Table of Content

10 April 2015, Volume 34 Issue 4

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Effects of strong wind-drift blowing on the growth and physiological properties of Pinus sylvestris var. mongolica seedlings.

ZHAO Ha-lin1**, LI Jin1, ZHOU Rui-lian2, YUN Jian-ying1, QU Hao1, PAN Cheng-chen1

2015, 34(4):  901-906. 

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In order to understand physiological and ecological responses of Pinus sylvestris var. mongolica seedlings to strong winddrift blowing, a winddrift blowing experiment with a 18 m·s^-1 wind speed and three wind blowing times (10, 20 and 30 min) was conducted in spring, 2013 in Horqin Sand Land of Inner Mongolia. The results showed that with the increase of wind-drift blowing time, the growth rate of plant height decreased, while that of stem diameter and crown width and the number of etiolated and fallen leaves increased. The height growth decreased by 52.6%, stem diameter growth, crown width growth and the number of etiolated leaves increased by 251.9%, 256.0% and 466.7%, respectively, in the 30 min treatment compared to the CK. With the increase of wind blowing time, relative water content (RWC) and superoxide dismutase (SOD) activity decreased, and malondialdehyde (MDA) contents, membrane permeability, peroxidase (POD) activity, soluble sugar and proline contents tended to increase. The RWC and SOD activities decreased by 4.1% and 1.9%, and MDA, membrane permeability, POD activity, soluble sugar and proline increased by 10.3%, 9.3%, 55.5%, 26.4% and 50.0%, respectively, in the 30 min treatment compared to the CK. The results suggested that strong wind-drift blowing could result in water stress, inhibition of height growth, etiolated and fallen leaves, increase of membrane lipid peroxidation and cell membrane damage. In order to adapt to the strong winddrift blowing, the seedlings speeded up the growth of the stem diameter and crown width, and increased POD activity and soluble sugar and proline contents to reduce the damage of cell membrane and maintain normal cell turgor.

 

Species composition and flora analysis of alien invasive plants in Changchun.

QU Tong-bao, MENG Fan-yong, WANG Yu**

2015, 34(4):  907-911. 

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In order to understand the distribution patterns and their influence factors of invasive plants, the species composition and flora of invasive plants in Changchun City were analyzed. A total of 85 species of alien invasive plants, which belong to 64 genera and 26 families, are identified and recorded in Changchun, with 4 harmful quarantine weeds among the invasive plants. Alien invasive species are mainly composed of Compositae, Amaranthaceae, Gramineae, Leguminosae and Solanaceae. Among them, Compositae has 18 species, occupying 21.18% of the total invasive species. Herbaceous plants have 81 species, occupies 95.29% of the total, indicating that herbaceous plants are more invasive than woody plants. Flora analysis showed that the floristic types of invasive plants in Changchun are mainly in the family of world distribution, and are in mainly the genus of world distribution, followed by the genera of North temperate and pantropic distributions. Accordingly, relevant measures and advice are made for preventing invasion of exotic plants in Changchun.

 

Characteristics of seed germination and seedling growth of Caragana korshinskii under different light intensities.

YAN Xing-fu1**, LIU Jian-li1, BEI Zhan-lin1, LIU Cun-de1, GAO Yong-feng2, WANG Rui-xia2

2015, 34(4):  912-918. 

