Table of Content

10 March 2014, Volume 33 Issue 3

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Niche characteristics of Pinus koraiensis population of different forest types on Changbai Mountain.

BAO Ye1,2, MENG Ying-ying1,2, ZHOU Wang-ming1, YU Da-pao1, ZHOU Li1, WEI Ya-wei1,2, FANG Xiang-min1,2, DAI Li-min1**

2014, 33(3):  555-559. 

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The niche characteristics and dynamics of Pinus koraiensis population were calculated and analyzed by methods of Levin’s niche breadth, Hurlbert niche breadth, and Pianka niche overlap in different forest types on Changbai Mountain. The results showed that P. koraiensis population was dominant in original broadleaved and Korean pine forests and the order of niche breadth in the three forest types was: primary forest (OP) > birch forest (BF) > broad leaved and larch mixed forest (MF). Compared with other populations, shadetolerant trees had a higher niche breadth than intolerant trees in OP and it was contrary in the two secondary forests. Additionally, P. koraiensis partially overlapped with other populations in all forest types, and it had an obvious trend of resource sharing with other species in OP and BF. P. koraiensis had the same or similar demands for resource with Acer mono, Tilia amurensis, Acer tegmentosum, Betula platyphylla in OP, Acer mono, B. platyphylla in BF, and Tilia amurensis, Quercus mongolica, Larix olgensis in MF, and would compete with one another under resource shortage.

Combined effects of ozone and drought on leaf stomata of Acer truncatum.

WEN Zhi1,2, WANG Li1**, WANG Xiao-ke2, LI Li2, CUI Jian2

2014, 33(3):  560-566. 

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An open-top chambers (OTCs) experiment was carried on the combined effects of ozone and drought on leaf stomata of Acer truncatum Bunge. Four treatments were designed: control (ambient air without drought stress), drought (ambient air with 40-50% of soil waterholding capacity), enhanced ozone (ambient air with additional 118 μg·m^-3 ozone without drought stress), and enhanced ozone and drought (ambient air with additional 118 μg·m^-3 ozone and 40-50% of soil waterholding capacity). 41 days after treatment, the stomatal density did not change significantly under ozone exposure, but increased significantly under drought stress and combined stress (P<0.05). 41 and 62 days after treatment with ozone and drought stresses, there were no significant differences in stomatal area, length and width among treatments (P>0.05), while 110 days after treatment with ozone and drought, the stomatal area, length and width were smaller than those of the control (P<0.05). Compared with the control, stomatal index increased significantly 110 days after treatment by ozone and drought (P<0.05). The stomatal opening degree reduced significantly when A. truncatum was exposed to enhanced ozone and drought (P<0.05). These results suggested that accumulating effects were reflected on stomatal characteristics of A. truncatum under ozone stresses. Ozone and drought stresses influenced the stomatal characteristics interactively. The synergistic effect of ozone and drought stresses was evidenced on the stomatal aperture. It was suggested that drought could protect plants against ozone-induced damage by causing the closure of stomata and preventing the entry of ozone into the leaves.

Ecosystem carbon storage in poplar plantations of different stand ages in Tianjin plain.

LI Ping1,2, XIAO Yu1**, YANG Yang3, ZHANG Chang-shun1

2014, 33(3):  567-574. 

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Forest is the most important carbon pool of terrestrial ecosystems, of which the forest plantations become more and more crucial. We investigated the differentaged poplar plantations in Tianjin through field surveys and laboratory measurements, estimated the carbon stock in the tree layer, herb layer, litter layer and soils (0-100 cm). The results showed that the biomasses of the tree layer in the young, medium and matured poplar plantations were 43.65, 56.18 and 121.59 t·hm^-2, respectively. The proportions of different organs to the tree biomass were in the order of stem>root>branch>leaf  in the young and medium age stands, and of stem>branch>root>leaf in the matured poplar plantations. The biomasses of the herb layer of the three age plantations were 4.60, 2.92 and 1.58 t·hm^-2, respectively, and that of the litter layer were 0.46, 0.35 and 0.66 t·hm^-2, respectively. The total ecosystem carbon storage values of the young, medium and matured poplar plantations were estimated to be 84.34, 121.03 and 121.72 t C·hm^-2, respectively. Among the carbon storage of the three age groups, plant communities accounted for 25.85%, 22.25% and 46.58%, respectively, and soils accounted for 74.15%, 77.75% and 53.42%, respectively. The carbon storage values of the tree layer in the young, medium and matured poplar plantations were 20.04, 25.78 and 55.95 t C·hm^-2, respectively. The carbon storage values of the herb layer in the three age groups were 1.63, 1.05 and 0.57 t C·hm^-2, respectively, and that of the litter layer were 0.14, 0.10 and 0.19 t C·hm^-2, respectively. The soil organic carbon storage values (0-100 cm) in the three age groups were 6253, 94.10 and 65.03 t C·hm^-2, respectively. The proportions of the carbon storage in the 0-30 cm soil layer to that of the total soil layer were 33.91%, 37.64% and 44.16%, increasing with the stand age.  It was showed that the ecosystem carbon storage of the poplar plantations in Tianjin increased with the increasing stand age. Nowadays, the young poplar plantations account for a large proportion of the total forest plantations in Tianjin. Thus, the poplar plantations in Tianjin would have a huge carbon sequestration potential in the future.

Characteristics of microclimate in a mixed coniferous and broadleaf forest in Dinghushan Biosphere Reserve.

OUYANG Xu1,2, LI Yue-lin1**, ZHANG Qian-mei1

2014, 33(3):  575-582. 

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Forest microclimate monitoring is of great importance in evaluating the responses and feedbacks of forest to global climate change. One-year meteorological data in 2010, namely temporal patterns of air temperature, relative humidity, soil temperature and soil moisture at two sites from a mixed coniferous and broadleaf forest and an open land without forest in the Dinghushan Biosphere Reserve were analyzed and compared. The results showed that the annual average air temperature, relative humidity, soil temperature in the mixed forest were 19.8 ℃, 86.5%, and 20 ℃, respectively, while those in the open land were 22.1 ℃, 79.1%, and 24 ℃, respectively. Soil volumetric water content was significantly higher in the mixed forest, suggesting a cooling, humidifying and waterconserving function of this forest. Differences in air temperature, relative humidity and soil temperature during the daytime (10:00-17:00) between the two sites were much higher than that at nighttime, supporting the above assertion of better cooling and humidifying functions of the mixed forest at daytime. Differences in monthly air and soil temperature between the two sites were higher during the rainy season than in dry season, while the difference in monthly relative humidity was more apparent in dry season, indicating better cooling effects in rainy season and better humidifying effects in dry season. The pattern of microclimate in the mixed forest was controlled by local climate and vegetation type in lower subtropical China.

Allocation of fine root biomass and its response to nitrogen deposition in poplar plantations with different stand ages.

