Table of Content

10 October 2008, Volume 27 Issue 10

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Articles

Spatial distribution patterns of tree species in a secondary forest in Changbai Mountain.

ZHANG Yun¹;ZHANG Chun-yu¹;ZHAO Xiu-hai¹;WU Yao-xiang²;ZHOU Hai-cheng²

2008, 27(10):  1639-1646 . 

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By using Ripley’s K function, the spatial distribution patterns of tree species in a 5.2 hectares secondary forest plot in Changbai Mountain of Northeast China, as well as the spatial distribution and association of dominant tree species at their different growth stages, were analyzed. 34 tree species (27 common species and 7 rare species) were recorded, with a total of 15 688 individuals. Among the 27 common species, 23 species were mainly in aggregate distribution, and the other four had a random distribution. All the 7 rare species were distributed randomly. With the sequence of sapling → small tree → big tree, Acer barbinerve, Acer pseudosieboldianum, Fraxinus mandshurica, Abies nephrolepis, and Pinus koraiensis had a decreased aggregate distribution and tended to be distributed randomly, while other species showed no obvious change pattern in their spatial distribution. Among 45 pairs of 10 dominant tree species, 11 pairs had significant positive association, and 1 pair showed significant negative association.

Effects of farmland afforestation on ecosystem carbon stock and its distribution pattern in semiarid region of Northwest China.

BAI Xue-shuang^1,2;HU Ya-lin^2,3;ZENG De-hui²;JIANG Zhi-rong^1,4

2008, 27(10):  1647-1652 . 

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Taking the farmlands under different years (0, 5, 10, and 15 a) of poplar afforestation in semiarid region of Northwest China as test objects, this paper studied the effects of farmland afforestation on the ecosystem carbon (C) stock and its distribution pattern. The results showed that with increasing year of afforestation, the biomass C increased gradually, and most of it was allocated in tree stem. Compared with the control (CK1), the soil organic C content in 0-10, 10-20, 20-40, and 40-60 cm layers after afforested for 5 years was decreased by 7.65%, 36.66%, 51.94%, and 21.4%, while that after afforested for 10 years was increased by 69.63%, 62.46%, 17.07% and 66.94%, respectively. After afforested for 15 years, the soil organic C content in 0-10, 20-40 and 40-60 cm layers was increased by 31.96%, 81.50%, and 58.05%, respectively, but that in 10-20 cm layer was decreased by 13.38%, compared with the control (CK2). The C stock in 0-60 cm soil layer was decreased by 31% after afforested for 5 years, but increased by 47% and 41% after afforested for 10 and 15 years, respectively. The total C stock in 5 year-old poplar plantation was decreased by 10%, but that in 10- and 15-year-old poplar plantations was 3 and 6 times of the farmland. It was indicated that after farmland afforestation with poplar, the ecosystem C stock increased significantly, and most of the increased C was allocated in aboveground biomass C pool. At the early stage of afforestation, soil organic C stock tended to decrease, but thereafter, this stock increased gradually and was even higher than the control.

Floral syndrome and breeding system of Mirabilis jalapa L.

CHEN Xiang^1,2;HU Xue-hua¹;XIAO Yi-an^1,2,3;XIE Qian¹;WANG Chun-xiang^1,2;LI Yun^1,2;DAI Wen-hong¹

2008, 27(10):  1653-1658 . 

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Flowering and breeding characteristics are important for understanding plant population reproduction. In this paper, the flowering dynamics and breeding system of Mirabilis jalapa L. were studied by using the data of pollen－ovule ratio (P/O), pistil recipient phase, out-crossing index (OCI), pollen viability, numbers of pollen grains and their germination ratio on stigma, and emasculation. The results showed that the flowering period of M. jalapa was about four months (from June to October), and the life span of individual flower was generally 2-3 days. For each flower, the flowering process could be divided into five periods, i.e., pre－dehiscence, initial dehiscence, full dehiscence, perianth closure, and withering, based on the changes in floral morphology and anther dehiscence. In the period of perianth closure, the percentage of stigma inside of closed perianth was 66.80% when it was sunny, 81.65% when it was cloudy, and 99.22% when it was rainy. The floral diameter was 22-28 mm. In the majority of M. jalapa, there was a temporal isolation between male and female organs within the same flower, i.e., the gynoecium ripened early, stigmas and anthers were arranged at the same height, and the outcrossing index (OCI) was 3. However, in a lesser percentage of flowers, there were temporal and spatial isolations betweenmale and female organs within each flower. The gynoecium ripened early, with an out-crossing index (OCI) of 4. According to the criteria put forward by Dafni, most of M. jalapa individuals had the breeding system of self－compatible and only requiring pollinators sometimes, and fewer were of outcrossing, partially self-compatible, and requiring pollinators. The pollen－ovule ratio (P/O) was approximately 269. Based on Cruden’s criterion, the breeding system could be termed as facultative autogamy. For about 6 hours after flowering, when stigmas were at the highest receptivity, 56.29% of the pollen was viable. According to the results of emasculation, bagging, and artificial pollination, there was no agamospermy, and the breeding system of M. jalapa was determined to be largely self-compatible, and only requiring pollinators sometimes. M. jalapa preserved a high percentage of stigma inside of closed perianth, which could be regarded as an adaptive strategy for reproduction under unfavorable environmental conditions.

