰) > peduncle (-26.620‰±0.342‰) > leaf (-28.327‰±0.370‰), which suggested that there was a distinct post-photosynthetic δ¹³C fractionation between photosynthetic and non-photosynthetic organs. During the growth period of S. chinensis, the δ¹³C value of fruit remained relatively stable, that of peduncle decreased, and that of leaf decreased significantly (P<0.001). The δ¹³C value of fruit had a slight increase with
increasing latitude, and had an insignificant negative relationship with atmospheric CO₂. The variation of fruit δ¹³C value with latitude could be used
 as an indicator to distinguish different origins of S. chinensis.

Characteristics of vegetation composition and copper contents of dominant plant species on Mayang copper mine: Implication for screening metallophytes.

2010, 29(12):  2358-2364. 

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In order to screen potential metallophytes, an investigation of soil and vegetation was conducted at the natural copper-outcropping ores, wasted mining pitheads, and the soils scattered or covered with copper ore and slag in Mayang copper mine. Chemical analysis showed that the concentrations of soil total Cu and DTPA-extractable Cu were 3250 and 393 mg·kg^-1, respectively, which were far higher than the concentrations of soil Zn, Pb, and Cd. Fifty-four plant species belonging to 47 genera and 28 families were found, and half of them fall into 4 families of Compasitae (9 species), Poaceae (7 species), Legumeceae (6 species), and Polygonaceae (5 species). Furthermore, Rumex acetosa, Polygoum capitatum, and Ficus tikoua were identified as the three distinctly dominant plant species in the habitats, and accumulated 120, 203, and 133 mg·kg^-1 of Cu in their shoots, respectively, with the bio-enrichment factor ranged from 0.01 to 0.1. These results suggested that high concentration of soil Cu might be the main factor limiting the plant natural colonization on Mayang copper mine, and the three dominant plants might act as Cu exudators or low Cu accumulators to adapt to soil Cu exposure, being able to be used for the phytoremediation of heavy metals-polluted soils.

Root growth patterns of four coastal shelter forest tree species in response to salt stress.

2010, 29(12):  2365-2372. 

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Taking 8-year old subtropical coastal shelter forest tree species Ligustrum lucidum, Fraxinus pennsylvanica, Casuarinn equiestifolia, and Taxodium mucronatum as study objects, this paper investigated their root growth characteristics with relation to soil salt content, and compared the root biomass pattern, functional root distribution percentage, specific root length, and root length density among the four tree species. The results indicated that soil salt content was the most important factor limiting the vertical root growth, and the latter had a negative relationship with horizontal root growth. The test tree species had different salt-tolerance characters, resulting in the difference of their functional root biomass pattern. The smaller the lateral root diameter, the larger the lateral root water- and nutrient absorbing capacity; the larger the lateral root diameter, the stronger the capacity of the lateral roots in anchoring and supporting plant. For T. mucronatum, its salt threshold was > 0.45%, and its vertical root distribution was at the soil depth of 0-95 cm, which resulted in a good capability to resist typhoon and soil salt stress. For C. equiestifolia and F. pennsylvanica, their tap root length was 25 cm and 29 cm, and their anchor root occupied 87.2% and 56.3%, respectively. These two tree species had definite capability to resist typhoon, and could be planted on the coastal tidal flat with salt content < 0.36%. For L. lucidum, its salt threshold was < 0.21 %, tap root length was 20 cm, and anchor root occupied 51.0%, suguesting that it was not adaptable to plant in the coastal areas with high salt content and typhoon.

Distribution of potential planting area for Panax ginsen in eastern Liaoning Province.

2010, 29(12):  2373-2378. 

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The forest tenure reform carried out in 2003 has made the farmers become the main entity of forest management and play a major role in forest management. On the basis of the survey on the farmers in the mountain area of eastern Liaoning Province, this paper analyzed the farmers’ choices to the environmental conditions of the regions for planting Panax ginseng, and, according to the choices, studied the distribution of the potential planting areas of P. ginseng under forests by using ArcGIS, aimed to supply theoretical supports for forest management plan under forest tenure reform. The results showed that the environmental conditions chosen by the framers were consistent with the physiological demands of P. ginseng. The planting areas of P. ginseng were always located in the regions under broad-leaved forests or conifer broadleaved mixed forests, at north slope, the gradient between 10° and 25°, and the elevation height between 300 m and 1000 m, with >500 m as the priority regions. Xinbin, Qingyuan and Huanren counties were the main potential planting areas for P. Ginseng in eastern Liaoning Province.