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Under different light intensities \[55.4%, 18.9%, 5.5%, 2.2%, 0.5% of natural sunlight (NS)\] created by shading, we examined the effects of light intensity on the seed germination and seedling growth of Caragana korshinskii. The results showed that the maximums of germination percentage, germination rate, germination index and germination value of C. korshinskii seeds were all observed under the treatment of 18.9% NS and all these four parameters decreased with the decrease of light intensity. The reduction of light intensity resulted in the gradual increase of vigor index. Basal stem diameter, paripinnate number, taproot length and total dry mass of C. korshinskii seedlings all declined continuously or with fluctuation, while shoot height increased when the light density decreased gradually, indicating that lower light intensity not only affect the growth of basal stem diameter and the increase of paripinnate number but also restrict the elongation of taproot and the accumulation of dry matter of seedlings. Increase in specific leaf area of seedlings was detected with the weakness of light intensity. Root/shoot ratio, however, decreased with the decline of irradiance. In summary, our results suggested that seed germination of C. korshinskii was in part dependent on the light intensity, and shortterm water stress resulted from high light intensity could contribute to the inhibition of seed germination. The facilitation of high light intensity to the growth of seedlings suggested the adaptation of C. korshinskii to sufficient light resource of its natural distribution regions, and seedlings had great morphological plasticity across different light regimes.

Influence of simulated sand burial on recovery growth of Cynodon dactylon in lowwaterlevelfluctuating zone of the Three Gorges Reservoir.

LI Qiang**, DING Wu-quan, ZHU Qi-hong, SONG Li

2015, 34(4):  919-924. 

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To study influence of sand burial depths on the sprouting and growth of Cynodon dactylon in low-water-levelfluctuating zone of the Three Gorges Reservoir after flooding, C. dactylon was transplanted and buried by 10 cm and 20 cm depth sands, respectively. Results showed that 10cmdepth sand burial significantly inhibited the sprouting of C. dactylon, and its sprouting rate was reduced by 15.5%. On the contrary, 20cmdepth sand burial increased the sprouting rate by 75.9%. During the experiment, sprouted seedlings of 10cmdepth sand burial could penetrate the cover layer of the sands and formed ramets, but the seedlings of 20cmdepth sand burial couldn’t. For the former, stem length, stem width, internode number, total internode number, ratio of internode number to stem length, leaf length, leaf number, fresh weight, dry weight, ratio of dry weight to fresh weight were 19.2%, 8.2%, 45.4%, 16.8%, 42.7%, 7.2%, 4.0%, 19.1%, 35.3%, and 13.5% higher than those of the control, respectively. However, for the latter, stem length, internode number, fresh weight, dry weight, ratio of dry weight to fresh weight were 76.3%, 20.3%, 88.3%, 92.6%, and 36.7% lower than those of the control, respectively. Furthermore, under the 10cmdepth sand burial, total stem length of seedlings, total leaf number of seedlings, total fresh weight of seedlings, total dry weight of seedlings, ratio of total fresh weight of seedlings to total population fresh weight, ratio of total dry weight of seedlings to total population dry weight were 4.2%, 36.3%, 31.9%, 22.7%, 24.4%, and 12.4% lower than under the control, respectively. Under the 20cmdepth sand burial, total stem length, total fresh weight of seedlings, total dry weight of seedlings, ratio of total fresh weight of seedlings to total population fresh weight, ratio of total dry weight of seedlings to total population dry weight were 65.3%, 74.5%, 83.8%, 76.4%, and 86.7% lower than under the control, respectively. These results indicated that 10cmdepth sand burial could promote the elongation of stems and leaves and the formation of internodes and leaves of C. dactylon, reducing sand burial’s injury. However, 20cmdepth sand burial couldn’t make seedlings grow normally.

Effect of harvesting methods on branch modular population characteristics of the planted pharmaceutical raw material forest of Taxus yunnanensis.

BIAN Fang-yuan1, SU Lei2, SU Jian-rong1**, LIU Wan-de1, LI Shuai-feng1

2015, 34(4):  925-932. 

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An experiment was carried out to explore the effect of different harvest methods and harvest intensities on the branch modular population characteristics of sixyear old Taxus yunnanensis plantations, in Maguan County in Yunnan Province. There were three treatments (i.e., harvesting  trunks and their top branches, keeping the trunks but harvesting the top branches, and keeping the trunks but harvesting the bottom branches) and three levels (i.e., harvesting the 1/4 of the crown length, harvesting 2/4 of the crown length, and harvesting 3/4 of the crown length). The results showed that the branch growth increased with the increasing harvest intensity. The proportion of sprouting new shoots from old branches, the number of new shoots, shoot length and volume after harvesting 3/4 of crown length were significantly higher than those of the control. In addition, the new branch length and volume after harvesting the top crown branches were higher than those after harvesting the bottom crown branches. More branches, therefore, can grow out after harvesting the top crown branches and trunk because of removing the apical dominance. Our results indicated that harvesting the 3/4 of crown length and trunk was the optimal harvest option, which could make more branches to be harvested and keep the sustainable use of the Taxus yunnanensis forest.

