Table of Content

18 July 2013, Volume 24 Issue 7

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Distribution pattern of neutral sugar in forest soils along an altitude gradient in Changbai Mountains, Northeast China.

TIAN Qiu-xiang1,2, ZHANG Bin1,2, HE Hong-bo1, ZHANG Xu-dong1,3, CHENG Wei-xin1

2013, 24(7):  1777-1783. 

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In July 2010, soil samples were collected from five typical forests (Pinus koraiensis and broadleaved mixed forest, Picea and Abies forest, Larix and Abies forest, Betula ermanii forest, and alpine tundra) along an altitude gradient on the northern slope of Changbai Mountains to investigate the distribution and quantity of neutral sugar in the soils and related affecting factors. The origins of the neutral sugar were differentiated to probe into the biochemical accumulation mechanisms of soil organic matter. There was a significant difference in the neutral sugar content among the forest soils. The relative content of soil neutral sugar’s carbon to soil organic carbon ranged in 80.55-170.63 mg C·g^-1, and tended to be increased with elevated altitude. The multiple regression analysis showed that the mean temperature in growth season was the main factor affecting the relative content of soil neutral sugar, and low temperature was conducive to the accumulation of neutral sugar. The ratio of (galactose + mannose) / (arabinose + xylose) in the five soils was around 1.62-2.28, and had an increasing trend with elevated altitude, illustrating that the contribution of soil microbial neutral sugar to soil organic matter increased with elevated altitude. Soil microbial metabolic quotient declined significantly along elevated altitude, suggesting that in low temperature environment, soil microbial activity decreased but the carbon utilization efficiency enhanced. As a result, a significant portion of decomposed plant residues was transformed into microbial neutral sugar and accumulated stably in soil, and thus, increased the proportion of soil microbial neutral sugar.

Characteristics of soil microbial biomass and community composition in three types of plantations in southern subtropical area of China.

WANG Wei-xia1, SHI Zuo-min1, LUO Da1, LIU Shi-rong1, LU Li-hua2

2013, 24(7):  1784-1792. 

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By using fumigationextraction method and phospholipid fatty acids (PLFAs) analysis, this paper studied the characteristics of soil microbial biomass and community composition in the Erythrophleum fordii, Castanopsis hystrix, and Pinus massoniana plantations in south subtropical China. The soil microbial biomass, total PLFAs, bacterial PLFAs, and fungal PLFAs in the plantations were significantly affected by the plantation type and season, and the soil microbial biomass, total PLFAs, and individual PLFA signatures were higher in dry season than in rainy season. The C. hystrix plantation had the highest soil microbial biomass carbon and total PLFAs, while the E. fordii plantation had the highest soil microbial biomass nitrogen. There was a significant positive correlation between the soil pH and arbuscular mycorrhizal fungal (AMF) PLFA (16:1ω5c). The soil total PLFAs, grampositive bacterial PLFAs, saprophytic fungal PLFA (18:2ω6,9c), and the ratio of gram-positive to gram-negative bacterial PLFAs were significantly positively correlated with soil organic carbon, total nitrogen, and total phosphorus, suggesting that the soil organic carbon, total nitrogen, and total phosphorus contents were the most important nutrient factors affecting the numbers and types of the soil microorganisms. In addition, the ectomycorrhizae fungal PLFA
(18:1ω9c) and AMF PLFA were significantly correlated with the soil C/N ratio.

Cleistogenes squarrosa population at different restorative succession stages in Inner Mongolia of China: A point pattern analysis.

WANG Xin-ting1,2, WANG Wei1, LIANG Cun-zhu1, BAO Jun-jiang2

2013, 24(7):  1793-1800. 

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In this paper, the spatial pattern of Cleistogenes squarrosa population in different restorative succession communities of the typical steppe dominated by Stipa grandis and Leymus chinensis in Inner Mongolia was measured by photography orientation, and analyzed by complete spatial randomness model, Poisson cluster process, and nested double-cluster process. In severely degraded community, C. squarrosa population fitted well nested double-cluster process for all scales, i.e., high density small clusters existed at the centers of large clusters; whereas in 5-, 8-, and 21-year-old restored communities, C. squarrosa population fitted well Poisson cluster process for all scales, i.e., high density small clusters did not exist at the centers of the clusters. It was suggested that facilitation was the dominant interaction in severely degraded community, while competition dominated in restored communities. The differences in the spatial pattern of C. squarrosa population during the restorative succession could be induced by the shift from facilitation to competition along the gradient of grazing stress.

Soil nutrient accumulation and its affecting factors during vegetation succession in karst peak-cluster depressions of South China.

ZHANG Wei1,2, WANG Ke-lin1,2, LIU Su-juan1,2, YE Ying-ying1,2, PAN Fu-jing3, HE Xu-yang1,2

2013, 24(7):  1801-1808. 

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Taking the typical karst peakcluster depressions in Huanjiang County of northwest Guangxi as the objects, and by using the method of replacing time with space, an analysis was made on the dynamic changes of top soil (0-15 cm) nutrients and their dominant controlling factors during the process of vegetation succession. With the positive succession of vegetation (herb-shrub-secondary forest-primary forest), the soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) contents increased significantly, with the soil SOC, TN, and TP increased from 29.1 g·kg^-1, 2.48 g·kg^-1, and 0.72 g·kg^-1 in herb community to 73.9 g·kg^-1, 8.10 g·kg^-1, and 1.6 g·kg^-1 in primary forest, respectively, which indicated that the positive succession of vegetation was helpful to the soil nutrient accumulation. The soil cation exchange capacity (CEC) had close relationships with the soil SOC and TN, being the primary controlling factor for the accumulation of the soil C and N. The litter P content, C/P ratio, and N/P ratio were the major factors controlling the P accumulation in the topsoil. The litters higher P content and N/P ratio and smaller C/P ratio were helpful for the P accumulation. Topographic indices (slope, aspect, and rock exposure ratio) had little effects on the soil nutrients.

Effects of drought stress on the growth, photosynthetic characteristics, and active oxygen metabolism of poplar seedlings.

JING Da-wei1,2, XING Shang-jun2,DU Zhen-yu2, LIU Fang-chun2

2013, 24(7):  1809-1816. 

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A pot experiment was conducted to study the effects of different water treatments (normal irrigation, light drought, moderate drought, and severe drought) on the growth, gas exchange, chlorophyll fluorescence characteristics, and active oxygen metabolism of poplar (Populus× euramericana cv. ‘Neva’) seedlings in the experimental nursery of Shandong Forestry Academy from April to October, 2011. As compared with those under normal irrigation, the growth of the seedling’s basal diameter under light, moderate, and severe drought stress decreased by 12.8%, 44.5%, and 65.6%, and the height growth decreased by 12.2%, 43.1%, and 57.2%, respectively. With the increasing extent and duration of drought stress, the maximal photochemical efficiency of PSⅡ, quantum yield, photochemical quenching coefficient, net photosynthetic rate, and stomatal conductance of the seedling leaves decreased gradually under light drought stress, while decreased rapidly under both moderate and severe drought stress. The nonphotochemical quenching coefficient increased significantly under light drought stress, but decreased after an initial increase under moderate and severe drought. The leaf superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities under drought stress decreased after an initial increase, but definite differences existed in the responses of the three enzymes to drought stress and reactive oxygen. The leaf relative electric conductivity and malondialdehyde (MDA) content under drought stress increased significantly, plasma membrane was damaged, and massive ions leaked out. The most serious damage of plasma membrane was found under severe stress. Under light drought stress, the seedlings had higher photosynthetic efficiency and stronger oxidative enzyme defense system; under moderate and severe drought stress, the photosynthetic efficiency decreased significantly, and the oxidative enzyme defense system was damaged remarkably.