XU Yu1, XU Kai1, YU Shui-qiang1**, RUAN Hong-hua1, FAN Huan1, YANG Yue1, XU Chang-bai2, CAO Guo-hua2

2014, 33(3):  583-591. 

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Nitrogen deposition is a hot topic issue of global change. Understanding the response patterns and feedback mechanisms of forest ecosystems associated with this continued, increased nitrogen deposition and rapid nitrogen cycle is vital for the maintenance of forest ecosystem health and productivity. Increasing nitrogen deposition may alter the distribution structure of fine roots, such as vertical distribution and diameter size distribution formed in the longterm evolution process. We conducted an experiment to examine the allocation of fine root biomass and its response to nitrogen deposition in poplar plantations with different stand ages in the coastal plain of Dongtai, Jiangsu. The randomized block design was used with five nitrogen deposition concentration treatments, i.e. N₀ (0 g N·m^-2·a^-1), N₁ (5 g N·m^-2·a^-1), N₂ (10 g N·m^-2·a^-1), N₃(15 g N·m^-2·a^-1), and N₄ (30 g N·m^-2·a^-1) in the field. The results showed that: (1) The fine root biomass was obviously enriched in the surface soil, with 70%-80% of fine root biomass allocated to the 0-20 cm soil layer. With the increase of exogenous nitrogen, the proportion of fine root biomass at the 0-10 cm soil layer increased in the young plantation (4 years old), while reduced in the midaged and mature plantations (8 and 15 years old, respectively) to some extent. (2) Fine root biomass was mainly distributed in the diameter class of 0-0.5 and 0.5-1.0 mm, and about 50% of the fine root biomass (<2.0 mm) was allocated in the diameter class of 0-0.5 mm. Exogenous nitrogen increased the proportion of very fine root biomass (0-0.5 mm), especially in the young plantation. (3) In the 30-40 cm soil layer, fine root biomass was allocated with a greater proportion in 0-0.5 mm diameter class in the mature plantation than in the young and mid-aged plantations, which showed that small fine roots had a decreasing trend with the increase age. (4) Four factors (plantation age, soil layer, diameter class, and nitrogen concentration) in combination explained 66.3% of variation of fine root biomass. Plantation age, soil layer, and diameter class respectively explained 17.6%, 16.1%, and 10.4% of variation, with significant effects (P<0.01), and the increase of nitrogen deposition only explained 0.24% of variation of fine root biomass, with no significant effect (P>0.05).

Early influence of forest gap harvesting on soil phosphorus in Pinus massoniana plantation in a hilly area of the reaches of Yangtze River.

OU Jiang, LIU Yang, ZHANG Jian**, ZHANG Jie, CUI Ning-jie, DENG Chang-chun, JI Tuo-wei, HE Run-lian

2014, 33(3):  592-601. 

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The seasonal variations of soil microbial biomass phosphorus (MBP), available phosphorus (AP) and total phosphorus (TP) were observed in seven size gaps (G1: 100 m², G2: 225 m², G3: 400 m², G4: 625 m², G5: 900 m², G6: 1225 m², G7: 1600 m²) of a masson pine plantation in a hilly area of the upper reaches of Yangtze River. The results showed that the soil MBP in the forest gaps was most sensitive to cutting disturbance, followed by soil AP, while TP was relatively stable. The effects of gap size were significant on soil MBP and AP, but not on soil TP. The center of forest gap with a size of 625-900 m² was more conducive to increase soil MBP, the center of larger gap (900-1600 m²) had a higher level of soil AP as well as the edge of medium-sized gap (225-625 m²), and the center of forest gap (625 m²) had a high level of soil TP. MBP and AP had significant changes in different periods of the growing season, but TP had no significant changes. Soil MBP of the centers of all gaps and the edges of gaps less than 625 m² was lower in the early period, but that of other areas was higher in early and lower in middle of growing season. Soil AP in the gap center was higher in the middle and lower in the early of the growing season, while lower in the early stage of gap edge. In addition, the interaction of gap size and seasonal variation had significant impacts on soil MBP. The location within forest gap had no significant influence on MBP, AP and TP, but the soil AP and TP of all gaps in the middle and late growing season were higher than in the understory soil, while the soil MBP of large-sized gap was only lower in the middle growing season. It is suggested that soil phosphorus was improved in a certain degree after the formation of forest gaps. Correlation analyses showed that soil MBP was significantly positively correlated with TP, but significantly negatively correlated with soil temperature, and soil MBP and TP were significantly positively correlated with soil water content. Therefore, soil temperature and moisture were major environmental factors affecting soil phosphorus in early formation of forest gaps.

Evaluating fire potential of non-commercial pine-beech forests in Tiger Mountain, Nanning.

HUANG Xiao-rong**, SHEN Wen-hui, PANG Shi-long, PENG Yu-hua, HE Feng, HUANG Zhi-ling

2014, 33(3):  602-610. 

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The Fuel Characteristic Classification System (FCCS) was used to evaluate fire hazard of non-commercial pine-beech forests in Tiger Mountain, Nanning. The data collection, input and output for FCCS were introduced, especially the input of environmental variables and their effects on the calculation of surface fire behavior. The results showed that all the forest types were of low reaction intensity and low rate of spread during the inventory season (AprilMay, 2013). If the environment becomes dry and reaches the FCCS D2L2 moisture condition, plot 3 (an open forest of pine, 28-year-old) may have a high FCCS potential with a high reaction intensity and a high spread rate. As it can be customized with small-scale plot inventory data, FCCS may provide reliable fire hazard predictions to guide fire control decision making, identify high risk locations and prioritize fuel treatment of the locations

Genetic diversity of the invasive plant Eupatorium catarium populations in Hainan Island and Guangdong of China based on ISSR analysis.

LI Li-qian1,2, LI Ni-ya1,2, LIU Qiang1,2**

2014, 33(3):  611-617. 

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Inter-simple sequence repeat (ISSR) markers were used to analyze genetic diversity and differentiation in eight populations of invasive plant species Eupatorium catarium Veldkamp distributed in Guangdong and Hainan in Southern China. Ten ISSR primers used in this study produced 98 loci, of which 9.8 were polymorphic. At the species level, the percentage of polymorphic loci (P) was 100%, Shannon’s information index (I) 0.4440 and Nei’s gene diversity (h) 0.2916, indicating high genetic diversity in E. catarium. Based on Nei’s G_st value, 72.39% of genetic variance was among individuals within population, 27.61% among populations. Gene flow among populations was 1.3107. Average genetic similarity of the eight populations was 0.8828, while average genetic distance was 0.1257. Unweighted pair group method with arithmetic mean (UPGMA) analysis separated the eight populations into three groups. The six populations of Haikou, Danzhou, Qiongzhong, Sanya, Heshan and Yangjiang were clustered into one group, and Qionghai and Xuwen populations were clustered into two independent groups, respectively. The Mantel test suggested that there was no significant correlation between the genetic distance and geographic distance of the eight E. catarium populations, thus it was likely that the spread of the invasive species in the studied regions was mainly attributed to the events of humanmediated longdistance dispersals of seeds or propagules.