 

Spatial distribution characteristics of photosynthetic photon flux density and air temperature in gaps at two different slope directions of secondary forest ecosystem in montane area of eastern Liaoning Province.

WANG Yi1,3, LIU Jiang1, ZHANG Jin-xin2,3, LI Xiu-fen1,3**, ZHU Cheng-yao1,3, ZHAO Tong-bin1, YUE Yuan1, ZHAN Shen-ye1

2015, 34(4):  933-940. 

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Aiming to determine the characteristics of gap disturbance in secondary forest ecosystem in a montane area of eastern Liaoning Province, the spatial distribution of photosynthetic photon flux density (PPFD) and air temperature in gaps at two different slope aspects were explored in this study. The selected gaps were formed after trees had been damaged by snow or wind. The results showed that the spatial distribution patterns of PPFD and air temperature were similar on the northeast and southeast slopes, but differing in values. Frorn 8:00—10：00, the highest PPFD existed in the west of gap center (169 μmol·m^-2·s^-1 on northeast slope, 350 μmol·m^-2·s^-1 on southeast slope) and it occurred in the north direction of gap center  (234 μmol·m^-2·s^-1 on northeast slope, 400 μmol·m^-2·s^-1 on southeast slope) between 11:00 and 14:00. However, from 14:00 to 16:00, the highest PPFD occurred in the east direction (74 μmol·m^-2·s^-1 on northeast slope, 56 μmol·m^-2·s^-1 on southeast slope) of the two gaps. There was a significant difference in PPFD between the two gaps at the two slope aspects during various periods (P<0.05). The average air temperature in the two gaps was higher at western points and lower at eastern points between 8:00 and 10:00, but was opposite between 14:00 and 16:00. From 11:00 to 13:00, the average air temperature at northern points was higher than at southern points. The air temperature in the gap of northeast slope was significantly lower than that of southeast slope between 8:00 and 10:00 (P<0.01) and between 11:00 and 13:00 (P<0.01), but significantly higher than that of southeast slope between 14:00 and 16:00 (P<0.01). The results indicated that the heterogeneity of PPFD and air temperature in gaps resulted from differences in slope aspects and positions, playing a critical role in forest regeneration and succession via affecting seed germination, seedling growth as well as species distribution.

Morphometric changes in branches, leaves and flower buds of Populus euphratica at different developmental stages.

LI Jia-hao, LIU Shuai-fei, LI Zhi-jun**

2015, 34(4):  941-946. 

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Field sampling and laboratory analysis were conducted to study the morphometric changes in branches, leaves and flower buds, along with the diameter at breast height (DBH) of Populus euphratica under the same site conditions. The results showed that with the increase of DBH, leaf index, shoot length, and the number of leaves on each branch decreased, while leaf area and perimeter, petiole length, diameter of branches, number of flower buds on each branch, flower bud length and diameter increased. Correlation analysis showed that DBH had very significant negative or positive correlations with the morphological and quantitative parameters of branches, leaves and flower buds as indicated above, suggesting a gradual phase changes as the trees grow. ANOVA analysis showed that the branches length and number of leaves on each branch had significantly reduced in 4th diameter level. The branch diameter and number of flower bud on each  branch,  flower bud length and width synchronization began to stepwise increase significantly in 10th diameter level. Meanwhile leaf index and petiole length also started to significant changes in 10th diameter. The number and morphology in branch, leaf and flower bud showed significant difference on stages, and  was closely related to phase change of P. euphratica.

