Table of Content

08 September 2010, Volume 29 Issue 09

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Articles

Effects of environmental factors on bolting and flowering of ephemeral plant Lepidium perfoliatum L.

2010, 29(09):  1679-1684. 

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Cruciferat species Lepidium perfoliatum, a typical early-spring ephemeral plant in Xinjiang desert, was planted on three types of growth substrates
 under different growth conditions and with various vernalization durations, aimed to study the effects of environmental factors on the bolting and flowering of L. perfoliatum. On the substrate vermiculite∶perlite=3∶1, the percentage of L. perfoliatum seedling emergence was significantly higher than that on nutrient soil or natural habitat soil. Growth substrate had little effects on whether bolting or not, but affected the bolting time and fecundity. Artificial vernalization at 4 ℃ promoted the bolting of the plants grown on the three substrates in closed balcony, but had no significant effects on the bolting when the substrates were placed in cultivation room or outdoor environment. The bolting and flowering of L. perfoliatum responded most remarkably to illumination and temperature. The interaction between the photoperiod changed from short to long and the certain period of low temperature at seedling stage was the key factor promoting the bolting and flowering of L. perfoliatum.

Population structure and community characteristics of Artemisia giraldii in Erdos hilly and gully loess area of Inner Mongolia.

2010, 29(09):  1685-1690. 

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An investigation was made on the population structure and community characteristics of Artemisia giraldii in different habitats in Erdos hilly and gully loess area of Inner Mongolia. On the sunny slope of the area, where the natural conditions were relatively poor, A. giraldii formed mono-dominant community, and the population structure was stable; on the shady slope where natural conditions were better, A. giraldii formed a community with Poa sphondylodes and Calamagrostis pseudophragmites, and the population structure was in improving; while on the top ridge where the conditions were superior, A. giraldii was a companion species. The A. giraldii on the shady slope had the largest expansion, and produced density effect within the population. On the sunny slope, the population expansion was inferior; while on the top ridge, the individuals within the population distributed independently. All the results indicated that in the habitats in gully and valley loess area, where the resources were redistributed, A. giraldii had its unique ecological adaptability, and made itself become a specific ‘gully and valley plant’.

Ecological conditions for natural regeneration of artificial Haloxylon ammodendron plantations in Minqin oasis.

2010, 29(09):  1691-1695. 

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Aiming at the poor regeneration status of artificial Haloxylon ammodendron plantations in Minqin oasis and from the viewpoint of the necessary conditions for their natural regeneration, a comparative study was made on the necessary ecological conditions for the seed germination, seedling survival, and growth of H. ammodendron at different sites, with the limiting factors for the regeneration of artificial H. ammodendron plantations in the oasis analyzed. The annual mean precipitation in the oasis from 1971-2002 was 116 mm, being suitable for H. ammodendron growth, but the seasonal variation of the precipitation affected the natural regeneration of H. ammodendron. Due to the drought climate in winter and spring, soil moisture had a long term deficit before rainy season, and accordingly, the seed germination and seedling emergence rates of H. ammodendron were low. There were great differences in the growth and seed setting of H. ammodendron among different sites, and thus, site type was another factor affecting the natural regeneration of artificial H. ammodendron plantations.

Fine root dynamics of different aged triploid Populus tomentosa pulp forests during growth period.

2010, 29(09):  1696-1702. 

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Taking 3-, 5-, 6-, and 7-year-old triploid Populus tomentosa pulp forests as test objects, this paper studied the monthly dynamics and vertical distribution of their fine root biomass, root length density, and fine root surface area during the growth period April-November 2008. In the growth period, the dynamics of the fine root biomass, root length density, and fine root surface area all presented a unimodal curve, with the maximum of fine root biomass observed in August, and the maximum of root length density and fine root surface area observed in September. The mean values of the fine root biomass, root length density, and fine root surface area all increased with tree age, being 658.3, 750.6, 1048.1 and 1115.0 kg·hm^-2, 12.490×10³, 9.983×10³, 9.227×10³ and 5.921×10³ m·m^-3, and 12.17, 18.68, 22.23 and 25.28 m²·m^-3 for the 3-, 5-, 6-, and 7 years old stands, respectively. Surface soil had the greatest distribution of fine root biomass, root length density, and fine root surface area, and the fine roots in surface soil increased with tree age. 46.36%-51.12% of fine root biomass, 62.77%-75.33% of root length density, and 61.74%-64.16% of fine root surface area were found in 0-10 cm soil layer.