Phenotypic plasticity and biomass allocation of Iris tenuifolia Pall. in different habitats.

ZHUO Lu1,2, GUAN Kai-yun1**, LI Wen-jun1,2, DUAN Shi-min1

2014, 33(3):  618-623. 

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Iris tenuifolia Pall. is distributed in arid regions as an ornamental flower species. The germination rate of I. tenuifolia seeds in nature is extremely low and the perennating rhizomes play an important role in its propagation. The purpose of this study was to understand the characteristics of phenotypic plasticity and ecological adaptation of I. tenuifolia. Three populations (populations 1, 2 and 3 represented severely dry, dry, and relatively humid habitats, respectively) in Xinjiang, China were chose to investigate the biological characteristics, above and underground biomass of I. tenuifolia. The results showed that the plant’s external morphology was significantly different among the three populations. The total root length and root/shoot ratio were significantly higher in population 1 than in the other two populations, but plant height was higher in population 3. Aboveground biomass of population 3 was significantly higher, but the underground biomass was lower. These findings indicated that, through adjusting the morphology and the allocation ratio of biomass, I. tenuifolia has better phenotypic plasticity to form adaptation strategies in favor of their growth and development at different soil moistures.

Allelopathic effects of aqueous extracts from Phragmites communis on the growth and photosynthesis of Solidago canadensis.

LIU Cheng1,2, WU Ming1**, CHEN Xiao-de2, YE Xiao-qi1, HE Li2

2014, 33(3):  624-630. 

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Allelopathy of aqueous extracts from Phragmites communis leaves on the growth and photosynthetic physiological characteristics of invasive plant Solidago canadensis was determined at different concentrations \[0 (CK), 0.025 g·mL^-1 (2.5%), 0.05 g·mL^-1 (5%) and 0.10 g·mL^-1 (10%)\]. The results showed that the height growth and biomass, net photosynthetic rate and stomatal conductance were not inhibited by the low concentration (2.5%) of leaf extracts, but were significantly inhibited at the high concentration (10%). The chlorophyll content, light saturation point and apparent quantum efficiency were promoted by the low concentration of extracts but inhibited by the high concentration. With the extract concentration increasing, carotenoids content increased gradually, and the dark respiration rate decreased gradually but was significantly higher than CK. Therefore, allelopathy of P. communis on the growth of S. canadensis was found through affecting photosynthesis, including chlorophyll content, leaf stomatal openness and the light response capability.

Effects of different LED light qualities on photosynthetic characteristics and curcumin contents of Curcuma longa L.

LIU Jian-fu1,2**, FAN Yan-ping1, WANG Ming-yuan2, WANG Qi-zhi2, TANG Yuan-jiang2

2014, 33(3):  631-636. 

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The effects of different light qualities generated by light emitting diodes (LED) on the photosynthetic characteristics of Curcuma longa L. were studied. The results showed that red light, blue light, and combined red + blue light all increased the curcumin content. In addition, red light increased the contents of chlorophyll a, total chlorophyll and soluble sugar. The blue light benefited the contents of caroteoids and protein, the activities of superoxide dismutase (SOD) and peroxidase (POD). The green light improved the contents of caroteoids and protein, while yellow light promoted the accumulation of protein. The chlorophyll and carotenoid concentrations, SOD activities and the ratio of F_vF_o significantly increased by 14.23%, 23.60%, 18.18%, 22.60% and 66.65% respectively under the red/blue light=7:3 treatment, suggesting that the ratio of 7:3 was optimum for the growth and curcumin accumulation of C. longa.

Phytoplankton community structure and its relation to environmental factors in a newly excavated landscape river.

XU Yu-ping1, LIU Cai-hong1, ZHANG Yao-yao2, ZHANG Wei1,3, LIU Xin-pu1, WANG Li-qing1,3**

2014, 33(3):  637-645. 

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To explore the phytoplankton community structure and its relationship with environmental factors, a survey was conducted in the newly excavated landscape river (Port B, Lingang, Shanghai) from December 2011 to November 2012. The results showed that there were 223 phytoplankton species, which belong to seven Phyla. Phyla Chlorophyta had the most species, followed by Cyanophyta and Bacillariophyta. The phytoplankton abundance ranged from 7.52×10⁶ to 212×10⁶ cells·L^-1, with an average of 66.27×10⁶ cells·L^-1. The species abundance in the rainy period was significantly higher than in the drought period, while cell density was vice versa. The dominant species was simplex for each season, which mainly consisted of the Merismopedia spp. Canonical correspondence analysis (CCA) showed that the distribution of phytoplankton in the four quadrants was homogeneous, which reflected the typical characters of subtropical climate. PCA and CCA indicated that salinity and nutrients (TN and TP) were the main driving factors for the dynamic change of phytoplankton community. Chroococcus minor, Merismopedia glauca, Tetraedron tumidulum and Synedra sp. could be used as efficient indicators for salinity, while Fragilaria brevistriata, Synedra acus, Ntizschia closterium and Chroococcus tenax showed a potential value for indicating the organic pollution.

An investigation on summer algal blooms in Xiangxi Bay of Three Gorges Reservoir.

XU Tao1, WANG Yu-chun2**, LIU De-fu1,3, YANG Zheng-jian1, CHEN Wen-zhong1, WU Ya1

2014, 33(3):  646-652. 

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Taking Xiangxi River, a tributary of the Three Gorges Reservoir as the study object, and according to the monitoring data obtained in summer of 2011, the temporal and spatial distribution characteristics of nutrients and chlorophyll a in the tributary bay before and after an algal bloom, and their relevance were analyzed. The results showed that the algal bloom lasted during June 21-29, 2011, and the maximal value of chlorophyll a achieved 125.8 mg·m^-3. The algal bloom had a significant influence on the spatial distribution of DIN and DIP, and the nutrients were at high concentrations in middle reaches, and low concentrations in the estuary, but diminished from the estuary to the upper reaches, and sharply declined in the algal bloom area. The high background concentrations of nutrients in Yangtze River increased the risk of algal blooms in the tributary bay. The outflow position of the Yangtze River water with high background concentrations of nutrients in the Xiangxi River bay was just the region with the most severe algal bloom. The nutrient supply of mainstream water to the tributary bay surface water was the key factor affecting the algal bloom fluctuation.

EAG responses of the yellow-spined bamboo locust, Ceracris kiangsu Tsai towards human urine volatiles.

SHU Jin-ping, TENG Ying, ZHANG Ya-bo, LIU Jian, WANG Hao-jie**

2014, 33(3):  653-658. 

