Table of Content

18 August 2014, Volume 25 Issue 8

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Species composition and community structure of  a spruce-fir forest and a larch forest  on the northern slope of Changbai Mountains, Northeast China.

KUANG Xu1,2, XING Ding-liang1,2, ZHANG Zhao-chen1,2, SONG Hou-juan1,2, WANG Yun-yun1,2, FANG Shuai1,2, YUAN Zuo-qiang1, YE Ji1, LIN Fei1,2, WANG Xu-gao1, HAO Zhan-qing1

2014, 25(8):  2149-2157. 

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Spruce-fir forest is the best protected forest vegetation, while larch forest is intrazonal vegetation on the northern slope of Changbai Mountains. To further understand their species composition and community structure, we established a 4 hm² forest permanent plot in each of these two forests in 2010. All free-standing plant species with DBH (diameter at breast height) ≥1 cm were mapped, tagged, and identified to species. The results showed that there were 9257 stems belonging to 8640 genotype individuals, 22 species, 6 genera and 12 families in the sprucefir forest plot, while 4060 stems belonging to 3696 genotype individuals, 22 species, 8 genera and 16 families in the larch forest plot. Species composition in the two plots was very similar. Most of the species belonged to the Changbai Mountains plant flora. The analysis of species’ importance values showed that there were dominant species in both communities. The spruce-fir forest was dominated by Abies nephrolepis and Larix olgensis, whose importance values accounted for 38.7% and 23.9% of the sum of importance values over all species in the plot, respectively. The larch forest was dominated solely by L. olgensis, whose importance value accounted for 61.9% of the sum of importance values over all species in the plot. Both forests were in good condition of regeneration and showed a reversed ‘J’ type in tree size distributions at community level. However, different species showed different shapes in size distribution in the two forests. A. nephrolepis showed a reversed ‘J’ type size distribution in the spruce-fir forest, while L. olgensis with DBH≥10 cm showed a hump-shaped distribution in the larch forest. Spatial distribution patterns of the main species changed differently with size class and spatial scales. Common species had different spatial distribution patterns in the two plots.

Effects of snow patches on the release of N and P during foliar litter decomposition in an alpine forest of western Sichuan, China.

HE Jie1, JIANG Xian-min2, YANG Wan-qin1, NI Xiang-yin1, XU Li-ya1, LI Han1, WU Fu-zhong1

2014, 25(8):  2158-2166. 

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A field experiment using litterbags was conducted in an alpine forest of western Sichuan in order to understand the effects of snow patches on the dynamics of N and P during decomposition of six representative species foliar litter in different periods of winter. Net N immobilization during foliar litter decomposition was observed in the whole snow cover season regardless of species. In contrast, P mainly released from foliar litter in the snow cover season, with a rapid rate of P release in the snow melt stage. Thick and moderate snow patches showed higher P release rates, but lower N release rates of foliar litter. The rate of N release was negatively related to daily mean temperature regardless of species, but the rate of P release was positively related to daily mean temperature with the exception of fir needle litter. The decrease of snow cover in the scenario of global warming could inhibit P release but promote N release from foliar litter decomposition in winter in the alpine forest.

Ecosystem carbon exchange in Artemisia ordosica shrubland of Ordos Plateau in two different precipitation years.

GAO Li1, DONG Ting-ting2, WANG Yu-qing1, YAN Zhi-jian1, BAOYIN Tao-ge-tao2, WANG Hui1, DAI Ya-ting1

2014, 25(8):  2167-2175. 

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Characteristics of ecosystem carbon exchange and its impact factors in Artemisia ordosica shrubland in 2011(low precipitation) and 2012(high precipitation), Ordos Plateau, were studied using eddy covariance methods. The results showed that the diurnal dynamics of ecosystem carbon exchange could be expressed as singlepeak and doublepeak curves in the two different precipitation years. In 2011, three carbon absorption peaks and three carbon release peaks of ecosystem carbon exchange presented in the growing season. In 2012, four carbon absorption peaks and one carbon release peak appeared in the growing season. The A. ordosica shrubland was a net carbon sink from June to September and a carbon source in October in 2011. In 2012, A. ordosica shrubland was a net carbon sink in the whole growing season. The amount of carbon fixed by A. ordosica shrubland in the growing season in 2012 was 268.90 mg CO₂·m^-2·s^-1  higher than that in 2011. The ecosystem carbon exchange of A. ordosica shrubland was controlled by PAR (photosynthetically active radiation) on the day scale, and  affected by both abiotic (precipitation and soil water content) and biotic (aboveground net primary productivity) factors on the growing season scale.

Response of fine root decomposition to simulated nitrogen deposition in Pleioblastus amarus plantation, Rainy Area of West China.

TU Li-hua, CHEN Gang, PENG Yong, HU Hong-ling, HU Ting-xing, ZHANG Jian

2014, 25(8):  2176-2182. 

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As an important contributor to carbon (C) flux in the global C cycle, fine root litter decomposition in forests has the potential to be affected by the elevated nitrogen (N) deposition observed globally. From November 2007 to January 2013, a field experiment involving monthly simulated deposition of N in a Pleioblastus amarus plantation was conducted in the Rainy Area of West China. Four levels of nitrogen deposition were included as control (0 g N·m^-2·a^-1), low nitrogen (5 g N·m^-2·a^-1), medium nitrogen (15 g N·m^-2·a^-1) and high nitrogen (30 g N·m^-2·a^-1). After 3 years of simulated N deposition experiment (January 2011), a twoyear fine root decomposition experiment was conducted in the simulated N deposition plots using litterbag method, under monthly experimental N deposition. The decomposition rates of fine roots were fast first and then slow. Mass loss of fine roots in the first year of decomposition was up to 60%, and the change of the remaining mass was very slow in the second year. The time of 50% and 95% mass loss of fine roots was 1.20 and 5.17 years, respectively, under the conditions of no addition N input. In general, decomposition rates were underestimated using negative exponential model.  Simulated N deposition significantly inhibited the decomposition of fine roots. The remaining mass in the high nitrogen treatment was 51.0% higher than that in the control, after two years of decomposition. Simulated N deposition increased C, P and K contents in the remaining mass of litter. Compared with the control, soil pH decreased significantly in the medium and high nitrogen treatments, soil organic C, total N, ammonium and nitrate contents and fine root biomass of P. amarus increased significantly in the high nitrogen treatment after simulated N deposition for 4.5 years.

Effects of simulating acid rain on photosynthesis and chlorophyll fluorescence parameters of Quercus glauca.

WANG Sai1,2, YI Li-ta1, YU Shu-quan1, ZHANG Chao1, SHI Jing-jing1

2014, 25(8):  2183-2192. 

