Table of Content

10 December 2009, Volume 28 Issue 12

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Articles

Effects of sandbarrier near interdune lowlands on the vegetation restoration of mobile sand dunes.

2009, 28(12):  2403-2409. 

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Interdune lowlands of mobile sand dunes have big soil seed bank rich in species, but the significance of this soil seed bank in vegetation restoration is little known. In this study, willow branch sandbarriers were settled on the windward slope of mobile sand dunes near the interdune lowlands in Horqin Sand to investigate the effects of the sandbarriers on the soil seed bank, seedling emergence, and plant establishment of the lowlands. In the plots within sandbarriers, the species number and density of soil seed bank were significantly higher, the seed density at the soil depth 5-10 cm accounting for 60% of the total, while that in control plots being less than 50%. The seedling emergence and establishment rates of psammophytes in the plots within sandbarriers were also significantly higher than those in control plots. Both in the plots within sandbarriers and in control plots, the seedling emergence of nonpsammophyte was less than 1 seedling·m^-2, and the plant establishment was as low as 0.1 seedling·m^-2. The correlations of seed density with seedling emergence and establishment were higher in control plots than in the plots within sandbarriers, and higher for psammophytes than for non psammophytes. In the same, the similarity coefficients of the species numbers of soil seed bank and the seedling emergence and establishment were higher in control plots than in the plots within sandbarriers, and higher for psammophytes than for nonpsammophytes. This study suggested that sandbarrier could intercept the seeds in interdune lowlands, increase the species richness and seed density of soil seed bank, and alter the spatial pattern of soil seed bank. The establishment of sandbarrier could improve the seedling emergence and establishment of psammophytes but not of nonpsammophytes.

Emission characteristics of biogenic volatile organic compounds from four tree species in Shenyang, China.

2009, 28(12):  2410-2416. 

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By the methods of thermal desorption and gas chromatography, the emission characteristics of biogenic volatile organic compounds (BVOCs) from Populus alba × berolinensis, Salix babylonica, Ulmus pumila, and Gleditsia japonica) in Shenyang urban area were studied. The BVOCs emissions varied with test tree species. P. alba ×berolinensis and  S. babylonica had obviously higher BVOCs emissions than the other two tree species, and mainly emitted isoprene; while U. pumila and  G. japonica  mainly released limonene. The BVOCs emissions from test tree species had obvious diurnal and seasonal variation patterns,i.e., with a peak at noon or afternoon and less isoprene released at night, and higher in summer than in spring and autumn.

Effects of |Cunninghamia lanceolata plantations at different developmental stages on soil microbial community structure.

2009, 28(12):  2417-2423. 

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By the method of denaturing gradient gel electrophoresis (DGGE), the polymorphism of soil bacterial 16S rRNA and fungal 28S rRNA specific fragments in 3-, 11-, 17-, 21-, and 24-year old Cunninghamia lanceolata plantations was studied, with the effects of  C. lanceolata plantation’s development stage on soil microbial community structure analyzed. The Shannon diversity index (H ) and richness (S) showed that the soil microbial community diversity increased significantly with the development of C. lanceolataplantation, but was still significantly lower than that in secondary broadleaved forests (P<0.05). Cluster analysis (UPGMA) indicated that the soil fungal community similarity in different aged C. lanceolata plantations was less than 60%, whereas that of soil bacterial community similarity was up to 65%, suggesting that the shift of soil fungal community structure with the development of C. lanceolataplantation was more obvious than that of soil bacterial community structure. The soil microbial diversity had significant correlations with soil available N content and C/N ratio (P<0.05). This study indicated that longterm silviculture with pure plantations could affect soil microbial community via altering soil properties, which in turn, could affect the nutrient cycling in forest ecosystem and the plantation productivity.

Effects of land use change on ecosystem carbon stock in semi-arid region.

2009, 28(12):  2424-2430. 

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Land use change has remarkable effects on ecosystem carbon (C) stock. To evaluate the carbon sequestration capability of terrestrial ecosystem under different land use types is of significance in the ecosystem management, and in mitigating the impact of global climate change. Taking sandy grassland (SG), sparse woodland mixed with Pinus sylvestrit-Armeniaca sibirica (SW), and poplar shelterbelt (PS) as test objectives, a quantitative study was made on the ecosystem C stock and allocation under effects of  land use chamges. After the conversion from SG to PS and SW, the aboveground C stock increased at a rate of 0.17 t·hm^-2·a^-1  in SW and 4.45 t·hm^-2·a^-1 in PS. In SG, SW, and PS, the root C stock was 1.382 t·hm^-2, 1.706 t·hm^-2, and 18.541 t·hm^-2, and the soil C stock was 26.11 t·hm^-2, 25.20 t·hm^-2 and 41.36 t·hm^-2, respectively. The rootand soil C stocks in PS after conversed from SG increased at a rate of 1.07 t·hm^-2·a^-1 and 0.5 t·hm^-2·a^-1, respectively. Among the three landuse types, SW had the least variation of C content and stock between soil layers. As a whole, the total C stock was the highest in PS (131. t·hm^-2), followed by in SW (30. t·hm^-2), and in SG (28. t·hm^-2)

Species diversity of forest communities in Pangquangou National Nature Reserve of Shanxi Province, China.

2009, 28(12):  2431-2436. 