Relationships between leaf epidermal morphology and dust-retaining capability of main garden trees in Chengyang District of Qingdao City.

LI Hai-mei;LIU Xia

2008, 27(10):  1659-1662 . 

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In this paper, the dust-retaining capability of 11 garden tree species in Chengyang District of Qingdao City was determined, and the micro-configuration of their leaf epidermis was observed. The results showed that there were great differences in the dust-retaining capability of test tree spices, with the maximum being 4 times or more of the minimum. Rainfall decreased the particulate density on leaf surface significantly, but the efficiency differed greatly with tree species. Different tree species had different leaf epidermal microconfiguration. The leaves of Fraxinus pennsylvanica and Pyracantha fortuneana had smooth surfaces, their cells and stomata arranged regularly, and thus, their dust-retaining capability was poor; while those of Platanus orientalis, Cercis chinensis, and Lagerstroemia indica had many tubercles or evident ridgelike rumple, and hence, their dust-retaining capability was stronger. The denser configuration and more obvious concave/convex of leaf epidermis were in favor of dust-retaining for trees.

Effects of nitrogen fertilization on fine root biomass production and turnover of Fraxinus mandshurica plantation.

MEI Li¹;WANG Zheng-quan²;ZHANG Xiu-juan³;YU Li-zhong⁴;DU Ying¹

2008, 27(10):  1663-1668 . 

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Fine root turnover has close relations with soil nutrient availability. However, owing to the differences in test objects and in the methodology for assessing fine root behaviors, some contradictory results could be obtained. In this paper, sequential soil core, in-growth core, and decomposition method were employed to study the effects of nitrogen fertilization on the fine root (diameter<1 mm) biomass production and turnover of Manchurian ash (Fraxinus mandshurica) plantation, and four calculation methods were used to determine the fine root’s standing biomass and turnover rate. The results showed that under nitrogen fertilization, the fine root’s standing biomass decreased, but its mean annual production (93.105 g·m^-2·a^-1) in 0-30 cm soil layer in 2003 and 2004 was similar to the control (93.505 g·m^-2·a^-1). The fine root’s mean turnover rate was higher under nitrogen fertilization (0.917 times·a^-1) than under the control (0.710 times·a^-1). Fine root production decreased significantly with soil depth, but its turnover rate was generally in adverse. Greater differences were observed in estimating the fine root production and turnover rate by the four calculation methods, with the highest values by sequential coring approach with compartmental-flow calculation, followed by in-growth-core, minimum maximum and adding increments method calculations.

Effects of elevated CO₂ and O₃ on modular growth of Ginkgo biloba.

XU Wen-duo¹;FU Shi-lei²;HE Xing-yuan¹;CHEN Wei¹;ZHAO Gui-ling³;ZHOU Yuan³;WEN Hua¹

2008, 27(10):  1669-1674 . 

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The study on the effects of elevated CO₂ and O₃ on the modular growth of Ginkgo biloba showed that elevated O₃ inhibited the growth of axialand lateral shoots significantly (P<0.01), while elevated CO₂ had no significant effects on the diameter growth of G. biloba (P>0.05). The diameter growth of G. biloba was inhibited significantly by elevated O₃ and its combination with CO₂ (P<0.01). Elevated CO₂ increased the leaf area, dry matter accumulation, water content, and drought resistance; while the combination of elevated CO₂ and O₃ only increased the leaf dry matter accumulation significantly (P<0.01) but had less effects on leaf -area. Elevated O₃ had significant inhibitory effects on the leaf modular growth of G. biloba, under which, the leaf area and dry matter accumulation decreased significantly (P<0.05), compared with the control.

Development characteristics of biotic crusts on Shapotou vegetated sand dunes.

LI Shou-zhong¹;ZHENG Huai-zhou¹;LI Shou-li²;SHEN Bao-cheng²

2008, 27(10):  1675-1679 . 

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In this paper, the biological and non-biological characteristics of biotic crusts on Shapotou sand dunes fixed with artificial vegetations were investigated, and the method of using time as the substitute of space was applied to study the development and succession patterns of the crusts. The results showed that the biotic crusts had a rapid soil formation process. Along with the duration of dune fixation, the thickness of the crusts and the clay content in them increased, while the bulk density showed a declining tendency. Lichen, algae, and moss were the dominant biotic species, and the formation and development of the crusts was also an important biological process. The development of the crusts involved the interactions between biotic and abiotic components during sand fixation, and was also a process of clay accumulation, biotic species development, and soil formation. A qualitative classification of three development stages of the crusts was summarized, based on the characteristics of their genesis.

Effects of NaCl stress on ion distribution and photosynthesis of Catharanthus roseus seedlings.