Spatial structure of Pinus tabulaeformis f. shekannesis community on Loess Plateau.

2010, 29(12):  2379-2383. 

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Three spatial structure indices of stand, i.e., neighborhood pattern, neighborhood comparison, and mingling, were used to analyze the spatial structure of Pinus tabulaeformis f. shekannesis  community on Loess Plateau. The tree species composition in the stand was 7:2:1 for Pinus tabulaeformis f. shekannesis , Quercus liaotungensis, and other tree species. The stand density was 1325 trees·hm², and Pinus tabulaeformis f. shekannesis  population was on an obvious dominant position. The average mingling in Pinus tabulaeformis f. shekannesis stand was 0.33, showing that the stand was at the transition period of weak mixed status to moderate status, and the isolation degree of the stand was moderate. The average neighborhood pattern of the stand was 0.57, indicating that the stand was assembly distributed. The average neighborhood comparison of DBH and tree height in the stand was 0.52 and 0.53, respectively, and the distribution of neighborhood comparison was quite even. The average neighborhood comparison of DBH and tree height was in great consistent advantage in reflecting tree growth.

Changes of plant leaf area and its relationships with soil factors in the process of grassland desertification.

2010, 29(12):  2384-2389. 

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This paper studied the changes of the main plant species leaf area and their relationships with soil factors in the process of grassland desertification under natural conditions. With the intensification of desertification, the specific leaf area (SLA) of Leymus chinensis and Cleistogenes squarrosa decreased significantly (P<0.01) at early desertification stage (gradient Ⅰ), and that of Potentilla tanacetifolia and Agrostis cristatum decreased significantly (P<0.05) at late desertification stage (gradient Ⅲ). The SLA of Carex duriuscula had no significant change (P<0.05), but that of Artemisia frigida and Melilotoides ruthenica decreased significantly from mid- and late desertification stage (P<0.05) and from early desertification stage (P<0.01), respectively. The leaf area index (LAI) of M. ruthenica increased significantly (P<0.01), while that of the others decreased significantly (P<0.01). The LAI of L. chinensis and C. squarrosa was significantly positively correlated with soil clay, C, N, and moisture contents (P<0.01), and significantly negatively correlated with soil C/N ratio (P<0.01); while the correlations of the LAI of A. frigida and M. ruthenica with the soil factors were quite opposite (P<0.05) from those for L. chinensis and C. squarrosa. The linear fitting between the LAI of C. squarrosa and soil C/N was the highest (R²=1), followed by that between the LAI of L. chinensis and soil moisture content (R²=0.992), and between the LAI of M. ruthenica and soil C/N (R²=0.268). Our results suggested that in the process of grassland desertification, soil C/N was the key factor affecting the leaf area of common species (P<0.5), with the order of the effect being C. squarrosa > L. chinensis > A. frigida > M. ruthenica.

Intraclonal resources sharing of stolon herb Fragaria vesca in response to heterogeneous habitat.

2010, 29(12):  2390-2394. 

