Table of Content

10 August 2014, Volume 33 Issue 8

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Community dynamics in different successional stages of secondary Pinus massoniana forest in south Anhui Province.

LI Wei-li1, YU Qian1, GUO Xue-yan1, DA Liang-jun1,2,3**

2014, 33(8):  1997-2004. 

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To explore successional dynamics of community structure and associated soil response within Pinus massoniana forests, species composition, community structure and habitat properties were determined among three forests differing in restoration stages (i.e., 10, 20-30 and 50 a) in Guniujiang Nature Reserve in Anhui Province, by using a spacefortime substitution approach. The results showed that 1) with the succession, the species richness decreased, but the Shannon diversity index increased. The dominance of deciduous trees declined, but the dominance of evergreen trees progressed in the canopy layer; 2) The distribution of diameter size followed the unimodal type for P. massoniana across the three successional stages, but changed from L to inverse-J type for Castanopsis eyrei through forest succession; evergreen shrubs exhibited good performance in growth; 3) With the forest succession, soil total nitrogen and organic matter contents increased, and soil fertility increased gradually, while the pH value decreased.

Leaf N, P and K resorption of major tree species in a montane region of eastern Liaoning Province, China.

YAN Tao1,2,3, YANG Kai1,2, ZHU Jiao-jun1,2**

2014, 33(8):  2005-2011. 

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Nutrient resorption, one of the important mechanisms for nutrient conservation in plant species, plays an important role in litter decomposition and nutrient cycling. To clarify the nutrient resorption between Larix spp. in the plantation forest and four native broadleaved tree species (i.e., Quercus mongolica, Acer mono, Juglans mandshurica and Fraxinus rhynchophulla) in the secondary forests, we measured N, P and K concentrations in mature and senescent leaves of these five tree species in a montane region of eastern Liaoning Province, China. The results showed that the N, P and K concentrations of senescent leaves were significantly lower than those of mature leaves, except for the K concentration of Larix spp. (P<0.05). The N resorption efficiency of J. mandshurica was significantly different from that of the other three broadleaved tree species (P<0.05). The P resorption efficiency of F. rhynchophulla was significantly different from that of Q. mongolica and A. mono (P<0.05). Furthermore, the K resorption efficiency of A. mono was significantly different from that of the other three broadleaved tree species (P<0.05). N, P and K resorption efficiencies of Larix spp. were generally lower than those of the broadleaved tree species, especially its P resorption efficiency was significantly lower than that of F. rhynchophulla (P<0.05) and its K resorption efficiency was significantly lower than that of J. mandshurica and F. rhynchophulla (P<0.05). All of these indicated that the larch made a positive feedback on soil nutrient availability via reducing the nutrient resorption efficiency and improving the litter nutrient input.

The alteration of carbon stock of forest ecosystem by tree species composition in Taiyue Mountain.

GUO Chao, ZHOU Zhi-yong**, KANG Feng-feng, SUN Jian-xin

2014, 33(8):  2012-2018. 

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Tree species is a vital biotic factor in determining the carbon stock of forest ecosystems. In the forested area of Taiyue Mountain, carbon storage in wood, herb and shrub, soil was separately investigated according to the vertical structure of forest ecosystem. Subsequently, the effects of forest type and tree species composition on forest carbon stock were studied. The carbon storage was 156.58, 145.05 and 128.52 t C·hm^-2 in broadleaved forest, coniferous forest and mixed forest, respectively. Significant correlations were found between the carbon storage of forest ecosystem and the proportions of Quercus liaotungensis and of Pinus tabuliformis in forest communities. Carbon storage in wood, soil and total carbon storage of forest ecosystem markedly increased with the volume proportion of Q. liaotungensis, but decreased with that of P. tabuliformis. Although similar relationships were found between wood carbon storage and the proportion of broadleaved tree species and of coniferous tree species, no effects of broadleaved and coniferous tree species were detected on carbon storage of herb and shrub in mixed forest ecosystems. In conclusion, Q. liaotungensis and P. tabuliformis played a more important role than broadleaved and coniferous tree species in manipulating the carbon storage of forest ecosystems in Taiyue Mountain.

Biomass allocation of aboveground components of Phyllostachys edulis and its variation with body size. 

WANG Chen1, JIANG Ze-hui2, GUO Qi-rong2, LIU Guang-lu2, LI Zhan-dong1, SHI Lei2**

2014, 33(8):  2019-2024. 

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To clarify biomass allocation and its variation with culm body size of Moso bamboo (Phyllostachys edulis) is of theoretical and practical significance, contributing to a better understanding of the intraspecific variation in biomass and thus improving the estimation accuracy of both biomass and carbon stock. The results of such study can also be applied to the oriented cultivation and production and lead to added values of Moso bamboo, thus increasing farmers’ income. Here, a destructive sampling method was employed to examine biomass allocation, its variation with body size, and the respective relationships of biomass of leaf, branch and culm of Moso bamboo based on 227 standard bamboos. The mean individual biomass values of leaf, branch and culm were 0.84, 1.42 and 6.84 kg, accounting for 9.21%, 15.60% and 75.19% of the total aboveground biomass, respectively. The biomass values of three aboveground components mutually showed strong linear relationships (R² > 0.75, P < 0.001). Significant correlations were respectively found between the diameter at breast height (DBH) or the culm height (H) and the biomass allocation of aboveground components, both of which could be expressed with power functions. It was inferred from the power functions that the culm of Moso bamboo with smaller DBH (or H) had a larger proportion of biomass in the upper components (e.g., leaf), compared to those with larger DBH (or H). The results of this study are consistent with the allometric partitioning theory, namely, the biomass allocation of a plant is constrained by its body size. A further experiment is needed to verify whether the biomass allocation of Moso bamboo also complies with the optimal partitioning theory.

Seed predation and dispersal of Hevea brasiliensis in Xishuangbanna introduction area.

ZHOU Hui-ping**, CHEN Guo-yun, YUE Hai, CUN Ming

2014, 33(8):  2025-2030. 

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Tagged seeds of Hevea brasiliensis were separately released in five habitats. The seed fate and seed predators were observed. The results showed that, in the pure rubber plantation and the seasonal rainforest, most seeds remained untouched in situ (>80% and >98%, respectively), while in the rubberbamboo mixed forest and in the secondary forest seed predation was almost 100%, and in the neighboring rubber plantation it was 50%. Chisquare test indicated that the seed predation rate of the rubberbamboo mixed forest was significantly higher than that of the pure rubber plantation and the seasonal rainforest, and it was obviously higher in the secondary forest than in the neighboring rubber plantation (P<0.001). Most seeds were predated in situ or after removing, with a very small amount of seeds being stored. Most seeds (>80%) were transported <10 m away. By infraredsensor camera and feeding experiment, Rattus tanezumi and Rattus surifer were confirmed as the primary seed predators. This study indicated that seeds of H. brasiliensis mainly predated by small rodents with a high predation intensity, low storage rate and shortdistance dispersal (<10 m) in Xishuangbanna introduction area.