WANG Jing-yan;LIU Zhao-pu;LIU Ling;LIU Chong

2008, 27(10):  1680-1684 . 

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Catharanthus roseus seedlings were treated with 1/2 Hoagland solutions containing different concentrations (0, 50, 100, 150, 200, and 250 mmol·L^-1)of NaCl. After 5day treatment, the seedlings biomass, relative contents of inorganic ions in cells of different tissues, leaf chlorophyll content, and photosynthetic parameters were estimated. The results showed that NaCl stress decreased the seedlings fresh mass and dry mass significantly. Under NaCl stress, the relative contents of Na⁺ and Cl^- in cells increased significantly, but the increment somewhat differed with different tissues. In root and stem, epidermal cells had the greatest increment, followed by cortex cells, and stelar cells; while in leaf, epidermal cells had the greatest increment, followed by cortex cells, spongy tissue cells, and palisade tissue cells. The relative contents of cell K⁺ and Ca²⁺ were decreased under NaCl stress, and the decrement was also differed with different tissues. In root and stem, epidermal cells had the greatest decrement, followed by cortex and stelar cells; while in leaf, palisade tissue cells had the greatest decrement. In a word, NaCl could inhibit the growth of C. roseus seedlings, and disrupt their ion balance. To avoid the damage caused by NaCl stress, the seedlings would congregate excessive Na⁺ and Cl^- in their epidermal cells. Under NaCl stress, the chlorophyll content, photosynthetic rate (P_n), intercellular CO₂ concentration (C_i), stomatal conductance (G_s) and transpiration rate (T_r) decreased while stomatal limiting value (L_s) was in adverse, indicating that stomatal limiting was the main factor reducing the photosynthetic rate of C. roseus seedlings.

Effects of one precipitation process on CO₂ flux and thermal transportation in alpine meadow of Qinghai-Tibetan Plateau.

ZHANG Fa-wei¹;LI Ying-nian¹;ZHAO Xin-quan¹;GU Song¹;WANG Qin-xue²;DU Ming-yuan³;TANG Yan-hong²

2008, 27(10):  1685-1691 . 

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The thermal transportation and carbon budget in alpine meadow of Qinghai-Tibetan Plateau are highly sensitive to climate change, but little research was made about the influence of precipitation because of its complicacy. Based on the data measured by three-dimensional ultrasonic anemometer and fast-response open-path infrared CO₂/H₂O analyzer, the effects of one precipitation process from 8-17 August, 2002 on the thermal transportation and CO₂ flux in alpine meadow of northeastern Qinghai-Tibetan Plateau were analyzed. The results showed that the precipitation process decreased the air temperature, soil temperature, total radiation, surface reflected radiation, photosynthetically active radiation (PAR), net radiation, soil heat flux, latent heat flux, and sensible heat flux by 23.3%, 23.1%, 61.9%, 58.9%, 61.7%, 57.9%, 268.3%, 61.6%, and 71.0%, and increased the atmospheric humidity and CO₂ flux by 27.0% and 38.6%, respectively. Precipitation weakened the influence of PAR on the daytime net CO₂ exchange (NEE) of the alpine meadow ecosystem, but enhanced the effects of soil temperature on nighttime respiration. Precipitation intensity had no significant influence on the daytime NEE, but decreased the nighttime respiration.

Correlations between leaf area index and hyperspectral vegetation index of spring wheat on Loess Plateau.

ZHANG Kai¹;WANG Run-yuan¹;WANG Xiao-ping¹;GUO Ni¹;HAN Hai-tao²

2008, 27(10):  1692-1697 . 

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In a field plot experiment, the canopy spectral reflectance at different developmental stages of four spring wheat varieties (Dingxi24,Longchun8139, Gaoyuan602 and Dingxi38) under different planting densities was measured, and the leaf area index (LAI) corresponding to the spectra was determined. In order to estimate the LAI and to establish the best prediction model, nine spectral vegetation indices in common use were calculated, and their correlations with and predictabilities for LAI were analyzed and estimated. The results showed that the nine spectral vegetation indices had good correlations with LAI, and could better predict the LAI at four different growth stages, with the best at heading and flowering stages. The correlations between vegetation indices and LAI were more significant and the predictions were better in the whole growth period than in any growth stages. Among the vegetation indices, R₈₁₀/R₅₆₀ produced the best prediction of LAI. Therefore, by selecting vegetation index R₈₁₀/R₅₆₀(x) as independent variable, the prediction model about spring wheat LAI (y),y=0.1769x^1.5261, was established, and evaluated and tested by the experiment data of different varieties and different planting densities. The average precision (R²) and the RMSE and accuracy of the estimation were 0.9280, 0.0762 and 0.9068, respectively, indicating that this prediction model had preferable reliability and wide applicability.

Temporal variation of soil respiration and its affecting factors in a maize field during maize growth season.

HAN Guang-xuan¹;ZHOU Guang-sheng²;XU Zhen-zhu²

2008, 27(10):  1698-1705 . 