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At three levels of simulated acid rainfall intensities with pH values of 2.5 (severe), 4.0 (medium) and 5.6 (light) respectively, the responses of chlorophyll fluorescence and photosynthetic parameters of Quercus glauca seedlings were studied in three acid rainfall treatments, i.e. only the aboveground of seedlings exposed to acid rain (T₁), both of the seedlings and soil exposed to acid rain (T₂), only the soil exposed to acid rain (T₃) compared with blank control (CK). Under the severe acid rainfall, T₁ significantly inhibited chlorophyll synthesis, and thus reduced the primary photochemical efficiency of PSⅡ (F_v/F_m), potential activity of PSⅡ (F_v/F_o), apparent quantum (Y), net photosynthetic rate (P_n), and transpiration rate (T_r), but increased the light compensation point (LCP) and dark respiration rate (R_d) of Q. glauca seedlings. T₂ inhibited, but T₃ played a little enhancement on the aforementioned parameters of Q. glauca seedlings. Under the conditions of medium and light acid rainfall intensities, the above parameters in the three treatments were higher than that of CK, except with lower R_d. The chlorophyll fluorescence and photosynthetic parameters showed a similar tendency in the three treatments, i.e. T₂＞T₃＞T₁. It indicated that T₁  had the strongest inhibition on seedlings in condition of the severe acid rainfall, while T₂ had the most dramatic facilitating effect on seedlings under the medium and light acid rainfall. Intensity of acid rainfall had significant influences on SPAD, F_v/F_m, F_v/F_o, Y, P_n, T_r and maximum photosynthetic rate (A_max), whereas treatments of acid rainfall affected SPAD, F_v/F_m, Y, P_n, T_r, A_max and light saturation point (LSP). The interaction of acid rainfall intensities and treatments played significant effects on SPAD, F_v/F_m, Y, P_n and A_max.

Rainfall redistribution traits of three main forest types in Dagangshan Mountains of Jiangxi Province, China.

LI Dao-ning1, WANG Bing2, CAI Ti-jiu3, YIN Zhuo1, JU Cun-yong3

2014, 25(8):  2193-2200. 

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The redistribution processes of rainfall due to the canopy were studied on three typical forest types (Chinese fir forest, evergreen broadleaved forest and Phyllostachys pubescens forest) in Dagangshan Mountains of Jiangxi Province. The results showed that from April to June, 2012, the total precipitation was 531.6 mm, with the maximum single rainfall of 61.7 mm. The rainfall in this area was mainly  light and moderate. During the research period, the total throughfall of P. pubescens forest was the greatest, and that of evergreen broadleaved forest was the smallest. The throughfall of P. pubescens and Chinese fir forest were almost equal at the same rainfall intensity. However, the throughfall of evergreen broadleaved forest was  smaller than those of the other two types of forest at the same high rainfall intensity. Throughfall presented a distinct spatial variability within each forest. Stemflow of Chinese fir forest, evergreen broadleaved forest and P. pubescens forest were 1.4%, 8.9% and 8.8%, respectively. There were significant differences (P<0.01) in stemflow between the Chinese fir forest and the other two types of forests. In addition, the moisture degree of forests before a rain event greatly influenced the quantity of the stemflow. The effect was strongest in the Chinese fir plantation and weakest in the P. pubescens forest. The proportion of interception to rainfall was in a descending order of 30.5%, 25.5% and 19.2% for the Chinese fir forest, the evergreen broad-leaved forest and the P. pubescens forest, respectively. The Chinese fir forest had the obviously greater interception rate than the other two types of forests under usual rainfall in the study area.

Comparison on concentrations and quality of dissolved organic matter in throughfall and stemflow in a secondary forest of Castanopsis carlesii and Cunninghamia lanceolata plantation.

LU Mao-kui1,2, XIE Jin-sheng1,2, JIANG Miao-hua1,2, LUO Shui-jin3, ZENG Shao-juan1,2, JI Shu-rong1,2, WAN Jing-juan1,2, YANG Yu-sheng1,2

2014, 25(8):  2201-2208. 

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In this paper, monthly variation of dissolved organic matter (DOM) concentrations as well as humification and aromaticity indices in throughfall and stemflow from secondary broadleaved Castanopsis carlesii (BF) forest and Cunninghamia lanceolata plantation (CP) were measured. The DOC concentrations in throughfall were significantly higher with greater variation in BF than in CP. The concentrations of DOC in throughfall were averagely 7.2 and 3.2 times of those in rainfall in BF and CP forests, respectively. The DOC concentrations of stemflow in CP were averagely 2.5 times as much as those in BF, and the DOC concentrations in stemflow tended to be greater in dry season than in rain season for the two forests. A significantly negative relationship was found between the DOC concentrations in stemflow and the amounts of stemflow for both BF and CP. Moreover, the humification and aromaticity indices of DOM in throughfall in BF was significantly greater than in CP. In contrast, the humification and aromaticity indices of DOM from stemflow of CP were significantly greater than those of BF. This result indicated that the structure of DOM from throughfall was more complex  in BF than in CP, and the structure of DOM from stemflow was vice versa. These results indicated that DOM in stemflow and throughfall showed significant variations in quantity and quality between BF and CP and may greatly impact the accumulation of soil organic carbon.

 

Trunk sap flow dynamic changes in response to the slopes of plantation of Toona ciliata var. pubescens.

LIU Jun1, CHEN Wen-rong2, XU Jin-liang3, ZOU Jun2, JIANG Jing-min1, LI Yan-jie1, DIAO Song-feng1

2014, 25(8):  2209-2214. 

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The sap flow and environmental factors, including temperature, water content and water potential of soil, were continuously measured by using an autodata collection system at the upper and lower slopes of Toona ciliata var. pubescens plantation in July to October, 2012 to investigate the relationships between the sap flow and environmental factors. The results showed that, the trunk sap flow velocity of the two positions both presented a typical singlepeak curve, with high values in the daytime and low values in the nighttime. The average sap flow of the lower slope was significantly  higher than that of the upper slope. Soil temperature of the upper slope was significantly higher than that of the lower slope, and soil water content and water potential were vice versa. Soil water content and water potential were the leading environmental factors affecting the trunk sap flow velocity at the lower slope, while soil temperature and water potential were the main environmental factors at the upper slope.

Carbon storage of forest stands in Shandong Province estimated by forestry inventory data.

LI Shi-mei1, YANG Chuan-qiang2, WANG Hong-nian2， GE Li-qiang3

2014, 25(8):  2215-2220. 

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Based on the 7th forestry inventory data of Shandong Province, this paper estimated the carbon storage and carbon density of forest stands, and analyzed their distribution characteristics according to dominant tree species, age groups and forest category using the volume-derived biomass method and average-biomass method. In 2007, the total carbon storage of the forest stands was 25.27 Tg, of which the coniferous forests, mixed conifer broad-leaved forests, and broad-leaved forests accounted for 8.6%, 2.0% and 89.4%, respectively. The carbon storage of forest age groups followed the sequence of young forests > middle-aged forests > mature forests > near-mature forests > overmature forests. The carbon storage of young forests and middleaged forests accounted for 69.3% of the total carbon storage. Timber forest, non-timber product forest and protection forests accounted for 37.1%, 36.3% and 24.8% of the total carbon storage, respectively. The average carbon density of forest stands in Shandong Province was 10.59 t·hm^-2, which was lower than the national average level. This phenomenon was attributed to the imperfect structure of forest types and age groups, i.e., the notably higher percentage of timber forests and non-timber product forest and the excessively higher percentage of young forests and middleaged forest than mature forests.

Diversity and classification system of weed community in Harbin City, China.

CHEN Xiao-shuang1, LIANG Hong1,2, SONG Kun1, DA Liang-jun1

2014, 25(8):  2221-2228. 

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To analyze the causes of weed community diversity and their strategies of adaption to the high heterogeneity of urban habitats, weed communities in the central urban area of Harbin, China were studied, and a classification system was established for the weed communities. There were 175 weed species, belonging to 128 genera and 38 families. The heterogeneous urban habitats and species’ temporal niche differentiation resulted in the highly diversified weed communities. The high proportions of mono-species dominance and annual species dominance communities were their response to the unstable urban habitats under human disturbances with high intensities and frequencies. A fourlevel classification system was established in terms of plant species and habitat conditions. Within this system, the identified 1763 weed communities could be categorized into two types of life form, 5 types of dormancy form, 22 community groups, and 119 dominance communities.