Comparative study of biomass of modules and morphological plasticity of four Asteraceae species at the flowering stage.

WANG Ju-hong1, CHEN Wen2**

2014, 33(8):  2031-2037. 

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The biomass and allocation of modules, as well as their variation of four Asteraceae species including two invasive alien species Bidens pilosa and Conyza canadensis, and two native species Gnaphalium adnatum and Vernonia cinerea at the flowering stage were studied, and the correlation models on plant height and each module of four species under three habitats, and on reproductive and nutritional modules were built to reveal the strategy of reproductive allocation of these species in different habitats, and to determine whether the phenotypic plasticity of invasive species is greater than that of noninvasive ones. The result showed that the biomass of stems of B. pilosa in the nutrientpoor and dry habitat exhibited an increasing tendency, and that of leaves and capitulums decreased. The biomass values of stems, leaves, capitulums, and total biomass of C. canadensis in the nutrientrich and moist habitat were significantly greater than in the other two habitats (P<0.01). The biomass of roots of G. adnatum and V. cinerea in the nutrientpoor and dry habitat had an increasing tendency, and that of stems, capitulums decreased. It is indicated that the invasive plants can regulate their growth and biomass allocation to adapt to the heterogeneous environment. In addition, the coefficients of variation of modules of B. pilosa, C. canadensis, V. cinerea were greater than that of G. adnatum. The correlation of reproductive and nutritional modules of those species displayed a tendency of allometry, indicating that these three species may have a high phenotypic plasticity to enhance the tolerance and adaptability to diverse environments.

Precipitation in May is a key factor to determinate the distribution of ephemeral plants in Gurbantünggüt Desert.

LI Qiao-mei1, ZENG Yong1, SUN Qin-ming1, LIU Tong1**, HAN Zhi-quan2, LI Yong-guan1, LIU Hua-feng1

2014, 33(8):  2038-2045. 

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Ephemeral plants are a unique part of desert flora. They are mainly distributed in the Junggar Basin and are of great importance to the stability of dunes in the Gurbantünggüt Desert. However, quantitative information on the relationship between precipitation and ephemeral plant distribution remains poorly studied. In 2009, 2011, and 2012, ephemeral plants in 73 plots located on the southern edge of Gurbantünggüt Desert were investigated. Using ArcGIS 10.0 software, daily precipitation data of each plot were obtained by spline interpolation at 0.05° resolution from daily realtime gridded precipitation data of China. Using richness and coverage of ephemeral plants as the dependent variables, and precipitation during the growth period, season and month as independent variables, stepwise multivariate linear regression and principal component analysis were conducted to determine the effects of different precipitation types on the distribution of ephemeral plants and on the distribution of ten widespread and ten rare species. Results indicated that the richness of ephemeral plants was correlated with precipitation in spring, leaf expansion period, and May (classified according to different criterions), while their coverage was correlated with precipitation in spring, fruiting period and May. Precipitation in May and June had a significant impact on the widespread species, and precipitation in March, April, May and July had a significant impact on the rare species. Altogether, precipitation in May is a critical factor on the distribution of ephemerals in Gurbantünggüt Desert.

 

Climatic index and risk analysis of winter freezing injury for winter wheat in Hebei.

DAI Li-qin1,2**, KANG Xi-yan1,2, YAO Shu-ran1,2, Li Chun-qiang1,2, YU Chang-wen3, WANG Meng4

2014, 33(8):  2046-2052. 

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Based on the data of daily meteorological factors in winter, winter wheat freezing injury and winter wheat cultivars in Hebei Province from 1981 to 2010, the three types of climatic indexes of winter wheat freezing injury, including severe temperature downing in early winter, winter with long cold days and freezethawing, were established by using rank sum test and Bayesian discriminant analysis. According to the risk analysis principle and probability density function, the climatic models of risk probability index for winter wheat freezing injury were set up, and the freezing risk of winter wheat in Hebei was assessed. The results showed that the freezing injury due to severe temperature downing in early winter was affected mainly by the variation range of temperature and the extreme minimum temperature during the temperature downing process. The freezing injury due to winter with long cold days was influenced mainly by the cold intensity of winter season, including the number of days of winter wheat overwintering stage, the mean temperature, the number of days with the minimum temperature being lower than the critical temperature, and the accumulated negative temperature during the same period. The freezing injury due to freezethawing was affected mainly by the extreme minimum temperature in the microthermal process with daily average temperature above 0 ℃. The major risk of winter wheat freezing injury in the north Hebei was due to winter with long cold days, and the high and subhigh risks of such freezing injury mainly occurred in the middlenorth part of Tangshan and Qinhuangdao and northwest of Baoding. The main risk of winter wheat freezing injury in the middle and south Hebei was freezethawing and severe temperature downing in early winter, and the high and subhigh risks of such freezing injury mainly occurred in the east part of Xingtai and Handan, and northwest part of Baoding.

Effect of deficit irrigation on development and quality of muskmelon in plastic greenhouse.

YUAN Bao-zhong1**, QIAN Jing-jing1, BIE Zhi-long2, KANG Yao-hu3

2014, 33(8):  2053-2059. 

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In this study, five water treatments (T₈₅, T₇₅, T₆₅, T₅₅ and T₄₅, standing for 85%, 75%, 65%, 55% and 45% of the soil waterholding capacity, respectively) were set and a drip irrigation (10 mm each time) was triggered when the soil water level reached the designed lower limit of relative soil water content during the reproductive period of muskmelon to investigate the effects of water deficit on fruit development and quality in a plastic greenhouse. The results showed that there were three stages of fruit development, about 7-10 days (the growth rate of the fruit diameter was 3-5 mm·d^-1) after pollination was the first stage, 10-19 days (1-2 mm·d^-1) was the second stage, and 19-35 days (<1 mm·d^-1) was the third stage. Fruit growth rates in the different water treatments showed a fluctuating trend with supplemental irrigation. Under different irrigation treatments, supplemental irrigation produced different compensation effects on yield due to the water deficit stress. With the decrease of irrigation water amount, the yield was decreased by 0.60%, 3.59%, 10.18% and 16.17% compared with T₈₅. T₇₅ had no difference in weight of single fruit compared with T₈₅, but had significant differences with other treatments. The fruit diameter decreased, the fruit coat became lighter, and fruit shape index decreased with decreasing the irrigation amount. The soluble solid, limbic sugar and center sugar contents were raised firstly and then reduced, with the highest in T₇₅. Soluble sugar and protein contents were the highest in T₇₅, but no significant difference was found among the different treatments. Fruit Vc and free amino acid contents were the highest in T₆₅, being significantly different with other treatments. The contents of sugar and acid were the highest in T₇₅, being significantly different with those in T₆₅, T₅₅, and T₄₅. Overall, T₇₅ was suitable as a soil water lower limit for muskmelon at the reproductive period in plastic greenhouse in Wuhan.

Effects of stubble and mulching on soil wind erosion.

CONG Pei-fei1,2, YIN Guang-hua1**, GU Jian1,2, LI Wen-hui1,2, HUANG Peng-fei1,2

2014, 33(8):  2060-2064. 