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Based on the continuous measurement of soil respiration in a maize field in Northeast China during maize growth seasons in 2004 and 2005, the temporal variation of soil respiration was studied, with the effects of heat and water factors, soil properties, root biomass, and leaf area index (LAI) analyzed. The diurnal variation of soil respiration showed an asymmetric pattern, with the minimum appeared at 6:00-7:00 and the maximum at 13:00.There was a great fluctuation of soil respiration during the growth season in 2005. The mean soil respiration rate was 3.16 μmol CO₂·m^-2·s^-1, with a maximum of 4.77 μmol CO₂·m^-2·s^-1 on July 28 and a minimum of 1.31 μmol CO₂·m^-2·s^-1 on May 4. Statistic analysis showed that soil temperature was the driving factor to the diurnal variation of soil respiration. Soil temperature and soil moisture were the dominant environmental factors affecting the seasonal variation of soil respiration, and explained 87% of its variability. LAI and root biomass were positively related to soil respiration rate, indicating that biotic factors also affected the seasonal variation of soil respiration. However, soil properties such as soil organic content, total nitrogen content, and C/N ratio had poor correlations with soil respiration. Top-dressing nitrogen fertilizer increased soil respiration significantly.

Stability of rice grain’s milling quality in relation to genotype × environment interaction and climatic factors.

LI Xiu-fen¹;JIA Yan²;DENG Yuan³;LIU Jiang¹;JIANG Xiu-ying³;SHEN Feng³

2008, 27(10):  1706-1710 . 

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Based on AMMI model, the genotype (G) ×environment (E) interaction on the grain’s milling quality of 25 rice cultivars from Liaoning Province was studied, with the stability of the milling quality in relation to the eco-climatic adaptability of these cultivars discussed. The results showed that there existed significant differences in the brown rice rate and head milling rice rate among different sites, varieties, and G×E interactions. The cultivars with high stability in brown rice rate were V12 (Huajing 49), V3 (Liaojing 294), and V4 (0163), while those with high stability in head milling rate were V3, V1 (XianS 38), and V18 (LDC 248). For brown rice rate, cultivars V15 (Shennong 9810), V19 (Yutian 301), and V7 (Qiao 201-2) had special eco-climatic adaptability to low or high temperatures; for head milling rate, cultivar V22 (Ying 9207) presented special eco-climatic adaptability to high temperature, V11 (0157) to low temperature and drought, and V15 (Shenong 9810) and V16 (Longpan 5) to rainless or pluvial conditions, respectively.

Comparisons of Terra- and Aqua MODIS in band reflectance and vegetation index.

WANG Jing; GUO Ni

2008, 27(10):  1711-1717 . 

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The comparisons of single band reflectance and vegetation index between Terra MODIS and Aqua MODIS showed that Terra MODIS and Aqua MODIS had significant correlations in single band reflectance and vegetation index, and the correlations for vegetation index were more obvious than for single band reflectance. The values of single band reflectance from Terra MODIS were lower than those from Aqua MODIS, but vegetation indices were in reverse. In addition, the differences of single band reflectance and vegetation index between Terra MODIS and Aqua MODIS changed over time, and they were greater in winter for vegetation indices, and in summer and autumn for single band reflectance. For different vegetation types, the differences of vegetation indices between Terra MODIS and Aqua MODIS showed a similar rule, while the differences of single band reflectance between Terra MODIS and Aqua MODIS were complicated. The differences in single band reflectance and vegetation index between Terra MODIS and Aqua MODIS were smaller for meadow and plain than for other vegetations, but greater for broadleaf forest and annual doubleharvest crops.

Spatial distribution of major grassland species and its relations to environment in Yanhe River catchment based on generalized additive model.

HE Xiao-hui^1,2;WEN Zhong-ming²;WANG Jin-xin¹

2008, 27(10):  1718-1724 . 

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A quantitative study on the relationships between the spatial distribution of major grassland species in 145 sampling plots in Yanhe River catchment and the 12 environmental factors extracted by GIS spatial analysis was conducted, and the geographic distribution of individual species with relations to environmental gradient was analyzed by using generalized additive model (GAM). The results showed that the main environmental factors affecting the spatial distribution of the grassland species were mean annual precipitation, mean annual air temperature, and evaporation, followed by seasonal fluctuation of air temperature, and slope position and grade. There existed close relationships between the major grassland species and the environment, and each species had its own specific environmental gradient space, with different responses to the environment factors. GAM could better depict the relationships between species spatial distribution and environment factors, and it was feasible to employ this model to explore the relationships between single species distribution and environment in a catchment scale.

Application of ISSR in identifying Flammulina velutipes strains.

SU Hong-yan;WANG Lei;MING Yong-fei;LIU Lin-de

2008, 27(10):  1725-1728 . 

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In this paper, ISSR molecular fingerprinting markers were employed to identify six strains of Flammulina velutipes by using 8 primers selected from 20 ISSR primers. A total of 136 DNA fragments were amplified, of which, 111 (81.6% of all bands) were polymorphic. The standard genetic identity among the test strains ranged from 0.5674 (between Nongda04-1 and Quanhe04-1) to 0.8947 (between Taihang05-1 and Hebei03-1). The UPGMA cluster analysis based on the standard genetic distances showed that cultivated F. velutipes strains could be divided into three groups. It was indicated that ISSR marker was an effective tool for the strain identification and fingerprint analysis of F. velutipes.