Comparison analyses of DCA, CCA and DCCA on relationships between plant community distribution and soil properties of Horqin Sandy Land.

ZHOU Xin1,2**, ZUO Xiao-an1, ZHAO Xue-yong1, WANG Shao-kun2, LIU Chuan2, ZHANG Jing1,2, LU Peng1,2, ZHANG Jian-peng1,2

2015, 34(4):  947-954. 

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Based on the field investigation and laboratory analysis, we analyzed the relationship between plant community distribution and soil properties in four habitats (mobile dune, semifixed dune, fixed dune, and grassland) in Horqin Sandy Land. We also examined the effects of key soil factors on the distribution of 24 plant communities by using three different methods: detrended correspondence analysis (DCA), canonical correspondence analysis (CCA) and detrended canonical correspondence analysis (DCCA). The results showed that the first axes of DCA, CCA and DCCA presented the consistent soil gradient that was related to the soil carbon (C), nitrogen (N), pH, EC, bulk density, silt and clay content, accounting for 33% of total variance of the speciessoil properties relationship. The soil gradient mainly determined the changes of communities’ niche which further affected the distribution pattern of plant community. The second axes of three methods could not express environmental gradient ideally and the correlations with these second axes and soil properties differed greatly. Second axis of DCA only had a significant positive relationship with fine sand content, while the second axis of CCA had a negative relationship with soil C:N ratio and fine sand content. Second axis of DCCA positively correlated with soil C:N ratio and fine sand, but negatively correlated with coarse sand content. Shannon index and Simpson index had significant correlations with the first two axes of DCA, CCA and DCCA, respectively, and the explanation of regression models of Shannon index was better than that of Simpson index. The first two axes of CCA explained 58.6% of speciesenvironment relationship, which was higher than DCA and DCCA did. Our results indicate that CCA performs better in interpreting speciesenvironment relationships than the other two methods.

Sprouting characteristics of tree species in 15hm² plot of northern tropical karst seasonal rain forest in Nonggang, Guangxi, southern China.

GUO Yi-li, WANG Bin, XIANG Wu-sheng, DING Tao, LU Shu-hua, WEN Shu-jun, HUANG Fu-zhao, LI Dong-xing, LI Xian-kun**

2015, 34(4):  955-961. 

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Sprouting is a significant part in natural regeneration strategy, playing an important role in sustaining forest community stability. By using Torustranslation tests, we examined sprouting characteristics of woody plants in a fully mapped 15hm² plot in a northern tropical karst seasonal rain forest in Nonggang, Guangxi, southern China, analyzed the differences of sprouting ability among three habitat types (gully, hillside and ridge), and tested the relationship between sprouting ability and environmental factors. A total of 190 species showed sprouting ability, with 1831 individuals per hectare. The sprouting ability significantly differed among the three habitat types, being stronger in ridges but lower in hillsides. In addition, the habitat-associated sprouting ability was correlated to DBH (diameter at breast height) class of sprouts. Spearman’s correlation analyses with Torus-translation tests showed that the sprouting ability was significantly positively correlated with elevation, convex, slope, and cosine values of aspect, while significantly negatively correlated with the total cross-sectional area at breast height of all individuals in each quadrat. Our results revealed that sprouting regeneration was common in this karst seasonal rain forest, and there might be an association between the sprouting distribution pattern and environmental factors. However, long-term dynamic monitoring data would be necessary to reveal the underlying ecological processes and mechanisms of this sprouting pattern.

 

Effect analysis of water physiological integration of Indocalamus decorus based on antioxidant system.

HU Jun-jing1,2, CHEN Wei-jun1, GUO Zi-wu2**, CHEN Shuang-lin2, YANG Qing-ping2, LI Ying-chun2

2015, 34(4):  962-966. 