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The essential resources for plant growth could be negatively correlated with each other within the patches. In this paper, the clonal fragments of stolon herb Fragaria vesca from two altitudes (1800 m and 3900 m above sea level) were subjected to reciprocal patchiness of light and soil nutrient resources. The fitness-related traits (biomass and number of ramets) and the plasticity of the species in root/shoot ratio and leaf area were investigated. Our results demonstrated that the biomass and number of ramets in proximal clonal part, distal clonal part, and whole clonal fragment from the two altitudes had a significant increase in the resources heterogeneity treatments (Ⅲ and Ⅳ), compared with in the resources homogeneity treatments (Ⅰand Ⅱ). The proximal ramets in the treatment with low light and high nutrient allocated more biomass to the below-ground as connected to the distal ramets grown in high light and low nutrient than as connected to the distal ramets grown in low light and high nutrient. The proximal ramets in the treatment with high light and low nutrient allocated more biomass to the above-ground as connected to the distal ramets grown in low light and high nutrient than as connected to the distal ramets grown in high light and low nutrient. The similar allocation patterns were observed in the distal ramets. The proximall ramets grown in high light and low nutrient presented larger leaf area as connected to the distal ramets grown in low light and high nutrient than as connected to the distal ramets grown in high light and low nutrient. The similar allocation patterns were observed in the distal ramets. These results suggested that there existed a reciprocal translocation of assimilates and nutrients between the interconnected ramets, while root/shoot ratio and leaf area were plastic, which led to an environmentally induced specialization for uptake of locally abundant resources. Therefore, sharing intraclonal resources was very significant for the survival and growth of clonal plants in heterogeneous habitat.

Diurnal rhythms of Chinese bulbul (Pycnonotus sinensis) body temperature, body mass, and energy metabolism.

2010, 29(12):  2395-2400. 

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The diurnal variation of physiological rhythm is an important adaptation mechanism of animals to the environment. In order to understand the diurnal variation of the physiological rhythm of Chinese bulbul (Pycnonotus sinensis), the adult Chinese bulbuls in Wenzhou of Zhejiang Province were live-trapped by mist net in June 2008, and their diurnal body temperature (T_b), body mass (M_b), and basal metabolic rate (BMR) were measured by inserting a digital thermometer (Beijing Normal University Instruments Co., model TH-212) into cloaca, weighed with a Mettler-Toledo balance (model PL3001-S), and determined with a closed circuit respirometer at controlled temperature (±0.5 ℃), respectively. The T_b and M_b of the adult Chinese bulbuls had  obvious diurnal variation, being significantly lower at 4:00 than at 18:00, but the amplitude of variation was remarkably higher at night time than at day time. The BMR was significantly lower at night time than at day time. The diurnal variation of the rhythms of T_b, M_b, and energy metabolism reflected an inner physiological energetic balance of Chinese bulbul, and played important roles in the diurnal acclimatization of the bird.

Selection mechanisms of Calliptamus italicus on four different host plants.

2010, 29(12):  2401-2407. 

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Calliptamus italicus is a predominant pest on Xinjiang grassland. In this paper, GS-MS and olfactometer were applied to study the selection mechanisms of C. italicus on its host plants Artemisia frigida, Seriphidium santolinum, Medicago falccata, and Melilotus officinali. The results showed that terpenoid and alcoholic compounds were the main volatile substances in the four host plants. The terpenoid content in A. frigida, S. santolinum, M. falccata, and M. officinal was 51.76%, 9.00%, 20.52%, and 19.46%, and the alcoholic compounds content was 1.74%, 20.26%, 16.80% and 33.48%, respectively. Different host plants had different attraction effect on C. italicus, with the attraction rate of A. frigida, S. santolinum, M. falccata, and M. officinali being 56.00%, 36.12%, 30.47%, and 10.00%, respectively. Statistical analysis indicated that the host plant biomass eaten by C. italicus was negatively correlated with the flavone content in host plants (r=-0.601). C. italicus preferred A. frigida, in which, the flavone content was the lowest, and repelled M. officinali, in which, the flavone content was the highest. It was suggested that the terpenoid in host plants had obvious attraction effect to C. italicus, while the alcoholic compounds and flavone contents had obvious repellent effect.

Foraging habitat selection of wild boar in Laotudingzi Natural Reserve of Liaoning Province in winter.

2010, 29(12):  2408-2413. 

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To understand the characteristics of foraging habitat selection of wild boar (Sus scrofa) in Laotudingzi Nature Reserve of Liaoning Province in winter, an investigation was made from November 2009 to March 2010, with 14 ecological factors, including vegetation type, altitude, slope position, and aspect, etc., at each sampling site examined by trace test and principal component analysis. The S. scrofa preferred the gentle sunny slope with more food, low human disturbance, high sheltering, near water source, and foraged at the places with no or very few fallen trees, stumps, and stones. The five most important factors affecting the foraging habitat selection of S. scrofa in winter were human disturbance, water source, food, sheltering, and shrub, and their contribution rates were 19.45%, 14.04%, 13.03%, 12.19%, and 10.37%, respectively.