Genetic diversity of eight Schlechtendalia chinensis populations from Guizhou Province: A study with inter-simple sequence repeats markers.

WANG Ding-jiang¹;YANG Han-yuan¹;ZHONG Yang²;REN Zhu-mei³

2008, 27(10):  1729-1733 . 

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Inter-simple sequence repeat (ISSR) molecular markers were used to detect the genetic diversity among 139 individuals from 8 populations of Chinese sumac aphid Schlechtendalia chinensis collected from Guizhou Province, China. 12 ISSR primers were evaluated for their ability to produce polymorphic bands, and these primers yielded a total of 133 scorable bands, averaged 11 bands each primer. There was no population-specific marker, which was present in one population but absent in the others. Popgene analysis indicated that 100% of these loci were polymorphic, even though the primers were not intentionally selected for high variability. The genetic similarity was 0.899-0.955, and the genetic distance was 0.046-0.106, indicating a lower genetic diversity of S. chinensis populations. Cluster analyses showed that the aphid populations were divided into 2 groups, and the genetic diversity had no evident correlation with geographic area but negatively correlated with the mean air temperature and rainfall in March.

Quantitative distribution of pelagic polychaetes in coastal waters of East China Sea and its relations to environment.

HUANG Mei-ling^1,2;XU Zhao-li¹

2008, 27(10):  1734-1739 . 

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Based on the data of four seasons investigations in the coastal waters of the East China Sea (28°00′ N-32°00′N, 122°00′ E-123°30′E) from 2002 to 2003, this paper studied the seasonal characteristics of the changes in total abundance and species of pelagic polychaetes, the relationships between these changes and water masses, the quantitative changes of dominantspecies and their contribution to polychaetes, and the environmental adaptation of dominant species, with the ecological characteristics of pelagic polychaetes in the outer East China Sea compared. The results showed that the total abundance of pelagic polychaetes in study area had an obvious seasonal change, with the highest average abundance (1.30 ind·m^-3) in summer and the lowest (0.04 ind·m^-3) in spring. A total of 15 species of pelagic polychaete were identified, and Typhloscolex muelleri, Vanadis sp., Plotohelmis capitata were the dominant species. Among the dominant species, only T. muelleri appeared in four seasons, and its dominance was higher in summer and winter, being 0.16 and 0.1, respectively. Vanadis sp. only appeared in summer, while P. capitata was in autumn. The contribution of T. muelleri was higher in spring and summer, being 1 and 0.94, respectively, which suggested that this species adapted well in warm waters and euryhaline environment. Our study indicated that the complex species composition and the greater spatiotemporal change in species number were the characteristics of pelagic polychaetes in the coastal waters of the East China Sea.

Growth characteristics of Oxyeleotris marmoratus under artificial breeding.

HUANG Xiao-rong^1,2;ZHUANG Ping^1,2,3; ZHANG Long-zhen^1,2;ZHANG Tao¹, FENG Guang-peng^1,2;ZHAO Feng^1,2

2008, 27(10):  1740-1743 . 

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The study on the growth characteristics of Oxyeleotris marmoratus under artificial breeding showed that after two months growth, the body length (L) of O. marmoratus increased from （17.36±0.99）cm to （19.05±0.57）cm, and its body mass (W) increased from （139.13±12.90）g to （205.50±15.78）g. Different duration of breeding had no significant effects on feeding ratio (FR) (P>0.05), but affected specific growth rate (SGR), feed conversion ratio (FCR), and growth efficiency (GE) significantly (P<0.05). The body length had a linear relationship with breeding duration, and the body mass had an exponential growth with the duration. There was an exponential relationship between body length and body mass, and the exponential value b within different durations was all close to 3, suggesting an isometric growth between the body length and body mass of O. marmoratus.

Mitigation effects of spermine on Hg injury of Nymphoides peltatum’s antioxidant enzyme system.

WANG Xue;XU Heng-jian

2008, 27(10):  1744-1748 . 

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This paper studied the effects of different concentration exogenous spermine (Spm) on the activities of antioxidant enzymes (SOD, CAT, POD, APX), generation rate of O^-·₂, and contents of MDA, free polyamines (PAs), chlorophyll and soluble protein inNymphoides peltatum leaves under 15 μmol·L^-1 Hg stress. The results showed that under the Hg stress, 0.05-0.5 mmol·L^-1 of exogenous Spm could significantly increase the contents of leaf spermidine (Spd), Spm, chlorophyll, and soluble protein, promote the activities of SOD, CAT, and APX, and decrease the generation rate of O^-·₂ and the accumulation of MDA. It was suggested that 0.05-0.5 mmol·L^-1 of exogenous Spm could enhance the resistance of N. peltatum to oxidant stress, and mitigate the toxic effects of Hg. The optimum dose of exogenous Spm was 0.05-0.1 mmol·L^-1, while 5 mmol·L^-1 of Spm could aggravate the toxic effects of Hg.