Decomposition of herbaceous species in reservoir riparian region of Three Gorges Reservoir under flooding condition.

YUAN Qing-ye1,2, XIE Zong-qiang1, YANG Lin-sen3, XIONG Gao-ming1, LI Zhao-jia1,2, FAN Da-yong1

2014, 25(8):  2229-2237. 

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A total of 10 annuals and perennials of herbaceous species were investigated in reservoir riparian region of Three Gorges Reservoir. The correlations between the plants’ nutrient release rate and the substrate composition and structural matter were studied under flooding condition. The decomposition rates of different species differed substantially, with the maximum of Alternanthera philoxeroides (decomposition rate constant k=0.0228 d^-1) and the minimum of Microstegium vimineum (k=0.0029 d^-1). There was no significant difference in k between annuals and perennials. There was no significant difference in nitrogen and phosphorus contents between annuals and perennials. Paspalum paspaloides and Bidens pilosa released more nutrients into the water than the other species. A. philoxeroides had a higher potential to release nitrogen while it had little effect on water phosphorus compared with the other species. Total N, P contents in the water were negatively correlated with the plants’ decomposition rate, initial C content, C:N ratio, lignin:N ratio, and positively correlated with initial contents of K, Ca and N in plants.

Exploration of a quantitative methodology to characterize the retention of PM_2.5 and other atmospheric particulate matter by plant leaves: Taking Populus tomentosa  as an example.

ZHANG Zhi-dan1, XI Ben-ye1, CAO Zhi-guo2, JIA Li-ming1

2014, 25(8):  2238-2242. 

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Taking Populus tomentosa as an example, a methodology called elutionweighingparticle sizeanalysis (EWPA) was proposed to evaluate quantitatively the ability of retaining fine particulate matter (PM_2.5, diameter d≤2.5 μm) and atmospheric particulate matter by plant leaves using laser particle size analyzer and balance. This method achieved a direct, accurate measurement with superior operability about the quality and particle size distribution of atmospheric particulate matter retained by plant leaves. First, a preexperiment was taken to test the stability of the method. After cleaning, centrifugation and drying, the particulate matter was collected and weighed,  and then its particle size distribution was analyzed by laser particle size analyzer. Finally, the mass of particulate matter retained by unit area of leaf and stand was translated from the leaf area and leaf area index. This method was applied to a P. tomentosa stand which had not experienced rain for 27 days in Beijing Olympic Forest Park. The results showed that the average particle size of the atmospheric particulate matter retained by P. tomentosa was 17.8 μm, and the volume percentages of the retained PM_2.5, inhalable particulate matter (PM₁₀ , d≤10 μm) and total suspended particle (TSP, d≤100 μm) were 13.7%, 47.2%, and 99.9%, respectively. The masses of PM_2.5, PM₁₀, TSP and total particulate matter were 8.88×10^-6, 30.6×10^-6, 64.7×10^-6 and 64.8×10^-6g·cm^-2, respectively. The retention quantities of PM_2.5, PM₁₀, TSP and total particulate matter by the P. tomentosa stand were 0.963, 3.32, 7.01 and 7.02 kg·hm^-2, respectively.

Effects of environmental factors at different altitudes on leaves and fruit quality of Fuji apple.

LUO Wen-wen, GAO Chen-xi, ZHANG Dong, HAN Ming-yu, ZHAO Cai-ping, LIU Hang-kong

2014, 25(8):  2243-2250. 

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To inquire the different performances of the leaves and fruit quality of Fuji apple tress at various altitudes and their responses to the environmental factors, indices including leaf morphology, anatomy, δ¹³C, and fruit quality of the Fuji apple trees at respective altitudes of 1375 m, 1575 m and 1715 m were investigated and their responses to environmental factors were determined following stepwise regression analysis. The results showed that 6 factors like the warmth index, Bailey’s index, photosynthetically active radiation (PAR), coldness index, ultraviolet B and the annual precipitation dominantly affected the characteristic parameters of leaves and fruit. Elevation increase was matched by the decreasing warmth index, rising Bailey’s index, intenser PAR, higher coldness index, stronger ultraviolet B and heavier annual precipitation; meanwhile, the leaf structure and fruit quality parameters also displayed evident trends of change accordingly, namely, leaf parameters like leaf thickness, cuticle thickness, ratio of palisade and spongy, maximum conduit diameter, δ¹³C and nitrogen content per unit area increased gradually, and oppositely, leaf lengthwidth ratio, specific leaf area, stoma lengthwidth ratio and ratio of upper and lower epidermis to the leaf thickness decreased gradually; similarly, fruit parameters such as fruit shape index, fruit hardness, sugaracid ratio, total color and the a/bvalue ascended while the titratable acid and the hue angle descended. With increasing the altitude, the photosynthetic rate and water use efficiency of leaves were enhanced, and the fruit sugaracid ratio climbed and the fruit flavor and color improved. Therefore, it could be safely concluded that within the altitude range between 1375 and 1715 m, environmental factors at a higher altitude favored Fuji apple growth.

Effects of drought and waterlogging on carbohydrate contents of cotton boll and its relationship with boll biomass accumulation at the flowering and bolling stage.

YANG Chang-qin1,2, LIU Jing-ran1, ZHANG Guo-wei2, LIU Rui-xian2, ZHOU Zhi-guo1

2014, 25(8):  2251-2258. 

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Cotton cultivar NuCOTN 33B was planted in isolated pools treated with drought or waterlogging for 7 or 14 d to explore their effects on cotton boll carbohydrate content and its relationship with the biomass accumulation. The results showed that the drought treatment reduced the carbohydrate content of cotton boll shell on middle fruit branches, but had a weak effect on cotton boll shells on lower fruit branches. Soluble sugar, starch and sucrose contents of cotton boll shell on upper fruit branches under the drought condition and on whole plant branches under  waterlogging treatment changed similarly, namely, the soluble sugar and starch content increased, while the sucrose content went down firstly and then increased later, which indicated that the exportation of sucrose from boll shell was inhibited and became worse with the increase of waterlogging duration. Compared with the boll shell, the carbohydrate contents of cotton seed were less affected by the drought and waterlogging treatments at the flowering and bolling stage. Under the treatments of drought and 7 dwaterlogging, the biomass accumulation of cotton bolls on the middle fruit branches initiated earlier but lasted less days, and the maximum speed at lower and upper fruit branches reduced, while the treatment of waterlogging for 14 d caused the decline of maximum speed of biomass accumulation of bolls on whole branches. On the other side, the correlation analysis showed the significant positive relationships among the boll biomass, the maximum speed and the contents of soluble sugar and sucrose in the boll shell respectively. In conclusion, the treatment of drought and waterlogging at the flowering and bolling stage retarded the outward transportation of sucrose from cotton bolls, changed the boll biomass accumulation characteristics, and therefore were detected as the important cause of cotton boll total biomass reduction.

Effects of irrigation and planting patterns on photosynthetic characteristics of flag leaf and yield at late growth stages of winter wheat.

DONG Hao1,2, BI Jun1, XIA Guang-li1, ZHOU Xun-bo2, CHEN Yu-hai2

2014, 25(8):  2259-2266. 