Eucalypt growth and nitrogen storage in the current year and next year of nitrogen topdressing.

2010, 29(09):  1703-1708. 

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A field experiment was conducted to study the biomass accumulation and nitrogen (N) storage in different parts of eucalypt in the current year (2007) and next year (2008) of N topdressing. Compared with the control, N topdressing increased the eucalypt biomass, and the increment was much higher in 2008 than in 2007, suggesting that N topdressing had definite positive and cumulative effect on eucalypt growth. Nitrogen topdressing also increased the N storage in eucalypt, with the increment in 2007 and 2008 being 30.2% and 73.5%, respectively. Compared with that in 2007, the eucalypt biomass and N storage in the control in 2008 was increased by 35.9% and decreased by 13.1%, respectively, while those under N topdressing in 2008 were increased by one-fold and 15.7%, respectively. The main reason for these was the foliage yield reduction in 2008. Among the organs of eucalypt, leaf had the most obvious decrease in N storage. In 2008, the leaf N storage in the control and under N topdressing was decreased by 46.5% and 36.9%, respectively, compared with that in 2007.

Differences in foliar carbon isotope ratio of dominant plant species in representative habitats on karst hill slopes of northwest Guangxi, China.

2010, 29(09):  1709-1714. 

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Based on the measurements of the foliar δ¹³C values of seven dominant plant species on the continuous rock outcrops and nearby soils on karst hill slopes of northwest Guangxi, China, this paper analyzed the differences in the foliar carbon isotope ratio of the plants in different habitats and different seasons. The foliar δ¹³C values of test plants were significantly higher in dry season than in wet season (P<0.05). Radermachera sinica, Vitex negundo, and Clematis kweichowensis had no significant differences in their foliar δ¹³C values in wet season and dry season (P>0.05), but Rhus chinensis, Alchornea trewioides, Nephrolepis auriculata, and Pteridium aquilinum had significantly higher foliar δ¹³C values in dry season than in wet season (P<0.05), which suggested that the seasonal differences in rainfall had less effects on the foliar δ¹³C values of R. sinica, V. negundo, and deep-rooted shrub, but had great effects on those of shallow-rooted grass and shrub. No significant differences were observed in the foliar δ¹³C values of R. sinica, A. trewioides, and V. negundo on the continuous rock outcrops and nearby soils both in dry and in wet seasons (P>0.05), but the foliar δ¹³C values of the shrubs differed greatly in the two habitats both in dry and in wet seasons, suggesting that habitat condition had great effects on the foliar δ¹³C values of shrub than of deep-rooted tree.

Effects of grazing on plant root distribution and soil physicochemical properties in Stipa baicalensis grassland.

2010, 29(09):  1715-1721. 

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A field experiment was conducted on the Stipa baicalensis grassland in Inner Mongolia to study the effects of grazing on plant root distribution, and analyzed the correlations of the root distribution with soil physicochemical properties. Grazing induced a significant change in root distribution. The root biomass in 0-10 cm soil layer accounted for 65.9%-82.6% of the total biomass in 0-40 cm soil layer. The roots with diameter ≥2 mm and <1 mm were more sensitive to grazing. The root distribution had definite correlations with soil bulk density, moisture content, contents of total nitrogen, phosphorus, and organic carbon, and cation exchange capacity. Grazing affected the distribution of plant roots with different diameters mainly through affecting soil physicochemical properties, and the characteristics of the root distribution had certain feedback on the soil physicochemical properties.

Soil alkaline phosphatase activity at different vegetation succession stages in karst peak-cluster depression.