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The yellow-spined bamboo locust, Ceracris kiangsu (Orthoptera: Oedipodidae) is an important bamboo pest in south China. To better understand the mechanism of the urine puddling behavior of C. kiangsu, we examined the EAG responses of C. kiangsu adults towards the volatiles of human urine fermented for different days and the solutions of ammonium bicarbonate and indole. The results showed that the EAG responses of C. kiangsu adults towards human urine volatiles were influenced significantly by the duration of human urine fermentation. Compared with fresh urine and human urine fermented for 7, 15, 30, 45 and 60 days, the volatiles emitted from human urine incubated for 30 days elicited the strongest EAG response in both female and male adults. In addition, the solutions of indole, ammonium bicarbonate and urine in different concentrations could evoke strong EAG response in male and female adults respectively. The EAG response elicited by different chemical solutions were significantly weaker than that evoked by human urine (P<0.05). The EAG responses towards the volatiles emitted from human urine and chemical solutions were affected by sex, and the human urine fermented for 0 and 15 days elicited stronger EAG responses in females than in males, while the EAG responses evoked by the human urine and the solutions of ammonium bicarbonate and indole were respectively weaker in females than in males.

Reduction of nitrogen amendment and irrigation influences paddy soil nematode community.

SUN Zhen, LIU Man-qiang, GUI Juan, LI Hui-xin, HU Feng, JIAO Jia-guo**

2014, 33(3):  659-665. 

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A fully 2×4 factorial experiment was conducted with four levels of nitrogen fertilization amendments, i.e. decreasing the nitrogen amendments from a routine amount 300 kg N·hm^-2 to 10%, 20% and 40% of the routine amount, respectively, with conventionally continuously flooded irrigation or controlled non-continuously flooded irrigation. Across all the eight treatments, there were 16 families and 28 genera of soil nematodes, belonging to 7 families and 12 genera of bacterivores, 3 families and 4 genera of fungivores, 3 families and 5 genera of plant-parasites, and 3 families and 7 genera of omnivore-predators, respectively. Among all the nematodes, the genus Filenchus was dominant with a relative abundance of 35.4%-47.9%. Regarding the nematode trophic groups, the fungivores accounted for the highest proportion of soil nematodes, followed by bacterivores as the second, and then the plant-parasites, and the omnivore/predators at the minimum. The total nematodes under the conventionally flooded irrigation were slightly higher than under the controlled non-continuously flooded irrigation. When reducing the nitrogen amendment to 80% of the routine application rate (i.e. 240 kg N·hm^-2), the total number of nematodes increased significantly, but no further changes were found when even less nitrogen was amended.

Characteristics of soil nematode community in Fenghuang Dancong tea plantations.

XING Shu-wen**, ZHU Hui, ZHANG Dong-hong, FAN Hong-meng, LUO Guo-hong, QIU Shao-tian

2014, 33(3):  666-673. 

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To uncover the nematode resource and soil health degree in Fenghuang Dancong tea gardens, soil nematodes were sampled, isolated and identified from four types of Dancong tea gardens, including ancient tea plantation, organic tea plantation, pollutionfree tea plantation and ordinary tea plantation. Results showed that a total of 19341 nematodes were identified in the four tea plantations, which belong to 2 phylum, 6 order, 18 family and 42 genera, respectively. Shannon index in the ancient tea plantation was significantly lower than in the other three tea plantations, with the highest in the organic tea plantation. Margalef richness index and DensityGroups index of nematodes in the organic tea plantation and ancient tea plantation were higher than in the other two tea plantations. Soil nematode communities displayed vertical distribution patterns in all tea plantations, and the groups and individuals of nematodes decreased with the increase of soil depth. Structure characteristics of nematode trophic groups showed bacteria-feeding nematodes and fungi-feeding nematodes in the organic tea plantation were significantly higher than in the other three tea plantations. The PPI index of herbivorous nematodes in the ancient tea plantation and ordinary tea plantation was higher than in the other two plantations. PPI/MI ratio was significantly higher in the ancient tea plantation than in the other three plantations, suggesting that the ancient tea trees had significant disturbance to soil environment. In conclusion, the characteristics of soil nematode community can effectively reflect the health status of tea garden soil, which can be an important biological indicator for ecological environment assessment of tea garden soil.

Effects of detection timeofday on wintering water birds counts at the north bay of Erhai Lake, Yunnan.

LI De-pin1, FU Gui-quan1, WANG Ming-yang1, ZHAO Zhi-hong2, YANG Rui-feng2, XIAO Wen1**

2014, 33(3):  674-679. 

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In order to clarify the effect of hourly variability on water birds counts, and provide basic information for the designing of reasonable methods for water birds monitoring, data on water birds species and population were collected using the quadrat method at two sites situated along the estuary of north Erhai Lake, from January 28 to March 15, 2011. Twenty three species belonging to eight families and six orders were recorded in this survey. The detection numbers of individuals showed a significant diurnal variability during the session of investigation, with least detection from 8:00 to 9:59 and most detection between 16:00 to 18:00. The lower detection of water birds from 8:00 to 9:59 is likely due to the higher activity frequency of fishing boats during these hours. Within the different groups, hourly variations in the detections of population size of swimming birds were significant, but no significant correlations were found for wading birds, migrant birds and resident birds. Among twelve common species, individual species differed in patterns of activities in a day, and hourly variations in the detection of population size of five species were significant. Our results suggested that monitoring the water bird community of Erhai Lake should be conducted after 16:00.

Evaluation of heavy metal toxicity in sediments using the midge Chironomus tepperi

DENG Xin1,2, Vincent PETTIGROVE3, YANG Xiao-nan4, LI Xiao-jun1, LIU Wan1, Kallie TOWSEND3, TAI Pei-dong1**

2014, 33(3):  680-686. 

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Six sediment samples were collected from different outfield places. A five-day growth experiment and a twenty-day chronic toxicity experiment with the sediments were conducted with first instar Chironomus tepperi larvae. Head capsule width, body length, average time to male and female adult emergence, growth rate, total survival, emergence rate, and sex ratios were employed to evaluate the effects of contaminants in the sediments on C. tepperi. The results showed that body length, total survival and total emergence rate were significantly inhibited by zinc, copper, arsenic, lead, and cadmium contamination (P<0.05), while time to female adult emergence, time to male adult emergence and growth rate were significantly increased by zinc, copper, arsenic, lead, and cadmium contamination (P<0.05). Head capsule width and sex ratio of C. tepperi were not significantly correlated with metal concentrations in the sediments. The whole eight indicators were not significantly affected by chrome, nickel and cobalt. Among all the factors, body length of C. tepperi larvae, time to adult C. tepperi emergence, emergence rate and total survival rate were important in testing sediment quality.

Effect of different kinds of soil on  osmotic adjustment ability and membrane injury of various organs of rice Changbai 9 after heading.

WU Zhi-hai1,2, ZHANG Ting-ting2, YANG Mei-ying2, QI Chun-yan1, LIU liang1, HOU Li-gang1**

2014, 33(3):  687-693. 

