Table of Content

08 November 2010, Volume 29 Issue 11

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Articles

Effects of nitrogen input on meadow marsh soil N₂O emission and organic carbon mineralization.

2010, 29(11):  2091-2096. 

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A laboratory incubation test was conducted to study the effects of different nitrogen inputs (N0: 0 mg·g^-1; N1: 0.1 mg·g^-1; N2: 0.2 mg·g^-1; N3: 0.5 mg·g^-1) on the characteristics of N2O emission and organic carbon mineralization in a meadow marsh soil, and the variation patterns of soil microbial carbon and nitrogen. During the incubation period (23 d), the N₂O emission in treatments N0, N1, N2, and N3 was 91.12, 133.02, 147.75, and 303.45 μg·kg^-1, respectively, illustrating that nitrogen input promoted soil N₂O emission. Except at the late phase of incubation, the mineralization rate of soil organic carbon under nitrogen input lowered, suggesting that nitrogen input restrained the mineralization of soil organic carbon to some degree. Compared with treatment N0, the soil microbial biomass carbon in treatments N1, N2, and N3 was significantly lower (P<0.05), but no significant difference was observed among the latter three treatments. Soil microbial biomass nitrogen increased linearly with increasing nitrogen input, and there were significant differences among different nitrogen inputs (P<0.05). Our results suggested that supplying exogenous nitrogen affected the structure and composition of soil microbes, and the related mechanisms should be studied further.

Effects of aluminum stress on Pinus massoniana seedlings root morphology and activity.

2010, 29(11):  2097-2101. 

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By the method of sand culture, this paper studied the effects of different concentration (0, 50, 100, 150, and 200 μmol·L^-1) aluminum (Al) on the root length, root dry weight, root plasma membrane permeability, root total absorption area, root active absorption area, and root activity of Pinus massoniana seedlings after 30, 60, and 100 days of treatment. Low concentration (0-50 μmol·L^-1) Al had less impact on the physiological characteristics of root system, medium Al stress (100 μmol·L^-1) was the turning point for the root growth and activity, while high Al (150-200 μmol·L^-1) decreased the root physiological indices markedly. Root length, root mass, root plasma membrane permeability, and root activity could be used as the identification indices of Al toxicity during the seedling stage of P.massoniana. When the rhizosphere Al treatment was less than 30 days, the P. massoniana seedlings had stronger adaptability, and the root growth was less inhibited; when the stress was longer than 30 days, the root responses would be more severe with extending stress time.

Effects of vegetation restoration type on soil carbon, nitrogen, and microbial quantity in Guandi Mountain.

2010, 29(11):  2102-2110. 

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Taking four vegetation restoration types, including abandoned land, Hippophae rhamnoides shrub, Larix principis-rupprechtii plantation, and mixed forest (mainly consisted of L. principis-rupprechtii, Betula platyphylla, Populus davidiana), in Guandi Mountain as test objects, this paper studied the seasonal variations of soil organic carbon, total nitrogen, NO^-₃-N, NH⁺₄-N, and of the quantities of soil microbes relating to nitrogen metabolism (bacteria, actinomycetes, fungi, N-fixing bacteria, nitrifiers, and denitrifiers). In the four vegetation restoration types, an obvious seasonal variation was observed in the soil inorganic N content and microbial quantity, and the soil organic carbon, total nitrogen, NO^-₃-N, NH⁺₄-N, and microbial population were decreased significantly with increasing soil depth. Compared with abandoned land, the soil organic carbon, total nitrogen, NO^-₃-N, NH⁺₄-N, and microbial population in H. rhamnoides shrub, L. principis-rupprechtii plantation, and mixed forest were all higher, with the highest values in mixed forest, in which, soil carbon and nitrogen, and soil microbial population increased by 0.21%-2.05% and 0.09%-19.25%, respectively, soil fungi increased up to 19.25%, and soil inorganic nitrogen increased by 0.01%-0.49%. There were significant positive linear relationships between soil organic carbon, total N, NO^-₃-N, and NH⁺₄-N and soil microbial population. In sum, vegetation restoration improved soil fertility, and the effect was most significant in mixed forest.

Change patterns of different carbon-containing compounds in dairy manure during its aerobic composting and assessment of composting maturity.

2010, 29(11):  2111-2116. 

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An investigation was conducted on the change patterns of different carbon-containing compounds in dairy manure during its aerobic composting, and an assessment was made on the composting maturity, based on the changes of maturity indices. According to the requirements for maturity indices (temperature, seed germination rate, germination index, coliform flora, and mortality of ascarid egg), the dairy manure after composting could reach the demand of maturity. During composting, the contents of total carbon and readily oxidizable carbon in the manure decreased, but that of humic acid carbon increased. The microbial biomass carbon and water soluble carbon increased (0-14 d) first, decreased (14-28 d) then, and kept stable finally (28-70 d). K_os (oxidation stability factor) and the H/F (humic/fulvic acids) ratio decreased first (0-14 d)and increased then (14-70 d), while the E₄/E₆(absorption coefficient ratio of 465 nm to 665 nm) of humic acid carbon had a change trend opposite to K_osand H/F ratio. Through the correlation analysis among different organic carbon-containing compounds, it could be drawn that readily oxidizable carbon and humic acid carbon were the main factors affecting the change pattern of total carbon during composting, and the readily oxidizable carbon, humic acid carbon, K_os, H/F ratio, and E₄/E₆ could well express the humification and stability degree of dairy manure compost. During composting, microbial biomass carbon and water soluble carbon could transform each other.