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Based on the investigation data collected from 84 field plots in the forests at altitude 1630-2430 m in Pangquangou National Nature Reserve of Shanxi, China, the forest communities’ species diversity and its relationships with environmental factors were investigated. With the altitudinal variation of forest communities, i.e., from Larix principis-rupprechtii+shrubs at 1630-2000 m to L principisrupprechtii + Picea sp. +Betulaat 2000-2200 m to L. principisrupprechtiiCarex lanceolataat 2200-2430 m, the richness (R₀) and ShannonWiener index (H) increased first and reached the maximum at medium elevation, and then decreased gradually; while the Simpson index (λ ) and Pielou evenness index (E) exhibited an increasing trend. Elevation had significant negative correlations with R₀ and H (r=-0.541，and -0.377, respectively; P<0.01) but positive correlation with  λ(r=0.495, P<0.01), and slope direction was significantly negatively correlated with R₀ and H (r=-0.365, P<0.01; r=-0.250, P<0.05, respectively) but positively correlated with  λ (r=0.356, P<0.01). Slope grade and soil thickness had no significant relationships with diversity indices. Tree layer coverage had significant positive correlations with R₀ (r=0.238, P<0.05) and H (r=0.217, P<0.05), herb layer coverage had significant correlations with R₀ (r=0.275, P<0.05) and  λ(r=-0.381, P<0.01), while shrub layer coverage had no significant correlations with the diversity indices.

Landscape pattern change and its cumulative environmental effects of coastal wetlands in southern Laizhou Bay.

2009, 28(12):  2437-2443. 

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Based on the classification of wetland landscape, and by using remote sensing and GIS techniques, the Landsat 5 and Landsat 7 false color TM images of coastal wetlands in southern Laizhou Bay in 1987 and 2002 were obtained, and the landscape pattern change and its cumulative environmental effects were studied with patch dynamic index, patch density index, landscape diversity index, and patch fragmental index. In 1987-2002, the total area of the wetlands in southern Laizhou Bay kept unchanged, but the natural wetland decreased by 491%. The disappeared natural wetland was converted into culture ponds and salt fields. The landscape diversity index decreased, while the patch fragmental index increased. Some cumulative environmental effects were induced by the landscape pattern change, e.g., the total net primary productivity of natural wetland decreased, the functions of natural wetland in purifying environment and defending marine disasters weakened, some mesophytes, xerophilous plants, and harmful plants invaded the coastal wetlands, and the ecosystem services value of the coastal wetlands declined.

Primer screening and optimization of ISSR reaction condition for endangered medicinal plant |Magnolia officinalis.

2009, 28(12):  2444-2451. 

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To optimize the inter simple sequence repeat (ISSR) reaction condition for Magnolia officinalis genomic DNA, the concentrations of Mg²⁺, Taq polymerase, primers, deoxyribonucleot-ide triphosphate (dNTP), and template DNA were studied with an orthogonal experimental design, and the optimal anneal temperature of different primers and cycles were determined through gradient PCR. The optimal PCR system for ISSR analysis was 1.5 mmol MgCl₂·L^-1, 03 μmol primer·L^-1 0.04 U Taq polymerase·μl^-1, 0.2 mmol dNTP·L^-1, 4 ng DNA template·μl^-1, and 1×Buffer in 25 μl reaction solution, and the augmentation procedre was predenaturation at 94 ℃ for 5 min, denaturation at 94 ℃ for 30 s, annealing at 50 ℃-60 ℃ for 45 s, extension at 72 ℃ for 90 s, reaction with 40 cycles, and extension at 72 ℃ for 8 min. Twentyone ISSR primers were screened by using the optimal reaction system, and the genetic diversity was analyzed with some primers.

Seed dormancy and germination of xeric shrub Indigofera lenticellata.

2009, 28(12):  2452-2459. 

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Indigofera lenticellata is a leguminous shrub widely distributed in the dry valley of Hengduan Mountains. Its characteristics in seed dormancy and germination were studied in this paper.  I. lenticellataseeds had the characteristics of physical dormancy, and the waterimpermeability of seed coat was the main cause of difficulty to germinate. Hard seeds occupied about 85% of the total. Perforating the seed coat by a needle and scarifying the seeds by sand were the effective measures to break I. lenticellata seed dormancy. Scarification by sand for 7 h was the best treatment measure to improve the germination. The seeds germinated in a wide temperature range from 10℃ to 30 ℃, with the optimum temperature between 20 ℃ and 30 ℃. Low temperature was not beneficial to the germination. I. lenticellata had definite droughtresistant capability. Under the 25% polyethylene glycol 6000 (PEG)simulated drought stress, the seed germination rate could reach to 100%. However, drought stress decreased the germination rate, retarded the germination process, prolonged the germination cycle and preparing period, and lagged the germination peak phase. The parameters reflecting the sensitivity of I. lenticellata seed germination to drought stress were in  order of germination exponent > germination potential > germination rate. It was suggested that the optimal time for sowing I. lenticellata seeds in the field was early April, and the seeds should be scarified by sand for 7 h before sowing.

Bryophyte as an indicator of air quality in Shenyang City.

2009, 28(12):  2460-2465. 