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To explore the effect of the different stubble height and mulching biomass on soil wind erosion, a field experiment by using the quadratic general rotary unitized design was conducted in a windy desert area of western Liaoning Province. Results showed that the wind erosion of the routine farming practices was 15.74 t·hm^-2. The stubble height and the straw mulching quantity significantly affected soil wind erosion, and the effect of straw mulching quantity was greater than that of the stubble height. The stubble height and mulching interactively affected soil wind erosion. When the stubble height was higher than 18.0 cm and the straw mulching quantity was more than 2500.0 kg·hm^-2, the intensity of soil wind erosion reduced significantly (up to 54%). The established regression model of stubble height and straw mulching quantity showed that, when the stubble height and the straw mulching quantity were 33.9 cm and 4255.7 kg·hm^-2, respectively, the intensity of soil wind erosion in cropland was the lowest, with only 0.42 t·hm^-2.

Soil dissolved organic carbon concentration under different land-use patterns in a hilly area of central Hunan Province, China.

ZHANG Shi-ji1, XIANG Wen-hua1,2**, SUN Wei-jun1, FANG Xi1,2

2014, 33(8):  2065-2071. 

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In order to understand the effects of land-use patterns on soil organic carbon (SOC) pool, a study was conducted to examine the seasonal variation of soil dissolved organic carbon (DOC) and its correlation with soil moisture content, carbon (C) and nitrogen (N) concentrations in six adjacent land use types: (1) Lithocarpus glaber + Cyclobalanopsis glauca secondary forest, (2) Cunninghamia lanceolata plantation, (3) Phyllostachys edulis forest, (4) seedling nursery land, (5) slope cropland, and (6) paddy field in a hilly area of central Hunan, China. The results showed that DOC concentrations decreased with soil depth and with the minimum difference of DOC concentrations between soils layers occurring in autumn, while the proportion of DOC increased with increasing the soil depth. Soil DOC concentrations were significantly different among the land use types. Soil DOC concentrations decreased by 10%-12%, 11%-12%, 13%-19%, 18%-25% and 37%-42% in P. edulis forest, C. lanceolata plantation, paddy field, slope cropland and seedling nursery land, respectively, as compared with L. glaber + C. glauca secondary forest. The differences in DOC concentration among different land use types were maximum in summer. Seasonal variations in DOC concentration were considerable but a similar change pattern was found in the six land use types. Soil DOC concentrations were significantly higher in spring, summer and winter than in autumn. Positive correlations were found between DOC concentrations and soil moisture content, TOC, MBC, ROC, MOC, total N, and available N. These results demonstrated that landuse patterns significantly affected soil DOC concentration and its spatial distribution. Soil DOC concentrations were significantly reduced when secondary forests were converted to plantations or agricultural lands.

Characteristics of carbon fluxes for tea garden ecosystems in the hills of western Lake Taihu Basin, China.

SUN Xiao-xiang1,2, YANG Gui-shan1**, XU Xi-bao1

2014, 33(8):  2072-2077. 

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This paper analyzed the characteristics of carbon fluxes for tea garden ecosystems in the hills of western Lake Taihu Basin. Three representative types of tea garden ecosystems with various ages (3, 9, and 20 a) were selected, and carbon fluxes were measured by static chamber/IRGA. Diurnal and seasonal variations of carbon fluxes for tea garden ecosystems showed a single peak of -1.10 mg·m^-2·s^-1. Tea garden ecosystems presented as a carbon sink on sunny days, while as a carbon source on cloudy days. Tea picking reduced carbon fluxes in March and April, especially for the tea gardens with 9 and 20 a. Pruning promoted carbon fluxes for the tea gardens at 3 and 9 a with a similar trend from May to September, which largely reduced their carbon sequestration capacity. Tea garden ecosystems were a significant carbon sink, and the net carbon flux reached -304.04 g C·m^-2·a^-1. Carbon sequestration capacity for the tea garden ecosystems is similar to that of forest ecosystem, and thus the exploitation of tea garden ecosystems would not lead to a reduction of carbon sink.

Carbon sequestration service valuation of Zhalong wetland ecosystem.

PANG Bing-liang, CUI Li-juan**, MA Mu-yuan, LI Wei

2014, 33(8):  2078-2083. 

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As its abundant carbon storage, wetland ecosystem plays an important role in slowing down global climate warming. Taking Zhalong wetland as an example, the carbon sequestration values of both plant and soil were assessed, based on Carnegie-Ames-Stanford Approach model (CASA). The results showed that the total value of carbon sequestration of Zhalong wetland was 0.98 billion Yuan in 2011, of which 0.24 billion Yuan for plant, and 0.74 billion Yuan for soil. The carbon sequestration value of marsh per unit area was the largest in all kinds of landscape types, being 5993.4 Yuan per hectare, followed by meadow, cultivated land, other types and open waters. Carbon sequestration value of Zhalong wetland was higher in the center than in periphery areas. Protecting and restoring the marshes of Zhalong wetland would have a positive influence on its carbon sequestration ability.

Insect community diversity of different habitats in Caizihu wetland at the middle and lower reaches of the Yangtze River.

GE Yang, GUO Miao, CAO Yu-yan, WU Yuan-yuan, WAN Xia**

2014, 33(8):  2084-2090. 

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To understand the response of insects to excessive reclamation of natural wetlands, species richness and distribution of insect fauna were investigated in the Caizihu Wetland Nature Reserve, a changing subtropical wetland landscape in southern Anhui, east China by light trap and hand collection periodically from May to August of 2013. Species were recorded from the two traditional land-use types (cropland and intertidal-grass area), and from the recently established grass-shrub zone. A total of 7251 insect individuals belonging to 235 species, 207genera, 89 families and 8 orders were recorded. The dominant orders were Diptera, Hemiptera, and Orthoptera, accounting for 27.61%, 25.54% and 15.96% of total individuals, respectively. Species richness was the highest in the cropland, the lowest in the grass-shrub, and the intertidal-grass area showed an intermediate value. The diversity comparison among the three habitats based on Shannon index and ACE estimate value showed that there were no significant differences between grass-shrub and intertidal-grass area, and both of their richness indices were significantly lower than that of the cropland habitat (P<0.05). The mean value of similarity indexes of the three habitats was 0.25±0.02, showing both vegetation type and excessive reclamation had great impacts on the insect community diversity.

Annual variation of rotifer community structure in the northern branch of the Yangtze River Estuary

LIU Xiao, LIU Liang, SUN Wei, XUN Jun-zeng, WU Hui-xian**

2014, 33(8):  2091-2095. 