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Highyield winter wheat cultivar Jimai 22 was used to study effects of irrigation and planting patterns on water consumption characteristics and photosynthetic characteristics of winter wheat in field from 2009 to 2011. Three different planting patterns (uniform row, widenarrow row and furrow) and four irrigation schedules (W₀, no irrigation; W₁, irrigation at jointing stage; W₂, irrigations at jointing and anthesis stages; W₃, irrigation at jointing, anthesis and milking stages. Each irrigation rate was 60 mm) were designed in the experiment. Results showed that, with the increasing of irrigation amount, flag leaf area, net photosynthesis rate, maximum photochemical efficiency and actual light transformation efficiency at late growth stages of winter wheat increased. Compared with W₀ treatment, the other irrigation treatments had higher grain yields, but lower water use efficiencies. Under the same irrigation condition, the flag leaf net photosynthesis, maximum photochemical efficiency and actual light transformation efficiency were much higher in furrow pattern. Grain yields of winter wheat under furrow pattern and W₂ treatment were significantly higher than that of the other treatments. Taking grain yield and WUE into consideration, furrow pattern combined with irrigation at jointing and anthesis stages might be the optimal watersaving and planting mode for the winter wheat production in North China Plain.

Effect of reduced N application on soil N residue and N loss in maize-soybean relay strip intercropping system.

LIU Xiao-ming1, YONG Tai-wen1, LIU Wen-yu1, SU Ben-ying1, SONG Chun1,2, YANG Feng1, WANG Xiao-chun1, YANG Wen-yu1

2014, 25(8):  2267-2274. 

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A field experiment was conducted in 2012, including three planting pattern (maizesoybean relay strip intercropping, monocultured maize and soybean) and three nitrogen application level \[0 kg N·hm^-2, 180 kg N·hm^-2 (reduced N) and 240 kg N·hm^-2 (normal N)\]. Fields were assigned to different treatments in a randomized block design with three replicates. The objective of this work was to analyze the effects of planting patterns and nitrogen application rates on plant N uptake, soil N residue and N loss. After fertilization applications, NH₄⁺-N and NO₃^- -N levels increased in the soil of intercropped maize but decreased in the soil of intercropped soybean. Compared with monocrops, the soil N residue and loss of intercropped soybean were reduced, while those of intercropped maize were increased and decreased, respectively. With the reduced rate of N application, N residue rate, N loss rate and ammonia volatilization loss rate of the maize-soybean intercropping relay strip system were decreased by 17.7%, 21.5% and 0.4% compared to mono-cultured maize, but increased by 2.0%, 19.8% and 0.1% compared to mono-cultured soybean, respectively. Likewise, the reduced N application resulted in reductions in N residue, N loss, and the N loss via ammonia volatilization in the maize-soybean relay strip intercropping system compared with the conventional rate of N application adopted by local farmers, and the N residue rate, N loss rate and ammonia volatilization loss rate reduced by 12.0%, 15.4% and 1.2%, respectively.

Effects of different tillage methods on phospholipid fatty acids and enzyme activities in calcareous cinnamon soil.

PEI Xue-xia, DANG Jian-you, ZHANG Ding-yi, WANG Jiao-ai, ZHANG Jing

2014, 25(8):  2275-2280. 

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In order to study changes of physical and chemical characteristics and microbial activities in soil under different tillage methods, effects of four tillage methods, rotary tillage (RT), subsoil tillage (ST), conventional tillage (CT) with corn straw returned to soil, and rotary tillage with no corn straw returned to soil (CK), on phospholipid fatty acids (PLFA) characteristics and hydrolase enzymes activities in calcareous cinnamon soil were investigated. The results showed that soil hydrolase enzymes activities, nutrient contents, microbial diversity varied greatly with the different tillage methods. Returning corn straw to soil increased the kinds, amount of soil total PLFAs, bacteria PLFAs and actonomycetes PLFAs, while decreased the fungi PLFAs, indicating that fungi was more adaptable than bacteria to an infertile environment. ST and CT resulted in higher amounts of total PLFAs, which were 74.7% and 53.3% higher than that of CK, indicating they were more beneficial to the growth of plants. They could also improve soil physical and chemical properties, increase alkphosphatase, protease and urease activities, which would provide a favorable soil condition for high and stable crop yields.

Effects of biochar addition into soils in semiarid land on water infiltration under the condition of the same bulk density.

QI Rui-peng1, ZHANG Lei1, YAN Yong-hao2, WEN Man1, ZHENG Ji-yong1,2

2014, 25(8):  2281-2288. 

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Making clear the effects of biochar addition on soil water infiltration process can provide the scientific basis for the evaluation of the influence of biochar application on soil hydrology in semiarid region. In this paper, through the soil column simulation method in laboratory, the effects of biochar of three sizes (1-2 mm, 0.25-1 mm and ≤0.25 mm) at 4 doses (10, 50, 100 and 150 g·kg^-1) on the cumulative infiltration, the permeability and the stable infiltration rate of two different soils (anthrosol and aeolian sandy soil) were studied. The results showed that the infiltration capacity of the anthrosol was obviously increased compared to the control, however, the one in the aeolian sandy soil was decreased due to the biochar addition. At 100 minutes after infiltration starting, the averaged cumulative infiltration was increased by 25.1% in the anthrosol with comparison to the control. Contrarily, the averaged cumulative infiltration was decreased by 11.1% in the aeolian sandy soil at 15 minutes after infiltration starting. When the dose was the same, biochar with different particle sizes improved the infiltration for the anthrosol, but for the different dose treatments, the particle size of biochar which showed the greatest improvement was different. As for the aeolian sandy soil, the infiltration increased at the dose of 10 g·kg^-1 after the addition of biochar with different particle sizes, while decreased at the higher dose of 50, 100 and 150 g·kg^-1. The cumulative infiltration of the aeolian sandy soil was decreased with the increase in addition amount of biochar with the same particle size, while it was not so for the anthrosol. The determination coefficient fitted by the Philip infiltration model ranged from 0.965 to 0.999, suggesting this model was suitable for the simulation of soil water infiltration process after biochar application. Statistical analysis of main effects showed that the biochar particle size, the biochar addition amount, and the interactive effect had statistically significant effect on the soil permeability and stable infiltration rate in the two soils. In conclusion, the biochar had different effects on the soils with different textures, moreover, there was a positive correlation relationship between the impact and the addition amount.

Controlling effects of dual mulching on soil moisture in an apple orchard.

TIAN Fei1, XIE Yong-sheng1,2, SUO Gai-di1, DING Ya-dong2

2014, 25(8):  2289-2296. 

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To investigate the controlling effects of dual mulching on soil moisture in an apple orchard on the Weibei rainfed highland, soil moisture in the 0-600 cm soil profile of the apple orchard was measured under four mulching treatments (plastic film plus straw, plastic film and straw mulches, as well as a nonmulching control), and meanwhile the apple yield and branch growth increment were analyzed statistically. Results showed that the dual mulching treatment had the best effect on soil moisture conservation, and the soil water storage in such a soil profile was 6.7% higher than the control treatment. Longterm dual mulching could effectively alleviate soil desiccation occurring in deep soil layer in the region, and the monthly averaged soil water storage in stable layer (240-600 cm) was 64.22 mm higher than that of the control treatment. Both plastic film plus straw and plastic film mulches were able to reduce the temporal fluctuation of soil moisture in shallow soil (0-60 cm) and enhance the temporal stability of soil moisture in the layer. Compared with the single mulching treatments, the dual mulching treatment could effectively decrease the vertical variation of soil moisture in the profile and improve the stability of the vertical soil moisture distribution. The apple yield under the dual mulching treatment was evidently increased by 48.2%, as compared with the control treatment. All the analyses showed that dual mulching had more advantages in controlling soil moisture and improving apple yield than single mulching.

Effects of scale-like pit and mulching measures on soil moisture of dryland jujube orchard in North Shaanxi Province, China.

2014, 25(8):  2297-2303. 