Occurrence and damage characteristics of gall wasp (Quadrastichus erythrinae) on five Erythrina species.

2010, 29(12):  2414-2418. 

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This paper investigated the occurrence and damage characteristics of erythrina gall wasp (Quadrastichus erythrinae) on five Erythrina species (E. variegate var. orientalis, E. variegate var. orientalis cv. golden vein, E. corallodendron, E. variegate, and E. cristagalli) in Wutong Mountain Forest Farm, Binzhou Crossroads of Xinzhou Futian District, and Bijia Hill Park in Shenzhen. Among the five Erythrina species, E. variegate var. orientalis and E. variegate var. orientalis cv. golden vein were seriously damaged by Q. erythrinae, E. corallodendron was damaged slightly, while native species E. variegate and E. cristagalli were not damaged. At different positions of E. variegate var. orientalis canopy, the leaves at east position had a higher percentage of damage grade III, and their injured index was significantly different from that of the leaves at mid position. In the canopies of E. variegate var. orientalis and E. variegate var. orientalis cv. golden vein, Q. erythrinae preferred the upper leaves.

Isolation of Bacillus subtilis ZD 02 and its application in intensive culture of Litopenaeus vannamei.

2010, 29(12):  2419-2424. 

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Six strains of Bacillus spp. were isolated and screened from the environment of aquaculture, and their protease and amylase activities were determined. Based on the determination of the activities of the two digestive enzymes, the strain ZD 02 was selected as test object, and its heat-stability was evaluated. The strain ZD 02 identified as Bacillus subtilis had higher tolerance to high temperature. Its survival rate at 90 ℃ for 10 min, 95 ℃ for 5 min, and 100 ℃ for 5 min was 93%, 93%, and 82%, respectively. At 95 ℃ and 100 ℃ for 2 min, the survival rate of the strain was less affected. Moreover, the survival rate of ZD 02 remained 94% at 102℃after adding other feed materials and manufactured into grains. Then, the ZD 02 was cultured through fermentation, and applied to the intensive culture of Litopenaeus vannamei. Three experimental groups were installed. In control group, only basal diet provided by Guangdong Evergreen Group Co., Ltd. was added; in group A, basal diet amended with 0.3% B. subtilis was supplied; in group B, 0.3% B. subtilis was applied on the basis of unchanged cost of diet description. The results showed that the survival rate of L. vannamei in experimental groups A and B was higher than that in control group (P<0.05). Compared with the control, the output of groups A and B increased by 43.0% and 36.7% (P<0.05), production value increased by 35.4% and 21.0% (P<0.05), feed conversion ratio decreased by 9.9% and 8.7%, (P<0.05), expenses including regulation substances of aquaculture, medicines, and energy expending were economized by 21.3% and 22.3%, respectively (P<0.05). No significant differences were observed in the survival rate, output, production value, feed conversion ratio, and such expenses as medicines and energy expending between groups A and B (P>0.05). The results demonstrated that the reasonable application of B. subtilis in aquaculture could promote the output and production value of L. vannamei.

Morphological differences of three Plagiognathops microlepis populations.

2010, 29(12):  2425-2430. 

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By using traditional morphological data and modern truss network data, this paper analyzed the morphological characteristics of three Plagiognathops microlepis populations (Longwo Lake population, Liangzi Lake population, and Huaihe Rive population), and approached the relative relationships among the populations. One-way analysis of variance (ANOVA) indicated that there were no significant differences (P>0.05) in 8 countable characters among the populations. Cluster analysis demonstrated that Liangzi Lake population was grouped with Longwo Lake population first, and then clustered with Huaihe Rive population. In discriminant analysis, 7 parameters were selected from 28 measured parameters to establish discriminant functions of the populations. Discriminant accuracy was 93.55%-100%, and synthetic discriminant accuracy was 96.81%. The three populations could be separated each other by discriminant functions, with highly significant differences (P<0.01). Three principal components with accumulative variance percentage 82.99% were summarized in principal component analysis. The principal components 1, 2, and 3 reflected the morphological variations of trunk, head, and caudal peduncle, with the variance percentage being 52.83%, 22.22% and 7.94%, respectively. The 2D-plot of principal components 1 and 2 showed that the three populations could be clearly separated each other, though there was a small overlap between Longwo Lake population and Liangzi Lake population. The coefficient of morphological dissimilarity was less than 1.28, suggesting that the morphological differences among the three populations were still within the level of subspecies.