Main nutrients contents in wetland soil under different cover stations in Shuangtaizi estuarine.

2010, 29(11):  2117-2121. 

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Aimed to understand the effects of different cover condition on the main nutrients contents in wetland soil, three kinds of wetland plots in Shuangtaizi estuarine, i.e., land with living vegetation (PA), land with dead vegetation (PD), and bare beach (GT), were selected, and a total of 21 soil samples were collected, with their total nitrogen (TN), phosphorus (TP), and potassium (TK) contents determined. In the plots GT, PD, and PA, the soil TN content was averagely 0.79, 1.01, and 1.29 g·kg^-1, soil TP content was averagely 0.49, 0.50, and 0.52 g·kg^-1, and soil TK content was averagely 22.29, 23.01, and 23.40 g·kg^-1, respectively. Soil TN content differed significantly with cover condition (P<0.05), but soil TP and TK contents had no significant differences among the three plots (P>0.05;P>0.05), indicating that vegetation could increase soil TN content effectively, but had little influence on soil TP and TK contents. In vertical direction, soil TN and TP contents showed similar distribution pattern, i.e., PA>PD>GT, while soil TK was in the order of PA>GT>PD. With the increase of soil depth, soil TN content decreased after an initial increase, soil TP content changed little at 0-30 cm but increased below 30 cm, with a significant increase in PA, while soil TK content changed greatly from the surface to deep layer. In the degrading process of PA-PD-GT, soil TN, TP, and TK contents decreased by 38.6%, 6.9%, and 4.7%, respectively.

Effects of reduced UV-B radiation on tobacco leaf glandular trichome development and density.

2010, 29(11):  2122-2130. 

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Taking tobacco cultivar K326 as test object, a pot experiment was conducted to study the effects of reduced UV-B radiation on the dynamic changes of the morphology and density of tobacco leaf glandular trichome from flowering to post-technological maturity stage. Four treatments were installed, i.e., natural UV-B radiation (CK), and reduced 25% (T₁), 50% (T₂), and 65% (T₃) of natural UV-B radiation via canopy-covering with different thickness transparent plastic film, and scanning electron microscope was used to observe the dynamic changes. It was first reported that K326 leaf had branched glandular trichome. The glandular trichome on adaxial epidermis was sensitive to UV-B radiation at the stages of flowering, physiological maturity, and pre-technological maturity, while that on abaxial epidermis was sensitive to UV-B radiation at the stages of flowering and posttechnological maturity. Treatment T₃ caused the lower density of glandular trichome and delayed its development, while treatments T₁ and T₂ induced the higher density of glandular trichome and its secondary development at technological maturity stage. In all treatments, long stalk glandular trichome was the dominant, and its density on abaxial epidermis was higher than that on adaxial epidermis except in treatment T₃, in which, the glandular trichome density on the two epidermises was almost the same. Reduced UV-B radiation was conducive to the development of long stalk glandular trichome on abaxial epidermis. Trichome type, which induced the secondary development, varied with treatments and growth stages. Our results indicated that a certain higher intensity of UV-B radiation played an important role in promoting the development of glandular trichome on tobacco leaf, and in the experimental field, reduced 25%-50% of UV-B radiation was suitable for the development of the glandular trichome.

Effects of sowing date on the growth characteristics of direct seeding rice.

2010, 29(11):  2131-2138. 

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Taking three representative rice cultivars as test materials, a field experiment was conducted to study the matter production and yield formation of direct seeding rice under the conditions of different sowing dates. With the delay of sowing date, the grain yields of the three rice cultivars all decreased significantly, but the decrements varied. Under the delay of sowing date, the whole period of growth and development shortened notably, the growth dynamics of stems and tillers became not smooth and intensified as the sowing date further delayed, the leaf area index increased gradually at early growth stage but relatively declined at the middle and late growth stages, the photosynthetic potential at various growth stages displayed a declining trend, the dry matter accumulation increased at jointing stage but reduced at heading and maturity stages, the harvest index descended, and the population growth rate at various stages showed a significant decreasing trend. It was suggested that considering the suitable secure sowing date, the rice varieties favorable to promote in the study region would be the medium-maturing medium japonica and late-maturing medium japonica, and the early-maturing late japonica varieties could also be grown there. To attain high yield, all the rice cultivars should be sowed as early as the time for harvesting previous crop allows. Yet, from the view point of the security for reproduction, the medium-maturing medium japonica cultivars should be planted no later than June 30, the late-maturing medium japonica varieties no later than June 25, and the early-maturing late japonica varieties no later than June 20.