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Soil moisture is a key factor affecting jujube growth in the semiarid Northern Shaanxi Province. The impacts of different engineering and mulching measures on soil moisture were investigated via in situ measurements in a typical dryland jujube orchard. The results showed that the mean soil moistures (0-180 cm) of scale-like pit + branch mulching, scale-like scale + straw mulching, and soil moisture of scale-like pit with no mulching were increased by 14.2%, 9.4%, and 4.8% than control, respectively. Different measures, especially for the scale-like pit + branch mulching, significantly increased the soil moisture in the soil surface (0-20 cm) and the main root zone layer (20-100 cm) during the jujube growth stage. Individual precipitation events had great impacts on soil moisture in the 0-100 cm, while its effect on soil moisture in deep layers was not apparent. There was no significant difference among the soil moistures in different soil depths of scale-like pit with no mulching when compared with the control under high, medium, and low soil humidity conditions. This study indicated that using the clipped jujube branches as mulching could both save materials cost and achieve the goal of reserving more water in dryland jujube orchard in north Shaanxi Province.

Comparison of three daily global solar radiation models.

YANG Jin-ming, FAN Wen-yi, ZHAO Ying-hui

2014, 25(8):  2304-2310. 

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Three daily global solar radiation estimation models (A-P model, ThorntonRunning model and model provided by Liu Kequn et al.) were analyzed and compared using data of 13 weather stations from 1982 to 2012 from three northeastern provinces and eastern Inner Mongolia. After crossvalidation analysis, the result showed that mean absolute error (MAE) for each model was 1.71, 2.83 and 1.68 MJ·m^-2·d^-1 respectively, showing that A-P model and model provided by Liu Kequn et al. which used percentage of sunshine had an advantage over ThorntonRunning model which didn’t use percentage of sunshine. Model provided by Liu Kequn et al. played a good effect on the situation of nonsunshine, and its MAE and bias percentage were 18.5% and 33.8% smaller than those of A-P model, respectively. High precision results could be obtained by using the simple linear model of A-P. A-P model, ThorntonRunning model and model provided by Liu Kequn et al. overvalued daily global solar radiation by 12.2%, 19.2% and 9.9% respectively. MAE for each station varied little with the spatial change of location, and annual MAE decreased with the advance of years. The reason for this might be that the change of observation accuracy caused by the replacement of radiation instrument in 1993. MAEs for rainy days, nonsunshine days and warm seasons of the three models were greater than those for days without rain, sunshine days and cold seasons respectively, showing that different methods should be used for different weather conditions on estimating solar radiation with meteorological elements.

Optimization of application parameters of soil seed bank in vegetation recovery via response surface methodology.

HE Meng-xuan1, LI Hong-yuan1, MO Xun-qiang2, MENG Wei-qing2, YANG Jia-nan1

2014, 25(8):  2311-2316. 

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The thickness of surface soil, the covering thickness and the number of adding arbor seeds are all important factors to be considered in the application of soil seed bank (SSB) for vegetation recovery. To determine the optimal conditions, the BoxBehnken central composite design with three parameters and three levels was conducted and DesignExpert was used for response surface optimization. Finally, the optimal model and optimal level of each parameter were selected. The quadratic model was more suitable for response surface optimization (P<0.0001), indicating the model had good statistical significance which could express ideal relations between all the independent variable and dependent variable. For the optimum condition, the thickness of surface soil was 4.3 cm, the covering thickness was 2 cm, and the number of adding arbor seeds was 224 ind·m^-2, under which the number of germinated seedlings could be reached up to 6222 plants·m^-2. During the process of seed germination, significant interactions between the thickness of surface soil and the covering thickness, as well as the thickness of surface soil and the number of adding arbor seeds were found, but the relationship between the covering thickness and the number of adding arbor seeds was relatively unremarkable. Among all the parameters, the thickness of surface soil was the most important one, which had the steepest curve and the largest standardized coefficient.

Assessing dynamic patterns of forest fragmentation based on a landscape mosaic indicator: A case study of Oregon State, USA.

REN Xin-yu, LU Ying-ying, LI Ming-shi

2014, 25(8):  2317-2326. 

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Effectively assessing landscape pattern characteristics and predicting their dynamics have been a basic prerequisite for more reasonably regulating and managing forest landscape, and maintaining landscape security patterns. In this study, based on three U.S. National Land Cover Databases (1992, 2001 and 2006), the landscape mosaic indicator in combination with the Markov model was adopted to analyze forest fragmentation patterns and changes in the characteristics of spatial interactions between forests and other land use types in Oregon State, USA. The results showed that conversion from the developmentdominated type  D to the single development type DD in landscape mosaic model had the highest transition probability 0.319, indicating that urbanization has been the major force responsible for the change of regional landscape patterns. In the forest security model, the highest rates of forest loss occurred in agriculture and the developed landscape mosaic type (ad), showing that in the development and agriculture dominated landscapes, encroaching upon forests was at the highest likelihood. The areal percentage of forest over the total study area was less than 50% when reaching a steadystate distribution, with an accelerating rate of forest fragmentation, and the landscape spatial distribution tended to be a mixed landscape pattern. The Kappa coefficient between the simulated values and the observed values from the 2006 landscape mosaic model was estimated at 0.82, indicating this model had a high precision. However, the accuracy of the forest security model was poor, with a Kappa coefficient of 0.21.

 

Landscape connectivity of waterbody network in the new reclamation region of Lianyungang based on effective distance model.

QIAO Fu-zhen1, ZHENG Zhong-ming1, LI Jia-lin2, ZHENG Wen-bing1

2014, 25(8):  2327-2333. 

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Landscape connectivity is an important indicator to measure effectiveness of landscape ecological services. Waterbody connectivity in Lianyun New City, the new reclamation region of Lianyungang, was investigated based on GIS technology and effective distance model. The results showed that the total connectivity of waterbodies was poor in Lanyun New City. Connectivity of patches was related to characteristics of ecological process, ecological services value and spatial arrangement. The higher the ecosystem services value of patches was, the greater its contribution to the overall water landscape connectivity was. Some patches with long strip structure played a key role to improve the landscape connectivity. By classifying the importance of connectivity and functional groups of waterbody patches, planning of waterbodies in Lianyun New City conformed to the theory of nonsubstitutable pattern developed by Forman. Waterbody patches with corresponding functions should be considered with priority when planning and building a new city. The present study demonstrated that connectivity of patches should be an important factor to be considered in ecological landscape planning. Construction of ecological corridors should not only take the number of ecological landscapes into consideration, but also pay attention to spatial arrangement of landscapes in order to improve the overall landscape connectivity.

Effects of bamboo charcoal on the growth of Trifolium repens and soil bacterial community structure.

LI Song-hao, HE Dong-hua, SHEN Qiu-lan, XU Qiu-fang

2014, 25(8):  2334-2340. 

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The effects of addition rates (0, 3% and 9%) and particle sizes (0.05, 0.05-1.0 and 1.0-2.0 mm) of bamboo charcoal on the growth of Trifolium repens and soil microbial community structure were investigated. The results showed that bamboo charcoal addition greatly promoted the early growth of T. repens, with the 9% charcoal addition rate being slightly better than the 3% charcoal addition rate. The effects of different particle sizes of bamboo charcoal on the growth of T. repens were not different significantly. Growth promotion declined with time during 120 days after sowing, and disappeared completely after 5 months. DGGE analysis of the bacterial 16S rDNA V3 fragment indicated that bamboo charcoal altered the soil bacterial community structure. The amount and Shannon diversity index of bacteria in the bamboo charcoal addition treatments increased compared with CK. The quantitative analysis showed that the amount of bacteria in the treatment with bamboo charcoal of fine particle (D<0.05 mm) at the 9% addition rate was significantly higher than in the other treatments. The fine bamboo charcoal had a great effect on soil bacteria amount compared with the charcoal of other sizes at the same addition rate.