2010, 29(09):  1722-1728. 

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This paper studied the variation pattern of soil alkaline phosphatase activity and its relationships with soil physical and chemical properties at four different stages of vegetation succession in a typical karst peak-cluster depression of northwest Guangxi, China. Succession stage and soil depth had significant effects on the soil alkaline phosphatase activity, but slope position had less effects. During the succession of original forest- secondary forest, bush forest- grass, and with the increase of soil depth, the soil alkaline phosphatase activity decreased, and had significant difference among different soil layers. The soil alkaline phosphatase activity had significant positive correlations with soil pH and soil organic matter, total N and P, available N, P, and K, silt, and sand contents, and significant negative correlations with soil bulk density and soil total K and clay contents. The canonical correspondence analysis (CCA) showed that succession stage and bare rock rate had primary effects on soil alkaline phosphatase activity, while slope gradient, slope position, and slope direction also had great effects on it.

Diversity of arbuscular mycorrhizal fungi in Artemisia sphaerocephala rhizosphere in desert habitat.

2010, 29(09):  1729-1735. 

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In April, July, and October 2007, soil samples (0-10, 10-20, 20-30, 30-40, and 40-50 cm layers) were collected from the rhizosphere of Artemisia sphaerocephala in Shapotou area, the southeastern edge of Tenger desert, aimed to investigate the spatiotemporal variation and diversity of arbuscular mycorrhizal (AM) fungi in the rhizosphere. The hyphal colonization rate of AM fungi in the rhizosphere was 90.5%, with the spore density averaged by 5.4 ind·g^-1soil. There was an obvious spatiotemporal variation in the colonization among seasons, which was significantly correlated with soil microenvironment. A total of 21 AM fungi taxa belonging to 5 genera were isolated and identified, and the dominant species was Acaulospora laevis. Most species were found in July. The spore density was significantly positively correlated with soil organic matter content, and the species richness was significantly negatively correlated with soil available P content but positively correlated with soil temperature, spore density, and hyphal colonization rate. A. sphaerocephala could establish well symbiosis with AM fungi under natural conditions, which was the main reason for the
enhancement of the endurance capability of A. sphaerocephala in rigorous circumstance and for the maintenance of the integrity and stability of desert ecosystem.

Effects of transgenic soybean on the diversity of nitrogen-fixing bacteria in rhizosphere soil.

2010, 29(09):  1736-1742. 

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In order to understand the effects of planting transgenic soybean on the nitrogen-fixing bacteria in rhizosphere soil, PCR-DGGE was used to study the molecular diversity of nifH genes in the plots planted with transgenic soybean, parent non-transgenic soybean, and local soybean. The sequences showed that low GC Firmicutes were on the top of the DGGE gel, and were significantly affected by sampling date. Chlorobi were not affected by either sampling date or soybean variety. Among the 46 sequences, 28 sequences were of Proteobacteria, occupying 60.8% of the total and showing in all area of the DGGE gel, and most of them were stable, not affected by sampling date or soybean variety. No significant differences were observed in the diversity of nitrogen-fixing bacteria in rhizosphere soils among the treatments of planting transgenic soybean, parent non-transgenic soybean, and local soybean at different sampling dates, suggesting that planting transgenic soybean had less effects on the diversity of nitrogen-fixing bacteria in rhizosphere soil.

Community characteristics of phytoplanktons in closed ponds of Xixi wetland and related affecting factors.

2010, 29(09):  1743-1748. 