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With the combination of the index of atmospheric purity (IAP) and the chemical analysis of heavy metals (Mn, Fe, Cu, Cr and Pb) contents in mosses, the air quality in Shenyang City was evaluated. According to the air quality, Shenyang City could be divided into three regions, among which, urban area had a far worse air quality than rural area, and the western urban area was worse than the eastern area, and southern urban area was worse than the northern area. In all the regions, Pbpollution was most serious, and should be taken attention. The results mentioned above were consistent with the air pollution index (API) obtained by monitoring stations.

Ecological adaptability of alien species Spartina alterniflora Loisel seed germination.

2009, 28(12):  2466-2470. 

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Different regimes of germination temperature at night and day, storage temperature and duration, and salt concentration were installed to study the characteristics of the seed germination and embryonic growth of Spartina alterniflora. Under the same germination temperature, the seed germination was not affected by light or dark, and the optimal temperature for germination was 16/26 ℃ (night/day), with a germination rate>90%. At the storage temperature -5, 0, 5, and 10 ℃, the germination rate of the seeds after 120 days storage exceeded 74%, indicating that S. alterniflora seeds could safely overwinter. When the salt concentration was 75-225 mmol NaCl ·L^-1, the germination rate was >90%. The optimal salt concentration for embryo growth was 150 mmol NaCl·L^-1. The growth of coleoptile and hypocotyl occurred before that of plumule and radicle, and the inhibition effect of salt on the growth of hypocotyl and coleoptile was smaller than that on radicle and plumule growth, which made the seedlings quickly unearth and well adapt the intertidal environment.

Regulation effect of nitric oxide on anti-oxidation system of tall fescue leaves under high light stress.

2009, 28(12):  2471-2476. 

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By applying exogenous NO or depleting endogenous NO, this paper studied the regulation effect of NO on the leaf antioxidation system of tall fescue (Festuca arundinacea) cultivars Arid3 and Houndog5 in hydroponic culture under high light stress. Comparing with the control, the endogenous NO production under high light stress in Arid3 leaves was increased by 201.5%, while that in Houndog5 leaves was only increased by 21.1%. Houndog5 leaves were more liable in suffering oxidative damage than Arid3 leaves, with the electrolyte leakage and MDA content increased by 72.6% and 85.1%, and 36.1% and 30.1%, respectively. Pretreatment with 0.2 mmol·L^-1of NO eliminator 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) obviously aggravated the oxidative damage to Arid3 and Houdog5, while supplementing with 0.1 mmol·L^-1 of NO donor sodium nitroprusside (SNP) alleviated the high light induced electrolyte leakage and malondiadehyde (MDA) and H₂ O₂ contents in both Arid3 and Houndog5 leaves. The production of superoxide (O₂^X) was reduced, the activities of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) were increased, and the lipoxygenase (LOX) activity was decreased. The effect of SNP was reverted when a NOspecial scavenger PTIO was added. It was suggested that NO could effectively protect Arid3 and Houndog5 leaves from oxidative stress by increasing the activities of ROS-scavenging enzymes under high light stress.

Ecosystem respiration and its affecting factors in typical marsh and shrub swamp in Xiaoxing'an Mountains.

2009, 28(12):  2477-2482. 

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Abstract: 〖WT5BZ〗
By using static chamber and gas chromatography, the seasonal and interannual variations of CO₂ fluxes in the Carex schmidtii marsh and Betula ovalifolia-C. schmidtii shrub swamp ecosystems in Xiaoxing’an Mountains were studied in the growth seasons of 2007 and 2008, with the relationships between these variations and environmental factors analyzed. The annual total CO₂emissions from C. schmidtii marsh and B. ovalifolia-C. schmidtii shrub swamp were 17841.78 and 20130.56 kg·hm^-2 in 2007, and 16331.78 and 18294.24 kg·hm^-2 in 2008, respectively. There was an obvious seasonal variation in the CO₂  emissions during the whole observation period, with the peak in summer (487.89 and 549.62 mg·CO₂ m^-2·h^-1 in 2007, and 391.53 and 438.31 mg·CO₂  m^-2·h^-1  in 2008 for the marsh and shrub swamp, respectively). A significant difference in the CO₂ emissions was observed between the two ecosystems, but no difference was found between years. Temperature was the key factor affecting the seasonal and interannual variations of CO₂  fluxes, and there existed significant positive relationships between the CO₂  fluxes and the air temperature, temperature inside the chamber, and soil temperature at 0-20 cm depth. Ground water level was also the main factor controlling the CO₂ emissions.

Turf weeds community composition and niches in Pearl River Delta Region in four seasons.

2009, 28(12):  2483-2488. 

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By using inverted ‘W’ sampling method, a field survey was conducted to study the seasonal dynamics of weed community in 32 plots of 5 cities in Pearl River Delta Region. The weed community was mainly consisted of Kyllinga brevifolia + Desmodium triflorum + Cynodon dactylon + Asiatic pennywort  in spring, K. brevifolia + D. triflorum + Cyperus rotundus + Hedyotis corymbosa in summer, K. brevifolia + D. triflorum+ H. corymbosa + C. dactylon in autumn, and A. Pennywort + K. brevifolia + Hydrocotyle sibthorpoioides + D. triflorum  in winter. The analysis of the weed niches in different seasons based on improved Levins niche breadth index and Pianka niche overlap index showed that most weeds had a niche breadth of < 0.5, and the weeds having a niche breadth of >0.5 included K. brevifolia (in four seasons), D. triflorum (in autumn), C. dactylon (in spring), and Oxalis pescaprae (in spring). For the dominant weeds, their niche overlap indices >0.60 were appeared most in spring and least in winter, and the maximum was appeared in summer, being 0.85 between H. sibthorpoioides and Lindernia crustacean, and Hedyotis diffusa and Ophioglossum vulgatum.