Effects of chitosan on meat chicken’s anti-oxidation activity and production performance.

LU Mei-luan¹;QIU Xiao-yan³;ZHENG Sen-lin¹;JANG Tu-yan³;ZHANG Wei⁴; SONG Yu-fang²

2008, 27(10):  1749-1752 . 

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In a pilot hennery, chitosan agents were applied to approach their functions on meat chicken’s anti-oxidation activity and production performance by determining the superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activities and malondialdehyde (MDA) concentration in blood serum, and the immune organ index, percentage of abdomen fat, and ratio of chicken meat mass to feedstuff. The experiment was designed as 6 groups, with 100 one-day-old chickens for each. It was indicated that after applying two chitosan agents with different molecular weight at low doses, the serum SOD activity was significantly higher (P<0.05) in 60-day-old chickens, but had less difference in the chickens of other ages. The chitosans applied had no significant effects on the serum MDA concentration and GSH-PX activity. Compared with those fed with antibiotics, the chickens fed with chitosans had an enhanced survival rate, but the percentage of their dissected abdominal fat (PDAF) and the ratio of meat mass to feedstuff decreased slightly. It was suggested that chitosan could be a potential natural green product to replace antibiotics for chicken feeding.

Wetland eco-hydrological models: A review.

WANG Yu-li;WANG Xuan;SUN Tao

2008, 27(10):  1753-1762 . 

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To establish response models between ecological factors and hydrological factors of wetlands is a new field in wetland research, which can provide a scientific basis for wetland protection, assessment, and management. Based on the characteristics of wetland eco-hydrological processes, the wetland eco-hydrological models were classified into estimation models of ecological water circulation, simulation models of eco-hydrological chemical processes, and response models of organisms to hydrological process. The research progress of wetland eco-hydrological models was reviewed, and its development trend was discussed.

Scenario analysis and its application in ecosystem research.

ZHANG Xiang-long; WANG Jun;YANG Xin-jun;SUN Jing

2008, 27(10):  1763-1770 . 

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Ecosystem is a self-adaptive, complex system with multi-stable state, and its fate is hardly to be predicted precisely because of the high uncertainties. In recent years, scenario analysis has being employed to better understand the mechanism of the multistable state of ecosystem to avoid the limitations of traditional prediction and modeling methods. Scenario analysis is a systemic method for the creative thinking about the ecosystem’s possible complex and uncertain futures. Its central idea is to consider a variety of possible futures that include many important uncertainties rather than to focus on the accurate prediction of a single outcome. Through positing several informed, plausible, and imagined alternative future environments, the purpose of scenario analysis is to change current mental models, enhance the participation of stakeholders, and improve decision-making. This paper reviewed the concept and process of scenario analysis, clarified the differences between scenario analysis and traditional methods, and, based on several successful cases, summarized the development of the methodology of scenario analysis and its application in ecosystem research.

Effects of great volcanic eruption on historical vegetation succession on eastern slope of Changbai Mountains.

DAI Lu^1，2;WU Yao-xiang³;HAN Shi-jie²;LI Yu-wen¹

2008, 27(10):  1771-1778 . 

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A great volcanic eruption with the characteristics of Plinian eruption was happened in Changbai Mountains 800 years ago. This eruption was classified into two large scale eruption periods and the thenceforth several small scale eruptions. Great amount of volcanic particles was released at the time of the outbreak. These particles were blown to the east by the strong deflective west wind, and mainly deposited on the eastern slope of Changbai Mountains, making the vegetation in this area experience extinction several times. The vegetation type on the eastern slope was larch (Larix olgensis) forest, which differed greatly from the vegetations on the other slopes, possibly due to the devastating damage of volcanic eruption to the vegetation on the eastern slope. In this study, the original vegetation on the eastern slope before volcanic eruption was reverted through identifying the pollen spore and carbonized wood. The relationships between historical changes in vegetation and volcanic activities were analyzed, aimed to demonstrate the changes in vegetation on the eastern slope before eruption and the impacts of volcanic eruption on the evolution process of vegetation. It was suggested that larch forest is the transitional community established after the volcanic eruption.

Research methods and affecting factors of hydraulic redistribution between the interface of root and soil: A review.

YANG Xin-guang^1,2;NIU De-cao¹;FU Hua¹

2008, 27(10):  1779-1784 . 

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Hydraulic redistribution is defined as a process of water translocation along vertical or horizontal direction by roots between the interface of root and soil. The earlier experiments of hydraulic redistribution were conducted with split-root apparatus under laboratory condition, and the soil water content was determined by gamma densitometry, weighing method, drying method, and TDR, etc. Under field condition, the hydraulic redistribution was studied with four methods,i.e., measuring the diurnal and seasonal fluctuations of soil water potential by thermocouple thermometry, deuterium labeling, measuring the sap flow in root xylem, and measuring the soil volumetric water content by TDR. The factors affecting hydraulic redistribution include soil water, soil texture, plant species, and transpiration, etc. In the future, the researches on the occurrence conditions of hydraulic redistribution between the interface of root and soil, as well as the relationships between the affecting factors and the frequency and quantity of hydraulic redistribution should be strengthened, so as to provide theoretical basis for making better use of the water regulation functions of hydraulic redistribution.