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In order to screen out the better ratio of black soil and saline-alkali soil for planting rice Changbai 9, the effects of five kinds of soil on the osmotic substances and membrane injury of Changbai 9 leaves, panicle stem and sheath after heading were studied. The results showed that free amino acid, proline and soluble protein contents of treatment C (black soil∶alkaline soil =1∶1) were higher than that of other soil combination treatments. When the ratio of black soil and salinealkali soil was 3∶1, the soluble protein and soluble sugar contents were consistent with black soil, but free amino acid and proline contents were closer to that of treatment C. The contents of osmotic adjustment substances of different organs were relatively small after heading of Changbai 9 grown in the original salinealkali soil, and MDA content and O₂^-_· production rate were obviously higher than in other treatments. The accumulation amounts of osmotic adjustment substances of different organs of Changbai 9 from heading to mature were in the order of leaf > panicle > precedes stem > sheath. This suggested that the original salinealkali soil with a high Na⁺ concentration and a high pH value reduced the osmotic adjustment ability and accelerated the injury of membrane of Changbai 9. The ratio of black soil to salinealkali soil at 1:1 or higher can effectively regulate the soil Na⁺ concentration and pH value, and enhance the osmotic adjustment ability of Changbai 9 organs, especially for leaf and panicle.

Corn yield, nutrient uptake and soil nutrient budget under different long-term phosphorus fertilizations.

HUANG Ying1,2, ZHAO Mu-qiu3**, WANG Yong-zhuang1,2, LU Cai-yan1, SHI Yi1, CHEN Xin1

2014, 33(3):  694-701. 

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A 12-year field micro-plot trial with meadow brown soil planted with corn was conducted in Shenyang to study corn yield, nutrient uptake and soil nutrient budget under the longterm impact of different P fertilization methods (application rate and frequency). The results showed that P was not the most important factor affecting the corn yield in this area. Fertilization increased nutrient uptake, with the treatment order of NP>N>CK, and P application once per six years was better than annual P application. Compared with the background values of soil, fertilization increased the concentrations of total P, OlsenP, total N and alkali hydrolyzable N in soil plough layer (0-20 cm) with the treatment order of NP>N>CK, while the concentrations of total K and available K declined with the treatment order of NP>N>CK due to long-term lack of K application. Soil OlsenP concentration decreased in the treatment with no fertilization and increased in the treatment with only N fertilization, but they both did not change obviously. The soil OlsenP concentration was increased gradually under the annual P application treatment. In contrast, when under the once per six years P application treatment, the soil OlsenP concentration was the maximum in the first year after P application, and decreased thereafter, which implied that P application once per six years was better than annual P application for the establishment of soil “grand” available P pool. On the premise of adequate N application, the quantity of P application was equal to or slightly higher than that of corn uptake with a N/P ratio between 1:0.167 and 1:0.5 for the balance of soil nutrient budget.

Evaluation of landscape ecological risk of soil and water erosion in the Bailongjiang watershed in Southern Gansu, China.

XIE Yu-chu, GONG Jie**, ZHAO Cai-xia

2014, 33(3):  702-708. 

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Bailongjiang watershed, a typical soil erosion area located in the ecotone among the Loess Plateau, Tibet Plateau and Qinba Mountains, was selected as a case to study the landscape ecological risk of soil and water erosion at the watershed scale. We integrated the revised universal soil loss equation (RUSLE) and landscape ecological risk index (LERI) by raster layers in a GIS workstation to identify and assess the spatiotemporal characteristics of landscape ecological risk (LER). The factors used in RUSLE and LERI were obtained by using different data from meteorological stations, soil surveys and maps, digitized topographic maps, NDVI, DEM and Landsat TM images. And then, the LER of water and soil erosion was classified into five levels: low, slight, moderate, intense and severe, and dynamically monitored from 1990 to 2010 with the spatial analyst tool of ArcGIS 9.3. The results showed that: (1) the value of LER was high and the proportion of above the moderate erosion risk level was up to 48%. As to the spatial distribution pattern, the high risk area mostly located along the Bailongjiang and its tributaries, Minjiang River, northern and northwestern parts of Diebu County. (2) The change of LER pattern was small and tended to be weakened during the period of 1990-2010; especially after 2002, the low erosion risk area increased obviously with an increase of 280.89 km², showing that the performed water and soil conservation measures were very effective. (3) The higher risk of the soil and water erosion mainly occurred on the slope cultivated land and unused land, while the lower risk type was the forestland. At the same time, the ecological risk of water and soil erosion in Wudu district was the highest (55.38%). Consequently, more attention should be paid on these towns, such as Majie, Luotang, Anhua, Hanwang, Yulong, Putian, Xiongchi, Jiegan, and northern Liangshui of Wudu District, to control the soil and water loss in the future. Our study showed that the RUSLE-GIS model was a useful tool for evaluating and mapping LER of water and soil erosion quantitatively.

Effects of clear-felling on soil nutrient pools and nitrogen mineralization and nitrification in Tiantong, Zhejiang Province.

LI Guang-yao1,2, YANG Xiao-dong2,3, SHI Qing-ru2,3, MA Wen-ji2,3, WANG Xi-hua2,3, YAN En-rong2,3**

2014, 33(3):  709-715. 

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Revealing the effects of forest clear-felling frequencies on soil nutrient pools and nitrogen transformation is important for understanding the response of nutrient cycling to clearfelling. In this study, three pairs of control and clear-felling (at different frequencies) communities were selected in evergreen broad=leaved forests in Tiantong, Zhejiang Province, to study the influence of clear felling on soil organic carbon, nitrogen and phosphorus pools, as well as soil nitrogen mineralization and nitrification. The results showed that repeated clear felling significantly lowered the stocks of soil total nitrogen and organic carbon (P<0.05), while significantly increased soil phosphorus, ammonium and nitrate contents, and soil bulk density (P<0.05). Repeated clear felling did not cause significant changes in soil nitrogen mineralization and ammonification rates (P>0.05), but significantly increased the soil nitrogen nitrification rate (P<0.05).

Spatial autocorrelation analysis on soil moisture of Melica przewalskyi patch in a degraded alpine grassland of Qilian Mountains, Northwest China.

YANG Quan, ZHAO Cheng-zhang**, SHI Li-li, DANG Jing-jing, ZHA Gao-de

2014, 33(3):  716-722. 

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A prerequisite in using conventional statistical methods, such as regression models in investigating spatial distribution of soil moisture, is that the data regarding soil moisture should be statistically independent and identically distributed. However, soil moisture generally exists with spatial autocorrelation to some degree, which contains some useful information. In this paper, the spatial autocorrelation analysis of soil moisture in Melica przewalskyi patch was investigated based on Moran’s I index on the north slope of the Qilian Mountains. Moran’s I was applied to describe spatial autocorrelation of soil moisture, and analyze the scales of spatial autocorrelation. Meanwhile, standard multiple linear regression model and spatial autoregressive model of soil moisture were constructed. The results showed that distribution of surface soil moisture all displayed spatial autocorrelation characteristics. In addition, the spatial aggregation characteristics of the 20-30 cm depth were higher than that of the 0-10 and 10-20 cm depths. It was found that the Moran’s I decreased with the increase of the scale of spatial analysis. The spatial autocorrelation of surface soil moisture resulted from different soil depths. At the 10-20 cm depth, the community height and Melica przewalskyi coverage had significant effects on the spatial autocorrelation, while at the 20-30 cm depth, the Stipa krylovii coverage and community height significantly affected the spatial autocorrelation. Our analysis showed that spatial autoregressive model was better than the standard multiple linear regression model due to the spatial autocorrelation exerting more impact on the latter one.