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In September 2009, an investigation was made on the phytoplankton communities in 31 closed ponds of Xixi wetland, the first national wetland park in Hangzhou City, China. A total of 124 phytoplankton species were recorded, belonging to 61 genera of 7 phylums (Chlorophyta, Cyanophyta, Bacillariophyta, Cryptophyta, Euglenophyta, Pyrophyta, and Chrysophyta), among which, most species were of Chlorophyta, and fewer were of Cyanophyta and Cryptophyta but in higher abundance. Two-way indicator species analysis (TWINSPAN) and detrended correspondence
 (DCA) analysis showed that the species composition of the phytoplanktons in the 31 ponds could be classified into four groups, and all the groups were well separated on DCA axis, illustrating that there existed a distinct spatial differentiation of the phytoplankton communities in these ponds. Canonical correspondence analysis (CCA) was also applied to explore the relationships between the phytoplankton communities and the main environmental factors, and the results showed that NO₃-N, PO₄-P, SD, Chro, and COD_Mn were the main factors affecting the distribution and abundance of the phytoplankton communities.

Coupling effects of water and fertilizer on nitrogen content of maize grain.

2010, 29(09):  1749-1753. 

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A long-term field experiment with four factors (irrigation, nitrogen and phosphorus applications, and straw mulching) and five levels was conducted on a cinnamon soil in semi-arid area of western Liaoning to study the coupling effects of water and fertilizer on the nitrogen content in maize grain, with the regressive model built up by the quadratic rotation design statistic analysis method. The results showed that single factor had significant effects on the nitrogen content in maize grain, and the sequence was nitrogen application > straw mulching > phosphorus application > irrigation. When the irrigation amount was 700 m³·hm^-2, nitrogen application rate was 180 kg·hm^-2, phosphorus application rate was 120 kg·hm^-2, and straw mulching was 7500 kg·hm^-2, the maize grain had a high yield of 12000 kg·hm^-2, with the nitrogen content being 11.7 g·kg^-1 and the protein content being 73 g·kg^-1, suggesting that such a water-fertilizer combination was in optimum in both economy and ecology, and thus, could be applied in the practical maize production in western Liaoning.

Community structure and seasonal dynamics of soil fauna at different altitudes in Baishanzu Nature Reserve of Zhejiang Province.

2010, 29(09):  1754-1767. 

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From 2008 to 2009, an investigation was made on the soil fauna at five sites along an altitudinal gradient in Baishanzu Nature Reserve of Zhejiang Province. A total of 2409 soil animals were collected, belonging to 18 orders, 7 classes, and 3 phyla, among which, Acarina and Collembola were the dominant orders. With increasing altitude, the Margalef index, Shannon index, and Pielou index of the soil fauna all had a decreasing trend. As for the seasonal dynamics, the Margalef index of the soil fauna at the five altitudes was the highest in summer, slightly lower in autumn and winter, and the lowest in spring, the Shannon index increased slowly from spring to autumn and decreased then, with an overall trend as autumn > summer > spring > winter, the Pielou index had the same variation trend as the Shannon index, while the Simpson index varied with a trend opposite to that of Shannon index.

Effects of sediment environment on distribution pattern of benthic chlorophyll-a in southern intertidal area of Yellow River Delta.

2010, 29(09):  1762-1769. 

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In September 2007 and in April and July 2008, sediment samples were collected from the southern intertidal area of Yellow River Delta to study the distribution pattern of benthic chlorophyll-a (Chl-a) content and its relations to sediment grain size. In study area, the Chl-a content increased from the north to the south. In the spring, the Chl-a content ranged from 0.623-8.734 μg·g^-1 with an average of 2.542 μg·g^-1 and increased from high tide zone to low tide zone; while in summer and autumn, the Chl-a content ranged from 0.307-5.195 μg·g^-1 (averaging 1.832 μg·g^-1) and 0.426-4.749 μg·g^-1 (averaging 1.591 μg·g^-1), respectively, and decreased from high tide zone to low tide zone. The sediments were unanimously composed of silt, with the median size ranging from 0.025-0.081 mm (averaging 0.045 mm) and increased from high tide zone to low tide zone. The distribution pattern of benthic Chl-a was primarily affected by the grain size of sediment, and had significant correlation with the content of fine particles. There was anegative relationship between benthic Chl-a content and elevation height, suggesting that soft, flat, and stable sediment could benefit the growth and reproduction of benthic micro-algae.

Community structure and its seasonal variation of small mammals in Xishuangbanna of Yunnan, China.