Effects of Eucalyptus grandis leaf litter at its early stage of decomposition on the growth and photosynthetic characteristics of Cichorium intybus.

WU Xiu-hua1, LI Yi-qiao1, HU Ting-xing1, CHEN Bao-jun2, YANG Yong-gui2, CHEN Hong1, HU Hong-ling1

2013, 24(7):  1817-1825. 

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From March to May, 2010, a pot experiment was conducted to investigate the effects of Eucalyptus grandis leaf litter at its early stage of decomposition on the growth and photosynthetic characteristics of Cichorium intybus. Four treatments with different application rate of the leaf litter, i.e., 0 g·pot^-1 (CK), 30 g·pot^-1 (A₁), 60 g·pot^-1 (A₂), and 90 g·pot^-1(A₃), were installed. Each pot contained 12 kg soil mixed with the leaf litter, and then, C. intybus was sown. The growth indicators of the C. intybus were measured at the 30, 45, 60, and 75 d after sowing, and the photosynthetic characteristics of the C. intybus in treatment A₃ were studied after the seedlings third leaf fully expanded. At each measured time, the biomass accumulation and leaf area growth of C. intybus in treatments A₁, A₂, and A₃ were inhibited significantly. At the early stage of the leaf litter decomposition, the synthesis of  photosynthetic pigments of the C. intybus seedlings was inhibited significantly, and the inhibition effect was getting stronger with the increasing amount of the leaf litter addition. The diurnal change of the seedlings photosynthetic rate in all treatments showed a bimodal curve with midday depression, the stomatal conductance and water use efficiency had the same variation trend with the net photosynthetic rate, and the total diurnal photosynthesis decreased in the order of CK > A₁> A₂> A₃. The GCMS analysis showed there were 33 kinds of small molecule compounds released gradually with the decomposition of the leaf litter, among which, allelopathic substance terpenoid dominated.

Evaluation index system of swamp degradation in Zoige Plateau of Sichuan, Southwest China under drainage stress.

YANG Yong-xing1, LI Ke1, YANG Yang2

2013, 24(7):  1826-1836. 

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The evaluation index system of swamp degradation is one of the key scientific issues in the frontier field of international wetland science research. On the basis of longterm swamp field reconnaissance, and according to the  fixed position ecological investigation of plant communities and  the analysis of soil samples in 20 swamp plots in three belt transects of swamp degradation research under the stress of drainage in 2009, the swamps in the Zoige Plateau of Sichuan were classified into three groups with seven swamp communities, i.e., undisturbed (A type), disturbed by longterm and weak drainage (B-D type), and disturbed by shortterm and strong drainage (E-G type), according to the species importance value and by Two-Way Indicator Species Analysis (TWINSPAN). The degradation degree of the swamps was graded by the method of Principal Components Analysis (PCA), and the swamp vegetation evaluation index (SVEI) and soil evaluation index (SSEI) were developed. Based on the SVEI, the swamps were classified as pristine swamp, lightly degraded swamp, moderately degraded swamp, and severely degraded swamp. Based on the SSEI, the swamps in Hongyuan County were divided into three grades, i.e. pristine swamp, lightly degraded swamp, and severely degraded swamp, while those in Ruoergai County were divided into lightly degraded swamp, moderately degraded swamp, and severely degraded swamp. The similarity of TWINSPAN classification results and SVEI/SSEI evaluation results was above 70%, indicating that both SVEI and SSEI were effective for the swamp degradation grading, and different classification methods should be combined to comprehensively evaluate the swamps in the Plateau.

Correlations between standing trees trunk decay degree and soil physical-chemical properties in Korean pine-broadleaved mixed forest in Xiao Xing’an Mountains of Northeast China.

SUN Tian-yong1, WANG Li-hai2, SUN Mo-long3

2013, 24(7):  1837-1842. 

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Standing trees decay often causes vast loss of timber resources. To investigate the correlations between the standing trees decay and the site conditions is of importance to scientifically and reasonably manage forests and to decrease wood resources loss. By using Resistograph and meter ruler, a measurement was made on the decay degree of the trunk near root and the diameter at breast height (DBH) of 15 mature Korean pine standing trees in a Korean pine-broadleaved mixed forest in Xiao Xing’an Mountains in May, 2011. In the meantime, soil samples were collected from the root zones of standing trees and the upslope and downslope 5 meters away from the trunks, respectively. Five physical-chemical properties including moisture content, bulk density, total porosity, pH value, and organic matter content of the soil samples were tested. The regression equations concerning the trunk decay degree of the standing trees, their DBH, and the 5 soil properties were established. The results showed that the trunk decay degree of the mature Korean pine standing trees had higher correlations with the bulk density, total porosity, pH value, and organic matter content (R=0.687), and significant positive correlation with the moisture content (R=0.507) of the soils at the root zones of standing trees, but less correlation with the 5 properties of the soils at both upslope and downslope 5 meters away from the trunks. The trunk decay degree was decreased when the soil moisture content was below 18.4%. No significant correlation was observed between the trunk decay degree of mature Korean pine standing trees and the tree age.

Desorption characteristics of phosphorus in tea tree rhizosphere soil.

YANG Wei, ZHOU Wei-jun, BAO Chun-hong, MIAO Xiao-lin, HU Wen-min

2013, 24(7):  1843-1848. 

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In order to explore the phosphorus (P) release process and its supply mechanism in tea tree rhizosphere soil, an exogenous P adsorption and culture experiment was conducted to study the P desorption process and characters in the tea tree rhizosphere soils having been cultivated for different years and derived from different parent materials. The least squares method was used to fit the isotherms of P desorption kinetics. There was an obvious difference in the P desorption process between the rhizosphere soils and nonrhizosphere soils. The P desorption ability of the rhizosphere soils was significantly higher than that of the nonrhizosphere soils. As compared with nonrhizosphere soils, rhizosphere soils had higher available P content, P desorption rate, and β value (desorbed P of per unit adsorbed P), with the average increment being 5.49 mg·kg^-1, 1.7%, and 24.4%, respectively. The P desorption ability of the rhizosphere soils derived from different parent materials was in the order of granite > quaternary red clay > slate. The average available P content and P desorption ability of the rhizosphere soils increased with increasing cultivation years.

 

Biological soil crust nitrogenase activity and its responses to hydro-thermic factors in different erosion regions on the Loess Plateau, China.

MING Jiao1,2,3, ZHAO Yun-ge1,2, XU Ming-xiang1,2, YANG Li-na1,2,3, WANG Ai-guo2

2013, 24(7):  1849-1855. 