Effect of land-use type on soil labile carbon pool and carbon management index.

GUO Bao-hua1, FAN Shao-hui1**, DU Man-yi1,2, LIU Guang-lu1, SU Wen-hui1

2014, 33(3):  723-728. 

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To study the effect of different land uses on soil labile organic carbon pool and carbon management index (CMI), four types of land use, including abounded land (AL) and three forest lands \[Phyllostachys edulis forest (PE), P. edulis and Schima superba secondary forest (SS), Cunninghamia lanceolata forest (CL)\] were selected in Anfu County, Jiangxi Province. The result showed that soil labile organic matter pools in the different landuse types were in the order of PE (14.56 t·hm^-2) > SS (14.41 t·hm^-2) > CL (13.39 t·hm^-2) > AL (9.53 t·hm^-2), and the values in the forest lands were significantly higher than in AL. After the land use was changed to forest land, total soil organic carbon, soil labile organic carbon, stable carbon content, carbon pool index were greatly improved; the values of labile carbon and labile carbon index were highest in SS, while the value of coefficient of oxidation stability was highest in PE. Taking AL as a reference, the CMI values of the different landuse types were in the order of SS (184.61) > PE (172.58) > CL (150.50) > AL (100). It is indicated that forest lands could function to improve soil fertility and were in good management situation, especially for SS.

Effects of bio-char on soil physical properties and clomazone degradation.

LI Yu-mei1,2, WANG Gen-lin3, LI Xin-jie1,4, YU Hong-jiu3, GUO Wei3, WEI Dan1**, LIU Zhong-tang3

2014, 33(3):  729-734. 

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The effects of bio-char derived from rice straw on soil physical properties and clomazone residual degradation were studied by barrel column and pot experiments simulating the degradation of persistent herbicides in soil environment. The results showed that when applying 2-32 mg·kg^-1 of bio-char in soil, the soil bulk density was decreased on average by 0.126 g·cm^-3, the solid phase ratio was reduced by an average of 21.2%, and the gas and liquid phase ratios were increased by 29.8% and 15.3%, respectively, which meant that soil physical properties were improved. The barrel column test indicated that clomazone was mainly distributed in the soil layer above 30 cm, and its residue in soil was greater when its initial concentration was higher. Bio-char promoted the degradation of clomazone in the soil. With the increase of biochar content in soil, clomazone residue in soil was reduced, decreasing its biological hazard to crops.

Application of the approaching degree method in riparian zone health assessment in Tieling section of Liao River.

ZHAO Zhi-miao, SUN Li-na**, CHEN Su, WANG Hui

2014, 33(3):  735-740. 

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The approaching degree is a fuzzy evaluation method which has a recognizing function. This method is used for grading division and has certain applicability. Now it has been widely used in evaluation on pollution status of heavy metals in soil and water environmental quality. In this paper, based on monitoring the riparian zone in Tieling section of Liao River, the approaching degree method was applied to assess the riparian health. The riparian zone of Tieling section of Liao River was at a good healthy level. The suitability of the method was examined according to both the goodnessoffit between the evaluation result and the actual situation, and the deviation degree of the evaluation results. We concluded that the approaching degree method was suitable for the riparian health assessment.

Composition and seasonal fluctuation of nitrogen from precipitation in urban area of Shenyang.

SONG Huan-huan, JIANG Chun-ming, YU Wan-tai**

2014, 33(3):  741-747. 

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In the  urban area of Shenyang, we sampled precipitation from February to December in the year of 2012, investigated the nitrogen (N) concentration and deposition flux from precipitation, and elucidated the possible factors influencing the variation of N deposition. The results showed that the average concentrations of NH₄⁺-N, NO₃^--N and DON were 1.57, 0.87 and 0.82 mg N·L^-1, respectively. The total N deposited from precipitation was 26.17 kg N·hm^-2·a^-1, among which the deposition of NH₄⁺-N, NO₃^--N and DON were 12.56, 7.02 and 6.59 kg N·hm^-2·a^-1, respectively. The N deposition was positively correlated with precipitation when fitted with a power equation. Seasonal fluctuations of different N forms suggested N deposition was mainly derived from the local industrial and agricultural production; in the meantime, the precipitation amount also played an important role.

Numerical modeling of local air pollutant dispersion characteristics in Tianjin Binhai New Area.

LI Ming-cai**, YANG Yan-juan, GUO Jun, XIONG Ming-ming, REN Yu

2014, 33(3):  748-754. 

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Taking a petrochemical project of Nangang industrial area situated in the southern Binhai New Area, Tianjin as a case, the characteristics of dispersion and transport of air pollutant NO_x were simulated by using a boundary layer model, and its environmental impact was analyzed with consideration of its atmospheric stability and mixed layer thickness. The results showed that there were no apparent differences in the NO_x concentration at the 150 m height diffusion center among four seasons, whereas at the height of 10 m above ground the NO_x concentration had large differences in different seasons. NO_x concentration was highest in winter (0.03 μg·m^-3), followed by summer (0.024 μg·m^-3), but NO_x concentrations in spring and autumn were only 25%-50% of that in winter and summer. The dispersion direction of NO_x was consistent with the dominant wind direction in this area. In winter, NO_x dispersed to southeast due to the dominant northwest wind and thus the influence of pollutants on inland areas was least because NO_x mainly dispersed to the sea. Southwest wind prevailed in spring and autumn, leading to the dispersion of NO_x to the northeast to weakly affect the Tanggu coastal region. Different from other seasons, southeast wind prevailed in summer and NO_x dispersed to the northwest, making a certain impact on the inland. However, the concentration of NO_x after approximately 30 km diffusion to the northwest was only 0.002 μg·m^-3, which met the air quality standard for NO_x. Considering the high sensitivities of petrochemical production, storage and transport to high temperature and the characteristics of air pollutant dispersion, it is recommended to reduce the production scale and increase pollution control efforts in summer in order to decrease the risk of high temperature and the impact on the inland.

Variation characteristics of sunshine duration and its impact factors in Dongting Lake area during 1960-2012.

HUANG Ju-mei1**, LAI Ding-mei2, XIANG Tao3, ZHANG Jian-ming4

2014, 33(3):  755-760. 