2010, 29(09):  1770-1776. 

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In October 2008-June 2009, an investigation was made on the community structure, species richness, and seasonal variation of small mammals in seven types of habitats in Xishuangbanna, Southwest China. The relative densities of the small mammals were surveyed by trap-night method. A total of 127 individuals belonging to 10 species and 3 families were trapped, with an average capture rate being 6%. Within the small mammal community in study area, Chinese White-bellied rat (Niviventer confucianus) was the dominant, and its capture rate varied significantly among seasons (P=0.023) but insignificantly among habitats (P>0.05). Among the seven habitats, tropical rain forest had the highest species diversity index (H=1.91), tropical lower montane evergreen broad-leaved forest had the highest evenness (E=0.95), tropical seasonal moist forest had the highest dominance (D=0.94), while rubber forest had no small mammals captured. The highest relative population density was found in dry season. This study showed that the species diversity of small mammals in different types of habitats was related to the intensity of human disturbances, i.e., the higher intensity the human disturbances, the lower the diversity indices of the small mammals in the habitats. The changes in food abundance among seasons possibly affected the capture rate of small mammals.

Dynamic distribution of microcystin-LR in tilapia (Oreochromis niloticus) body.

2010, 29(09):  1777-1781. 

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By the method of intraperitoneal injection, this paper studied the dynamic distribution of microcystin-LR (MC-LR) in the muscle, liver, serum, gallbladder, gill, and intestine of tilapia (Oreochromis niloticus). During the experiment, MC-LR was detected in the liver, serum, gallbladder, gill, and intestine, but not detected in the muscle. A distinct difference was observed in the MC-LR residues in different tissues or organs. The MC-LR residue was the highest (0.902-4.938 mg·kg^-1) in liver, and was in the range of undetected  to 0.390 mg·L^-1 in serum, undetected  to 0.236 mg·kg^-1 in gallbladder, 0.0134-0.0369 mg·kg^-1 in gill, and 0.007-0.016 mg·kg^-1 in intestine, respectively. At 84 h after injection, the MC-LR residue in the liver, gill, serum, and gallbladder decreased significantly, and no MC-LR was detected in serum and gallbladder, which meant that O. niloticus had very strong detoxic ability on MC-LR. The MC-LR concentration in the liver and gallbladder had a sharp decrease at 36 h after injection, suggesting that liver and
 gallbladder could be the main detoxic organs of MC-LR. No MC-LR was detected in the muscle during the experiment, which meant that MC-LR could not be accumulated in muscle when O. niloticus was injected with low dosage MC-LR.

Quantitative detection of rice stripe virus in Laodelphax striatellu under different CO₂ concentrations.

2010, 29(09):  1782-1787. 

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Accurate detection of populations virus-carrying rate and individuals rice stripe virus (RSV) content of small brown planthopper (Laodelphax striatellu) is one of the important references to predict whether the rice stripe disease could outbreak under elevated CO₂ concentration. In this study, qualified RT-PCR assay (qRT-PCR) was employed to detect the RSV content in L. striatellu under different CO₂ concentrations. Among the test three CO₂ concentrations (370, 470, and 570 μl·L^-1), 470 μl·L^-1 of CO₂ was most favorable to the multiplication of RSV in L. striatellu. Compared with the commonly used ELISA (enzyme-linked immunosorbnent assay) and DIBA (dot immunobinding assay), qRT-PCR was more rapid, sensitive, and specific, and didn’t need antiserum preparation, being easily to be popularized.

Spatial variability of heavy metals concentration in cedar (Cedrus deodara) needles in Luoyang urban area.

2010, 29(09):  1788-1793. 