Ecological groups of plants in Ebinur Lake Wetland Nature Reserve of Xinjiang.

2009, 28(12):  2489-2494. 

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By using the χ²-test with contingency table and the Spearman correlation coefficient, the interspecific relationships among the main plant species in Ebinur Lake Wetland Nature Reserve were investigated. The main plant species in the Reserve were divided into 4 ecological groups, i.e., Haloxylon ammodendron + Halocnemum strobilaceum + Poacynum henclersonii + Kalidium foliatum + Reaumuria soogarica + Suaeda glauca + Karelinia caspica + Alhagi sparsifolia + Seriphidium kaschgaricum + Nitraria schoberi + Phragmites australis, Aeluropus littoralis + Tamarix ramosissima + Atriplex patens + Suaeda microphylla + Halimodendron halodendron + Cynanchum sibiricum + Halostachys caspica, Populus euphratica + Haloxylon persicum, and Lactuca auriculata + Glycyrrhiza uralensis + Asparagus persicus + Leymus secalinus + Apocynum venetum. The plant species in each group had the largest connection and correlation, and the longterm evolution made each ecological group have the greatest adaptive capability to its environment. The four ecological groups lived separately in the salinized lowland plain of desert transitional zone, saline land of lakeside, desert, and the spots in desert’s dominant species in this area. For the protection and recovery of the plants in the Reserve, it would be more effective to protect and recover the whole ecological species group rather than the individual plant species.

Spectral analysis of turbulence characteristics under different atmospheric stability regimes in Horqin grassland.

2009, 28(12):  2495-2502. 

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By using eddy covariance method, this paper dealt with the power spectra and cospectra of turbulence under three atmospheric stability regimes, i.e., unstable, near neutral, and stable, in Horqin semi-arid sandy grassland. The power spectra of longitudinal and lateral velocities under the three atmospheric stability regimes were similar, and in accordance with the -2/3 law. The power spectra of vertical wind speed had no inertial sub-ranges under near neutral atmospheric stratification, which indicated that the three-dimensional sonic anemomcter didn’t totally capture the signal. Under the stable atmospheric condition, there were horizontal turbulence motions and molecular diffusions. Moreover, the power spectra of both CO₂ and H ₂O illustrated that the open-path eddy covariance system could satisfy the estimation of turbulence fluxes over canopy, and the peaks of the power spectra were shifted to the high frequency end. The cospectra of vertical wind speed with three scalars were similar, with the inertial subranges of cospectra becoming shorter from unstable to stable atmospheric conditions and conforming to the -4/3 law, which illustrated that the spatial separation of instruments didn’t affect the observed fluxes.

Variation patterns of annual runoff in Sanhuajian basin of Yellow River.

2009, 28(12):  2503-2507. 

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Based the 1956-2007 annual runoff data from four hydrological stations in the middle reaches of Yellow River from Sanmenxia to Huayuankou (Sanhuajian basin), and by using the statistical methods of trend analysis and wavelet transform, this paper studied the variation characteristics of annual runoff in the basin. There was a distinct decreasing trend of the annual runoff in the basin. On the whole, the annual runoff experienced an alternation of two wet and two dry periods, whose turn points occurred at 1969, 1982, and 1987. The time-frequency variation of the annual runoff was mainly a 25-year cycle or a 2-8-year cycle.

Spatial variability of soil moisture vertical distribution and related affecting factors in hilly and gully watershed region of Loess Plateau.

2009, 28(12):  2508-2514. 

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Taking the semivariogram in geostatistics as a main analytical tool, this paper studied the spatial variability of soil moisture vertical distribution, and its relations to the land use type and topography in hilly and gully watershed region of Loss Plateau. The semivariogram curve of soil moisture vertical distribution could be well fitted by spherical model, suggesting that there was a strong or moderate spatial autocorrelation. The variation range was 2-5 meters. Orchard mainly affected the soil moisture content at the depth of 1-2 meters. In May, the soil moisture content was maximal and showed a uniform distribution; while in August, the soil moisture content was minimal because of the high air temperature and strong leaf transpiration. In sloping farmland and terrace, soil moisture content was relatively high, and had less vertical change. Terrace had the minimal soil moisture content in September, one month later than sloping farmland. Due to the developed tree root system, woodland had greater effects on the variability of soil moisture vertical distribution, which was manifested in a trend of increase-decrease-increase-getting stable. Overall speaking, shrub land had lower soil moisture content, whose vertical variation mainly occurred at the depth of 0-2 meters, while grassland had higher soil moisture content, whose vertical variation mainly occurred at the depth of 1 meter or less. The spatial variability of soil moisture vertical distribution had no correlation with topographical factors slope and aspect.

Effects of row and plant spacing on winter wheat flag leaf sucrose metabolism and grain yield.

2009, 28(12):  2515-2520. 