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Based on field survey, the biological soil crusts at their stable development stage were collected from the water erosion region, water-wind erosion region, and wind erosion region on the Loess Plateau, aimed to study the effects of the variations of moisture and temperature on the crusts nitrogenase activity (NA). The NA of the crusts in the erosion regions decreased in the order of water erosion region (127.7 μmol·m^-2·h^-1) > water-wind erosion region (34.6 μmol·m^-2·h^-1) > wind erosion region (6.0 μmol·m^-2·h^-1), and the optimal temperature for the crust nitrogen fixation was 35 ℃, 25 ℃, and 15 ℃, respectively. At the optimal temperature and 100%-40% field water-holding capacity, the NA of the crusts from the water erosion and water-wind erosion regions had no significant difference. The NA of the crusts from the wind erosion region was more sensitive to the variation of moisture, showing a dramatic decline when the moisture decreased to 80% field water-holding capacity, and totally lost when the moisture decreased to 20% field water-holding capacity. The differences in the NA of the crusts from the three erosion regions and the responses of the NA to the variations of moisture and temperature were likely associated with the climate, environment, and the crust species composition.

Using ^137Cs and ²¹⁰Pb_ex to trace the impact of soil erosion on  soil organic carbon at a slope farmland in the  black soil region

FANG Hai-yan, SHENG Mei-ling, SUN Li-ying, CAI Qiang-guo

2013, 24(7):  1856-1862. 

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Soil cores were collected from a 28.5 hm² slope farmland in the black soil region of Northeast China. Based on the sampled data of ¹³⁷Cs, ^210Pb_ex and SOC, the potentials of applying ¹³⁷Cs and ²¹⁰Pb_ex for assessing SOC redistribution were evaluated, aimed to approach the impact of soil erosion on soil organic carbon (SOC) in black soil region. At both planar and vertical directions, the ¹³⁷Cs,²¹⁰Pb_ex and SOC in the farmland had similar distribution patterns. Although there were large planar variations in the ¹³⁷Cs and ²¹⁰Pb_ex areal activities and the SOC stock as affected by soil erosion and deposition, the ¹³⁷Cs, ²¹⁰Pb_ex and SOC had similar changing trends over the landscape. Two depth distribution profiles were also used to  study the relations of 137Cs and 210Pbex with SOC. At eroded site, the radioactivities of ¹³⁷Cs and ^210Pb_ex and the SOC mass fraction did not show large variations in 0-25 cm soil layer, but decreased sharply below 25 cm. For the deposition sample, the radioactivities of ¹³⁷Cs and ²¹⁰Pb_ex in 0-100 cm soil increased firstly and then decreased. The SOC mass fraction also had similar depth distribution pattern in this soil layer. The ¹³⁷Cs and ^210Pb_ex presented positive linear correlations with the SOC, indicating that ¹³⁷Cs, ²¹⁰Pb_ex and SOC moved with the same physical mechanism in the farmland, and fallout ¹³⁷Cs and ^210Pb_ex could be used to study spatiotemporal distribution characteristics of SOC in the black soil region under the condition of soil erosion.

Effects of irrigation quota on moisture and salt redistribution in apple orchard soil in arid region.

GUO Quan-en1,2, WANG Yi-quan3, NAN Li-li1, CAO Shi-yu2

2013, 24(7):  1863-1870. 

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Taking the salinized apple orchard soil in Qin’an County of Gansu Province, Northwest China as test object, a field experiment was conducted to study the effects of different irrigation quota (0, 900, 1800, 2700, and 3600 m³·hm^-2) on the redistribution of moisture and salt in 0-100 cm soil profile on the 10, 20, and 30 d during apple florescence stage. With the increase of irrigation quota, the leached depth of Na⁺ increased and its hysteretic effect of redistribution was more obvious, “the zero flux plane” of Ca²⁺ disappeared gradually, the scope of “the zero flux plane” of Mg²⁺ increased gradually, the leachingmigration mode of Cl^- changed from “fluctuation” to “straightline” and the evaporation-migration changed from “fluctuation” to “ladder”, the redistribution pattern of SO₄^2- showed “point”, and the position of redistribution and accumulation of HCO₃^- shifted gradually from the bottom to upper layer in soil profile. In the middle of the soil profile with deeper groundwater table, there existed a “zero flux plane” of salt, which shifted gradually from the upper layer to the bottom during the redistribution of moisture in soil profile, embodying the characteristics of moisture depletion in upland soils. When the irrigation quota was between 2700 and 3600 m³·hm^-2, irrigation was helpful to the leaching of salt and watersoluble Na⁺ in the 0-100 cm soil profile. However, when the irrigation quota was <1800 m³·hm^-2, irrigation accelerated the salt accumulation in surface soil. Therefore, from the viewpoints of salt leaching and water-saving, an irrigation quota of 1800-2700 m³·hm^-2 in spring would be more appropriate for the salinized apple orchard soil in arid regions.

Effects of irrigation and planting pattern on winter wheat water consumption characteristics and dry matter production.

DONG Hao1,2, CHEN Yu-hai2, ZHOU Xun-bo2

2013, 24(7):  1871-1878. 

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Taking highyield winter wheat cultivar ‘Jimai 22’ as test material, a field experiment was conducted in 2008-2010 to study the effects of different irrigation and planting modes on the water consumption characteristics and dry matter accumulation and distribution of winter wheat. Three planting patterns (uniform row, wide-narrow row, and furrow) and four irrigation schedules (no irrigation, W₀; irrigation at jointing stage, W₁; irrigation at jointing and anthesis stages, W₂; and irrigation at jointing, anthesis, and milking stages, W₃; with 60 mm per irrigation) were installed. With increasing amount of irrigation, the total water consumption and the ratio of irrigation water to total water consumption under different planting patterns all increased, while the soil water consumption and its ratio to total water consumption decreased significantly. As compared with W₀, the other three irrigation schedules had a higher dry matter accumulation after anthesis and a higher grain yield, but a lower water use efficiency (WUE). Under the same irrigation schedules, furrow pattern had higher water consumption ratio, grain yield, and WUE. Taking the grain yield and WUE into consideration, furrow pattern combined with irrigation at jointing and anthesis stages would be the optimal watersaving and planting modes for the winter wheat production in North China Plain.

Effects of source-sink regulation on  water soluble carbohydrates of vegetative organs and thousand-grain mass of wheat under different water conditions.

LI Li1, YANG De-long1, LI Meng-fei1, CHANG Lei2, CHENG Hong-bo1, CHAI Shou-xi2, LI Wei1

2013, 24(7):  1879-1888. 

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Two winter wheat cultivars with different drought tolerance were selected to investigate the effects of source-sink regulation on the vegetative organs water soluble carbohydrates (WSC) content and 1000-grain mass (TGM) of wheat under drought stress (DS) and well watered (WW) conditions. Sink-cutting increased the WSC content of different vegetative organs significantly, and promoted the relative transportation of the WSC positively; while sourcecutting caused opposite responses. The effects of sourcesink regulation on the WSC content and its relative transportation amount (TA) and transportation rate (TR) were significantly higher under DS and sinkcutting than under WW and source-cutting, for droughtresistant cultivar (Longjian 19) than for drought-sensitive Q9086, and for peduncle internode and PedI than for penultimate internode and PenI. Under source-cutting, the superior organs of Longjian 19 in the TR of total WSC were sheath, PedI, and PenI, which also contributed to the fructan TR of the two cultivars, while those of Q9086 were the PenI and the third internode from top (ThiI). Source-cutting decreased the TGM of Longjian 19 and Q9086 significantly, with the decrement being 27.3% and 31.7% under DS and 25.3% and 12.1% under WW, respectively. The correlation coefficients of the WSC content and its TA and TR and the TGM were significantly higher under sink-cutting than under source-cutting, and also, under DS than under WW. There existed a higher correlation coefficient (r²> 0.900) of the TGM and the total WSC and fructan contents in different vegetative organs. The vegetative organs with closer correlation between their WSC content and its TA and TR and the TGM were mainly sheath and PedI. Under DS, the traits associated with the total WSC content had a higher correlation with TGM; under WW, the traits associated with sucrose and glucan contents generally showed a higher correlation with TGM. It was suggested that the effects of sourcesink regulation on the WSC content of vegetative organs and the TGM were significantly affected by soil water environment, wheat genotype, and vegetative organs location.