Interactions between seagrass and its epiphytic algae: A review.

ZHANG Jing-ping^1,2;HUANG Xiao-ping¹

2008, 27(10):  1785-1790 . 

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Seagrass bed is an important ecosystem in coastal wetland. The massive reproduction of epiphytic algae caused by eutrophication was supposed to be one of the main reasons inducing the worldwide large scale decline of seagrass beds in recent years. This paper reviewed the research advance in past two decades on the interactions between seagrass and its epiphytic algae, including the roles and functions of epiphytic algae in seagrass bed, the seagrass-epiphyte relationship in nutrient exchange, and the effects of over-densely covered epiphytes on seagrass leaves (mainly the decrease of light and nutrient availability). Some important aspects of further study on the seagrass-epiphyte relationship were suggested: 1) mechanisms in material exchange between seagrass and epiphytic algae, 2)competition in nutrient uptake between seagrass and epiphytic algae, 3) impact of epiphyte biomass on the decrease of light availability and photosynthesis capacity of seagrass, 4) contributions of seagrass and its epiphytic algae on the primary productivity of seagrass bed in relations to environmental factors, and 5) modeling of seagrass growth regulated by biological factors based on in-situ observation data.

Research advances in antioxidant enzymes for diagnosing environmental contamination.

LIU Shuo¹;ZHOU Qi-xing^1,2

2008, 27(10):  1791-1798 . 

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Antioxidant enzymes play a significant part in reactive oxygen scavenger and antioxidant defense systems. With increasing attentions to environmental problems, antioxidant enzymes have been widely used as the biomarkers for diagnosing environmental contamination and assessing the toxic effects of pollutants on living organisms. In this review, the varieties and characters of antioxidant enzymes were introduced, with their combined effects discussed. The responses of antioxidant enzyme activity and gene expression to environmental contamination were analyzed based on different pollutant exposures, and some factors affecting the enzymes were summarized from the aspects of species sensitivity and environmental condition. The focuses of further studies on the effective biomarkers for diagnosing environmental contamination were put forward.

Effects of acid deposition on methane emission and carbon cycling in peatland.

LIU Zheng-zheng;ZENG Cong-sheng;ZHONG Chun-qi; TONG Chuan

2008, 27(10):  1799-1805 . 

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Peatland is a large carbon reservoir, which can act as a source or sink of greenhouse gases. Recent researches show that the SO₄^2- from acid rain can stimulate sulfate-reducing bacteria into a population capable of outcompeting methanogens for substrates, and thereby, can suppress methane emission. This microbemediated interaction may have a significant effect on northern peatlands’ and global methane emission. It is most likely that sulfate concentration, sulfur cycling, substrates, and temperature are the main factors limiting the competition of sulfate-reducing bacteria with methane-producing bacteria in peatlands. Through rapid sulfate cycling, acid deposition could suppress the production and emission of methane from peatland, but at present, the effects of acid deposition on the carbon pool and carbon cycling in peatland were still not drawn a conclusion. This paper reviewed the research advances in the effects and action mechanisms of acid deposition on the methane emission and carbon cycling in peatland, and put forward the prospects for the future researches in China.

AGNPS model and factors affecting its prediction deviation.

HUANG Zhi-lin¹;TIAN Yao-wu^1,2; XIAO Wen-fa¹

2008, 27(10):  1806-1813 . 

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Agricultural nonpoint source (NPS) pollution induces serious and extensive environmental and water quality problems that are characterized by the emissions being either difficult or too expensive to observe. The NPS pollution is potentially affected by any type of land use, and relates to the geographical location of pollution sources diffusion and controlling measures implementation, involving in complex ecological processes and landscape patterns. Spatial simulation modeling is commonly accepted in dealing with the NPS pollution problems, but associated with spatial uncertainty. The annualized agricultural nonpoint source (AnnAGNPS) model designed by U.S. Department of Agriculture (USDA-ARS and NRCS) is a continuous and distributed simulation model widely used for watershed assessment, which expands the capabilities of its predecessor AGNPS, a single eventmodel. In this paper, the features, spatial and temporal scales, and limitations of AnnAGNPS 4.0 Model were introduced, with its uncertainty and the factors affecting its prediction deviation analyzed. It was thought that the parameters in USDA-ARS and NRCS handbook and agricultural handbook (Number 703) fall short of in most cases in China, and there were obvious errors in the results of simulation when the parameters were used. According to the action mechanisms of AnnAGNPS, the principles and methods of applying the parameters were advanced, which could be helpful for the valid application of AnnAGNPS 4.0 in China.

Considerations on the establishment and improvement of eco-compensation mechanism in China.