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Base on the observations at 24 meteorological stations in the Dongting Lake area during 1960-2012, the variation characteristics of sunshine duration and its impact factors were analyzed by linear trend analysis, MannKendall test, and wavelet analysis. The results showed that the sunshine hours had a significant decrease trend of 46.0 hours per decade, being most notable in summer (29.5 hours per decade), followed by winter (14.6 hours per decade), and no obvious change in spring and fall. The decrease rate in the northern part of the Lake was higher than in the south, and the greatest decrease rate was observed at the Jianli Station (97.8 hours per decade). The annual sunshine hours during the 1960s to 1970s were higher than the normal, and the turn point was in 1980; thereafter, the annual sunshine hours were below the normal. The annual sunshine hours had three variation cycles of 2, 6 and 10-11 years. The decrease of annual sunshine hours might be caused by the decrease of wind speed and increase of precipitation, cloud amount and foggy days in the Dongting Lake area.

Spatiotemporal variation patterns of the beginning and ending dates of snowfall, and snowfall days in Qinghai Province during 1962 to 2012.

ZHU Xiao-fan, ZHANG Ming-jun**, WANG Sheng-jie, LI Xiao-shou, DONG Lei, REN Zheng-guo

2014, 33(3):  761-770. 

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Based on the daily snowfall data from 27 meteorological stations in Qinghai Province from 1962 to 2012, the spatiotemporal variation patterns of the beginning and ending dates of snowfall and snowfall days were analyzed by means of inverse distance-weighted interpolation, and Mann-Kendall mutation test. The results show that the beginning date of snowfall in Qinghai Province mainly concentrated in September, October and November, but the ending date mainly concentrated in April and May. The earliest snowfall occurred in the Three-River headwaters region, and the latest was in the Qaidam Basin. In addition, the beginning date of snowfall in most areas of Qinghai Province was gradually delayed, but the ending date of snowfall was brought forward. The snowfall days concentrated on March, April and October (mainly light and heavy snows), and showed a decreasing trend at rates of 1-3 days per decade. An obvious abrupt change existed in the beginning and ending dates of snowfall and snowfall days. Latitude, altitude and annual mean temperature correlated strongly with the beginning and ending dates of snowfall and snowfall days, and the correlations of the beginning and ending dates of snowfall with the average daily temperature (mean, maximum and minimum values) were different in different months. Besides, a positive correlation between snow season length and mean snowfall days existed.

Agro-meteorological disaster risk evaluation of tea planting in Zhejiang Province.

JIN Zhi-feng1,2**, HU Bo1,3, YAN Jia-zhen4, YANG Zai-qiang2, LI Ren-zhong1, YE Jian-gang5

2014, 33(3):  771-777. 

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Evaluating the agrometeorological disaster risk (AMDR) of tea planting can enhance the natural disaster defense ability of tea industry. Based on the statistical data of natural disasters and agricultural data of 64 observation stations in Zhejiang Province during 1971-2010, an assessment model of AMDR is developed by applying fuzzy mathematics and weighted index sum method. The AMDR of tea planting in Zhejiang is divided into three levels: low, moderate and high. By integrating the climate zoning result of tea planting into the risk assessment model, we get the refined AMDR zoning map of tea planting in Zhejiang. The high AMDR area of tea planting mainly locates in the northwest and middlenorth of Zhejiang; the moderate AMDR area includes the middle and northeast of Zhejiang; the low AMDR area mostly locates in the south of Zhejiang. The low suitable regions of tea planting mostly locate in the southeast and southwest of Zhejiang.

Applying stable carbon isotope techniques to detect different sources of organic matters in lake sediments from Beijing parks.

WANG Chun-yu1,2, GUO Qing-jun1**, ZHU Guang-xu1,2, PETERS Marc1, YANG Jun-xing1, ZHANG Han-zhi1,2, WEI Rong-fei1,2, TIAN Li-yan1,2, WAN Ying-xin3

2014, 33(3):  778-785. 

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Lake sediment can be a source as well as a sink of water pollutants and, hence, represents an important factor in lake ecology. Thus, more and more attention has been paid on the water quality of Beijing park lakes and the chemical characteristics of the sediments. This study detected variations in δ¹³C_org, C/N ratios, TOC and TN contents in the sediments from 19 Beijing park lakes collected in 2012 and 2013. The analyses focused on the sources of organic matter, the productivity and the eutrophic status of the lakes. The results showed that the δ¹³C_org and C/N values, and TOC and TON concentrations were significantly different among superficial sediments from different lakes, and the productivity and the eutrophic status of the lakes were also different. The sediments of three lakes showed minor contamination, whereas the other lakes were characterized by higher degrees of organic pollution. According to the δ¹³C_org values (-27.6‰ to -22.1‰) and C/N ratios (8.2-58.1), the sedimentary organic matter was mainly derived from sewage. Hence, the pollution of the lakes could be lowered by controlling the discharge of wastewater.

Screening and identification of bacteria for degradation of pesticides carbofuran and chlorpyrifos.

WANG Xin**, LU Jia-liang, LIU Li, CUI Li, LIANG Ji-yan

2014, 33(3):  786-790. 

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Several strains of bacteria were applied in the degradation experiments of carbofuran and chlorpyrifos, and the preponderant bacteria were identified by comparison. The LLBK2 and LLBK10 showed the best degradation effect on the 100 mg·L^-1 of carbofuran, with the degradation rates of 58.0% and 60.0% in 48 hours, and 82.8% and 83.8% in the 72 hours, respectively. The LLBD2 and LLBD4 showed the best degradation effect on the 100 mg·L^-1 of chlorpyrifos, with the degradation rates of 70.6% and 61.5% in the 48 hours, and 92.3% and 91.4% in 72 hours, respectively. Through further microbiological identification, LLBK2, LLBK10, LLBD2 could be classified as Bacillus circus. The accessing numbers of their 16S rDNA gene sequences in the GenBank were JQ917438, HQ833023, and JX847612, respectively. LLBD4 could be categorized as Bacillus, which has the GenBank accessing number of JX010962.

The status and trend on the ecological sanitation system research.

GAO Hui1,2, WANG Ru-song1**, ZHOU Chuan-bin1, GAO Jie1, HAN Bao-long1

2014, 33(3):  791-798. 

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Ecological sanitation (EcoSan) is a new concept in the field of sustainable health, with the aim of changing how modern urban sanitation systems are viewed. It is based on a closedloop material cycle in an ecological system, and its design includes the circulation of water and nutrients. In this article, progress in EcoSan research was described from three perspectives, namely, technological innovation, program management, and applied social activities, on the foundation of the concept and various facets of EcoSan. Problems existing in the current studies include a lack of concern about local residents’ opinions, insufficient integration and demonstration of comprehensive EcoSan technologies, poor costbenefit analysis, and the lack of comparative studies examining how environmental and hygiene risks can be addressed. Meanwhile, in view of the national social and political environment, certain bottlenecks can be summarized as follows: (1) the EcoSan system has not yet achieved wideranging acceptability, (2) supporting policies and regulatory measures are absent, (3) key equipments remain to be developed, and (4) a complete set of auxiliary service systems is not yet present. In addition, the present study points out relevant suggestions from the perspectives of different urban-rural programs, establishment of management institutions, implementation of technical standards and criteria, enhancement of publicity and education, and formulation of policies and regulations. These are necessary in order to provide theoretical references for the development of effective ecological sanitation programs in China.