Change characteristics of rice yield and soil organic matter and nitrogen contents under various long-term fertilization regimes.

HUANG Jing1,2,3, GAO Ju-sheng2,3, ZHANG Yang-zhu1, QIN Dao-zhu2,3, XU Ming-gang2

2013, 24(7):  1889-1894. 

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A long-term (1982-2010) field experiment was conducted in the Red Soil Experiment Station of Chinese Academy of Agricultural Sciences in Qiyang County of Hunan Province, South-central China to investigate the dynamic changes of rice yield and soil organic matter (OM) and nitrogen contents under different fertilization treatments. The treatments included NPK, NPKM (M: manure), NPM, NKM, PKM, M, and CK. Fertilization increased the soil OM, total N, and alkaline-hydrolysable N contents and the rice yield. In treatment NPKM, the rice yield across the 28 years maintained at the highest level; while in treatment NPK, the yield showed a decreasing trend, being lower than that in other fertilization treatments. In the treatments applied with manure only or in combining with chemical fertilizers, the soil OM content increased rapidly in the first 16 years, and then fluctuated around a constant level (29.42-39.32 g·kg^-1). In the treatments of chemical fertilization, the soil OM content only had a quicker increase in the first 8 years, and then fluctuated within a relatively stable range. Fertilization with manure increased the soil OM significantly, as compared to fertilization with chemical fertilizers only. The soil total N content in all fertilization treatments showed a rapid increase in the first 8 years, and the increment was the highest in treatment NPKM. The soil alkalinehydrolysable N content in all fertilization treatments had a slower increase in the first 12 years, with an average annual increment of 0.66-2.25 mg·kg^-1·a^-1. In 1994-1998, the soil alkalinehydrolysable N content in fertilization treatments had a quicker increase, with an average annual increment of 6.45-32.45 mg·kg^-1·a^-1; but after 1998, the soil alkalinehydrolysable N content had a slight decrease. It was concluded that organic fertilization was the key measure to stably improve the physical and chemical properties and the productivity of red paddy soils by increasing their OM and nitrogen contents, and to sustain the rice production in red soil region in subtropical China.

Effects of low temperature stress on photosynthetic performance of different genotypes wheat cultivars.

GUAN Ya-nan, HUANG Zheng-lai, ZHANG Wen-jing, SHI Xiao-dong, ZHANG Pei-pei

2013, 24(7):  1895-1899. 

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Different genotypes wheat cultivars (spring wheat Yangmai 18, semi-spring wheat Zhengmai 9023, and semi-winter wheat Yannong 19) were chosen to study their photosynthetic and chlorophyll fluorescence characteristics at tillering and stem elongation stages under low temperature stress. After treated with low temperature (-10 ℃ at night) at tillering stage for 2 days, the net photosynthetic rate (P_n), stomata conductance (g_s), maximum quantum yield of PSII (F_v/F_m), photochemical quenching (q_P), non-photochemical quenching coefficient (NPQ), and acyclic photosynthetic electron transfer rate of PSII (ETR) of Yannong 19 were significantly higher than those of Yangmai 18 and Zhengmai 9023, the g_s,F_v/F_m,q_P, and NPQ of Zhengmai 9023 were significantly higher than those of Yangmai 18, while the intercellular CO₂ concentration (C_i) of Yannong 19 was significantly lower than that of Zhengmai 9023 and Yangmai 18. In addition, the minimal fluorescence (F_o) of Yangmai 18 was significantly higher than that of Zhengmai 9023 and Yannong 19. Similarly, after treated with low temperature (0  ℃ at night) at stem elongation stage for 3 days, the P_n, g_s, q_P, and F_v/F_m of Yannong 19 were significantly higher than those of Yangmai 18 and Zhengmai 9023, and the NPQ and ETR of Yannong 19 were significantly higher than those of Yangmai 18. In addition, the P_n, g_s, F_v/F_m, and q_P of Zhengmai 9023 were significantly higher than those of Yangmai 18, the F_o of Zhengmai 9023 was significantly higher than that of Yannong 19, and the C_i and F_o of Yangmai 18 were significantly higher than those of Zhengmai 9023 and Yannong 19. It was suggested that under low temperature stress at tillering and stem elongation stages, semiwinter wheat Yannong 19 had the highest photosynthetic activity and the best self-protection mechanism, followed by semi-spring wheat Zhengmai 9023, and spring wheat Yangmai 18.

 

Effects of tillage patterns on photosynthetic and chlorophyll fluorescence characteristics of maize in rainfed area of Northeast China.

SONG Zhen-wei1, GUO Jin-rui2, REN Jun2, YAN Xiao-gong2, ZHENG Cheng-yan1, DENG Ai-xing1, ZHANG Wei-jian1

2013, 24(7):  1900-1906. 

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In 2010-2011, a field experiment was conducted in Northeast China to evaluate the effects of different tillage patterns on the temperature and moisture in topsoil layer and the leaf photosynthesis and chlorophyll fluorescence of maize. The effects of tillage patterns on the soil temperature and moisture mainly manifested at sowingjointing stage. In treatments flat planting with ridging at early jointing stage (PL) and flat planting without ridging (PP), the soil moisture content at the depth of 0-40 cm was significantly higher than that in treatment ridge planting (LL), with the increment being 5.6% and 5.2%, 4.6% and 7.3%, and 3.9% and 4.8% at emergency, seedling, and jointing stages, respectively. The minimum temperature at the soil depth 5 cm at seedling stage in PL and PP was 1.4 and 1.3 ℃ higher than that in LL, respectively. Due to the improvement of soil water and thermal conditions, the leaf photosynthetic rate (P_n) and transpiration rate (T_r) at jointing stage in PL and PP were significantly higher than those in LL, whereas the PSⅡ potential activity (F_v/F_o) and PSⅡ maximal photochemical efficiency (F_v/F_m) had no significant differences among the treatments, indicating that the stomatal factors such as stomata conductivity and stomata limitation were the main factors inducing the photosynthesis differences among the treatments. Furthermore, the P_nandT_r at grain filling stage in LL and PL were higher than those in PP, mainly due to the high waterlogging risk in PP in strong rainfall season. Consequently, treatment PL could promote maize photosynthesis through improving soil water and thermal conditions, and further, increase maize grain yield.

Dynamics of Cry1Ab protein content in the rhizosphere soil and straw debris of transgenic Bt corn

LI Fan1, WANG Min1,2, SUN Hong-wei1, YANG Shu-ke1, LU Xing-bo1

2013, 24(7):  1907-1913. 