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A field plot experiment was conducted in the farm of Henan Agricultural University in 2006-2007 to examine the effects of row and plant spacing on the flag leaf sucrose metabolism and grain yield of winter wheat. Five ratios of row spacing to plant spacing, i.e., 1.5 (RP1), 3.4 (RP2), 6.0 (RP3), 10.5 (RP4), and 15.0 (RP5), were installed in a randomized block design with three replicates. The sucrose synthase (SS) and sucrose phosphate synthase (SPS) activities and soluble sugar and sucrose contents in flag leaves and the grain filling rate all showed a single peak variation with grain filling. Flag leaf SS and SPS activities and sucrose content increased with increasing row spacing but decreased with decreasing plant spacing, with the optimum in treatment RP3, which suggested that an appropriate row and plant spacing could effectively promote the allocation of photosynthates and their transformation into sucrose, supplying enough carbon assimilates for grain filling. The soluble sugar content in flag leaves in treatment RP3 was higher at early grain filling stage and had a relatively slow decrease at mid and late grain filling stages, compared with that in other treatments. In addition, the peak grain filling in treatment RP3 came later, and sustained a longer period with lower filling rate at early filling stage and with higher filling rate at late filling stage, keeping at 0.28 mg·d^-1 28-35 days after anthesis. The ear number, grain number per spike, and 1000-grain weight increased with increasing row spacing but decreased with decreasing plant spacing. Treatment RP3 had the harmonized yield-composing factors and the highest grain yield. Therefore, to reduce row spacing, enlarge plant spacing, and keep an appropriate ratio of row spacing to plant spacing would be an alternative in winter wheat planting.

Effects of nighttime temperature increase at different growth stage on the dry matter production and nutrient absorption of doublecropping rice.

2009, 28(12):  2521-2525. 

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Different nighttime temperature was established in two glasshouses to study the effects of nighttime temperature increase (NTI) at different growth stages on the dry matter production and nutrient absorption of doublecropping rice. The NTI from seeding to panicle differentiation promoted the dry matter production of early rice but suppressed that of late rice, whereas the NTI from panicle differentiation to heading exerted definite negative effects on the dry matter accumulation of both early and late rice. Post-heading NTI had less effects on the dry matter production of early rice, but slowed down the translocation of assimilates in early rice stem and sheath. On the contrary, postheading NTI increased the dry matter production of late rice, and promoted the translocation of assimilates in late rice stem and sheath. The NTI before panicle differentiation improved the root activity and nutrient accumulation of early rice but did the opposite to late rice, and the NTI from panicle differentiation to heading was not favorable to the nutrient accumulation of both early and late rice. The NTI at filling-ripening stage induced the root aging of early rice, but promoted the root activity of late rice. This study proved that the NTI at different growth stages of doublecropping rice had different effects on the dry matter production and nutrient absorption of early and late rice.

Feed conversion efficiency and growth characteristics of juvenile Chinese sturgeon (Acipenser sinensis) cultured with different diets.

2009, 28(12):  2526-2531. 

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Seven months old Chinese sturgeon (Acipenser sinensis) juveniles were fed with Limnodrilus sp. or artificial feed to study the feed conversion efficiency and growth characteristics of the juveniles. After 60-day growth trials, the body length of the juveniles fed with Limnodrilus sp. and artificial feed increased from 177.0 mm and 191.6 mm to 216.6 mm and 332.5 mm, and the body mass increased from 32.73 g and 44.39 g to 58.27 g and 264.71 g, respectively. The juveniles fed with Limnodrilus sp. and artificial feed had a feed conversion ratio 6.67-39.33 and 0.89-1.26, specific growth rate 0.19-2.33 and 1.38-3.94, and growth efficiency 2.54-14.99 and 79.56-204.44, respectively. There was an exponential relationship between the body length and body mass of the juveniles fed with Limnodrilus sp. or artificial feed, the exponential value being less than 3, which suggested the allometric growth of body length and body mass. The muscle’s crude protein and moisture contents of the juveniles fed with Limnodrilus sp. were (62.79±1.34) % and (82.23±0.79) %, respectively, slightly higher than those of the juveniles fed with artificial diet. Based on the feed conversion efficiency and the growth indices, it was concluded that artificial feed was better than Limnodrilus sp. for the growth of juvenile Acipenser sinensis.

Succession of phytoplankton community in exalted shrimp ponds during culture process.

2009, 28(12):  2532-2540. 