Effects of bamboo shoot-collecting on the shoot growth of giant panda’s diet bamboo Chimonobambusa szechuanensis.

2010, 29(11):  2139-2145. 

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Bamboo shoot-collecting is a lasting human disturbance activity in giant panda’s habitat. To estimate how the behavior of bamboo shoot-collecting affects the shoot growth of giant panda’s diet bamboo, a field experiment was conducted to study the shoot growth of Chimonobambusa szechuanensis affected by the shoot-collecting at different time from July to November, 2009 at Wawushan Town, Hongya County of Sichuan Province. Five different ways of shoot-collecting were set up during shooting period: A) early period (days 1-15) shoot-collecting, B) mid-period (days 16-30) shoot-collecting, C) late period (days 31-45) shoot-collecting, D) continual (days 1-45) shoot-collecting, and E) no shoot-collecting. The total amount of bamboo shoots in treatments A, B, and D was 1.53, 1.57, and 1.62 times of that in treatment E, respectively, but no significant difference was observed in the bamboo shoot amount between treatments C and E. Treatment A increased the amount of budding shoot in the early and mid-period. Treatment B only increased the amount of budding shoot in the mid-period, while treatment D increased this amount all the periods (P<0.05). There was significant difference in the stem height of young bamboo between treatments A, B, C, and E respectively (P<0.05). The amount and stem height of young bamboo in treatment D were significantly lower than those in other treatments, and the basal diameter of young bamboo in treatment D was only lower than that in treatment E (P<0.05). There were positive correlations between the amounts of shooting, withering, and collecting in all treatments except D (P<0.05). It was suggested that the mid-period of shooting was the optimal time for bamboo shoot-collecting, and the local government should pay more efforts to guide and support the economic development of the surrounding communities of giant panda’s habitats.

Biomass allocation of understory plants in a secondary forest in Northeast China.

2010, 29(11):  2146-2154. 

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Taking the secondary forest in Maoershan Mountain of Northeast China as study object, the biomass allocation of its understory plants (including tree-like plants and typical shrub categories) was investigated, and the allometry of the components biomass (foliage M_L, new branch M_NB, old branch M_OB, small root M_SR, large root M_LR, branch M_BR, aboveground M_AG, and belowground M_BG) versus each other and each component biomass against plant size was analyzed. The biomass allocation of the understory plants complied with allometry theory, and the allometry power exponents of the components biomass were plastic. The M_L∝M_NB(0.924-1.055), M_OB∝M_LR (0.917-1.024), M_BR∝M_LR (1.095-1.164), and M_AG∝M_BG (1.064-1.125) were isometry, the power (0.585-0.700) of new branch biomass scaling old branch biomass was nearly to 0.67, the foliage biomass nearly scaled the 0.75 power of branch biomass (0.742-0.795), the power exponent (0.853-0.918) of foliage biomass scaling root biomass was nearly to 0.86, and the allometry power of small root biomass scaling large root biomass was 0.658-0.750. The biomass allocation of understory plants complied with allometry partitioning theory, and the component biomass proportions of foliage, new branch, old branch, small root, and large root were 5.83%-20.60%, 0.83%-7.42%, 36.25%-68.24%, 1.32%-6.75%, and 16.38%-42.88%, respectively, with the root/shoot ratio being 0.272-0.866. The plant biomass allocation partitioning varied with plant species and plant size. For understory plants, the biomass allocation of foliage, new branch, and small root and the root/shoot ratio -decreased significantly (P<0.05) with plant growing, and the proportion of old branch biomass in plant biomass increased significantly (P<0.05), only for a few plants, the allocation of large root biomass did not vary significantly (P>0.05).

Nutrient distribution and biological cycle characteristics in different types of Phyllostachys pubescens forest in Northwest Fujian.

2010, 29(11):  2155-2161. 

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Taking the intensively managed pure bamboo (Phyllostachys pubescens) stand (Ⅰ), bamboo stand mixed with broadleaved trees (Ⅱ), and bamboo stand mixed with coniferous trees (Ⅲ) in Yong’an County of Fujian Province as test objects, this paper studied the distribution patterns of N, P, K, Ca, and Mg and the characteristics of biological cycle in the stands. The nutrient accumulation in the stands was in the order of Ⅱ > Ⅰ> Ⅲ, being 146196.59, 144466.35, and 105002.59 kg·hm^-2, respectively, and that in different layers of the stands was in the order of soil layer > tree layer > litter layer > shrub layer > herb layer, with the proportion in soil layer (0-60 cm) accounted for more than 99% of the total. The nutrient accumulation in vegetation layers was in the order of Ⅰ> Ⅱ> Ⅲ, and that in soil layer and litter layer was in the order of Ⅱ > Ⅰ> Ⅲ. Stand Ⅱ had the highest nutrient accumulation in its soil layer and litter layer, and thus, the greatest productive potentiality. The nutrient utilization coefficient of standsⅠ and Ⅱ were significantly higher than that of stand Ⅲ. The higher productivity depended on more nutrients. The nutrient cycling coefficient was in the order of Ⅲ> Ⅱ>Ⅰ. Stands Ⅲ and Ⅱneeded lesser nutrients than stand Ⅰ. The nutrient turnover time was in the order of Ⅰ> Ⅱ> Ⅲ, being 31.89, 12.39, and 12.23 years, respectively, and there was a significant difference between stands Ⅰ, Ⅱand Ⅲ. The bamboo stand mixed with broadleaved trees had higher productivity and stronger nutrient return ability, being a better management pattern of P. pubescens.