SONG Peng-fei^1,2;ZHANG Zhen-yun³;HAO Zhan-qing¹

2008, 27(10):  1814-1817 . 

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Eco-compensation is a hot topic in academic and social fields in recent years, and to construct a more complete theoretic system and an operating mechanism is a matter of great urgency. Beginning with the nature of eco-compensation, i.e., to internalize the externalities and to clarity the limits of property rights, the eco-compensation practice in China was briefly reviewed, and, based on the elaborate analyses on five core elements including account of compensation, compensation receivers, compensation payers, eco-compensation criteria, and forms of compensation, a practice path on eco-compensation was constructed. Finally, some critical issues on improving eco-compensation mechanism, i.e., determination of reasonable implementation program, appropriate balance between interests relations, and accurate positioning of managers roles, were put forward.

Effects of foliar-spraying anthraquinones from aloe at grain-filling stage of winter wheat on its leaf photosynthesis and grain yield.

WANG Tai-xia¹;DING Wei-hua¹;LI Jing-yuan¹;HU Zheng-hai²

2008, 27(10):  1818-1821 . 

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UV-B radiation is one of the factors that lead to the decrease of wheat photosynthetic activity. From May 2 to June 5, 2007, an experiment was conducted in Xinxiang of Henan Province to study the effects of foliar-spraying the anthraquinones from aloe at grain-filling stage of winter wheat on the leaf photosynthetic rate, photorespiration rate, chlorophyll content, and MDA content, aimed to explore new approaches to prevent or alleviate the UV harm. The results showed that after spraying 1 and 5 mg·L^-1 of anthraquinones, the photosynthetic rate raised by 38.03% and 39.73%, chlorophyll content increased by 3.53% and 3.83%, and MDA content decreased by 11% and 23%, respectively. The anthraquinones could absorb solar UV radiation, and convert the harmful UV into blue or yellow light which can promote plant photosynthesis. It was suggested that foliar-spraying appropriate concentrations of aloe’s anthraquinones could promote wheat photosynthetic activity, alleviate UV harm, and thus, increase wheat yield.

Transfer patterns of metal elements in soil-plant system in a contaminated area in Guangxi, China.

CUI Yu-jing;ZHANG Xu-hong;WANG Li-ming

2008, 27(10):  1822-1825 . 

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Heavy metal cadmium (Cd) is a very toxic element ubiquitous in the environment. The Cd in soil is easily absorbed by plants, and consequently, produces adverse effects on human health through food chain. Owing to the fact that the Cd transfer in soil-plant system and the adverse effects of Cd on human health are influenced by the interactions between Cd and some other metal elements, e.g., Ca, Cu, Fe, and Zn, the study on the mechanisms of the influences of these elements on Cd transfer through food chain and the accumulation of Cd in human body becomes a hotspot. In this study, a survey was performed on the vegetable field in a Cd-contaminated area in Guangxi. The results showed that in contaminated area, the concentrations of Cd, Ca, Cu, Fe, Pb, and Zn in vegetables were obviously higher than those in uncontaminated area, and different vegetable varieties had greater differences in the absorption and accumulation of Cd, Cu, Pb, and Zn. The transferring ability of these four metal elements in soil-plant system was Cd>Zn>Cu>Pb, and the transfer of Cd was affected by the elements in coexistence.

Effects of vegetation restoration pattern on microbial quantity and enzyme activity in iron tailings.

WANG Yan-chao¹;LI Yu-ling¹;WANG Hui¹;GUO Jiang²;WANG Ying¹;ZHANG Li-li¹; YUAN Yu-xin¹

2008, 27(10):  1826-1829 . 

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The analyses on the microbial quantity and enzyme activity in the Malanzhuang iron tailings in Qian’an City of Hebei Province under effects of different vegetation restoration patterns showed that there were significant differences in the quantities of major microbes in the tailings, with the most for bacteria, followed by actinomyces, and fungi. The microbial quantity and the enzyme activity in 0-20 cm layer of the tailings decreased in the orderof plantation>natural restoration>new tailing. Both the microbial quantity and the enzyme activity decreased significantly with increasing sampling depth. There were positive relationships between the microbial quantity and the enzyme activity in the tailings, but the correlation degree was different. It was concluded that both the natural restoration and the plantation could improve the microbial quantity and enzyme activity in iron tailings, and the effect of plantation was more significant.

Segmental rectification of tree ring photogrammetry.

LIU Qi-jing

2008, 27(10):  1830-1834 . 

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Digital photos can be used conveniently for measuring the width of tree ring, but geometric rectification is required because of image distortion. This paper introduced a new and easy-to-use method for the correction, which is called segmental rectification. By dividing a section into segments with certain intervals, the pixel resolution is determined for each segment, which is then used to calculate the tree ring width in corresponding segment. The basic process is: 1) divide the section into segments with 1 cm or smaller intervals, 2) calculate the resolution after counting the number of pixels in each segment, and 3) measure the tree ring width in pixels before converting to length unit based on segment-specific resolution. With common image processing software, the approach is simple and practical, and high accuracy can be secured.