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An investigation was made on the succession of phytoplankton community and the main physical and chemical factors of water body in exalted shrimp ponds in Beiliao and Anli villages of Donghai Island, Zhanjiang during culture process, with the influence of the succession on the culture process analyzed. A total of 140 species of phytoplankton belonging to 76 genera and 7 phyla were identified. The dominant species in the two ponds with normal shrimp growth in Beiliao village were Gyrodinium spirale, Platymonas elliptica, Thalassiosira sp. 2, Gomphosphaeria lacustris  var. compacta, Gymnodinium sp. 1,Oocystis sp., Microcystis sp., Scrippsiella  trochoidea, Chroococcus sp., and Chroomonas acuta, while those in the two ponds with shrimp disease occurrence in the process of culture in Anli village were Microcystis aeruginosa, Gyrosigma tenuissimum, Amphora coffeaeformis, Phormidium tenue, Anabaena circinlis, Synechocydtis aquetilis, Chlamydomonas sp. 2, hroomonas acuta, and Gyrodinium spirale. The phytoplankton species, including dominant ones, were more abundant and complex in normal ponds than in disease-affected ponds. In normal ponds, the dominant species succeeded rapidly and alternated in phyla, while in disease-affected ponds, only Bacillariophyta species were replaced by Cyanophyta species during the succession. The phytoplankton cell density increased during the culture process in normal ponds, but decreased after a temporary increase at early culture stage in disease-affected ponds. No significant relationships were observed between the phytoplankton cell density and the main physical and chemical factors in the ponds during culture process. The diversity and evenness of phytoplankton species were higher in the normal ponds in Beiliao than in the disease-affected ponds in Anli, while the dominance degree of species was in reverse. The mild variability of water body’s physical and chemical factors as well as the high diversity and evenness but low dominance degree of phytoplankton species played important roles in keeping aquatic environment steady and healthy during the culture process in exalted shrimp pond.

Ant community structure and species diversity in Eastern Henan Plain.

2009, 28(12):  2541-2545. 

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An investigation was made on the ant species in five habitats (forest plantation, uncultivated land, farmland, resident area, and hill) in Eastern Henan Plain in April and May, 2006. A total of 62703 ants were collected, belonging to 43 species, 18 genera, and 5 subfamilies. The ant species composition and diversity differed with habitat. The more humandisturbed the habitat, the lower the ant diversity index; the higher quality and heterogeneity the habitat, the higher the ant diversity index was.

Spatial niches of |Syrmaticus ellioti and Lophura nycthemera in autumn and winter.

2009, 28(12):  2546-2552. 

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In September 2008 and February 2009, an investigation was made on the habitat ecological factors of Syrmaticus ellioti and Lophura nycthemera in Guanshan National Nature Reserve in Jiangxi Province, with the niche breadth, niche overlap, and interspecific competition of the two species analyzed by eight habitat resource axes. The integrative niche breadth of S. ellioti and L. nycthemera was only 0.294 and 0.268, respectively, indicating a narrow niche. S. ellioti  had narrower altitude-and slope niche breadths but wider aspect niche breadth than L. nycthemera, while the other resource axes niche breadths of the two species were similar. The niche similarity of the two species was 0.425, and the competition coefficient was 0.584, indicating an intense competition between the two species. It was suggested that the protection of vegetation and water resources at low altitude should be strengthened, and human disturbances should be reduced.

Vertical distribution patterns of polycyclic aromatic hydrocarbons in Shantou mangrove wetland sediments.

2009, 28(12):  2553-2560. 

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Sediment samples at 0-10 cm and 10-20 cm depths were collected from Shantou mangrove wetland, and their particle sizes and the contents of polycyclic aromatic hydrocarbons (PAHs), organic carbon, and black carbon were determined by the methods of ultrasonic solvent extraction and GC-MS. The two sediment layers were dominated by 4-ring PAHs, followed by moderate molecular weight PAHs, and lower or molecular weight PAHs. The contents of PAHs, organic carbon, and black carbon, and the percentages of silt and clay were higher in 0-10 cm than in 10-20 cm layer, but the pH value had no difference between the two layers. Correlation analysis showed that in the two layers, PAHs content had no correlation with organic carbon content but significantly correlated with black carbon content (P<0.01), and significant correlations were observed among the contents of silt, black carbon, and PAHs (P<0.05), suggesting that silt content was the main factor affecting the PAHs distribution in Shantou mangrove sediments, and black carbon could be the essential factor for the stratification of PAHs in different sediment layers.

Endurance of Elodea nuttallii to high concentration of nitrogen and phosphorus.

2009, 28(12):  2561-2566. 

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In a growth experiment, five relatively constant gradients of total nitrogen (TN) and phosphorous (TP) concentrations were installed to study the endurance of Elodea nuttallii to high concentrations of nitrogen and phosphorus. The pH value, DO, planktonic chlorophyll a, and periphytic chlorophyll a in the culture solutions as well as the height, wet and dry weights, and chlorophyll a concentration of E. nuttallii were compared among the treatments. Elodea uttallii could endure the stress of TN=10 mg·L^-1and TP=0.4 mg·L^-1, and no abundant phytoplankton occurred under this stress. However, under the stress of TN=50 mg·L^-1and TP=2 mg·L^-1and of TN=100 mg·L^-1and TP=4 mg·L^-1, E. nuttallii growth was obviously limited, and plankton increased but periphyton decreased markedly, which suggested that the high concentration TN and TP in water body could have direct damage to E. nuttallii, and the shading caused by phytoplankton multiplication could partly limited the growth of E. nuttallii. As for Taihu Lake, in which, the average concentrations of TN and TP were lower than 10 mg·L^-1and 04 mg·L^-1, respectively, the decline of submerged aquatic macrophytes could not be caused by the direct harm and stress of nitrogen and phosphorus.

Inhibitory effects of different types aquatic macrophyte communities on blue-green algae.

2009, 28(12):  2567-2573. 