Characteristics of soil surface freezing and thawing in Hebei Province in response to climate change.

2010, 29(12):  2431-2437. 

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Based on the 1981-2006 phenological and meteorological data of Hebei Province, the spatiotemporal characteristics of soil surface freezing and thawing in the province in response to climate change were analyzed. An obvious regional difference was observed in the phenological phases of soil surface freezing and thawing. In the southeast coastal plain area of the province, the beginning phase of freezing was later, thawing phase was earlier, and frozen phase was shorter; while in the north and northwest mountain areas, they were in contrary. Compared with the past years average phenological dates, the beginning phase of freezing in the province before the early 1990s was earlier, thawing phase was later, and frozen phase was longer, but after the late 1990s, the beginning phase of freezing in most areas of Hebei Province delayed, beginning phase of thawing advanced, and frozen phase shortened. Air temperature had significant effects on the phenological phases of soil surface freezing and thawing in the areas with lower terrain. In case that the air temperature in autumn was increased by 1 ℃, the beginning phase of freezing would be delayed 3.8 days. If the temperature from February to March increased 1 ℃, the beginning phase of thawing would be 5.3 days earlier; if the air temperature from October to next March increased 1 ℃, the frozen phase would be shortened by 12.6 days.

Soil salinity and Achnatherum splendens distribution.

2010, 29(12):  2438-2443. 

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Achnatherum splendens distributes in the arid and semiarid areas of Eurasia, and has important ecological functions and multifold economic values. In this paper, the soil electric conductivity at 9 sites with the distribution of A. splendens and its adjacent zonal communities in Inner Mongolia and Qinghai was determined, aimed to reveal the effects of soil salinity on the spatial distribution of A. splendens community at habitat and regional scales, and to analyze the vegetation property of A. splendens community based on soil salinity characteristics. At regional scale, no direct correlation was observed between soil salinity and the distribution of A. splendens community. A. splendens could form community both on salt-rich and on salt-poor soils, being a saline-resistant plant with wide ecological amplitude. However, at habitat scale, A. splendens community was always found on the soil with higher salinity, compared with adjacent zonal Stipa community, implying that Stipa community was less saline-resistant. In fact, A. splendens  had a wide distribution in high salinity soil environment in Qinghai, implying its azonal vegetation characteristic. The distribution of A. splendens  community had no direct correlation with precipitation.

Land use patterns in Northeast China based on landform characteristics.

2010, 29(12):  2444-2451. 

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Supported by Landsat TM7 remote sensing images, SRTM DEM and soil maps, and using ArcGIS and ENVI software, hydrological analysis, spatial analysis and supervised classification models, the basic landform types and land use patterns in Northeast China were quantitatively analyzed. The total area across the east of Daxing’an Mountain ridge line and the north of Qilaotu Mountain ridge line was 1.0727×10⁶ km², and the basic landform types were mountain, hill, platform, and plain, occupying 21.2%, 35.6%, 16.1% and 27.1%, respectively. The locations, border lines, and inter-relationships of Songnen plain, Songliao plain, and Keerqin plain were clarified, and the traditional methods for qualitative determining border lines were improved. The land use patterns included forestland, grassland, cropland, sandy land, saline land, wetland, water area, and construction land, occupying 41.1%, 14.0%, 33.8%, 0.9%, 1.5%, 4.7%, 1.4%, and 2.8%, respectively. Some issues related to land use and landform were discussed.

Evaluation of typical planting modes in western Liaoning Province based on grey relational analysis.

2010, 29(12):  2452-2456. 