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By using ELISA test kits, a field investigation was conducted on the degradation dynamics of Cry1Ab protein in the rhizosphere soil of Bt corn MON810 at its different growth stages and in the MON810 straws returned into field after harvest. Three models (shiftlog model, exponential model, and biexponential model) were used to fit the degradation dynamics of the Cry1Ab protein from the straw debris, and the DT₅₀ and DT₉₀ values were estimated. There existed great differences in the Cry1Ab protein content in the rhizosphere soil of MON810 at its different growth stages, but overall, the Cry1Ab protein content was decreased remarkably with the growth of MON810. The degradation of Cry1Ab protein from the straws covered on soil surface and buried in soil showed the same twostage pattern, i.e., more rapid at early stage and slowstable in later period. Within the first week after straw return, the degradation rate of the Cry1Ab protein from the straws covered on soil surface was significantly higher than that from the straws buried in soil. At 10 d, the degradation rate of the Cry1Ab protein from the straws covered on soil surface and buried in soil was basically the same, being 88.8% and 88.6%, respectively. After 20 days, the degradation of Cry1Ab protein entered slowstable stage. Till at 180 d, a small amount of Cry1Ab protein could still be detected in the straw debris. All of the three models used in this study could  fit the decay pattern of the Cry1Ab protein from the straw debris in field. By comparing the correlation coefficient (R) and the consistency between the measured and calculated DT₉₀, biexponential model was considered to be the best.

Evaluation of cucumber’s chilling tolerance at germination and seedling stages.

MIAO Yong-mei1,2, NING Yu1, CAO Yu-jie1, SHEN Jia1, PANG Xin1, CUI Li1, CHENG Chun-yan1, CHEN Jin-feng1

2013, 24(7):  1914-1922. 

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A total of 13 cucumber materials were used to study the relationships of cucumber’s chilling tolerance with the 12 growth indices at germination and seedling stages. There existed significant differences in the relative germination rate, germination index, hypocotyl length, and vigor index at 17 ℃ among the 13 materials (P<0.05), which also significantly correlated to the chilling tolerance. At seedling stage, the physiology among the materials after treated at 4 ℃ for 2 days had obvious difference. Chilling injury index had significant correlation with the survival rate after recovery, but less correlation with the soluble protein (SP) content, electric conductivity (EC), and superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) activities. The chilling tolerance of the materials was classified into three levels by clustering analysis, and the cucumber’s chilling tolerance equations at the two stages were established through stepwise regression analysis. Based on confidence interval value, the chilling tolerance of cucumber could be well assessed.

Effects of different nitrogen forms and their ratios on broccoli yield, quality, and nutrient absorption.

LIU Zhao-fan1, ZHANG Guo-bin1, YU Ji-hua1, YANG Hai-xing2, SHI Gui-ying1, MA Yan-xia1, LI Jie1

2013, 24(7):  1923-1930. 

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A field experiment was conducted to study the effects of different nitrogen forms ((NH₂)₂CO_N, NO₃^--N, NH₄⁺-N, and NO₃^--NH₄⁺) and their ratios on the yield formation, quality, and nutrient (N, P, and K) absorption of broccoli (Brassica oleracea). Fertilization with NO₃^--N increased the accumulation of nitrate and soluble sugars in ball flower. When the NO₃^--N:NH₄⁺-N ratio was ranged from 3:7 to 5:5 and from 5:5 to 7:3, respectively, the accumulation of nitrate in the ball flower was reduced, while the soluble sugars content was promoted. Fertilization with (NH₂)₂CO_N and NH₄⁺-N was conducive to the improvement of Vc content in the ball flower. N fertilization increased the accumulation of N, P, and K in plants, with the highest contents of N, P, and K observed at rosette stage. Throughout the entire growth period, NH₄⁺-N fertilization improved the plant N content, whereas NO₃^--N fertilization improved the plant K content. At different growth stages, the effects of different N sources on plant P content varied. As compared with applying single N forms, the NO₃^--N:NH₄⁺-N ratio ranged from 3:7 to 5:5 could improve the yield significantly. It was suggested that a combined application of NO₃^--N and NH₄⁺-N with an appropriate ratio could improve the productivity, quality, and economic return of broccoli.

Estimation model for daily transpiration of greenhouse muskmelon in its vegetative growth period.

ZHANG Da-long1, LI Jian-ming1,2, WU Pu-te1,2, LI Wei-li3, ZHAO Zhi-hua1, XU Fei1, LI Jun1

2013, 24(7):  1938-1944. 

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For developing an estimation method of muskmelon transpiration in greenhouse, an estimation model for the daily transpiration of greenhouse muskmelon in its vegetative growth period was established, based on the greenhouse environmental parameters, muskmelon growth and development parameters, and soil moisture parameters. According to the specific environment in greenhouse, the item of aerodynamics in Penman-Monteith equation was modified, and the greenhouse environmental sub-model suitable for calculating the reference crop evapotranspiration in greenhouse was deduced. The crop factor sub-model was established with the leaf area index as independent variable, and the form of the model was linear function. The soil moisture sub-model was established with the soil relative effective moisture content as independent variable, and the form of the model was logarithmic function. With interval sowing, the model parameters were estimated and analyzed, according to the measurement data of different sowing dates in a year. The prediction accuracy of the model for sufficient irrigation and water-saving irrigation was verified, according to measurement data when the relative soil moisture content was 80%, 70%, and 60%, and the mean relative error was 11.5%, 16.2%, and 16.9% respectively. The model was a beneficial exploration for the application of Penman-Monteith equation under greenhouse environment and water-saving irrigation, having good application foreground and popularization value.

Branch growth of Korean pine plantation based on nonlinear mixed model.

WANG Chun-hong, LI Feng-ri, JIA Wei-wei, DONG Li-hu

2013, 24(7):  1945-1952. 

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Based on the branch analysis data from 36 sample trees in a Korean pine plantation in Mengjiagang Forest Farm of Heilongjiang Province, Northeast China, and by using Mitcherlich and Richards equations as the models of branch diameter and branch length growth, respectively, the effects of sampling plot and sample tree were investigated, and the nonlinear mixed models of branch diameter and branch length growth were established by the PROC NLMIXED procedure of SAS software. The evaluation statistics such as Akaike information criterion (AIC), Bayesian information criterion (BIC), -2Log likelihood, and likelihood ratio test (LRT) were used to compare the prediction precisions of the models. When considering plot effect, and taking α₁ and α₃ and β₁ and β₃ as the random parameters, respectively, the models of branch diameter and branch length growth had the best performance. When considering tree effect, and taking α₂ and α₃ and β₂ and β₃ as the random parameters, respectively, the models of branch diameter and branch length growth had the best performance. The nonlinear mixed model could not only reflect the mean variation of branch growth, but also show the differences among the individual trees. No matter considering plot effect or tree effect, the fitting precision of the nonlinear mixed model was better than that of the ordinary regression analysis model. Moreover, the fitting precision of the nonlinear mixed model was better when considering tree effect than considering plot effect.

Relationships between river water quality and land use type at watershed scale.

YANG Sha-sha1,2, TANG Cui-wen1, LIU Li-juan3, LI Xiao-yu3, YE Yin2

2013, 24(7):  1953-1961. 

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Based on the remote sensing images of 54 water quality monitoring stations within the Suzi River watershed, the riparian buffer zones at 6 scales were constructed by ArcGIS, and the 8 landscape indices at landscape and class levels were calculated with FRAGSTATS software. A correlation analysis on the landscape indices and river water quality was made from the viewpoints of landscape space pattern and composition. In the watershed, the landscape pattern in different riparian buffer zones had different effects on the river water quality. When the distance of the buffer zones was less than 300 m, the main landscape types were dry land, construction land, and paddy filed, and their area ratio, patch number, patch density, maximum patch index, maximum shape index, and aggregation index were higher. In these buffer zones, farmlands had higher connectedness, and thus, had greater effects on the river water quality. When the distance of the buffer zones was more than 300 m, forest land had a larger area ratio and a higher connectedness, which would benefit the improvement of river water quality to some extent. In the watershed, farmland and construction land played a key role in affecting the river water quality.