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Two common macrophytes Nymphoides peltatum and Hydrilla verticillata were chosen to construct three types of aquatic microphyte communities, i.e., N. peltatum community (floating-leaved), H. verticillata community submerged), and N. peltatum + H. verticillata compound community, which were respectively cultivated in a simulated eutrophic aquatic environment with the blue-green algae introduced from natural water body, aimed to study the inhibitory effects of these macrophyte communities on algal growth. All the test communities showed an evident inhibitory effect, with the sequence of N. peltatum community > compound community > H. verticillata community. By the end of the experiment, the chl-a concentration was decreased by 63.1%, 44.7% and 3.3%, respectively. N. peltatum community had an intensive inhibitory effect on Cyanophyta, whose total cell density was decreased by 99.5%, but the total cell density of Chlorophyta was increased by 31.6%. H. verticillata community showed more inhibition on Chlorophyta, but less impact on Cyanophyta. In N. peltatum + H. verticillata compound community, the total cell density of Cyanophyta decreased by 95.9%, and that of Chlorophyta remained at a lower level. The composition of algae varied with macrophyte communities. In N. peltatum community, the dominant algae changed gradually from Cyanophyta such as Microcystis and Chroococcoid to Chlorophyta such as Chlorella, Tetraedron, and Scenedesmus; in H. verticillata community, Cyanophyta remained dominant, and companied with less species such as Chlorella, Tetraedron, and Cryptomonas; and in the compound community, the variation of algal composition was similar to that in N. peltatum community. During the experiment, the total cell density of Cyanophyta decreased gradually, while Chlorophyta increased. Macrophyte biomass increased markedly, with the wet weight of N. peltatum and H. verticillata in their single and compound communities increased by 129.8% and 63.6%, and 108.8% and 66.5%, respectively. The macrophyte growth showed a distinct influence on the aquatic environment factors such as illumination, temperature and pH. In N. peltatum community, the reduction rate of illumination at water depth 20 cm had a significant correlation with the chl-a concentration in water body, suggesting that N. peltatum’s shading effect was the main cause of algal inhibition.

Bacterial diversity in oil wastewater during its treatment process.

2009, 28(12):  2574-2578. 

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The total DNA was directly extracted from the oil wastewater of Shuguang Wastewater Treatment Plant in Liaohe Oilfield, and by the methods of PCR-DGGE and conventional water quality analysis, the relationships between the bacterial diversity in the wastewater during its treatment process and the water quality were analyzed. There were significant differences in the bacterial communities at different treatment stages, not only some common bacterial species, but also the unique bacteria population. The bacterial diversity was negatively correlated with the CODcr and TPH concentrations in wastewater. The higher the CODcr and TPH concentrations, the lower the bacterial diversity was. During treatment process, the similarity coefficient (C_s) of bacterial communities in the wastewater increased with enhancing bacterial diversity, and finally formed a stable population structure.

Responses of leaflitter decomposition rate to acid mine drainage pollution.

2009, 28(12):  2579-2585. 

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According to the pollution gradient of Hengshishui River contaminated by the acid mine drainage (AMD) from Dabaoshan Mine of Guangdong, seven contaminated sites and three noncontaminated sites were selected from the upstream to the downstream of Hengshishui River and its branches. The leaf litters of Castanopsis fissa and Schima superba enclosed in 0.5 mm mesh bags were put in these sites to study their decomposition rate along the pollution gradient. With the increase of water pH and the decrease of heavy metals concentration in river water, the decomposition rates of the two species of leaf litters increased gradually, and were significantly lower in contaminated sites than in non-contaminated sites (P<0.05). At the non-contaminated site I, the decomposition rates of C. fissa and S. superba leaf litters were 6.5 and 10.5 times higher than those at the most contaminated site A which was closest to the Mine. The leaf litter decomposition rates were positively correlated with water pH, and negatively correlated with the Cu, Cd, Zn, and Pb concentrations in river water, suggesting that the lower water pH and the higher heavy metals concentration in river water could result in a lower leaf decomposition rate. Our results indicated that leaf litter decomposition rate was sensitive to the changes in water quality, and could be used as an indicator in the evaluation of stream ecosystem integrality.

Differentially rated growth and plate effect of settlement patches in city and town: A case study in Suzhou, Wuxi, and Changzhou regions.

2009, 28(12):  2586-2592. 

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To reveal the settlement growth pattern during  urbanization on regional scale, the relative growth rates (RGRs) and spatial autocorrelations of settlement patches in Suzhou, Wuxi, and Changzhou regions were studied, based on the multitemporal Landsat images acquired in 1979, 1991, 2001, and 2005. In the study regions, the settlements in city and town expanded significantly from 1979 to 2005, with an increase of 11.1 times in area, and went through three transitional phases, i.e., rapid growth (1979-1991), slow growth (1991-2001), and rapid growth (2001-2005), which differed from the economic growth rhythms. A significant positive global spatial autocorrelation in settlement RGR based on Moran’s I index was found in the three phases, indicating that the settlements with similar behaviors tended to be aggregated collectively. The results from local spatial association analysis (Getis-Ord G_i^* index) indicated that there existed several landscape plates, within which, the adjacent settlements manifested coupling behaviors in terms of relatively consistent high or low RGRs. These landscape plates could be changed in size and spatial location in different phases, but as a whole, there existed an eastward shift of growth focus in the study regions in 1979-2005.

Spatial identification of builtup land expansion and its significance.

2009, 28(12):  2593-2599. 