Effects of long-term tillage measurements on soil aggregate characteristic and microbial diversity.

LI Jing1, WU Hui-jun1, WU Xue-ping1, CAI Dian-xiong1, YAO Yu-qing2, LU Jun-jie2, TIAN Yun-long3

2014, 25(8):  2341-2348. 

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Soil aggregate stability and microbial diversity play important roles in nutrient recycling in soilcrop systems. This study investigated the impacts of different soil tillage systems on soil aggregation and soil microbial diversity based on a 15year longterm experiment on loess soil in Henan Province of China. Treatments included reduced tillage (RT), notillage (NT),  subsoiling with mulch (SM), wheatpeanut two crops (TC)， and conventional tillage (CT). Soil aggregates were separated by wet sieving method, and soil microbial (bacterial, archaeal and fungal) diversity was examined by using the techniques of denaturing gradient gel electrophoresis (PCRDGGE) analysis. The results showed that waterstable macroaggregates concent (R_0.25) and the mean mass diameter (MWD) in the surface soil significantly increased under NT, SM and TC, R_0.25 increased by 21.5%, 29.5% and 69.2%, and MWD increased by 18.0%, 12.2% and 50.4%, respectively, as compared with CT.
Tillage practices caused changes in bacterial, archaeal and fungal community compositions. With NT, SM and TC, the bacterial, archaeal and fungal Shannon indices increased by 0.3%, 0.3%, and 0.6%, and 20.2%, 40.5%, and 49.1%, and 23.7%, 19.5%, and 25.8%, respectively, as compared with CT. Both bacterial and archaeal Shannon indices were significantly correlated with the indices of R_0.25 and MWD, while the fungal Shannon index was not significantly correlated with these two indices. In conclusion, conservation tillage, including NT and SM, and crop rotation, including TC, improved soil aggregation and soil microbial diversity.

Microbial activity and functional diversity in rhizosphere of cucumber under different subsurface drip irrigation scheduling.

LI Hua, HE Hong-jun, LI Teng-fei, ZHANG Zi-kun

2014, 25(8):  2349-2354. 

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The effects of subsurface drip irrigation scheduling on microbial activity and functional diversity in rhizosphere of cucumber in solar greenhouse were studied in this paper. The results showed that the soil microbial biomass C and N, basal respiration, metabolic quotient and values of AWCD, Shannon and McIntosh indexes were increased at first and then decreased with the increase of irrigation water amount. The values of microbial C and N, basal respiration and metabolic quotient in I₂ treatments were significantly higher than those in I₁ treatments at the 0.8E_p irrigation level. The numbers of bacteria, actinomyces and nitrogenfixing bacteria, and the activities of
urease, phosphatase, sucrase, catalase and polyhenoloxidase were significantly higher in the 0.8E_p treatment than in the other treatments. The numbers of bacteria and nitrogenfixing bacteria, the activities of urease, phosphatase and sucrase in I₂ treatments were significantly higher than in I₁ treatment, the actinomyces number and activities of catalase and polyhenoloxidase had no significant difference between I₁ and I₂ treatments, however, the fungi number in I₂ treatments were significantly lower than in I₁ treaments at the 0.8E_p irrigation level. The microbial activity and functional diversity in rhizosphere of cucumber were strengthened in the I₂0.8E_p treatment, meanwhile, the soil microflora was improved and the soil enzymes activities were enhanced, therefore, the cucumber growth was promoted as well.

 

Allelopathic effects of phenolic compounds of melon root exudates on Fusarium oxysporum f. sp. melonis

2014, 25(8):  2355-2360. 

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In this study, the phenolic compounds of melon root exudates were identified by HPLC and seven phenolic compounds including gallic acid, phthalic acid, syringic acid, salicylic acid, ferulic acid, benzoic acid and cinnamic acid were observed. The laboratory experiment showed that ferulic acid, benzoic acid and cinnamic acid of 0.1 and 0.25 mmol·L^-1 could significantly promote the germination of Fusarium oxysporum f. sp. melonis spore while salicylic acid inhibited the spore germination to some degree. Syringic acid and ferulic acid significantly promoted the mycelium growth at the late stage of incubation. The pot experiments demonstrated that cinnamic acid, benzoic acid and ferulic acid enhanced melon infection at concentrations of 0.05, 0.1 and 0.5 mmol·L^-1.

 

Responses of soil nematode communities to long-term application of inorganic fertilizers in upland red soil.

ZHANG Wei1,2, LIU Man-qiang1, HE Yuan-qiu2,3, FAN Jian-bo2, CHEN Yan2

2014, 25(8):  2361-2368. 

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Soil biota plays a key role in ecosystem functioning of red soil. Based on the long-term inorganic fertilization field experiment (25-year) in an upland red soil, the impacts of different inorganic fertilization managements, including NPK (nitrogen, phosphorus and potassium fertilizers), NPKCaS (NPK plus gypsum fertilizers), NP (nitrogen and phosphorus fertilizers), NK (nitrogen and potassium fertilizers) and PK (phosphorus and potassium fertilizers), on the assemblage of soil nematodes during the growing period of peanut were investigated. Significant differences among the treatments were observed for total nematode abundance, trophic groups and ecological indices (P<0.01). The total nematode abundance decreased in the order of PK > NPKCaS > NPK > NP > NK. The total number of nematodes was significantly higher in NPKCaS and PK than in NPK, NP and NK except in May. Plant parasitic nematodes were the dominant trophic group in all treatments excepted in NPKCaS, and their proportion ranged between 38% and 65%. The dominant trophic group in NPKCaS was bacterivores and represented 42.1%. Furthermore, the higher values of maturity index, Wasilewska index and structure index in NPKCaS indicated that the combined application of NPK and gypsum could remarkably relieve soil acidification, resulting in a more mature and stable soil food web structure. While, that of the NK had the opposite effect. In conclusion, our study suggested that the application of both gypsum and phosphate is an effective practice to improve soil quality. Moreover, the analysis of nematode assemblage is relevant to reflect the impact of different inorganic fertilizer on the red soil ecosystem.

NO₃^-/NO₂^-  inhibits sulfatereducing activity of the enrichment culture of sulfatereducing prokaryotes from an offshore oil reservoir at Bohai Bay, China.

LIU Hong-yu1,2, SHI Rong-jiu1, ZHANG Ying1, SHI Zhen-guo1,3, ZHANG Ying-yue1,4, YU Liang5, ZHANG Xiao-bo5, TAN Tao5

2014, 25(8):  2369-2376. 

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Long-term injection of sulfaterich water into oil reservoirs stimulates the proliferation of sulfate-reducing prokaryotes (SRP) therein and results in production of a great amount of H₂S, leading to souring in oil reservoirs and related environmental problems. In this study, we first, using modified API RP 38 medium, enriched SRP present in production water from a producing well at Bohai Bay, China, and then examined the inhibitory effects of nitrate or nitrite on sulfate reduction activity of the SRP. Results showed that the enriched SRP culture exhibited a high sulfate reduction activity as indicated by a sulfatereducing rate of 10.4 mmol SO₄^2-·d^-1·g^-1 dry cell. In presence of 0.4, 0.8, 1.8, and 4.2 mmol·L^-1 nitrate, sulfate reduction was inhibited for 5, 9, 20, and over 35 days, respectively. With the addition of 0.6, 0.9, 1.4, 2.6 and 4.6 mmol·L^-1 of nitrite, the inhibitory period lasted 3, 12, 22, and over 39 days, respectively. The SRP enrichment culture could dissimilatorily reduce nitrate to ammonium. When sulfate, nitrate and nitrite coexisted, nitrate or nitrite was preferentially used over sulfate as electron acceptor by the enriched SRP. This competitive use of electron acceptor and the strong inhibitory effect of nitrite possibly accounted for the suppression of nitrate and nitrite on the sulfate-reducing activity of the enriched SRP cultures from offshore oil reservoir at Bohai Bay.