Competitive relationships of dominant tree species in Pinus tabulaefirmis f. shekanensis community on Loess Plateau.

2010, 29(11):  2162-2167. 

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By using two competition index models with diameter at breast height (DBH) and crown width as parameters respectively, the competitive units based on Voronoi diagram were applied quantitatively to analyze the intra- and inter-specificcompetition of Pinus tabulaeformis f. shekannesis and Quercus liaotungensis (Liaotung oak) in the P.tabulaeformis  f. shekannesis community on Loess Plateau. The results showed that P. tabulaeformis  f. shekannesis population suffered intense intra-specific competition for DBH and intense inter-specific competition for crown width. The maximum competitive stress appeared in the fast-growing period with DBH<10 cm, and the stress affected tree growth significantly. Liaotung oak population suffered greater inter-specific competition for crown width at DBH<5 cm, and greater intra-specific competition for crown width at 5 cm<DBH<10 cm. The inter-specific competition for crown width had no significant effects on the tree growth of Liaotung oak, indicating that P. tabulaeformis  f. shekannesis couldn’t exert the intense and continuous competition for crown width on Liaotung oak. The competition intensity of the two tree species declined with increasing diameter class of the trees. The relationship between the competition intensity (CI) and DBH (D) of target trees followed the equation CI=AD^B.

Genetic structure of six Magnolia officinalis populations in Sichuan Province.

2010, 29(11):  2168-2174. 

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In this paper, inter-simple sequence repeats (ISSR) technique was applied to study the genetic diversity and genetic differentiation of six Magnolia officinalis populations in Sichuan Province. For the 159 individuals of the six populations, 10 ISSR primers yielded a total of 114 bands sized 150-2000 bp, among which, 93 bands (81.58%) were polymorphic. The number of the bands per primer yielded varied from 10 to 13, with an average of 11.4 bands. A relatively low genetic diversity was detected at population level (the percentage of polymorphic loci PPB=48.25%, Nei’s genetic diversity H=0.189, and Shannon’s information index  I=0.277). However, the genetic diversity at species level was relatively high (PPB=81.58%, H=0.320, and I=0.469). The coefficient of genetic differentiation (G_ST) among populations was 40.42%, and the results of molecular variance analysis indicated that the genetic differentiation occurred mainly within populations (63.18%). The gene flow between M. officinalis populations was 0.737, and the average genetic distance was 0.211. The six populations were divided into three groups, according to UPGMA. Structure analysis showed that the genetic structure of the M. officinalis populations had the characteristics of independence.

Growth model of artificially bred Strongylocentrotus intermedius.

2010, 29(11):  2175-2180. 

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Sea urchin (Strongylocentrotus intermedius) purebreds were established by using artificial insemination (1♂:3♀), and the phenotype characters (shell length, shell height, and body weight) of thirty individuals of each purebred from 5-15 months old to sexual maturation (17 months old) were analyzed. The correlation analysis of the characters was carried out, and the growth prediction model was constructed. There were no significant differences (P>0.05) in the phenotype characters among the individuals of the purebreds at 5-15 months old, but significant differences for those at sexual maturation (P<0.05). The growth of shell length and shell height showed linear models, while that of body weight showed an exponential model. The multiple correlation coefficient (R²) of the phenotype characters was 0.68-0.86. The body weight at 17 months old could be predicted by that at 11 months old, with the accuracy of 73.6%. There was no strong relationship between the parents and the offspring in the phenotype characters (R²=0-0.25). This study contributed to deepen our understanding of the growth pattern of S. intermedius, and provided theoretical basis for the construction of healthy aquaculture mode.

Fast-start and escape performance of juvenile Spinibarhus sinensis.

2010, 29(11):  2181-2186. 

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At water temperature（25.0±0.5）℃, the movement trajectories of the center of mass (CM) of electricity-stimulated juvenile Spinibarhus sinensis(body length（6.9±0.1）cm, n=23) during its fast-start escape response were recorded by using high-speed cinematography, and the kinematics at three stages of the fast-start performance was analyzed. The results showed that all the escape responses observed were of C-type fast-start with either a right or a left turning direction, and there were no significant differences in the kinematics of fast-start performance with different directions (P>0.05). The distance (d) of the CM during the whole escape response process increased significantly (P<0.05), while the linear velocity (V) increased significantly (P<0.05) at the beginning and reached its maximum (36 ms) by the end of stage 2. The linear acceleration (a) presented the highest value by the end of stage 2 (P<0.05) and the lowest value at stage 3. The angular velocity (ω) presented the highest value at the beginning of fast-start response, decreased significantly (P<0.05) at the first and second stages, and remained unchanged at a lower level at stage 3. There was no significant relationship between V and relative turning radius (RT_r) at stage 1. The results indicated that juvenile S. sinensis favored higher velocity escape strategy in fast-start process, possibly due to its streamline shape and rapid water habitat.