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Evaluation of different planting modes is one of the hot spots in today’s cropping system research. In terms of western Liaoning Province’s natural characteristics and diverse planting modes, this paper evaluated six typical planting modes adopted in this region, based on experimental studies and expert questionnaire surveys and by the method of gray relational analysis. The results showed that whether under average or variable correlation of ecological indices or economic indices, the planting mode of Nanguo pear with pumpkin was most closely related to reforence pattern, with the correlation being 0.867, 0.920, and 0.841, followed by the planting mode of Nanguo pear with peanut, the correlation being 0.848, 0.901, and 0.821, indicating that the planting modes of Nanguo pear with pumpkin or peanut had the best ecological and economic benefits, being the optimal planting modes in western Liaoning Province. The planting mode of corn intercropped with soybean was less related to referential pattern, with the ecological and economic benefits being comparatively worse. This study would provide a theoretical support in protecting the ecological environment, developing the multi-dimensional agriculture, and enhancing the sustainable development of regional society and economy in western Liaoning Province.

Effects of grazing on the community structure of soil bacteria in Stipa baicalensis steppe.

2010, 29(12):  2457-2463. 

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PCR-DGGE technique was applied to study the effects of grazing on the community structure of soil bacteria in Stipa baicalensis steppe. Under the conditions of grazing, the bacterial community in 0-20 cm soil layer in the steppe was mainly consisted of α-, β-, γ-, and δ-Proteobacteria, Actinobacteria, Gemmatimonadetes, Chloroflexi, Firmicutes, Acidobacteria, Verrucomicrobia, Bacteroidetes, and Nitrospirae and among which, Proteobacteria and Actinobacteria were the dominant groups, while Verrucomicrobia was only detected in the soil under moderate-grazing. Canonical correspondence analysis showed that the soil bacterial community was closely correlated with grazing intensity and soil physical and chemical properties. Under light grazing, the bacterial diversity had a close correlation with soil organic C and soil C/N; under moderate grazing, there was a close correlation between bacterial diversity and soil total N; while under heavy grazing, the bacterial diversity was correlated with soil pH.

Effects of Bacillus preparation on metabolic function of microbial communities in tilapia ponds at early stock stage.

2010, 29(12):  2464-2470. 

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In order to understand the effects of Bacillus preparation on the metabolic function of microbial communities in tilapia ponds at early stock stage, Biolog ECO microplate was used to examine the changes of the metabolic function of microbial communities in the waters and sediments from four tilapia ponds, of which, two trial ponds were applied with Bacillus preparation at early stock stage. For the microbial communities in sediments, Bacillus preparation had obvious promotion effects on the metabolic activity, functional diversity, and utilization of six kinds of carbon sources; while for those in waters, Bacillus preparation had little effects on their metabolic activity and functional diversity, but promoted their utilization of six kinds of carbon sources. Our study indicated that putting Bacillus preparation into tilapia ponds at early stock stage could improve the metabolic function of microbial communities in the ponds, especially in sediments.

Effects of Fe(Ⅲ) on the growth and spectral characteristics of algae.

2010, 29(12):  2471-2476. 

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An indoor culture experiment was conducted to study the temporal change patterns of chlorophyll content and reflectance spectra of algae from Taihu Lake under different Fe(Ⅲ) supply. Derivative spectrophotometry and red edge optical parameter were employed to quantitatively extract the algal spectral data, and correlation analysis was made between the algal spectral data and algal chlorophyll and Fe(Ⅲ) contents. Based on these, the quantitative relationship of supplied Fe(Ⅲ) concentration – algal chlorophyll content – algal spectra was established. The results showed that supplying appropriate concentration (18 μmol·L^-1) Fe(Ⅲ) was conducive to the algal growth and chlorophyll synthesis. High concentration (30 μmol·L^-1) Fe(Ⅲ) promoted the synthesis of algae chlorophyll at the prophase of culture, but inhibited it at the anaphase. Fe-deficiency significantly inhibited the synthesis of chlorophyll. Under different Fe(Ⅲ) supply, there existed significant correlations (P<0.05) between the vegetation indices SR₇₀₅ and ND₇₀₅, red edge position, and the chlorophyll content of algae.

Seasonal dynamics of Cyanophyta and related affecting factors in Dianshan Lake.

2010, 29(12):  2477-2485. 