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Based on the determination of the Pb, Cu, Zn, and Cd concentrations in cedar(Cedrus deodara) needles in Luoyang urban area, this paper analyzed the distribution of these heavy metals in the atmosphere. The needle samples were collected from 10-15 years old trees (YS), fallen needles of 10-15 years old trees (YD), 20-30 years old trees (LS), and fallen needles of 20-30 years old trees (LD), and the sampling sites were at 11 different locations with different degrees of heavy metals air pollution in residential, commercial, industrial, and scenic regions. The mean values of the needles Pb, Cu, Zn, and Cd concentrations in the four regions were 1.606, 3.385, 18.151, and 0.198 mg·kg^-1, respectively. There were significant differences in the Cu and Zn concentrations, but no significant differences in the Pb and Cd concentrations among YS, YD, LS, and LD. The Pb, Cu, and Zn concentrations in the needles differed significantly with sampling sites, and decreased in the order of industrial region > commercial and residential region > scenic region, while the concentration of Cd had little difference. The spatial variability of test heavy metals in cedar needles was mainly affected by the industrial discharge of the metals, and could objectively indicate the heavy metals air pollution. It was suggested that cedar could be used as the good tree species indicating the heavy metals pollution of urban air environment.

Effects of transpiration rate and root character on cadmium absorption by pakchoi cultivars.

2010, 29(09):  1794-1798. 

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A hydroponic experiment with twelve pakchoi cultivars was conducted to study the cadmium (Cd) accumulation in their aboveground part, and the correlations of this accumulation with the transpiration rate and root characters (root length, root surface area, and root volume) of the cultivars. There were significant differences in the Cd absorption and accumulation among the cultivars. The Cd concentration in the fresh shoot of pakchoi ranged from 1.8 to 4.4 mg·kg^-1, with 1.5-fold difference among the cultivars. There were also significant differences in the transpiration rate and root morphology among the cultivars. Transpiration rate, root surface area, and root volume all had significant positive linear correlations with the Cd concentration and the total amount of absorbed Cd in the aboveground part of pakchoi (P<0.01), while root length only had a significant positive correlation with the total amount of absorbed Cd, suggesting that high intensity of transpiration and developed root system could promote the Cd accumulation in edible parts of pakchoi.

Land use change of rapidly urbanized small- and medium-sized coastal cities in China: Taking Cixi City of Zhejiang Province as an example.

2010, 29(09):  1799-1805. 

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Small- and medium-sized cities contribute equally and even more to the world urbanization than large and mega-cities, but the impacts of their urbanization on land use change have been less studied. Taking Cixi, a small coastal city of Zhejiang Province, as a case, this paper studied the land use change during its rapid urbanization from 1997 to 2007, based on the land use datasets derived from Landsat-TM/ETM images and CBERS image. A Markov model was also employed to predict the land use change of Cixi from 2010 to 2020. Our findings demonstrated that the urbanization of Cixi increased the urban industrial and residential lands, and decreased its cropland and natural landscapes (e.g., wetland). Such status would be continued, according to the prediction of Markov model. The rapid urbanization made the natural land use types in highly dynamic. The reclamation of coastal tidal flats, especially wetland, induced the increasing total area of Cixi to meet the continuous land demand of urbanization. Local government
’s policies, together with the encouraged accelerated industrialization and urbanization of towns and counties, as well as the market-oriented agricultural development, were the driving forces of the rapid land use change.

Ecological effect of the excretion from silver carp and bighead carp in algal bloom control: A review.

2010, 29(09):  1806-1811. 

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Using silver carp and bighead carp to control the excessive phytoplankton growth in eutrophic ecosystem remains controversial, because some authors reported that after stocking additional carps, there is a stimulation of small-celled plankton and an increase in the number and biomass of algae. Many reasons may cause these ecological problems, and the effect of the excretion from the carps cannot be ignored. This paper reviewed the researches on the composition of the excretion from silver carp and bighead carp, the growth and photosynthetic activity of phytoplankton passed through the intestine of silver carp and bighead carp, and the nutrient recycling and contribution in aquiculture system. Because of the complexity of the origin and biotransformation process of the nutrients in aquaculture systems, it’s hard to identify how the excretion nitrogen affects the structure of plankton communities and the transmission process by traditional methods. Therefore, chlorophyll fluorescence system and isotopic technique are suggested to be introduced to study the ecological effect of the excretion from the carps in controlling algal bloom, which would help to understand the mechanisms and feasibility of nontraditional bio-manipulation in cyanobacterial bloom control.