A comparative study on two polyculture modes of grass carp bases on ecological niche and water quality factors.

2010, 29(11):  2187-2191. 

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In this study, two polyculture modes of grass carp (i.e., polyculture of mud carp and grass carp named as “mud-grass mode” and polyculture of crucian carp and grass carp named as “crucian-grass mode”) were simulated, and the niche width, niche overlap, and specific growth rate of grass carp as well as the physical and chemical indices of water under the two polyculture modes were analyzed. There was no significant difference in the niche width of grass carp between the two modes, but the niche overlap of grass carp was significantly different, with the value being 0.5598 and 0.6478 in “mud-grass mode” and “crucian-grass mode”, respectively. The specific growth rate of grass carp in mud-grass mode was 1.524% per day, which was much higher than that (1.346% per day) in crucian-grass mode. The water NH⁺₄-N, NO^-₃, TN, TP, and reactive phosphate contents in mud-grass mode were higher than those in crucian-grass mode, while the water pH value and DO, NO^-₂, and chlorophyll-a contents were in adverse. These results suggested that the competition between crucian carp and grass carp was more severe than that of mud carp and grass carp, and mud carp was more suitable for grass carp than crucian carp in the polyculture.

Effects of bisphenol A on zebrafish (Danio rerio) liver and gonad.

2010, 29(11):  2192-2198. 

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Aimed to clarify the toxicological mechanism of bisphenol A (BPA) in aquatic animal, the toxicity and histological damage of BPA on zebrafish (Danio rerio) were studied. BPA had acute toxicity on zebrafish. The 96 h LC₅₀of BPA was 6.3 mg·L^-1. After 96 h exposure to BPA, the liver damage  were observed in concentration-dependent way. In high BPA group, the testis structure was damaged, and the atresia rate of ovarian follicle was 35%. In 0.2 mg BPA·L^-1 group, liver was slightly damaged, gonad had no morphological change, the rate of gametes number in late phase Ⅲ to that in phase Ⅳ in ovary had some increase, and oocyte size increased significantly (P<0.05). In 2 mg BPA·L^-1group, liver was damaged, hepatocyte cloudy swelling and pyknosis were observed, and the rate of gametes number in late phase Ⅲ to that in phase Ⅳ in ovary was slightly increased. In 6.1 mg BPA·L^-1 group, liver was badly damaged with cell vacuolization, necrosis, and cavity, testis structure was subject to certain damage, pyknotic nuclei were also observed, and atresia of overian follicle increased significantly. The results indicated that liver was the target organ of BPA. It remains to be further studied whether gonad damage is caused by toxicological influence or by endocrine disrupting.

Microhabitat selection of Platyope proctoleuca chinensis (Coleoptera: Tenebrionidae).

2010, 29(11):  2199-2203. 

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Habitat selection of animals is of complexity, while approaching its inherent mechanism is of significance in maintaining animal’s biodiversity. Taking the darkling beetle Platyope proctoleuca chinensis (Coleoptera: Tenebrionidae), a dominant beetle species in Gurbantunggut Desert of Xinjiang, China, as study object, a 2-year (2007-2008) investigation with pitfall traps was made on its population dynamics and burrows quantity in different habitats of the desert, with the habitat selection of this beetle on landscape and microhabitat scales analyzed. On landscape scale, the beetle  preferred sand dune than interdune, and was more plentiful in the lee slope than in the windward slope of sand dune. On microhabitat scale, the beetle was fond more of the top of sand dune, particularly the top of the lee slope of sand dune. The distribution pattern of the burrows was similar to the population dynamics of the beetle. The habitat selection of the beetle was correlated to the difficulty of burrow-building, while successful digging burrow was interrelated to soil quality, especially the composition of sand materials and soil rigidity.

Impacts of simulated acid rain on community composition and diversity of small and medium-sized animals in lateritic red soil in Guangdong Province.

2010, 29(11):  2204-2209. 

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In order to understand the impacts of acid rain on the community composition and diversity of small and medium-sized animals in lateritic red soil in Guangdong, a field plot experiment was set up, in which, the simulated acid rain was sprayed for 3 months, and the soil samples were collected once two weeks from December 1, 2008 to March 1, 2009. A total of 14997 small and medium-sized soil animals were captured, belonging to 4 phyla, 7 classes, and 13 orders. Nematoda was the only dominant group, accounting for 85.34%, and Collembola and Acarina were the common orders, occupying 13.46% of the total. There were 10 groups of rare orders, only taking a proportion of 1.2%. With the decreasing pH of acid rain, the individual number and biodiversity indices of the animals decreased. When the acid rain pH fell to 3.0, the total individual number and the diversity indices of the animals had a significant difference with those of the control. Our results also showed that the test soil animals had a trend to move down to the deeper soil layers under the impacts of acid rain.