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With the rapid development of economy and urbanization, built-up land expansion has posed an enormous pressure on land carrying capacity and ecological security. To identify and quantify the builtup land expansion pattern is one of the prerequisites of land consolidation. Taking Dongguan as an example, and based on GIS and RS techniques, an algorithm was established by spatial topology operation to quantitatively identify the builtup land expansion in different phases from 1979 to 2005. The builtup land expansion pattern in Dongguan in 1979-2005 could be described as a general process of leapfrog-edge-expansion-mixed-expansion-edge-expansion. Edge-expansion was the main expansion type, but leapfrog growth was dominant at the early phase. During the late phase of land expansion, the proportion of leapfrog growth decreased while that of infilling growth increased, because of the limited land resources and urban space.

Spatial heterogeneity of soil nutrients in Ejina oasis.

2009, 28(12):  2600-2606. 

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By the methods of geostatistics, the spatial heterogeneity of soil organic matter, total nitrogen, total phosphorus, and total potassium in Ejina oasis was studied. All the test nutrient variables had significant spatial heterogeneity. The spatial variation of soil organic matter fitted exponential model, while those of soil total nitrogen, total phosphorus, and total potassium fitted spherical model. Soil organic matter, total nitrogen, and total potassium were greatly affected by soil structural factors, while soil total potassium was coaffected by structural and random factors. The spatial variation ranges of soil total nitrogen, total phosphorus, and total potassium were 7.68-7.86 km, and that of soil organic matter was comparatively small, being 5.4 km. The spatial distribution of soil nutrients was high in south and north oasis, and low in central oasis.

Ecological functions of wheat/cotton intercropping system.

2009, 28(12):  2607-2612. 

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Wheat/cotton intercropping has a long history in China. This paper summarized the structural characteristics of this intercropping system, its functions in ecosystem material and energy cycling, and the relationships between these functions and the interactive effects of wheat and cotton. Some suggestions for further study were proposed on the arrangement modes of this intercropping system to maintain cotton field biodiversity and ecosystem balance, enhance land and natural resources (radiance, heat and water) utilization efficiency, and achieve higher ecological and economical benefits in cotton field.

Degradation and restoration of seagrass ecosystem: Research progress.

2009, 28(12):  2613-2618. 

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Seagrass bed is one of the coastal wetland ecosystems with the highest productivity and biodiversity, and experiencing degradation worldwide. Natural disturbance and anthropogenic impact are the causes for the degradation, and anthropogenic impact is the main one. Significant changes in the photosynthesis rate, photosynthetic pigments concentration, ratio of chlorophyll to carotenoid pigment, and enzyme activities are observed under stresses of heat, elevated light level, water salinity, and chemical pollutants, which are the physioecological mechanisms of seagrass degradation. Seagrass monitoring and protection programs have led to the recovery of some seagrass beds. Biodiversity maintenance, seagrass transplantation, and ecosystem services valuation should be the focuses in the further researches on the seagrass restoration in China.

Soil seed bank of forest communities in Southwest Karst Mountains: A review.

2009, 28(12):  2619-2623. 

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Soil seed bank is an important part of the study of Karst Mountains, especially for the structure, function, and dynamics of vegetations in Karst region. This paper reviewed the methodologies and main subjects in the study of soil seed bank in this region. Based on a comprehensive analysis on related achievements, some problems to be urgently approached were presented. It was considered that the soil seed bank under dominant or constructive species in forest communities, the dynamic changes of soil seed bank under effects of invasive species and their affecting mechanisms on the species diversity of forest communities, and the roles of soil seed bank in vegetation restoration, etc., should be further studied, which would provide theoretical guidance for the studies on the soil seed bank and the practices in vegetation restoration in Southwest Karst region of China.

Effects of sediment nutrition level on the interspecific relationship between two submerged macrophytes.

2009, 28(12):  2624-2627. 

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A 2 × 2 factorial field experiment was conducted to study the effects of sediment nutrition level on the interspecific relationship between two submerged macrophytes, exotic Elodea nuttallii and native Vallisneria spiralis. On the sediments with either high or low nutrition level, E. nuttallii had an obvious superiority in competition. Under the mixed planting with E. nuttallii, the growth of low density V. spiralis was less affected, but that of high density V.spiralis  was inhibited significantly. The same picture was observed in the E. nuttallii growth under the mixed planting with V. spiralis. Sediment nutrition level affected the growth of  E. nuttallii  at both low and high densities significantly, but only had significant effects on the growth of low density V. spiralis. It was suggested that exotic submerged macrophyte E. nuttallii  would affect the species distribution and structure of aquatic plant communities in lake ecosystems.

Application of fuzzy linear regression model in predicting river water total nitrogen concentration.

2009, 28(12):  2628-2632. 

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Taking the Aozhou section of Xiangjiang River as a case, the total nitrogen concentration in water body and related affecting factors were characterized with triangular fuzzy number, and the triangular fuzzy parameters were introduced into the existing fuzzy linear regression model to predict the total nitrogen concentration in water body. The relative errors between the predicted and measured values of total nitrogen concentration in the section in 2002-2005 were less than 20%, with a qualified prediction rate being 100%, which suggested that the modified fuzzy linear regression model had definite practicability in predicting the total nitrogen concentration in river water.