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In order to understand the Cyanophyta community and its relations with environmental factors in Dianshan Lake, a survey was conducted at nine sampling sites from May 2009 to April 2010. Canonical correspondence analysis (CCA) was made to explore the relationships between recorded Cyanophyta species and environmental factors by CANOCO 4.5, and ordination diagrams were drawn with the results of CCA. During the study period, a total of 15 genera and 46 species of Cyanophyta were recorded, among which, Microcystis spp. made up of 69.9%, followed by Oscillatoria spp., accounting for 20.55%. The Cyanophyta had a distinct seasonal abundance, ranging from 9.0×10⁴ to 7.6 ×10⁶ cells·L^-1. The cell density of cyanobacteria had a strong relevance to water chlorophyll a, total N (TN), and trophic state indices TSIM (chl-a) and TSIM (TN), indicating that the water TN content in the lake greatly affected the algal cell density, and in return, the algal cell density and relative abundance affected the water chlorophyll content and transparency. CCA analysis showed that in spring, the water body was more greatly affected by water temperature, biological oxygen demand, and TP, while in summer, TP, biological oxygen demand, and transparency were the most important environmental factors affecting the water body. However, none of the factors played the most important role in affecting Cyanophyta community in autumn. In winter, the Cyanophyta species positively correlated with water NH₄⁺-N and TN. M. aeruginosa and O. tenuis were regarded as the dominant species of the whole lake algae species. M. aeruginosa was significantly positively correlated with water temperature and TN and negatively correlated with water pH, while
O. tenuis appeared in four seasons and was significantly affected by water temperature and pH. The relationships between algae dynamics and environmental factors were as follows: in spring and winter, cyanobacterial communities were most affected by water temperature; in summer, they were significantly affected by water TP and TN; while in autumn, water transparency was the most relevant factor. This study showed a highlight to understand the seasonal dynamics of cyanobacteria, and could help manage the environment of lake ecosystems.

Distribution and related source identification of polycyclic aromatic hydrocarbons in surface water of Taizi River.

2010, 29(12):  2486-2490. 

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By the methods of shaking extraction-silica gel pole purification-high performance liquid chromatography detection with fluorescence detector and DAD detector, this paper measured the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) listed in the USEPA blacklist in the surface water of Taizi River. In dry season (April), wet season (July), and median water period (October), the total PAHs (TPAHs) concentration in the surface water was ranged in 454.5-1379.7 ng·L^-1, 1801.6-5868.9 ng·L^-1, and 367.0-5794.5 ng·L^-1, respectively. The surface water of Taizi River was more seriously contaminated by PAHs, compared with that of other rivers in the world. The distribution characteristics of PAHs differed greatly with seasons. In each sampling station, the TPAHs concentration in wet season was much higher than that in dry season. The 2-ring and 3-ring PAHs were the most common components in Taizi River, either in dry season, wet season, or in median water period. The representative speciation of PAHs also differed with seasons. The source identification of PAHs inferred that petroleum was the main PAHs source in dry season, while the combination of petroleum discharge and fuel combustion contributed most to the PAHs in wet season and median water period.

Ecological security assessment of Western Coast of Taiwan Strait under rapid urbanization.

2010, 29(12):  2491-2497. 

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The ecological environmental quality of the Economic Zone in Western Coast of Taiwan Strait ranks the top of China, but the ecological security is facing serious challenges due to the vulnerability and contamination of ecological environment and the rapid urbanization. Based on the pressure-support-response model of ecological security assessment, the indices of pressure, support, and response were calculated by the method of principal component analysis, and then, the ecological security of the Western Coast was assessed. Among the cities in the Western Coast, Quanzhou, Fuzhou, Xiamen, and Putian had a higher ecological security index (ESI), while Zhangzhou, Sanming, and Ningde ranked in lower place. The ESI was not only determined by environmental carrying capacity, but also closely related to the development degree of economy and society. A higher ESI needed stronger economic basis to support.

Review on forest health assessment.

2010, 29(12):  2498-2506. 