Hydraulic efficiency and spatial variation of nitrogen concentration in subsurface flow constructed wetlands with different multi-inflows.

2010, 29(11):  2210-2215. 

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Through tracer tests, the hydraulic efficiency of four kinds subsurface flow constructed wetlands with different inflow configurations (i.e., common horizontal flow and 3 kinds of multi-inflow) was examined, with the spatial variation of total nitrogen (TN) and ammonium nitrogen (NH⁺₄-N) in the wetlands and the correlation between the hydraulic efficiency and the nitrogen removal efficiency studied. Among the four inflow configurations, step-inflow had the highest hydraulic efficiency, because it had a long mean resident time and low residence time distribution (RTD), revealing that the flow pattern was much closer to a plug flow with weaker vertical mixture. Under the four inflow configurations, the TN and NH⁺₄-N showed stratified distribution, and TN varied obviously as a result of different inflow configurations. The step-inflow was in favor of the denitrification in the back end of the wetland bed. There were significant relationships between hydraulic efficiency and TN removal efficiency, while hydraulic efficiency did not affect the removal of NH⁺₄-N significantly.

Dynamic changes of landscape pattern in Coastal Economic Development Zone in Jinzhou Bay.

2010, 29(11):  2216-2222. 

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By using GIS, RS, and the theories and methodologies of landscape ecology, the 1992, 2000, and 2007 Landsat TM remote sensing images of Coastal Economic Development zone in Jinzhou Bay were interpreted, and the dynamic changes of landscape pattern in the zone were analyzed at both class and landscape levels. From 1992 to 2007, the landscape pattern in the zone had a significant change. At landscape level, the total number of patches increased significantly, patch density was increasing, while the largest patch index decreased, with the landscape shape tended to be much more complicated. At class level, the areas of cropland, woodland, and abandoned land decreased, patch numbers and fragmentation increased, and connectivity became weak. On the other hand, the areas of urban land, residential land, traffic land, and mining land, as well as the perimeter-area fractal dimension index increased, and the connectivity intensified. The rapid population growth and socio-economic development and the expansion of highway, railway, and other infrastructure investments had strong influence on the changes of the landscape pattern, leading to a deeper level of landscape fragmentation.

Effects of road network on landscape ecological risk: A case study of Red River watershed.

2010, 29(11):  2223-2228. 

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Large-scale construction of road affects landscape pattern around, and also, ecological process directly or indirectly. Taking the Red River watershed in Yunnan Province as a case, and by using GIS and RS technology, this paper analyzed the effects of road on landscape pattern and soil erosion, and, through the calculation of landscape ecological risk indices based on landscape pattern and process, approached the landscape ecological risk pattern under road network expansion. In the Red River watershed, the landscape types near roads were mainly arable land, woodland, and meadow, and the landscape ecological risk indices based on the landscape pattern of woodland and meadow generally decreased with increasing distance to roads, suggesting that the landscape patterns of woodland and meadow were influenced obviously by roads. The soil erosion modulus in the buffer zones of the first-class roads, third-class roads, and fourth-class roads decreased with increasing distance to roads, and the third-and fourth-class roads were widely distributed, more easily to be eroded. The landscape ecological risk index based on the landscape pattern and process had a certain positive correlation with road density in spatial distribution.

Correlations between landscape pattern and plant community structure in Xiamen urban parks.

2010, 29(11):  2229-2234. 

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Aimed to approach the correlations and the mutual adaptability between the landscape pattern and plant community structure in Xiamen urban parks, the landscape pattern indices (average patch size, patch density index, and landscape diversity index) and the plant community structure indices (forest area ratio, species diversity, and proportion of native species) were selectedto quantify the landscape pattern and plant community structure in the parks, and the mutual Pearson’s correlation coefficients were analyzed. In earlier constructed artificial parks, tree species were rich, with uniform collocation and with rational allocation of native species and exotic species. In later constructed artificial parks, tree species composition was simple, and the proportion of native species was low. In semi-natural parks, natural forests were well maintained, with rich tree species and high proportion of native species. Compared with artificial parks, semi -natural parks had larger average patch areas, lesser patch types, and lower landscape fragmentation and landscape diversity. The average patch size was positively correlated with the forest area ratio and the proportion of native species, while the landscape diversity index had a negative correlation with the forest area ratio, indicating that there existed a certain spatial correlation between plant landscape pattern and community structure in Xiamen urban parks.

Urban land growth and its driving forces in satellite cities of megacity: A case study of Songjiang district, Shanghai, China.

2010, 29(11):  2235-2240. 