Research progress on treeline response to climate change.

FU Yu1，HAN Yong-shun1，ZHANG Yang-jian2**，TAO Jian2

2014, 33(3):  799-805. 

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Treeline is one of the most obvious terrestrial ecosystem boundaries. Previous researches showed that treeline was sensitive to climatic change in the 20^th century. In this paper, the concept and characteristics of treeline were first discussed. Then research advances in responses of treeline to climatic change were reviewed. Since the 20th century, the response of treeline to climatic change has exhibited as climbing along altitude, increased forest density in treeline zone, lowering downhill along altitude, and nonchange. Among the four forms, the climbing along altitude accounted for 65% of the summarized studies and they were located in the Scandinavian Mountains, the Pyrenees, and the Polar Ural Mountains. The increased density accounted for 20% of the summarized studies, which were identified in the Scandinavian Mountains and the Polar Ural Mountains. The lowering downhill and non-change accounted for 15% of the summarized studies. Lastly, the reasons causing the treeline change and the future research trends were discussed.

Research progress on invasion mechanisms of Pomacea canaliculata.

GUO Jing1, ZHANG Jia-en1,2,3**

2014, 33(3):  806-815. 

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Pomacea canaliculata, the only freshwater snail among the 100 worst invasive alien species listed by the World Conservation Union, has caused incalculable agricultural and ecological harms worldwide. Owing to its wide habitat adaptability, strong adverse resistance, high reproduction rate and abundant genetic diversity, P. canaliculata can establish wild populations rapidly in new habitats, especially in some dissimilation and fragmentation environments. Defense abilities of P. canaliculata to natural enemies, bacteria and parasites are other effective ways to maintain its survival and reproduction. Declining biodiversity caused by P. canaliculata invasion can generate a vicious circle and further enhance the invasive incidence. In this paper, invasion mechanisms of ecological tolerance, population genetic variation and reproductive growth, defense and competition capacity of P. canaliculata with native species, ecological vulnerability of invaded habitats were reviewed and summarized. Some relevant research perspectives were also put forward, with an attempt to provide basic information and references for prevention and controlling of P. canaliculata invasion.

Research progress in mycorrhizal molecular biology.

WANG Ju-gang1, ZHENG Rong1,2, BAI Shu-lan1**, GAO Xiao-min3, LIU Min1

2014, 33(3):  816-824. 

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With the rapid development of molecular biology, the molecular biological technologies have been applied widely in the field of mycorrhizal research. In this paper, the research progress in the mycorrhizal molecular biology was reviewed, including DNA barcode and genomic sequencing of mycorrhizal fungi, gene expression during the formation of mycorrhia, relevant protein expression changes in the process of mycorrhizal symbiosis’ nutrient uptake, the response of mycorrhizal aquaporins and SOD to stress conditions, as well as the limiting factors for development of mycorrhizal molecular biology. We proposed that more attention should be paid on screening appropriate model plant and mutant for mycorrhizal research, optimizing invitro culture technology for AM fungi and increasing the application of high-throughput sequencing technology in the future research.

 

Research progress on nectar compositions and their ecological functions.

QING Zhuo1, SU Rui1,2, DONG Kun1**, HE Shao-yu1

2014, 33(3):  825-836. 

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The nectar compositions and their ecological functions have become one of the most active and promising areas among the recent pollination biology studies. The nectar ecological functions represent the coupled ecological significance of all nectar compounds in the context of plant-pollinator interactions. Currently, the nectar compounds are considered to be a tradeoff consequence of selective pressures on plant evolution in attracting pollinators, deterring nectar robbers and protecting nectar from microbial infestation for enhancing plant reproductive fitness. In this paper, we presented a review of the recent advances in the studies of chemical compounds that have been found in nectar rest on their ecological functions. The ecological functions of nectar sugars, amino acids, proteins, inorganic ions, lipids, phenols, alkaloids, and terpenoids were respectively proposed here. We further summarized the origins of nectar components and their differences among plants and emphasized the importance of nectar chemical characteristics research in the studies of pollinator guilds and pollination syndrome. In addition, for future research, we suggested that 1) molecular and ecological methods should be combined to elucidate the molecular mechanism of nectar production and thus to reveal the ecological adaptation mechanisms underlying the plant regulation on nectar composition and 2) experiments at the scale of the community and high taxonomic levels should be carried out to study nectar constituents combined with functions, to compare the variation of the nectar components for co-flowering species and thus to explore the interactive relationships among plants and their specialist or generalized pollinator groups, and to illustrate the potential mechanism of nectar chemical composition effect on pollination networks in plant community.

Chemotaxis of plant parasitic nematodes: A review.

ZHENG Ya-nan1,2, YANG Zhong-qi1**, WANG Xiao-yi1, TANG Yan-long1, ZHANG Yan-long1

2014, 33(3):  837-842. 

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The sensilla of nematode are mainly arranged in anterior and end portions of the body. The main concentration of sensilla is at the anterior end of nematodes. Amphidial secretions are closely related to the nematode sensory perception. Chemotaxis plays an important role in foodfinding, matefinding, and other aspects of nematode interactions. Nematode chemotaxis contains the response to host plants, and sex pheromones attraction. Electrophysiological technology makes up for the limitations and disadvantages of agar plate behavioral bioassays, which provides a better method and technique for analyzing the response of nematodes to chemical stimulation. As chemotaxis plays an important role in activity and life history of plant parasitic nematodes, studies on chemotaxis offer references for developing novel and non-environmentally hazardous control methods. This review focuses on nematodes sensilla, chemoreception, electrophysiological technique and control potential.

Seagrass-herbivore interactions in seagrass seabed: A review.

WANG Feng1,2, ZHOU Yi1**

2014, 33(3):  843-848. 

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The interactions between seagrasses and herbivores are important factors influencing the structure and function of seagrass ecosystem. This paper reviewed the research advance of plantherbivore interactions in seagrass bed, focusing on the following several aspects: 1) the defense of seagrass to herbivores: resistance and tolerance; 2) the adaptation of herbivores to seagrass’s defense, such as compensation feeding; and 3) the positive interactions between seagrass and herbivores including: herbivores could regulate and control seagrass community composition, structure and the epiphytes growing on seagrass leaves, and increase seagrass’s tolerance to eutrophication; the seagrass bed could also provide shelters for herbivores. Some important aspects for further study on the seagrassherbivore relationship were suggested: the effects of nutritional quality and chemical defenses on the consumption patterns of diverse types of herbivores; the effects of herbivores on plant chemistry, morphology, reproductive biology and species composition, and the effects of both direct and indirect interactions among plants and herbivores. Strengthening the research on the seagrassherbivore interactions in seagrass bed will benefit us to further understand the seagrass ecosystem, which, therefore, could provide better ecosystem services.