Spatiotemporal distribution characteristics and  causes of sunny days’ heat island effect in Chengdu City of Southwest China.

ZHANG Shun-qian1,2, ZHOU Chang-yan1

2013, 24(7):  1962-1968. 

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Based on 99 clear sky Terra satellite images of Chengdu City in 2005-2010, and by using a novel automatic extraction method of suburb temperature, i.e., each citycircle temperature jump, this paper studied the spatiotemporal variation characteristics of the urban heat island (UHI) effect in the City in 2005-2010, and analyzed the causes of the variation characteristics. In the study period, the central area of the largest and strongest UHI was in the Jinhua Town located in the southwest of Chengdu. The UHI effect had no significant spatial variation, but the range and intensity of the UHI effect tented to be decreased. The intra-annual UHI intensity and area within the ring roads showed a threepeak distribution pattern, with the peak values appeared in April, July, and October, and the intensity reached the maximum in July. The UHI intensity in Chengdu was attenuated by the decrease of air temperature and the increase of precipitation and urban vegetation cover.

Spatiotemporal patterns and driving forces of land use change in industrial relocation area: A case study of old industrial area in Tiexi of Shenyang, Northeast China.

WANG Mei-ling1, BING Long-fei1, XI Feng-ming1, WU Rui1,2, GENG Yong1

2013, 24(7):  1969-1976. 

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Based on the QuickBird remote sensing images and with the support of GIS, this paper analyzed the spatiotemporal characteristics of land use change and its driving forces in old industrial area of Tiexi, Shenyang City of Liaoning Province in 2000-2010. During the study period, the industrial and mining warehouse land pattern had the greatest change, evolving from the historical pattern of residential land in the south and of industrial land in the north into residential land as the dominant land use pattern. In the last decade, the residential land area increased by 9%, mainly transferred from the industrial and mining warehouse land located in the north of Jianshe Road, while the industrial and mining warehouse land area decreased by 20%. The land areas for the commercial service and for the administrative and public services were increased by 1.3% and 3.1%, respectively. The land area for construction had a greater change, with an overall change rate being 76.9%. The land use change rate in 2000-2005 was greater than that in 2005-2010. National development strategies and policies, regional development planning, administrative reform, and industrial upgrading were the main driving forces of the land use change in old industrial area of Tiexi.

Relationships between settlement morphology transition and residents commuting energy consumption.

ZHOU Jian1, XIAO Rong-bo1， SUN Xiang2

2013, 24(7):  1977-1984. 

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Settlement morphology transition is triggered by rapid urbanization and urban expansion, but its relationships with residents commuting energy consumption remains ambiguous. It is of significance to understand the controlling mechanisms of sustainable public management policies on the energy consumption and greenhouse gases emission during the process of urban settlement morphology transition. Taking the Xiamen City of East China as a case, and by using the integrated land use and transportation modeling system TRANUS, a scenario analysis was made to study the effects of urban settlement morphology transition on the urban spatial distribution of population, jobs, and land use, and on the residents commuting energy consumption and greenhouse gasses emission under different scenarios. The results showed that under the Business As Usual (BAU) scenario, the energy consumption of the residents at the morning peak travel time was 54.35 tce, and the CO₂ emission was 119.12 t. As compared with those under BAU scenario, both the energy consumption and the CO₂ emission under the Transition of Settlement Morphology (TSM) scenario increased by 12%, and, with the implementation of the appropriate policies such as land use, transportation, and economy, the energy consumption and CO₂ emission under the Transition of Settlement Morphology with Policies (TSMP) scenario reduced by 7%, indicating that urban public management policies could effectively control the growth of residents commuting energy consumption and greenhouse gases emission during the period of urban settlement morphology transition.

 

Effects of precipitation variation on the distribution pattern of soil fungal diversity in broad-leaved Korean pine mixed forest.

WANG Nan-nan1, YANG Xue1, LI Shi-lan1, SUI Xin2, HAN Shi-jie2, FENG Fu-juan1

2013, 24(7):  1985-1990. 

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Broad-leaved Korean pine mixed forest is a kind of zonal climax vegetation with ecological significance in Northeast China, whereas Changbai Mountain is an ideal area to study the effects of precipitation variation on temperate forest. Taking the virgin broad-leaved Korean pine mixed forest in Changbai Mountain as the object, and based on T-RFLP method, this paper analyzed the spatial heterogeneity of fungal diversity in 0-5 cm and 5-10 cm soil layers and in rhizosphere soil at three different precipitation plots (30% increase, 30% decrease, and the control). Both the increase and the decrease of precipitation increased the diversity of soil fungi, but the dominant population changed. In 0-5 cm and 5-10 cm soil layers, the T-RFs over 500 bp increased with precipitation; in rhizosphere soil, the T-RFs responded to precipitation variation were 380 bp, 455 bp, and 487 bp, and the response mode was more complicated than that in surface soil layers. The results of CCA showed that the fungal community composition was significantly affected by soil pH, organic carbon, total nitrogen, and organic phosphorus.

 

Microecological mechanisms of red-leaf disease occurrence in Salvia miltiorrhiza Bge.

DUAN Jia-li1, SHU Zhi-ming2, WEI Liang-zhu3, FU Liang-liang3, XUE Quan-hong1

2013, 24(7):  1991-1999. 

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A comparative study was made on the nutrient content in rhizosphere soil and the microflora in rhizosphere soil and on rhizoplane of healthy and red-leaf diseased Salvia miltiorrhiza plants, aimed to approach the microecological mechanisms of redleaf disease occurrence in S. miltiorrhiza. The N, P, K, and Mn contents in the diseased plant leaves were significantly lower than those in the healthy plant leaves (P＜0.05). No significant difference was observed in the available P content in the rhizosphere soils of diseased and healthy S. miltiorrhiza, but the available N and K contents were significantly higher (P＜0.05) in the rhizosphere soil of diseased S. miltiorrhiza. These results indicated that the red-leaf disease occurrence in S. miltiorrhiza was related to plant P deficiency, but the lack of P in the plants was not caused by the insufficient soil P supply. As compared with those in healthy S. miltiorrhiza rhizosphere, the bacterial number in diseased S. miltiorrhiza rhizosphere soil decreased by 41.3%, while the fungal and actinomycetes numbers increased by 156.6% and 189.5% (P＜0.05), respectively. Similar variations in the numbers of bacteria, fungi, and actinomycetes were observed on diseased S. miltiorrhiza rhizoplane. In the rhizosphere soil and on the rhizoplane of diseased S. miltiorrhiza, the predominant microbial species that might be harmful included six fungi (Fusarium solani, Myrothecium roridum, F. tricinctum, Aspergillus calidoustus, F. oxysporum, and Dothideomycetes sp.), four actinomycetes (Streptomyces lateritius, Lentzea waywayandensis, S. stelliscabiei and S. collinus), and two bacteria (Bacillus aryabhattai and Piscinibacter aquaticus). These predominant soil microbes likely caused plant P deficiency via negatively affecting the growth of roots and their absorption of soil nutrients. It was suggested that the red-leaf disease occurrence in S. miltiorrhiza was closely related to the plant P deficiency caused by the abnormality of soil microflora in the rhizosphere soil and on the rhizoplane of S. miltiorrhiza.