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A study was conducted from October 2010 to September 2011 to understand the rotifer community structure in the northern branch of the Yangtze River Estuary. A total of 19 species of rotifers were found. These species belong to 7 families and 17 genera. Brachionidae, Lecanidae and Gastropodidae were the most common families. Ascomorpha saltans and Polyarthra trigla were common species. A. saltans was the dominant species in spring, autumn and winter, whereas P. trigla was dominant in summer. The average density of rotifers for the whole year was 1.40±1.11 ind·L^-1. The monthly average density varied from 0.2 to 4.4 ind·L^-1, with the highest density values  occurring in autumn (2.25±1.7 ind·L^-1) and the lowest density values  in winter (0.93±0.69 ind·L^-1). The average density of rotifers was the lowest (1.00±0.67 ind·L^-1) at station 5 closer to the mouth of the river. Hierarchical clustering and MDS were applied to analyze the rotifer community structure, revealing two main groupings, one with data from January, February, March and September, and another with data from May, August and November. The CCA analysis showed that salinity was the main environmental factor affecting the rotifer community structure.

Volatiles from involucres of chestnut and their potential applications in control of Conogethes punctiferalis.

DU Yan-li1, ZHANG Jia-xin1, YANG Meng-meng1, SUN Shu-ling1, QIN Ling1, WANG Jin-bao2, ZHANG Zhi-yong1**

2014, 33(8):  2096-2100. 

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In order to identify plantoriginated attractants for forecasting and controlling of the yellow peach moth, Conogethes punctiferalis
 in chestnut orchards, volatiles emitted from involucres of four chestnut cultivars (Huaihuang, Huaijiu, Yanhong and Shisheng) widely planted in Beijing area, were collected and analyzed using headspace trapping and GC-MS techniques, during the young fruit period and mature fruit period respectively. The results showed that 10 volatile compounds were emitted from the four chestnut cultivars during the young fruit period, and 5 out of the 10 volatiles were shared in the four cultivars, including α-pinene, camphene, β-thujene, β-pinene, and (E)-2-butenoic acid,2-(methylenecyclopropyl) prop-2-yl ester. Cedrol and 3-carene were only detected in Yanhong cultivar, and D-limonene was only emitted by Huaijiu, Yanhong, and Shisheng cultivars. β-ocimene and farnesol were specifically released by Huaihuang and Huaijiu cultivars. In addition, the kinds and quantity of volatiles during the mature fruit period were both significantly lower than during the young fruit period. The results indicated that the volatiles from involucres of chestnut differed in different growth periods, and that some volatiles were shared by different chestnut cultivars while the others were cultivarspecific.

Information in beaks of Ommastrephes bartramii in the North Pacific Ocean using stable isotope technology.

JIN Yue1, CHEN Xin-jun1,2,3, LI Yun-kai1,2,3**, FANG Zhou1, GONG Yi1

2014, 33(8):  2101-2107. 

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The specimens of red flying squid (Ommastrephes bartramii) were caught by Chinese squid jigging vessels in the waters of 42°N-45°N and 153°E-157°E during July to October in 2012. 20 pairs of beaks were randomly selected to measure their stable carbon and nitrogen isotope values and to investigate the relationships between stable isotope values of beaks and the corresponding biological parameters of the squids, i.e. sex, body size and pigmentation stage. The results indicated that there are no significant differences in stable carbon and nitrogen isotope values of beaks between male and female. Stable carbon isotope values of upper and lower beaks have negative relationships with the body size, while stable nitrogen isotope values of upper and lower beaks have positive relationships with the body size. Pigmentation stage and stable nitrogen isotope values of beaks increase with the growth of squid, and pigmentation stage is associated with the content of catechols in beaks, which could increase the rigidity of beaks and help squid forage high trophic level organisms. As beaks are an important information carrier in feeding ecology studies of O. bartramii, especially in diet shift and migration patterns, they can provide a new tool for estimating the trophic position and function of O. bartramii in north Pacific ecosystem.

Age determination of Phoxinus oxycephalus from the JiulongPeak of the Huangshan Mountain.

CHENG Fang-yuan, CHENG Qing-qing, CHENG Le-hua, CHEN Meng-yun, CHENG Hui-jie, YAN Yun-zhi** 

2014, 33(8):  2108-2114. 

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Identifying the optimal bone structure for age determination is a basis for examining fish age composition and surveying fish biological and ecological traits. Based on the 132 specimens of Chinese minnow, Phoxinus oxycephalus, collected from the JiulongPeak of the Huangshan Mountain during April 2012, the annulus characteristics on the scale, operculum, vertebra and otolith were identified and, according to the “true age” determined from length frequency distributions, the precision and accuracy of the observed ages determined by operculum, vertebra and lapillus otolith were compared in this study. No distinct annulus marker was observed on the scales taken from both lateral body and caudal peduncle and on the asteriscus otolith, but annuli could be observed on operculum, vertebra and lapillus otolith. According to the average error percent of aging, both precision and accuracy in the age determined by operculum, vertebra and lapillus otolith varied across agegroups. Overall, the highest precision was observed for vertebra and the lowest for lapillus otolith; however, the accuracy showed an opposite pattern. These results suggest that lapillus otolith is the optimal structure for aging P. oxycephalus, of which the relatively low precision in age determination and its potential effect on the accuracy may be mitigated by improving the quantity of observed structures and by optimizing the aging method.

Distribution pattern of zooplankton in the south part of Hangzhou Bay during spring and autumn in relation to main environmental factors.

ZHANG Dong-rong1,2, XU Jia-yi1, XU Zhao-li1**, CHEN Jia-jie1, SUN Lu-feng1

2014, 33(8):  2115-2123. 

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To understand the community structure and distribution pattern of zooplankton in the south part of Hangzhou Bay and its response to main environmental factors in different seasons, two oceanographic comprehensive surveys were carried out during the September of 2011 (autumn) and May of 2012 (spring). An obvious seasonal variation was found in species composition of zooplankton. In total, 18 species from 8 groups were identified in spring with Tortanus vermiculus, Sinocalanus sinensis, Calanus sinicus, and Acanthomysis brevirostris being the dominant species, and 25 species from 7 groups were identified in autumn with Labidocera sinilobata, Sagitta bedoti, Labidocera euchaeta, and Pontella spinicauda being the dominant species. The Shannon diversity index of zooplankton was higher in autumn (1.60) than in spring (1.56), while the average biomass and abundance in autumn (580.58 mg·m^-3 and 578.88 ind·m^-3) were significantly higher than those in spring (61.82 mg·m^-3 and 41.61 ind·m^-3). The distribution patterns of biomass and abundance were mainly determined by the dominant species, which was related to ocean currents. In spring, both the biomass and the abundance increased gradually from outside the bay to inshore. In autumn, the biomass and the abundance increased from outside the bay to inshore and eastern area outside the bay. The correlation between community structure of zooplankton and environmental variables, calculated by the stepwise regression analysis, indicated that temperature and salinity were the two most important factors influencing the distribution pattern of zooplankton in the south part of Hangzhou Bay.

Effect of nitrogen-phosphorus ratio on the competitive relationship of Chlorella pyrenoidosa and Isochrysis zhanjiangensis. 

WEI Jie, WANG Yue-qi, LIU Qian, ZHAO Wen**, WANG Li, CONG Yu-ting

2014, 33(8):  2124-2128. 