Research progress on plant bud bank.

2010, 29(09):  1812-1819. 

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Bud bank is the aggregation of all buds that can be potentially used for vegetative regeneration. Both bud bank and seed bank compose the propagule bank which plays an important role in vegetation maintenance and recruitment. This paper summarized the research progress on bud bank from the aspects of 1) distinction and relations between bud bank and seed bank, 2) classification of bud bank, 3) effects of environmental factors on the establishment and dynamics of bud bank, 4) applications of theoretic models (e.g., matrix model, trigonometric function, and Markov model) in bud bank study, and 5) relationships between bud bank and aboveground vegetation. Future researches should pay more attention on the bud banks of different ecosystems, the relative contribution of bud bank and seed bank to the regeneration of aboveground vegetation, and the applications of bud bank in vegetation restoration and reconstruction.

Effects of forest litter on seed germination and seedling growth: A review.

2010, 29(09):  1820-1826. 

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Forest regeneration is the premise of maintaining forest ecosystem stability, and its early phase (seed germination and seedling growth) is very sensitive to climate change and markedly affected by forest litter. To deep understand the related affecting mechanisms can help us to further know the dynamics of forest regeneration and the direction of community succession. This paper summarized the research progress on forest litter, and discussed the physical mechanisms the forest litter affects seed germination and seedling growth (mechanical hinders of forest litter to seed and seedling emergence, changes in temperature, moisture, and light conditions of microenvironment, and so on), biochemical mechanisms (allelochemicals and nutrients release), indirect effects induced by the alternation of soil physical and chemical properties, and direct or indirect effects induced by the synergistic action of climate change and forest litter. The future directions in this research field were also discussed.

Microbial decomposition of forest litter: A review.

2010, 29(09):  1827-1835. 

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Forest litter decomposition is a key link of the material circulation and energy flow in forest ecosystem, while microorganism plays a crucial role in the process of this decomposition. This paper systematically described the process of forest litter’s microbial decomposition and its ecological significance, and summarized the research advance about this microbial decomposition from the aspects of microbial diversity, microbial quantitative dynamics and community succession, key affecting factors, and enzymology of microbial decomposition. The future research directions were also discussed.

Application of functional genes in the study of the ecology of denitrifying bacteria: A review.

2010, 29(09):  1836-1845. 

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Denitrifying bacteria are a diverse functional group with the members from almost all phylogenetic bacterial groups. Therefore, their denitrification capability cannot be easily detected by relying on taxonomic affinities identified by 16S rRNA gene probes. As an alternative approach, functional genes are applied to investigate the denitrifying organisms in the environment. In this review, we introduced the genetic basis of denitrification, the main molecular tools for exploring denitrifying bacteria, recent researches of denitrifying bacterial communities in different environments, the problems unresolved, and future developments in this field. Up to now, though the links between community structure and function are not yet established, the study of the ecology of denitrifying bacteria would provide fundamental data to apply denitrifying bacteria in solving environment problems.

Action mechanisms of allelopathy in inhibiting algae: A review.

2010, 29(09):  1846-1851. 

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This paper summarized the research progress on the action mechanisms of allelopathy in inhibiting algae, i.e., affecting the photosynthesis of algal cell, destroying algal cell membrane, changing the antioxidant enzyme activities in algal cells, and affecting algal cell ultrastructure and gene expression, etc. Mainly through reducing chlorophyll a content, destroying photosystem II and cell ultrastructure, making cell membrane structure lysis and gene expression abnormal, changing enzyme activities, and damaging antioxidant system, allelochemicals can reduce the number of algal cells and inhibit the growth of algae. The prospective research issues in this field were also proposed, with the focus on gene expression and molecular and genetic mechanisms, aimed to provide theoretical bases for developing safe and efficient allelochemicals in algal inhibition.

Applications of nanomaterials in remediation of contaminated water and soil: A review.