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During the process of rapid urbanization, megacity has the radiation effects upon and can promote the urbanization of its adjacent small and mediumsized cities and towns. However, how the adjacent cities and towns response has not been well addressed yet. In this paper, the land use datasets derived from the time series color infrared aerial photos of 1989, 1994, 2000, and 2005 were employed to characterize the urban land growth of Songjiang district, a satellite city of Shanghai, and to demonstrate the effects of megacity on the urbanization of adjacent cities and towns. Under the effects of megacity urbanization and rapid regional economic development, the urban land growth of Songjiang district exhibited an obvious spatial anisotropy, and the development of the urban form presented a distinct centripetalism to megacity. The urban land in satellite city grew in an accelerated speed faster than that in megacity. Our results well testified the urban morphology theory of aggregation and diffusion during the urbanization process of megacity. Local governmental policy, economic development, population growth, and traffic infrastructure were the main driving forces of the urban growth of Songjiang district from 1989 to 2005.

Asymmetric changes of extreme temperature in South China in 1961-2008.

2010, 29(11):  2241-2248. 

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Based on the 1961-2008 daily maximum and minimum temperature data of 110 observational stations in South China, the spatiotemporal change characteristics of annual and seasonal extreme maximum and minimum temperature were studied by using linear regression analysis and Mann-Kendall test. In the recent 48 years in South China, the annual extreme maximum and minimum temperature had an obvious increasing trend, and had an abrupt change in 2003 and 1978, respectively. Asymmetric changes were observed in the annual extreme maximum and minimum temperature. The linear increasing rate of annual extreme minimum temperature (0.48 ℃·10 a^-1) was obviously higher than that of annual extreme maximum temperature (0.20 ℃·10 a^-1). An obvious difference was also found in the changes of extreme maximum and minimum temperature among four seasons. The extreme maximum temperature was upward obviously in spring, but the extreme minimum temperature was upward obviously in summer and winter. There were also obvious regional differences in the changes of extreme temperature. The increasing trend of extreme temperature was most obvious in the Pearl River Delta area, southeast coastal areas of Guangdong, and part of Hainan, while the decreasing trend of extreme maximum temperature was obvious in southwest areas of Guangxi in winter.

New tools for prokaryote diversity study.

2010, 29(11):  2249-2257. 

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Prokaryote, which is widespread in nature, makes a big biomass and participates in a variety of global material cycles and energy transfer. However, the measurement of prokaryote diversity has been limited by technique for a long time. With the development of new techniques such as high-throughput sequencing technique and biochip,  the research approaches for prokaryote diversity study have being changed. At present, Genome Sequencer FLX (GS FLX) and Illumina Genome Analyzer are the major approaches for environmental prokaryote diversity study, and GeoChip is the representative of the biochips. Nevertheless, each new emerging technique has its own characters. Some problems as how to use a mass of sequences to measure the prokaryote diversity and which approaches be more appropriate are the issues confronted by the related researches. This paper reviewed and compared the newest research means and computer program tools for prokaryote diversity study, and summarized the main research approaches adapting to the present technical conditions for this study.

Effects of high rhizosphere temperature on plant growth and metabolism: A review.

2010, 29(11):  2258-2264. 

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As the main plant organ of absorbing and transporting water and nutrients, root system and its metabolism directly affect plant growth and development. Optimal and stable rhizosphere temperature is the important guarantee for root growth and metabolism. The heat stress around rhizosphere during hot summer is an important factor limiting the growth and yield of plants. On the basis of clarifying the concept of high rhizosphere temperature, this paper summarized the research progress in the effects of high rhizosphere temperature on plant growth and yield, water relations in plant, photosynthesis and dry matter production, respiration and mineral nutrition, hormone metabolism, and resisting enzyme system of plants. Further research aspects and application prospects of controlling high rhizosphere temperature were suggested.

Effects of management practices on forest plantation soil carbon: A review.

2010, 29(11):  2265-2271. 

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Forest plantation carbon sink plays an important role in the global carbon cycle and the reduction of greenhouse gases emission, while management practice is an important factor affecting the soil carbon balance of forest plantations. Appropriate ecosystem management can improve the soil carbon sequestration of forest plantations, being of great significance in mitigating the impact of climate change. In this paper, the research advances on the effects of main management practices, e.g., species selection, rotation period, cutting, irrigation, and fertilization, on the soil carbon stock and soil CO₂ efflux of forest plantations were reviewed. These practices could impose great effects on the soil carbon stock and soil respiration via regulating soil temperature, soil water content, soil nutrient contents, and soil structure. However, up to now, the researches on the effects of management practices on forest plantation soil carbon have not been adequate, and some of the management practices have not been examined yet. Therefore, more comprehensive and quantitative researches on the effects of management practices on forest plantation soil carbon should be further made.

Research advances on source classification and characteristics of contaminative urban surface runoff.

2010, 29(11):  2272-2279. 