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In order to understand interspecific competition of live prey microalgae, the effect of nitrogen-phosphorus ratio (N/P) on the interspecific competition of Chlorella pyrenoidosa and Isochrysis zhanjiangensis was investigated by adding NaNO₃ and KH₂PO₃ as N and P sources. Under monoculture mode, C. pyrenoidosa normally grew with N/P ranging from 4 to 22 and was inhibited when the ratio was over 22, while I. zhanjiangensis was not obviously affected. Co-culture mode could promote the growth of C. pyrenoidosa and inhibit the growth of I. zhanjiangensis. C. pyrenoidosa owned an obviously competitive advantage in the co-culture mode, especially when N/P was 13 and 16. C. pyrenoidosa could be co-cultured with I. zhanjiangensis in large scale production, which might increase the output of C. pyrenoidosa and provide the possibility to harvest mixed microalgae as live food for aquaculture.

Effects of enrichment on activity budgets of captive red goral.

HOU Xiao-yun1, LIU Zhen-sheng1,2, TENG Li-wei1,2**, WANG Ai-shan3

2014, 33(8):  2129-2135. 

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In recent years, many zoos have transformed their objectives from pure entertainment to public education, species conservation, and animal welfare, which were mainly accomplished by environmental enrichment. We conducted an enrichment experiment (two environmental enrichments and one feeding enrichments) of 10 captive red gorals (Naemorhedus cranbrooki) in Shanghai Zoo Breeding Center, China from November 2010 to February 2013, to analyze the effect of different forms of the enrichments on the activity budgets of red gorals. Ethograms were composed of standing, resting, moving, eating, grooming, stereotypic behavior, and other behaviors. The time on resting (P<0.01) and stereotypic (P<0.05) behaviors significantly decreased after adding the enrichment equipment firstly, while the time allocated for eating (P<0.05), moving (P<0.01) and grooming (P<0.01) behaviors increased dramatically, which was consistent with our expectations. Then we improved complexity of the environmental enrichment equipment (second environmental enrichment), and the time on resting behavior (P<0.05) reduced, whereas the time allocated for moving (P<0.05) and grooming (P<0.01) behaviors increased significantly. Meanwhile, there was no significant variation in time spending on several other behaviors, which was not identical to our expectations. Resting (P=0.44), stereotypic (P=0.19), and standing (P=0.31) behaviors did not show significant differences at the feeding enrichment and non-enrichment stages. Feeding enrichment and increasing complexity of environmental enrichment equipment helped red gorals make use of the enrichment equipment effectively. Red gorals added the time resting on the enrichment equipment from 2.07% during the feeding enrichment and 1.44% during the second environmental enrichment to 12.17% and 10.83%, respectively. After we increased the first enrichment equipment, the major activity on the equipment was standing behavior, followed by eating behavior. Nonetheless, the main activity transformed to resting behavior, and the secondary activity was standing behavior when we conducted the second enrichment equipment. Before the feeding enrichment experiment, the major activity of red gorals was standing behavior, followed by grooming behavior. During the feeding enrichment experiment, red gorals showed more time for eating behavior, and less time for standing behavior.

Physiological responses of Pinus sylvestris var. mongolica seedlings to the interaction between Suillus grevillei N40 and Trichoderma virens T43.

YIN Da-chuan1, DENG Xu2, Ilan Chet3, SONG Rui-qing1**

2014, 33(8):  2142-2147. 

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The effects of the interaction between Suillus grevillei and Trichoderma virens on Pinus sylvestris var. mongolica were studied using plant physiology and biochemistry. Seedling growth and physiological parameters were determined, including the biomass, photosynthetic pigment content, soluble protein content, antioxidant enzyme activities, rhizosphere soil enzyme activities and protective enzyme activities. In addition, an optimal resistance system involving T. virens, mycorrhizal fungus (Suillus grevillei) and P. sylvestris var. mongolica seedlings was constructed. Synergies between S. luteus and T. virens were observed and most of the parameters of Pinus sylvestris var. mongolica seedlings inoculated with S. luteus 30 days + T. virens were higher than other treatments. After three months, when compared the control, the S. luteus 30 days + T. virens treatment gave increases in height (43%), collar diameter (55.6%), soluble protein content (176.9%), chlorophyll a (76.2%), chlorophyll b (64.1%), carotenoids (103.6%), CAT activity (45.5%), SOD activity (43.7%), β-1,3glucanase activity (28%), chitinase activity (40%), rhizosphere soil urease activity (120%), and phosphatase activity (100%). These results indicated that there may be a stimulating factor between S. grevillei and T. virens when they are inoculated together (S. grevillei 30 days + T. virens).

Effects of Ca(NO₃)₂ on eggplant resistance to Verticillium wilt, physiological indexes and seedling growth.

ZHOU Bao-li**, CAI Lian-lian, BI Xiao-hua, ZHENG Ji-dong

2014, 33(8):  2148-2152. 

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The effects of adding different concentrations (80, 120, 160, 200 mg·L^-1) of Ca(NO₃)₂ on eggplant resistance to
Verticillium wilt, eggplant seedling growth and resistance physiology indexes were studied by inoculating eggplant seedlings with
V. dahliae. The results showed that, after adding the different concentrations of Ca(NO₃)₂, the disease incidence and disease index of eggplant V. wilt were both decreased, the growth of eggplant seedlings was promoted, and the related physiological indexes of resistance were increased. The 160 mg·L^-1 of Ca(NO₃)₂ had the best effect among all the treatments. Compared with the control (adding water), the plant height, stem diameter, ground fresh weight, and underground fresh weight after the different additions of Ca(NO₃)₂ increased by 32%, 22%, 93% and 114%, respectively; the chlorophyll content and root vigor increased by 35% and 63%, respectively; the relative electricity conductivity and MDA decreased by 51% and 54%, respectively; the activities of defensive enzymes (PAL, PPO, POD) increased by 60%, 721% and 144%, respectively.

 

Seasonal distribution of dissimilatory iron-reducing bacteria in reservoir sediments of Guiyang City.

LUO Guang-jun, HE Tian-rong**, YIN De-liang, LI Ting, AN Yan-ling

2014, 33(8):  2153-2160. 

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Using the rolling tube technique, biomass of dissimilatory ironreducing bacteria (DIRB) was detected in sediments of three reservoirs in Guiyang in different seasons, and at the same time, physical and chemical parameters, such as the iron and sulfate contents of pore water, pH, organic matter contents in the sediments were measured. The biomass of DIRB in the sediments of Aha Reservoir, Baihua Reservoir and Hongfeng Reservoir ranged from 1.09×10⁴ to 8.829×10⁵, from 1.05×10⁴ to 3.425×10⁵ and from 4.8×10³ to 4.467×10⁵ cells·g^-1, respectively. The biomass of DIRB in the warm season (June and September) was 1-2 orders of magnitude higher than that in the cold season (February), and the dissolved oxygen (DO) in the watersediment intersurface was correlated to DIRB biomass in the surface sediment, suggesting that DO and temperature had a great effect on DIRB biomass. In addition, the active areas of DIRB migrated to the top of the upper sediment with the alternation of the cold to warm season, as other electron acceptors such as O₂, SO₄^2- in the sediment controlled the profile distribution of DIRB. Aha Reservoir had been polluted by acid mine drainage, but the biomass of DIRB had no difference in orders of magnitude among the three reservoirs, probably because the high sediment organic matter contents (60-140 g·kg^-1) and optimum pH (6.2-7.1) in these reservoirs contributed to the growth of DIRB, but the peaks of the sediment DIRB biomass in Aha Reservoir were higher than in the other two reservoirs.