 

Host preference and fitness of Aphis citricola (Hemiptera: Aphididae) to mature and young apple leaves.

YIN Wan-dong, QIU Gui-sheng, YAN Wen-tao, SUN Li-na, ZHANG Huai-jiang

2013, 24(7):  2000-2006. 

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In order to understand the differences of Aphis citricola in its original and final selectivity to the apple leaves with different leaf age, and to ascertain the effects of mature and young apple leaves on the growth and development, survival, and fecundity of A. citricola, this paper studied the host preference of A. citricola to mature and young apple leaves, with the related agestage twotype life tables constructed. A. citricola more preferred to oviposit on the young leaves. There existed differences in the behaviors between oriented selectivity and penetration selectivity, and the latter was the key factor determining whether A. citricola fed and oviposited on the host. The total development time of immature A. citricola on the mature leaves was significantly longer than that on the young leaves, and the survival rate was also lower, with the aphids died at the first and fourth instar stages and at mature stage. As compared with those on the young leaves, the apterae rate of A. citricola adults on the mature leaves was lower, and the longevity and fecundity were significantly shorter and lower. The population dynamic parameters suggested that the population growth of A. citricola was quicker on the young leaves than on the mature leaves, and it was difficult for A. citricola to establish a stable population on the mature leaves.

Stock assessment and management for Illex argentinus in Southwest Atlantic Ocean based on Bayesian Schaefer model.

LU Hua-jie1,2,3,4, CHEN Xin-jun1,2,3,4, LI Gang1,2,3,4, CAO Jie5

2013, 24(7):  2007-2014. 

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Bayesian Schaefer model was applied to assess the stock of Illex argentinus in the Southwest Atlantic Ocean, with the risk of alternative management strategies for the squid analyzed. Under the scenarios of normal and uniform prior assumptions, the estimated model parameters and reference points were similar, and higher than the values under the scenario of logarithmic normal prior assumption. Under the three proposed scenarios, the fishing mortalities and the total catches in 2001-2010 were lower than the reference point F_0.1 and the maximum sustainable yield (MSY), indicating that the I. argentinus was in an expected sustainable exploited level but not in overfishing and over-fished. The results of decision analysis indicated that at the same harvest rate, the stock of the I. argentinus under the scenario of logarithmic normal prior assumption in 2025 would be the lowest, and the probability of collapse would be the highest. Under the three scenarios, the harvest rate in 2025 would be all 0.6 if the catch was the maximum. However, if the harvest rate was set to 0.6, the stock of the I. argentinus after 2025 would have definite risk, and thus, the harvest rate 0.4 and the catch 550000 t appeared to be the best management regulation or the baseline case.

Feeding habits of Trachurus japonicus in the East China Sea.

JIANG Ri-jin1,2, JIN Hai-wei1, ZHOU Yong-dong1, XUE Li-jian1, GUO Ai1

2013, 24(7):  2015-2024. 

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A total of 453 Trachurus japonicus specimens with a fork length (FL) of 46-250 mm were sampled in the seasonal light seine net surveys in the East China Sea in May, August, and November, 2008 and in February, 2009. The stomach contents of the specimens were analyzed, and the seasonal and ontogenetic variations in the feeding habits of the T. japonicus were examined by the Kruskal-Wallis test, chi-squared test, and cluster analysis. There were 124 prey species (including not identified) ingested by the T. japonicus, among which, planktonic crustaceans and small-scale marine fish made up the dominant prey groups. According to the percentage index of relative importance (IRI%), Bregmaceros macclellandi was the most dominant prey, accounting for 39.2%, followed by Macrura mysis larva (18.4%), brachyura zoea larva (7.6%), and Euphausia pacifica (6.6%). The feeding intensity of the T. japonicus varied significantly with its FL and season, being the highest for the T. japonicus with a FL of 140-159 mm, higher for the T. japonicus juveniles with a FL of 45-99 mm, while lower for the T. japonicus of other size classes, and the highest in spring and the lowest in winter. Cluster analysis revealed there was an abrupt change in the diet composition for the T. japonicus with a FL of about 100 mm FL. The average trophic level of the T. japonicus in four seasons was 3.51, indicating that the T. japonicus in the East China Sea was of low-level carnivores feeding on plankton and nekton.

Effects of aging time on the form transformation and eco-toxicity threshold (EC_x) of added Zn in typical China soils.

LIN Lei, CHEN Shi-bao, LIU Ji-fang, MA Yi-bing

2013, 24(7):  2025-2032. 

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Six typical China soils with different properties were selected and added with seven concentrations of ZnCl₂ to study the effects of different aging time (14, 90， 180, 360, and 540 days) on the form transformation and eco-toxicity threshold (EC_x) of added Zn in the soils, with the main affecting factors analyzed. The results indicated that with the increase of aging time, the fraction of 0.01 mol·L^-1 CaCl₂extracted Zn in the soils decreased sharply initially, then slowed down, and reached the dynamic balance after 540 d incubation. The ecotoxicity thresholds (EC_x, x=10, 50) of Zn to bok choy increased significantly with aging time (P<0.05), which implied the marked decrease of the phytotoxicity of Zn. The measured aging factors AF₁₀ and AF₅₀ of Zn ranged from 1.077-1.743 and 1.174-1.441, respectively, and increased with aging time. The balanced concentration of Zn in the soils was significantly negatively correlated with soil pH, CEC, and organic carbon (Org-C) content, and soil pH was the most important controlling factor, followed by CEC and Org-C. It took shorter time to reach Zn balance in the soils with higher pH. The prediction model of the EC_x of Zn was developed based on the aging factors and the main soil properties, and could be well validated by the measured EC_x under field condition. This study would provide theoretical basis for the normalization of the eco-toxicity thresholds of added Zn in different soils and the formulation of the environmental criterion of Zn in China soils.

Ecological characteristics of Zostera japonica population in Swan Lake of Rongcheng, Shandong Province of China.

ZHANG Xiao-mei1,2, ZHOU Yi1, WANG Feng1,2, LIU Peng1,2, LIU Bing-jian1, LIU Xu-jia3, YANG Hong-sheng1

2013, 24(7):  2033-2039. 

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In this study, a large area of well preserved Zostera japonica dominated meadow was found in a coastal lagoon, Swan Lake, in Rongcheng of Shandong Province. Due to its unique geographical position and high biomass, this meadow may act as a typical Z. japonica bed in the coastal area of Shandong. From September, 2011 to October, 2012, an annual investigation was conducted on the Z. japonica and its habitats in east coast of Swan Lake, and the distribution of the Z. japonica and its habitats ecological characteristics were preliminarily understood. The major ingredients of  sediments particles in the Z. japonica bed was  sand (81%) and silt (14%).  The C and N contents in the sediments were the highest in winter, and the C/N ratio was the highest in autumn. The shoot density, shoot height, and biomass of the Z. japonica were all significantly correlated with water temperature (P<0.05). There was an obvious change in the Z. japonica growth among seasons, with the peak biomass obtained in August-September. The C and N contents and C/N in Z. japonica leaves also varied with seasons. The leaf C content was significantly higher in autumn than in spring and summer (P<0.05), the leaf N content was significantly lower in summer than in spring and autumn (P<0.01), whereas the leaf C/N ratio was significantly higher in summer than in spring (P<0.05). The annual carbon sequestration by the Z. japonica in the Swan Lake was estimated to be 111.4 g C·m^-2.