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The pollution characteristics (e.g., the distribution and concentration of pollutants) of urban surface runoff depend on the sources of the pollutants. In this paper, three categorization methods were introduced to analyze the pollution sources of urban surface runoff and the pollution characteristics of each source, with the focus on the sources, characteristics, and ecological risks of the main pollutants in urban surface runoff, including suspended solid, persistent organic pollutants, pesticides, heavy metals, nutrient elements, organic matters, and other representative industrially derived compounds. The potential contribution of urban surface runoff to the acceptor water and related assessment approach were reviewed, and the pivots of further researches were suggested, based on the pollution situation and the research progress of urban surface runoff.

Physiological mechanism and ecological implications of wild bird stress response.

2010, 29(11):  2280-2285. 

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Stress response is the physiological, hormonal, and behavioral changes that enable an animal to cope with a stressor, and has great influence on the behaviors and survivability of the animal. Harsh weather, predation risk, and human disturbance can induce acute stress of wild birds, while food scarcity, predators, seasonal changes, and social domination are the main factors inducing chronic stress of wild birds. The acute stress can help the wild bird individuals withstand brief periods of stress, while the chronic stress can have adverse effects, e.g., suppressing immune and reproduction functions and reducing body mass, which finally devastate the survivability of wild bird population. This paper reviewed the physiological mechanism and ecological implications of wild bird stress response to encourage Chinese ornithologists to pay attention to the topic.

Applications of ultrasonic telemetry in aquatic animal ecology: A review.

2010, 29(11):  2286-2292. 

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The application of ultrasonic telemetry in aquatic animals study was based on the urgent demand of studying the behaviors and physiology of marine mammals. At present, it has been developed into one of the principal techniques in the ecological study of aquatic animals such as fishes, crustaceans, dolphins, and sea turtles. This paper reviewed the past 50 years progress of applying ultrasonic telemetry in aquatic animals study, introduced the composition of ultrasonic telemetry system, its operation, and applicable circumscription, analyzed the major problems in aquatic animal telemetry with this technique, and proposed associated recommendations and applications.

Species diversity and faunal characteristics of amphibians and |reptiles in Helan Mountains.

2010, 29(11):  2293-2297. 

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In order to understand the species diversity and faunal characteristics of amphibians and reptiles in Helan Mountains, field surveys were conducted by transects from 2007 to 2008. A total of 19 species belonging to 12 genera, 8 families, and 2 orders were recorded, among which, Elaphe carinata and E. mandarina were  new species records to Ningxia. The Shannon’s diversity index (H) and evenness index (E) of the amphibians and reptiles in Helan Mountains were 2.250 and 0.563, and the family and species numbers of the amphibians and reptiles accounted for 72.7% and 67.9% of those in Ningxia, and 66.7% and 50.0% of those in Inner Mongolia, respectively. In Helan Mountains, Bufo raddei, Rana chensinensis, Phrynocephalus przewalskii, P. frontalis,Eremias argus, and E. multiocellata were dominant species, Psammophis lineolatus, Coluber spinalis, and Rhabdophis tigrinus were common species, and others were rare species.Among the 19 species, 14 species belonged to the Palaearctic realm, and 5 species were widespread species. Species of Mongolia-Xinjiang Region were dominant, accounting for 42.6% of the total. This study showed that the amphibians and reptiles in Helan Mountains had the typical faunal characteristics of Western Desert Sub-region of the Mongolia-Xinjiang Region.

Life table of laboratory population of Ophraella communa (Coleoptera: Chrysomelidae).

2010, 29(11):  2298-2301. 

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Through the breeding and observation at constant temperature (26±1) ℃, the life table of laboratory population of Ophraella communa was constructed. The development duration of egg, larva, pupa, and preoviposition of O. communa was 7.51, 12.14, 7.67, and 4.75 days, respectively. The survival rate in each developmental period was from 77% to 94%, being the highest for egg, and the lowest for the 3rd instar larva. The population survivorship curve fitted Deevey’s type Ⅱ, the number of eggs laid per female was 193.8, the population trend index (I value) was 36.95, the average generation period (T) was 31.37 days, and the innate capacity (γ_m) and finite rate (λ) of population increase were 0.095 and 1.10, respectively.

Eco-hydrological regionalization based on SOFM artificial neural network.

2010, 29(11):  2302-2308. 

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Eco-hydrological regionalization plays an important role in relaxing the contradiction between water resources development and eco-environment protection. Based on the theory of SOFM (self-organizing feature map) artificial neural network, this paper established an eco-hydrological regionalization model. Several integrated indices containing most original information were extracted from a large number of eco-hydrological indices by using principal component analysis (PCA), and on this basis, a cluster genealogy chart was obtained by hierarchical cluster analysis (HCA). Then, the SOFM artificial neural network was constructed to make a rational eco-hydrological regionalization. Taking Quanzhou City as an example, its eco-hydrology was regionalized. The city was regionalized into four eco-hydrological zones, and each of them had its distinct characteristics. Aiming at the different characteristics of each eco-hydrological zone, four strategic options (general, enhancive, strict, and strictest) were proposed to protect the eco-environment and develop the water resources.