Joint effects of galaxolide and cadmium on bacteria and fungi quantities in soil.

LU Ze1,2, HU Xiao-min1**, WEI Wei3, AN Jing2, JI Zhan-hua2

2014, 33(8):  2161-2167. 

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Single and joint effects of galaxolide (HHCB) and Cd on bacteria and fungi quantities in the soil incubated 10 weeks were investigated in the laboratory. The results showed that single and joint exposures of HHCB and Cd had significant impacts on bacteria and fungi quantities
(P<0.01), except for Cd on bacteria. The growth of bacteria was inhibited firstly but promoted later after the applications of 500, 1000 mg·kg^-1 HHCB and 10 mg·kg^-1 Cd singly and jointly. However, the single and joint exposures of 100, 500 mg·kg^-1 HHCB and 10 mg·kg^-1 Cd promoted the growth of fungi. With the increase of HHCB concentration, the rate of inhibition decreased for bacteria during the 5th to 10th week, while increased for fungi during the 1st to 10th week except for single HHCB in the 1st, 4th and 10th weeks as well as joint pollution in the 4th and 10th weeks. It was suggested that the joint effects of compound pollution were synergistic on bacteria in the 1st week, but antagonistic on fungi from the 7th to 8th week.

Effects of biochar amendment on the abundance and community structure of nitrogen-fixing microbes in a coastal alkaline soil.

SONG Yan-jing1,2, ZHANG Xiao-li1, GONG Jun1**

2014, 33(8):  2168-2175. 

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Biochar amendment may affect abundance and diversity of soil microbial community. However, the effects of biochar amendment on nitrogen-fixing bacterial community in coastal alkaline soils remain unclear. Using realtime quantitative PCR and DGGE profiling, this study investigated the variations of abundance and diversity of nifH genes in a coastal alkaline soil amended with different doses (0, 5%, 10%, 20%, w/w) of biochar during an 84-day incubation. This microcosm experiment showed that the incubation time significantly influenced nifH gene abundance (P<0.05), but no differences were observed among treatments (P>0.05). Following 14-day incubation, the copy number of nifH genes was significantly stimulated. On the 42nd day, the nifH abundance in the 20% biochar treatment was significantly higher than that in the control. For the 10% biochar treatment, however, higher abundance of nifH was observed on the 56th day, compared with the control. NMDS and CLUSTER analyses showed that the samples could be separated into two major groups, the lowdose group (0 and 5% biochar treatments) and the high-dose group (10% and 20% biochar treatments). ANOSIM indicated that the dose of biochar application significantly affected the community structure of nitrogen-fixing microbes in the coastal soil (P=0.001). DGGE analysis and sequencing of the major bands indicated that the relative abundance of Ideonella and Skermanella increased following biochar amendment, whereas the population of Azospirillum, an important nitrogen-fixer, remained relatively stable.

Spatial correlation of major water quality indices between the lake and rivers in Taihu Lake Basin.

ZHONG Jing-jing1, LIU Mao-song1**, WANG Yu2, YANG Xue-jiao1, JIANG Xu-juan1, XU Chi1

2014, 33(8):  2176-2182. 

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Along with the rapid economic growth, water environment has drastically deteriorated in the Taihu Lake Basin (TLB) during the past decades. However, the spatiotemporal patterns of water pollution are not yet fully understood at landscape scales in the TLB. Especially, the relationship between the lakes and rivers has been rarely examined. Using redundancy analysis, we studied the correlation of water quality between the lake body of Taihu and its inflow and outflow rivers based on the observation records from 82 monitoring sites in the TLB during 2006-2012. The correlation was examined at five spatial scales, i.e., 5, 10, 20, 40 and 80 km. Water quality was generally poor in the whole basin during the study period. However, the proportion of the major water quality indices that exceeded the national standard III varied at different scales. In general, water quality of the lake body was better than that of the inflow rivers, while the outflow rivers showed worse water quality than the inflow rivers. The inflow rivers were the main source of nutrient input for the Taihu Lake. In terms of water quality indices that exceeded the standard, the inflow rivers explained over 50% of the variance in the lake body (75.9%, 67.4% and 57.4% for DO, TP and AN, respectively). At single spatial scales, water quality of the lake body generally responded to the changes of water quality of the inflow rivers within a distance of 5 km from the lake body while had no significant response at other scales. In contrast, water quality of the outflow rivers was less affected by that of the lake body. The lake body only explained less than 7% of the variance in the outflow rivers, in terms of water quality indices that exceeded the standard. Moreover, no obvious scale effect was observed. Water quality of the outflow area was more affected by the pollutants from the surrounding lands rather than those transferred from the inflow rivers.

Absorption and enrichment of heavy metals by Casuarina equisetifolia of different stand ages in a coastal zone.

JIN Ming-hua1, DING Zhen-hua1**, ZHOU Hai-chao1, YE Gong-fu2

2014, 33(8):  2183-2187. 

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To assess the absorption and enrichment of heavy metals by Casuarina equisetifolia, the concentrations of heavy metals including Cr, Cu, Zn, Cd and Pb in branchlet, fine root, litter and soil of C. equisetifolia forests at four ages (10, 16, 20, 30) were determined. The results showed that the enrichment degree of the heavy metals in C. equisetifolia ranked as Zn>Cr>Pb>Cu>Cd. Correlation analysis showed that Cr and Cu, Pb, Fe and Cu, Zn and Cd had significant synergies in the fine roots of C. equisetifolia. C. equisetifolia had a higher capability of absorbing and accumulating heavy metals. Annual accumulation of heavy metals was highest in 20 years old C. equisetifolia. Our results indicate that C. equisetifolia has a great potential for reducing the pollution of heavy metals, especially for the 20 years old forest.

Effects of organic acids on the uptake and translocation of cadmium by rice seedlings.

WAN Ya-nan1, ZHANG Jing-suo1，2, YU Yao1, LI Hua-fen1**

2014, 33(8):  2188-2192. 

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Effects of water (control), citrate, malate and ethylenediaminetetraacetic acid (EDTA) on the uptake and translocation of cadmium (Cd) by rice seedlings were studied in nutrient solution. The results indicated that the addition of organic acids to solution affected the Cd uptake and translocation by rice seedlings. Compared with the control, EDTA significantly decreased the Cd uptake, with 90% and 96% reduction in the Cd concentrations of shoots and roots respectively. However, the addition of EDTA enhanced the Cd transport from roots to shoots, accounting for 43.0%-55.9% of total uptake (only 20.0%-32.2% for the control). Whereas, citrate and malate did not significantly affect the Cd uptake and transport by rice seedlings. The influence of organic acids on the Cd uptake and translocation by three rice cultivars showed a similar trend. EDTA had a higher ability to desorb Cd from rice root than citrate and malate.