Deposition and burial of organic carbon in coastal salt marsh: Research progress.

CAO Lei1,2, SONG Jin-ming1, LI Xue-gang1, YUAN Hua-mao1, LI Ning1, DUAN Li-qin1

2013, 24(7):  2040-2048. 

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Coastal salt marsh has higher potential of carbon sequestration, playing an important role in mitigating global warming, while coastal saline soil is the largest organic carbon pool in the coastal salt marsh carbon budget. To study the carbon deposition and burial in this soil is of significance for clearly understanding the carbon budget of coastal salt marsh. This paper summarized the research progress on the deposition and burial of organic carbon in coastal salt marsh from the aspects of the sources of coastal salt marsh soil organic carbon, soil organic carbon storage and deposition rate, burial mechanisms of soil organic carbon, and the relationships between the carbon sequestration in coastal salt marsh and the global climate change. Some suggestions for the future related researches were put forward: 1) to further study the underlying factors that control the variability of carbon storage in coastal salt marsh, 2) to standardize the methods for measuring the carbon storage and the deposition and burial rates of organic carbon in coastal salt marsh, 3) to quantify the lateral exchange of carbon flux between coastal salt marsh and adjacent ecosystems under the effects of tide, and 4) to approach whether the effects of global warming and the increased productivity could compensate for the increase of the organic carbon decomposition rate resulted from sediment respiration. To make clear the driving factors determining the variability of carbon sequestration rate and how the organic carbon storage is affected by climate change and anthropogenic activities would be helpful to improve the carbon sequestration capacity of coastal salt marshes in China.

Adaptation mechanisms of alpine plants photosynthetic apparatus against adverse stress: A review

WANG Yu-ping1, GAO Hui-hui1, LIU Yue-shan1, MU Ping1, YU Xiao-jun1, AN Li-zhe3, ZHANG Feng1,2

2013, 24(7):  2049-2055. 

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Photosynthesis is one of the vital physiological processes easily affected by environmental changes. As a plant group growing in specific low temperature and strong irradiance environment, the photosynthetic apparatus of alpine plants have developed special morphologically and physiologically  mechanisms in adapting to this extreme adverse environment. However, due to the high heterogeneity of habitats, there exist great differences in the photo-protection and adaptation mechanisms among different alpine plants. This paper reviewed the recent researches about the morphology and ultramicro-anatomical structure of the chloroplasts in photosynthetic apparatus of alpine plants and the photo-protection and adaptation mechanisms of the plants, and proposed the further research directions on the physiological adaptation of the photosynthesis of alpine plants.

Effects of forest ownership regime on landscape pattern and animal habitat: A review.

LI Yue-hui1, WU Wen1,2, LI Na-na1,3, BU Ren-cang1, HU Yuan-man1

2013, 24(7):  2056-2062. 

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In some European and North American countries where forestry is highly developed, both public and private forest ownership regimes have being existed for a long time. Currently, the researches about both the dynamics of forest landscape and habitat pattern and the relationship between habitat pattern and biological conservation in multiownership forest landscape are increasingly becoming important. This paper reviewed the effects of multi-ownership regime on forest landscape pattern and animal habitat and emphasized on the ecological consequences of forest parcelization and land divestiture, including the provision of diverse habitats and fragmentation of the existing large-area habitat. This paper also summarized two ways (changing the ownership pattern and integrating the multi-ownership management by cross boundary coordination) for handling the conflicts between smallscaled multiownership management and biological conservation at large scale in forestry-developed countries and analyzed the reasons that those countries prefer to adopt the latter one. Furthermore, the methodological limitations in simulating ownership pattern were pointed out. Finally, the present status, challenges and opportunities in the above-mentioned research issues in China were discussed, and the suggestions for further researches were provided.

Assessment system for watershed ecological health in the United States: Development and application. 

ZHANG Hua, LUO Yong-ming

2013, 24(7):  2063-2072. 

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To meet the water quality goals of the Clean Water Act, the environmental agencies in the United States (U.S.) have developed a comprehensive ecological assessment system of watershed health in the last two decades. The system employs a watershed approach, and includes a large set of hydrological, chemical, and biological indices, having become an essential part of the watershed water quality management system in the U.S. and provided strong support for the protection of water environment and the restoration of aquatic system. In this paper, the development and application of the ecological assessment system of watershed health by the U.S. environmental regulators, especially the U.S. Environmental Protection Agency (US EPA), were overviewed from the aspects of related laws and regulations, ecosystem function analysis, ecological health indicators, comprehensive assessment system, and monitoring and data management systems, and the health assessment systems for the rivers, lakes, estuaries, coasts, and wetlands adopted by the National Aquatic Resource Surveys (NARS) were introduced. Some suggestions for the future development of the scientific ecological assessment system of watershed health in China were put forward based on the understanding of the protection and remediation practices of our water environment.

Effects of light on submerged macrophytes in eutrophic water: Research progress.

ZOU Li-sha, NIE Ze-yu, YAO Xiao-yan, SHI Ji-yan

2013, 24(7):  2073-2080. 

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The restoration of submerged macrophytes is the key to remediate eutrophic water and maintain the health of aquatic ecosystem, while light is the main limiting factor. This paper summarized the factors affecting the light extinction in water and the mechanisms of light intensity affecting the physiology of submerged macrophytes, with the focuses on the metabolic mechanisms of carbon, nitrogen, and phosphorus, the responses of antioxidant enzyme system, and the feedbacks of pigment composition and concentration in the common submerged macrophytes under low light stress. Several engineering techniques applied in the ecological restoration of submerged macrophytes were presented, and the framework of the restoration of submerged macrophytes in eutrophic water was proposed. Some problems in current research and several suggestions on future research were addressed, which could help the related research and engineering practices.

Application potential of siderophore-producing rhizobacteria in phytoremediation of heavy metals-contaminated soils: A review.

WANG Ying-li1, LIN Qing-qi1, LI Yu1, YANG Xiu-hong1,2, WANG Shi-zhong1,2, QIU Rong-liang1,2

2013, 24(7):  2081-2088. 

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Siderophore-producing rhizobacteria (SPR) are a group of plant growth-promoting rhizobacteria, being able to play an important role in assisting the phytoremediation of heavy metals- contaminated soils. Based on the comprehensive analysis of related researches at home and abroad, this paper elaborated the functions of SPR in alleviating the heavy metals stress and toxicity to plants and the mechanisms of SPR in improving the heavy metals bioavailability in soil, and indicated that SPR had good application potential in promoting the plant growth in heavy metals-contaminated soils and reinforcing the heavy metals accumulation in plants. The contradictory phenomena of SPR in increasing or decreasing heavy metals accumulation in plants, which existed in current researches, were also analyzed. Aiming at the deficiencies in current researches, it was suggested that in the future researches, the mechanisms of the interactions between SPR and plants, especially hyperaccumulators, should be further studied, the key factors affecting the heavy metals complexation and mobilization in soil by siderophores should also be further clarified, the effects of siderophores on the heavy metals bioavailability and its subsequent influence on the heavy metals uptake by plants should be comprehensively considered, and the measures for improving the colonization of SPR in heavy metalscontaminated soil should be explored.