Chemical characteristics of the rhizosphere soil of water spinach cultivars differing in Cd accumulation.

GONG Yu-lian1,2, YANG Zhong-yi2

2014, 25(8):  2377-2384. 

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A rhizobox experiment was conducted to investigate the chemical characteristics of the rhizosphere soils of two water spinach cultivars differing in Cd accumulation, QLQ (a lowCd cultivar) and T308 (a highCd cultivar). The results showed that the diethylenetriamine pentacetate acid extractable Cd (DTPA-Cd) concentration in the rhizosphere soil of QLQ was significantly higher than that of T308 (P<0.05). pH and Eh in the rhizosphere soil of QLQ were significantly higher than those of T308 (P<0.05), while EC was opposite. Contents of organic matter and dissolved organic matter (DOM) in the rhizosphere soil of QLQ were both higher than those of T308. In contaminated soil, the composition and concentration of low molecular weight organic acids in the rhizosphere between the two cultivars were both different. Acetic, propionic, citric and fumaric acids were detected in the rhizosphere soil of T308, and only citric and fumaric acids were detected in that of QLQ. The total concentration of low molecular weight organic acids in the rhizosphere soil of QLQ (1.93 nmol·g^-1DM) was lower than that of T308 (15.11 nmol·g^-1DM) (P<0.01). Compared with the highCd cultivar (T308), the chemical characteristics of the rhizosphere soil of the lowCd cultivar (QLQ) were obviously distinct, i.e., the relatively higher content of organic matter, the lower content of low molecular weight organic acids with a specific composition, less acidification of soil, and a lower ability in reduction, correspondingly lowering the mobility of Cd in soil and reducing Cd accumulation by plant.

Effects of silicon on the ultrastructures of wheat radical cells under copper stress.

ZHANG Dai-jing, MA Jian-hui, YANG Shu-fang, CHEN Hui-ting, LIU Pei, WANG Wen-fei, LI Chun-xi

2014, 25(8):  2385-2389. 

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To explore the alleviation effect of silicon on wheat growth under copper stress, cultivar Aikang 58 was chosen as the experimental material. The growth, root activities and root tip ultrastructures of wheat seedlings, which were cultured in Hoagland nutrient solution with five different treatments (control, 15 mg·L^-1 Cu²⁺, 30 mg·L^-1 Cu²⁺, 15 mg·L^-1 Cu²⁺ and 50 mg·L^-1 silicon, 30 mg·L^-1 Cu²⁺ and 50 mg·L^-1 silicon), were fully analyzed. The results showed that root length, plant height and root activities of wheat seedlings were significantly restrained under the copper treatments compared with the control (P<0.01), while these restraining effects were alleviated after adding silicon to copperstress Hoagland nutrient solution. Under copper stress, the cell wall and cell membrane of wheat seedling root tips suffered to varying degrees of destruction, which caused the increase of intercellular space and the disappearance of some organelles. After adding silicon, the cell structure was maintained intact, although some cells and organelles were still slightly deformed compared with the control. In conclusion, exogenous silicon could  alleviate the copper stress damages on wheat seedlings and cellular components to some extent.

Treatment effect of biological filtration and vegetable floating-bed combined system on greenhouse turtle breeding wastewater.

CHEN Chong-jun1,2, ZHANG Rui1, XIANG Kun3, WU Wei-xiang1

2014, 25(8):  2390-2396. 

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Unorganized discharge of greenhouse turtle breeding wastewater has brought several negative influences on the ecological environment in the rural area of Yangtze River Delta. Biological filtration and vegetable floatingbed combined system is a potential ecological method for greenhouse turtle breeding wastewater treatment. In order to explore the feasibility of this system and evaluate the contribution of vegetable uptake of nitrogen (N) and phosphorus (P) in treating greenhouse turtle breeding wastewater, three types of vegetables, including Ipomoea aquatica, lettuce and celery were selected in this study. Results showed the combined system had a high capacity in
simultaneous removal of organic matter, N and P. The removal efficiencies of COD, NH₄⁺-N, TN and TP from the wastewater  reached up to 93.2%-95.6%, 97.2%-99.6%, 73.9%-93.1% and 74.9%-90.0%, respectively. System with I. aquatica had the highest efficiencies in N and P removal, followed by lettuce and celery. However, plant uptake was not the primary pathway for TN and TP removal in the combined system. The vegetable uptake of N and P accounted for only 9.1%-25.0% of TN and TP removal from the wastewater while the effect of microorganisms would be dominant for N and P removal. In addition, the highest amounts of N and P uptake in I. aquatica were closely related with the biomass of plant. Results from the study indicated that the biological filtration and vegetable floatingbed combined system was an effective approach to treating greenhouse turtle breeding wastewater in China.

Spatial-temporal and environmental effects of catch rate on Antarctic krill fishery in the South Georgia Island in the austral winter season based on the fine scale data.

ZHU Guo-ping1,2,3, LIU Zi-jun1, XU Guo-dong4, ZHANG Ji-chang5, MENG Tao1, HUANG Hong-liang4, XU Yi-ying1, ZHU Xiao-yan1, XU Liu-xiong1,2,3

2014, 25(8):  2397-2404. 

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The waters around the South Georgia Island is one of the main fishing ground of Antarctic krill fishery and many predators such as sea seal and whale inhabited this island target Antarctic krill as a food source. So it is very important for further understanding Antarctic ecosystem to conduct the research on abundance fluctuation of Antarctic krill resource around this island. Consequently, based on the fine scale fishery data collected in the winter 2013, using the generalized additive model (GAM), the present study analyzed the relationship between environmental factors and the catch rate of Antarctic krill. The results showed the model could explain 32.0% of the accumulation of deviance of the catch rate. The variable that provided the maximum contribution was tenday with a contribution rate of 21.4% and followed by the latitude (4.4%). Generally, the catch rate decreased from the first 10 days of July to September. Higher catch rates occurred in the eastern fishing ground, particularly the centraleastern part of survey area, and lower catch rates presented in the northern part. The mean catch rate deceased with the increasing change rate of bathymetry. The oceanographic condition with wind scale below  4 was suitable for fishing operation and associated with the higher catch rate, but the wind direction did not significantly affect the catch rate. The mean catch rate increased with the increasing sea surface temperature  within 0.5 to 2.0 ℃.

Effects of microalgal diets on juvenile growth and survival of the ark shell, Scapharca broughtonii.

WANG Qing-zhi, ZHANG Ming, TENG Wei-ming, FU Cheng-dong, WANG Chao, LIU Zhong-ying, LI Shi-lei, LIU Xiang-feng

2014, 25(8):  2405-2410. 