The remobilization of heavy metals influenced by interaction of DOM and iron oxides.

ZHANG Lei1,2, SONG Liu-ting1,2**, ZHENG Xiao-di1,2, TENG Yan-guo1,2, WANG Jin-sheng1,2

2014, 33(8):  2193-2198. 

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The interactions between dissolved organic matter (DOM) and Fe oxdies are common in surface and subsurface water environments. The study of these interaction processes will help better understand the remobilization of toxic heavy metals and the risk of their secondary pollution. In this study, an experiment was carried out with different DOM concentrations on the remobilization of heavy metals influenced by the interaction of DOM and iron oxides. The Pb and As concentrations and the infrared spectra of iron oxides flocs showed that the interactions of iron oxides and flocs promoted a significant increase of remobilization of Pb, and a slight increase of As as well. Iron oxides interact with dissolved organic matter via complexation to hydroxyl and carboxyl groups. With the presence of DOM, iron oxides precipitated as flocs with smaller particle sizes and lower structural order, which made the formed iron oxides easy to be reductively dissolved to promote the remobilization of Pb and As as well. Furthermore, the iron secondary mineral precipitation was delayed by DOM, which would prevent the sequestration of Pb and As. Besides, the increase of Fe(II) concentration catalyzed the transformation of iron oxides from γ-FeOOH to α-FeOOH, further promoting the release of Pb and As into solutions. The competitive adsorption of NOM precluded the adsorption of Pb and As onto the iron oxides, which may also cause the increase of Pb and As concentrations in solutions. This study provides useful information for a better understanding of the secondary pollution risks of heavy metals, and provides further scientific evidence for the management and protection of water environments in a rational way.

Correlation between thermal field and landscape pattern in the Nanjing metropolitan region.

ZHOU Ya-xing1, LIU Mao-song1**, XU Chi1, FANG Fang1, ZHONG Jing-jing1, ZHANG Ming-juan2

2014, 33(8):  2199-2206. 

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Using the data of land use and land surface temperature (LST) retrieved from Landsat/ETM^+ images, we examined the relationships between the thermal field and landscape pattern in the Nanjing metropolitan region. The correlations between land use types (cropland, forest, water and settlements), mean LST and coefficient of variation (CV) of LST were quantified at three grain sizes (i.e., 1, 2.5 and 5 km). The relative importance of the effects of landscape composition, landscape structure (including landscapelevel and classlevel) and spatial factors on the thermal field pattern was distinguished quantitatively. The results showed that water bodies and forests played a significant role in lowering LST, while this cooling effect produced by croplands was relatively weak. Landscape composition and structure contributed most to explaining the thermal field pattern, while the location factors and the distance from the city center had minor effects. At all three grain sizes studied, considerable variances of mean LST and the CV of LST of each land use type could be explained by the class-level structure (especially at the grain size of 5 km). Landscape composition was the second important factor in explaining the mean and CV of LST, but its unique explanatory power was minimal. Landscape-level structure had a relatively small effect on mean LST but a relatively large effect on the CV of LST; and its unique explanatory power was prominent at the grain size of 2.5 km. Our results suggested that the regulation of land use structure could be a useful approach in order to relieve the urban heat island effect.

The characteristics and driving forces of LUCC in the middle and lower reaches of Shule River Basin.

QI Jing-hui1, NIU Shu-wen1**, MA Li-bang2， WANG Wen-die1

2014, 33(8):  2207-2220. 

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With the support of ArcGIS and ENVI, five sets of TM remote sensing images of the middle and lower reaches of Shule River Basin in 1987, 1996, 2000, 2006, and 2010 were interpreted. Nine types of land use and land cover were obtained, and the characteristics and causes of the land use and land cover were analyzed. In the past 23 years, the area of artificial vegetation with an expanding trend (an increase of 900 km² in total), while the natural vegetation showed a shrinking tendency (a decrease of 842.9 km²). Cropland, shrub land and urban construction land had a net increase in area; the area of non-vegetation land increased firstly and then decreased; and the others presented a net decrease. There were frequent conversions among the nine land use and land cover types, the main directions were that the high-coverage grassland was successively transformed into the grassland with medium coverage, low coverage and non-vegetation land; the increased shrub land was largely transformed from the grassland with medium and low coverage; the reduced wetland mainly changed into non-vegetation land or low-coverage grassland; the expansion of cropland primarily benefited from the decrease of non-vegetation land and low-coverage grassland; the non-vegetation land had a net decrease in the mutual conversion with the crop land, whereas had a net increase with lowcoverage grass land; the increase of urban construction land was largely brought by the reduced cropland and non-vegetation land; the snowice land was mainly transformed into non-vegetation land after they melt. The rate of the landuse and landcover change was relatively slow from 1987 to 1996, but it was quite rapid during 1996-2010. The vegetation coverage around irrigational areas presented an expanding trend, while it was in a degraded state in other areas. The driving force analysis showed that the main causes of land use and land cover change were the rapid growth of agricultural population, large-scale agricultural development, and the immigration policy, while natural factors, such as temperature, precipitation and annual runoff, had little influence.

Dynamic pattern of drought in crop (grass) growth season over Qinghai Province during last 52 years, based on standardized precipitation evapotranspiration index.

ZHANG Tiao-feng1,2**, LI Lin1, LIU Bao-kang3,4, LI Wan-zhi1, WANG Dong2, REN Pei-gui2

2014, 33(8):  2221-2227. 

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The standardized precipitation evapotranspiration index (SPEI) is a new climate drought index, which has been proved to be suited to drought monitoring and assessment at different time scales under global warming. This paper, based on SPEI, used the mean monthly temperature and monthly precipitation data from 47 weather stations in Qinghai from 1961-2012, to analyze the spatiotemporal variations of multiscalar drought risks in the growth season of crop and pasture in Qinghai in the past 52 years. The results showed there was a drying trend during the growth season, and the spatiotemporal variations of drought risks were significant. Under the background of global warming, the drying trend for the early growth stage was slightly weaker than those of the critical water demand stage and the whole growth period. As a result, the key feature of droughts during the growth season was the switch of drought from occurring in the early growth stage to occurring in the critical water demand stage. In addition, drought area showed a significant trend of further expansion. Given an average warming of 1.36 ℃ over the past 52 years, the drought risk with moderate or higher severities had increased by two times, suggesting a close relationship between the drought and climate change. Thus, climate warming may bring benefits for agriculture, but also increase the instability of agricultural production.

Construction of index system for regional environmental carrying capacity: A case study of the upper reaches of Yellow River Basin.

ZHENG Jia-yi1,2, FU Xiao1, WANG Chen-xing1,2, WU Gang1**

2014, 33(8):  2228-2234. 