2010, 29(09):  1852-1859. 

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Nanomaterials, due to their unique physical and chemical characteristics such as strong capacity of adsorption and high efficiency of catalysis, can not only overcome many shortcomings from the conventional remediation of contaminated water and soil, but also display higher remediation efficiency. Therefore, utilizing nanomaterials to remedy contaminated environment is becoming a research hotspot. This paper summarized the research progress in the applications of nanomaterials (including nanoiron, surface-modified nanomaterials, and nanochelating agents) in remediation of contaminated water and soil, and proposed some key issues in the research and application of nanomaterials in environmental science and engineering.

Landscape pattern of rocky desertification in karst depression areas.

2010, 29(09):  1860-1865. 

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Rocky desertification is one of the eco-geological disasters widely distributed in karst areas of Southwest China, and one of the hotspots and difficulties in ecology and environmental sciences. From the viewpoints of landscape ecology, and with the help of Erdas 9.1 and ArcGIS 9.0, a case study was made in the Puding County of Guizhou Province, aimed to understand the landscape pattern of rocky desertification in karst depression areas of Southwest China, and to compare it with those in the other karst geomorphologic areas. Overall, the rocky desertification in the karst depression areas of Puding County was not serious and presented a dispersed distribution, while that in other karst geomorphologic areas was much serious and showed an aggregate distribution pattern with big rocky desertification patches. In karst depression areas, the main types of rocky desertification were potential rocky desertification, light rocky desertification, and moderate rocky desertification. With the increasing degree of rocky desertification, patch fragmentation increased. The rocky desertification degree in karst depression areas was lower than that in other karst geomorphologic areas, but the karst depression areas in Puding County had much more serious rocky desertification than those in whole Guizhou Province or Anshun City,illustrating that the rocky desertification in karst depression areas in Puding County was rather serious, being a problem needed to be solved urgently.

Core habitat identification and gap analysis for Amur tiger (Panthera tigris altaica) based on least-cost distance model.

2010, 29(09):  1866-1874. 

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Biodiversity database information system of Sichuan Province.

2010, 29(09):  1875-1880. 

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Biodiversity database information system is the basis for evaluating biological diversity. Up to now, the existing biodiversity data of Sichuan Province have not been well integrated, and, due to the lack of the information about the spatial distribution of the species, the existing data are difficult to meet the environmental impact assessment. In this paper, we established a biodiversity database information system of Sichuan Province by the integration of the data of existing biodiversity, Ganzi terrestrial and aquatic biodiversity, environmentally sensitive areas in Sichuan Province, and biodiversity on-site survey. Through the development of the database and network, it’s realized to search for and reveal the spatial and attributive data of biodiversity to provide references for environmental management and environmental impact assessment.

Evaluation of air negative ions concentration in urban green space: A case study in Beijing Olympic Forest Park.

2010, 29(09):  1881-1886. 

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Negative air ions (NAIs) in urban green space play an important role in improving habitant health. Urban green area has great difference in its NAIs with the natural forest environment or urban industrial area, and thus, an intuitive, scientific, and accurate model of grading and evaluating ANIs is critical to evaluate the NAIs level in urban green space. In this paper, two models for grading and evaluating NAIs, Anbei evaluation model and forest air evaluation model, were employed to evaluate the NAIs concentration in Beijing Olympic Forest Park. There existed great differences in the ANIs concentration and air clear degree among sampling sites, due to the differences in plant community structure, vegetation type, and vegetation coverage. Through the comparison of the evaluation results of the two models, it was found that forest air ion evaluation index could comprehensively and systematically reflect the differences in the NAIs concentration among different sites, being convenient for public’s understanding, and more applicable to the grading of NAIs concentration and the evaluation of air clear degree of urban green space represented by the Beijing Olympic Forest Park. Opposite to the forest air ion evaluation index, the gradation standard of NAIs concentration had some deficiencies. A partial revision of this standard was made so as to make it more suitable for the analysis and assessment of the NAIs concentration in urban green space.