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Under hatchery conditions (temperature, 23.5-24.0 ℃; salinity, 29.5-30.0), effects of microalgal diets on growth and survival of the juvenile ark shell, Scapharca broughtonii, were investigated for 24 days by feeding with diets made of single or combinatory use of four different microalgae, Isochrysis galbana, Chlorella sp., Chaetoceros muelleri and Nitzschia closterium. The results showed that the survival rates were over 95% in all diet groups with no significant difference among them. When feeding with single microalgae, the best feeding effects on growth were observed in I. galbana, while the worst effects occurred in Chlorella sp. When feeding with various combinations of microalgae, the optimal effects on shell length and specific growth rate were observed in diets containing I. galbana compared to the other diets. The diet composed of I. galbana and Chlorella sp. (1:1) provided the best effects for S. broughtonii juveniles, resulting in a specific growth rate of 5.6%·d^-1 in shell length and 6.4%·d^-1 in shell height. These results should be valuable to direct the technique optimization of artificial breeding for the hatchery production of S. broughtonii seeds.

Trace elements in the statoliths of neon flying squid, Ommastrephes bartramii in the Northwest Pacific Ocean.

LU Hua-jie1,2,3,4, CHEN Xin-jun1,2,3,4, MA Jin1

2014, 25(8):  2411-2417. 

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Statolith is one of the most important hard tissues of cephalopods which is widely used in the research of fisheries ecology including population structure, life history reconstruction and so on. Trace elements of 18 statoliths of neon flying squid Ommastrephes bartramii collected in the Northwest Pacific Ocean in 2007 by Chinese jigging fishing fleets were analyzed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The results indicated that the statoliths of O. bartramii mainly contained 55 elements, and calcium (Ca), strontium (Sr), sodium (Na), phosphorus (P), potassium (K), silicon(Si), magnesium (Mg), boron (B), iron (Fe), barium (Ba) were the 10 most abundant elements. The analysis of variance showed that there was no significant difference in each element distribution between different sexual squid except for P, Si and B. Significant differences existed in the contents of Sr and Na but no significant difference was found in the contents of Ca, P, K, Si, Mg, B, Fe and Ba between different hatching populations. There were significant differences in the contents of Ca, Sr, Na, P,  Mg and Ba, but no significant difference was found in the contents of K, Fe, B and Si in the statoliths among different growth zones. This study presented Sr and Na could be the best two trace elements used in the research on the population structure and life history reconstruction for O. bartramii.

Preliminary assessment of habitat of juvenile Collichthys lucidus in the Yangtze estuary.

YANG Gang, ZHANG Tao, ZHUANG Ping, HOU Jun-li, WANG Yu, SONG Chao, ZHANG Long-zhen

2014, 25(8):  2418-2424. 

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To  evaluate the choice preference of fish habitat in the Yangtze estuary, juvenile Collichthys lucidus which is the dominant species in spring was selected. The 4 indicator factors, including abundance of Pseudograpsus albus, salinity, substrate type and water depth, were selected from 19 environmental factors. Then, the indices of the habitat suitability curves of the 4 indicator factors were established, and the HSI of juvenile C. lucidus at each site was calculated. The results indicated that HSI was almost more than 0.5 in North Branch, and less than 0.2 in South Branch. It showed that the North Branch of Yangtze estuary was the main nursery area of C. lucidus. The most suitable growth sector was the area with salinity more than 14, mean grain size of substrate less than 29 μm and water depth 2 to 5 m, which was consistent with the distribution of HSI. The study demonstrated that biological factors could be characterized by the response of juvenile C. lucidus to the environment. Chemical oxygen demand, ammonium nitrogen, total phosphorus and volatile phenol did not have significant correlation with the fish abundance, with which nitrite nitrogen, nitrate nitrogen and total nitrogen had significant positive correlation. It suggested that the eutrophication of the survey area had not damaged the habitat of C. lucidus. However, copper ion and cadmium ion had significant negative correlation with the fish abundance, which indicated that the heavy metal pollution had harmed the growth and distribution of juvenile C. lucidus. It was inferred that the heavy metal pollution was the restrictive factor influencing the fish habitat in Yangtze estuary.

Circadian rhythm of emergence and reproduction of Micromelalopha troglodyta (Lepidoptera: Notodontidae).

CHEN Lin, WANG Guang-li, WEI Hong-yi

2014, 25(8):  2425-2430. 

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Micromelalopha troglodyta (Graeser) is one of serious defoliators of poplars. In order to explore the occurrence regularity of emergence and reproductive behavior of M. troglodyte, which could provide references to the application of ecological control techniques, the circadian rhythms of emergence, calling, mating and oviposition were studied at (27±1) ℃ and (60±10)% RH under a 14L:10D photoperiod. The results showed that the emergence peak of the female occurred at the 7th day of the pupal stage, while the male at 8th day. As for the circadian rhythm during 24 hours, most individuals of both sexes emerged from the 6th hour of the photophase to the 2th hour of the scotophase. The 11th hour after initiation of the photophase was the emergence peak of female, while that of the male was 1 hour later. Female M. troglodyte after emergence did not call until the scotophase. The calling percentage reached the peak at the 6th-7th hour of the scotophase which increased with age of 1-3 days and reached 69.8% at the 3rd day, and then went down gradually. In the cage of only a pair of female and male, adults started mating after the 5th hour of the scotophase, and reached peak at the 7th-8th hour. But in the cage of multiple pairs of adult moths, they started mating after 0.5 hour of the scotophase, and the peak was 1.5 hours later than one pair’s. Eggs laid by females at the age of 1 to 3 days accounted for 68.4% of their total lifetime fecundity, and then the oviposition gradually reduced with the age.

Research progress in chemical communication among insect-resistant genetically modified plants, insect pests and natural enemies.

LIU Qing-song, LI Yun-he, CHEN Xiu-ping, PENG Yu-fa

2014, 25(8):  2431-2439. 

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Semiochemicals released by plants or insects play an important role in the communication among plants, phytophagous insects and their natural enemies. They thus form a chemical information network which regulates intra and interspecific behaviors and sustains the composition and structure of plant and insect communities. The application of insectresistant genetically modified (IRGM) crops may affect the chemical communication within and among the tritrophic levels, and thus cause disturbances to the biotic community structure and the stability of the farmland ecosystem. This has raised concerns about the environmental safety of IRGM crops and triggered research worldwide. In the current article we provided a brief summary of the chemical communication among plants, herbivores and natural enemies; analyzed the potential of IRGM crops to affect the chemical communication between plants and arthropods and the related mechanisms; and discussed the current research progress and the future prospects in this field. We hope that this will promote the research in this field by Chinese scientists and increase our understanding of the potential effects of growing of IRGM crops on the arthropod community structure.

Review on farmer’s climate change perception and adaptation.

2014, 25(8):  2440-2448. 

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As the most serious challenge that the humankind is facing, climate change has been strengthened vulnerability in many countries and regions, and how to scientifically adapt to climate change has become the global issue of common concern to the international community today. The impact of climate change on farming people depending on the nature resource is especially remarkable, and understanding farmers’ adaptation mechanism and process is very important to effectively make the adaptation policy. As the basis of understanding the human response action, public perception has provided a new perspective to verify the farmers’ adaptation mechanism and process about climate change. Based on the recent theoretical and empirical developments of farmers’ perception and adaptation, the impact of climate change on the farmers’ livelihood was analyzed, and the main adaptation obstacles which the farmers faced in response to climate change were summarized systematically. Then, we analyzed the relationship between the farmers’ climate change perception and adaptation, illuminated the key cognitive elements in the process of the farmers’ climate change adaptation and introduced the framework to analyze the relationship between the farmers’ climate change perception and adaptation. At last, this review put forward the key questions which should be considered in study on the relationship between the farmers’ climate change perception and adaptation.