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In terms of the concept model of environmental carrying capacity based on ecosystem health through the application of the analytic hierarchy process, we established an index system for regional environment carrying capacity, determined the basic weight value of each evaluation index of environmental carrying capacity, and calculated the environmental carrying capacity in the upper reaches of the Yellow River Basin in Qinghai through the application of this evaluation index system. The results showed that, in 1985-2009, the human potential index of the upper reaches of the Yellow River Basin in Qinghai Province fluctuated upward. Simultaneously, the ecological elasticity capability index fluctuated downward, and the resource carrying capacity index and the regional environmental carrying capacity index also showed a slow downward trend. Regional economic development and hydroelectric resource utilization can have a lifting effect on the regional ecological system and environment carrying capacity, and thus how to exert this effect is an issue that should be paid special attention in the future.

A review on iron plaque on rice (Oryza sativa) root surface and the morphology, physiology and molecular biology of its formation mechanism.

YANG Xu-jian, FU You-qiang, SHEN Hong**, GAN Hai-hua

2014, 33(8):  2235-2244. 

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This paper introduced two strategies of iron uptake in rice, the components of iron plaque on root surface and its significances for ecological environment and nutrient absorption. Two bases of iron plaque formation driven by increment of root oxidative capacity, i.e. formation of aerenchyma and the enzyme-mediated radical oxygen species (ROS) were analyzed emphatically. The formation of aerenchyma contributes to oxygen secretion enhancement as well as ameliorating phosphate deficiency and iron toxicity; besides, it also results in ROSmediated programmed cell death. By analyzing ROS scavenge by antioxidant enzymes, Fenton reaction was assumed to be the key reaction in the process of iron plaque formation, and the hypothesis that the class III peroxidase located at cell wall of epidermis and outer cortex tissue might be associated with the formation of iron plaque on rice root surface was put forward. Moreover, the functions of iron chelate reduction oxidase, iron transporter and peroxidase at molecular level were discussed, and strategy I like iron absorption pathway was regarded as a possible main source of iron for iron plaque formation. Finally, the hot spots needed to be solved on iron plaque were discussed after conclusively analyzing the process and condition of iron plaque formation.

Research status and existing problems of interdune lowland in arid inland desert.

YUAN Hong-bo**, WU Chun-rong, LIU Hu-jun, LIU Shu-juan, CHEN Fang, ZHANG Jin-hu, LI Yin-ke

2014, 33(8):  2245-2254. 

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The interdune lowland has good habitat conditions. It is the main place of the dynamic actions between biological and non-biological ingredients in dune ecosystems. It is called the “life island” of broken natural habitats, and is also the starting point for degraded habitat restoration. The interdune lowland plays a significant role in the reversal of habitat degradation and the promotion of soil development. Some conclusions can be made from the previous studies: (1) The concept and classification of interdune lowland, as an independent landform type, are not clear. (2) Very few studies have conducted on the ecological processes of interdune lowland which are mainly induced by wind and sand processes in arid regions. (3) The dominant factors of ecological processes of the interdune lowland and their interaction mechanism are unclear. (4) Few studies have focused on the relationship between dunes and interdune lowland as a whole dune system. Many researches explored the dune change and activity, while ignoring the influence of interdune lowland on sand activities in desertification combating. (5) The studies on the effects of human disturbance on the evolution of interdune lowland ecosystem need to be strengthened. (6) The interdune lowland in arid area obviously differs from the coast, lakeshore, semiarid and humid regions. Especially, it is the main place of human life or sources of land for agricultural production in the arid desert region, so the relevant studies should be strengthened. It has a great significance to strengthen the ecological characteristics and functional studies of interdune lowland in the arid inland sandy area for mastering evolution and degradation mechanism of arid desert ecosystems, protecting the biodiversity of the sandy area and promoting the restoration of degraded ecosystems and desertification control.

A review on the responses of various factors within soil-vegetation system to grazing in grassland grazing systems. 

DONG Quan-min1**, ZHAO Xin-quan2, LI Shi-xiong1, WANG Yan-long1, ZHENG Wei1, HOU Xian-kuan1, SONG Lei1

2014, 33(8):  2255-2265. 

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Based on the interface theory within pratacultural system, this paper summarized the responses of soil-vegetation factors to grazing in grassland grazing systems and the compensatory growth of plants under grazing. Grazing intensity has greater effects on plant community than other environmental factors within the same climatic region, therefore, it is the dominant factor influencing plant community characteristics. Besides, scientific grazing system and reasonable grazing intensity could ameliorate soil structure and improve soil resistibility against the change of external environment, otherwise it would accelerate soil erosion and degradation. The influence of grazing livestock feeding on plant productivity and the compensatory growth of plants is a general ecological process; however, over-compensatory plant growth is closely correlated with environmental conditions and states before and after plants are eaten, and also has a strong relationship with the grazing history of grassland. Consequently, we suggest that a grassland grazing system should be assessed by considering the grassland state and dynamic characteristics, and dynamic simulation of sustainable utilization of grassland, and the sustainable development of animal husbandry should be conducted through the model of dynamic programming and system optimization, and establishing grassland grazing management expert system.

Storage and decay of coarse woody debris: A review.

WANG Shun-zhong1, GU Hui-yan2, SANG Wei-guo1**

2014, 33(8):  2266-2273. 

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Coarse woody debris (CWD) includes standing dead trees and stumps, whole fallen trees and dead branches on forest floor. CWD is an important structural component of many forest ecosystems and plays a key role in a number of aspects of ecosystem function. CWD contributes substantially to the long-lived forest carbon pool， however, CWD is often overlooked in forest carbon inventories. CWD varies highly in different forest zones. CWD volume in the world and CWD carbon storage in the United States and China decreases with decreasing the latitude. Studies of naturally regenerated forests typically report a “Ushaped” temporal pattern of CWD. Other temporal patterns have also been noted. Occasionally, stands exhibit no clear temporal pattern at all. Local environmental conditions, in particular temperature and humidity, exert strong controls on the rate of CWD decomposition. Species-based variation in wood traits may also contribute to the observed variations in CWD decomposition. There are rich forest types in China, which provides favorable conditions for CWD study. A number of studies about storage and decomposition of CWD have been conducted in China. However, all of them are still far away from the advanced level. A combination of field surveys, long-term experiments and model simulation should be required to ascertain the current and future status of CWD carbon stocks.

A review on the 4th International Society for Seed Science Meeting.

KUANG Wen-nong1,2, LIU Zhi-min1**

2014, 33(8):  2274-2280. 

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The 4th International Society for Seed Science Meeting was held in Shenyang, China, on June 22-26, 2013. In total 136 abstracts were submitted to the conference, which covered the following six aspects: evolutionary seed ecology, seed dispersal, seed bank, seed germination and dormancy, seed longevity and storage, and the relationship between seed ecology and biodiversity conservation and vegetation restoration, demonstrating the latest progress in seed ecology. Here, we reviewed all of the presentations aiming to provide relevant information and references for the seed ecologists.