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Forest health assessment is currently a hot issue in forest ecology, which can provide useful information for forest management. This paper reviewed the recent researches on forest health assessment. Generally, the main forest health assessment units include stand, forest type, and sub-compartment, and the main indices are forest resources indicators, disasters indicators, and socio-economic indicators. The advantages and disadvantages of forest health assessment models were compared. Forest health assessment has the trend of quantification and visualization. Some mathematical methods such as fuzzy comprehensive evaluation (FCE), grey relational analysis (GRA), and artificial neural networks (ANN) are increasingly used for the quantitative assessment of forest health. At present, the selection of the assessment indicators and methods for forest health assessment should be further improved. To establish a set of quantitative indicators for forest health assessment, to strengthen the comparative study on assessment techniques and models, and to make a long term dynamic monitoring and assessment would be the most important fields in forest health assessment.

Research advances on biodiversity and ecosystem stability.

2010, 29(12):  2507-2513. 

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The relationship between biodiversity and ecosystem stability is a hot subject in ecological science. Focused on this issue, the research history and different academic viewpoints were reviewed, and the achievements in the theoretical and experimental fields as well as the existing problems were elaborated. In terms of theoretical study, the relationship between biodiversity and ecosystem stability is complicated, because the concepts of the two are multifold. In terms of experimental study, the existing research results only emphasize a few types of diversity and ecosystem stability, and rarely uncover the mechanisms resposible for ecosystem stability. In the studies of biodiversity and ecosystem functioning, the important problem is not merely the conclusions, but also the mechanisms hidden behind. A major future challenge is to understand how the biodiversity dynamics, ecosystem processes, and abiotic factors interact.

Roles of constructed wetland system in lake ecological restoration.

2010, 29(12):  2514-2520. 

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Lake plays an important role in the maintenance of water security, ecological security, and environment security. However, affected by the unreasonable artificial exploitation of water and soil resources and the global change, some lakes have being degenerated due to pollution, disordered reclamation, and the occupied ecological and environmental water requirements, resulting in the reduction of their ecological services and social economic values. Therefore, the ecological restoration of lake has become one of the resources and environmental problems, being jointly concerned by the government, academic circle, and social public. In the process of lake ecological restoration, artificial wetland system could efficiently reduce lake pollution load, and effectively regulate and control the abiotic environment of lake ecological system. In addition, it could help to conduct directive cultivation, proliferation, and protection. The lake pollution load reduction through artificial wetland system mainly includes the ecological interception of exogenous pollution load and the ecological extraction of endogenous pollution load. According to the inflow modes of exogenous pollution load, the ecological interception includes the zonal interception aimed at the unorganized discharge pollution load (mainly includes slope runoff in cropland and urban surface runoff) and the pre-reservoir interception and linear interception aimed at the organized discharge pollution. In the process of lake ecological restoration by utilizing artificial wetland system, there is a need to appropriately establish artificial wetland system and composite system at the right time and in the right place, and to fully exert the integrated ecological restoration function of artificial wetland system in the light of water-saving and land-saving principle, connecting with basic features, ecological degradation dynamic mechanism, and ecological restoration objective. In particular, it is necessary to avoid the damages of exogenous species to the lake ecosystem on the basis of multipart argumentation and ecological risk control.

Distribution, enrichment, and transfer of cadmium in spring wheat under cadmium stress.

2010, 29(12):  2521-2524. 

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A pot experiment was conducted to study the distribution, accumulation, and transfer of cadmium (Cd) in spring wheat under Cd stress. With the increasing concentration of exogenous Cd, the Cd contents in spring wheat roots, stems, leaves, and seeds increased, and the Cd accumulation in different plant parts was in the order of root > leaf > stem > seed. There was a significant correlation between the Cd contents of seed and soil. Different plant parts had different capability in enriching Cd, and the enrichment coefficient was reduced gradually with increasing concentration of added Cd. When the soil Cd content was low, different plant parts enriched Cd more easily. The transfer coefficient of Cd in plant aboveground part was in the order of stem and leaf > seed. During the growth period of spring wheat, no obvious change was observed in soil Cd content, but the root and plant Cd contents peaked on days 70 and 80, respectively, followed by a gradual decrease, which suggested that the Cd in wheat plant was gradually transferred into seeds during the process of ripening.