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To explore the occurrence condition, direction and intensity of water physiological integration in bamboo, an experiment with connected Indocalamus decorus clonal ramets under three water potential gradients of soil matrix (90%-60%, 60%-30%, 90%-30%) and three matrix relative water content (90%±5%, high water potential; 60%±5%, intermediate water potential; 30%±5%, low water potential) was conducted, and the activities of antioxidant enzymes and the contents of soluble protein and MDA were determined. The results showed that the contents of MDA and soluble protein and the activities of CAT and POD increased, while SOD activity decreased with the increase of treatment time. With the increase of water potential difference between I. decorus ramets, CAT and SOD activities and soluble protein content of ramets under the low water potential increased, while POD activity and MDA content decreased; but ramets under the high water potential had an opposite pattern. Antioxidant physiological indicators of ramets under the intermediate water potential had no significant differences during the treatment time. Our study indicated that water physiological integration existed in I. decorus clonal system under heterogeneous water environment and ramets needed first to guarantee its own water demand. Intense water transfer from high water potential ramets to low water potential ramets would take place when water surplus and deficit existed between ramets. The bigger the water potential difference of ramets, the stronger the intensity of physiological integration. Clonal ramets had “selfish” and “altruistic” behaviors on water physiological integration. This study provided a theoretical basis for artificial water supply of commercial bamboo forests.


 

Risk evaluation and regionalization of cold and freezing damage on guava introduction in Fujian Province.

CHEN Jia-jin1**, WANG Jia-yi1, HUANG Chuan-rong1, LIN Qi-ming2, WU Ting-jie1

2015, 34(4):  967-973. 

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Based on the disaster risk system analysis theory and disaster risk index method, the cold and freezing hazard, the vulnerability of riskbearing object, and the prevention capacity for cold and freezing damage of guava were analyzed by using the yearly meteorological data, planting areas, yield, and socioeconomic data in Fujian Province. The comprehensive risk evaluation index was calculated by using comprehensive weighted method, and the regionalization of cold and freezing damage was done in guava introduction regions by GIS. The results show that the regions of high hazard value of cold and freezing damage are distributed in Longyan City, the mountainous areas of western Zhangzhou and Quanzhou cities, northwestern Putian City, western Fuzhou City and the most areas of Ningde City. High vulnerability value of guava is distributed in Pinghe County. Low prevention capacity value of cold and freezing damage is distributed in some counties of eastern Fujian Province. The cold and freezing damage risk of guava introduction can be divided into four levels (mild, moderate, severe and violent) in Fujian Province by considering the comprehensive risk degree. The severe and violent risk regions are distributed in Longyan City, the mountainous areas of western Zhangzhou City, high elevation areas of Quanzhou and Putian cities, the inland mountainous areas of Fuzhou City, and the most areas of Ningde City.

 

Evapotranspiration process of cotton field under mulched drip irrigation of oasis in arid region.

MA Jin-long1, LIU Li-juan1, LI Xiao-yu1**, WANG Jin2, YANG Hui-jin1

2015, 34(4):  974-981. 

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Water resources are a major constraint on agricultural development in arid areas. In recent years, with the development of watersaving irrigation technology, the contradiction between supply and demand of water resources was alleviated and the irrigation area was expanded. Understanding the evapotranspiration process of cropland under nonfull irrigating has great scientific significance to reveal the water cycle process and guide watersaving practices. In this paper, based on eddy covariance data in 2012 from Wulanwusu Agrometeorological Experiment Station, the evapotranspiration process of cotton filed in the different growth stages under mulched drip irrigation in Manas River basin of Xinjiang were analyzed. Furthermore, the crop coefficients of cotton under mulched drip irrigation were calculated based on the estimated evapotranspiration of reference crop by FAO-56 Penman-Monteith equation. The results showed that evapotranspiration and its rate of cotton field under mulched drip irrigation in oasis peaked in the flowering stage, with the phasic evapotranspiration of 248.51 mm and average daily evapotranspiration rate of 3.94 mm·d^-1. Followed by the values in the budding stage, the phasic evapotranspiration was 98.34 mm, and the average daily evapotranspiration rate was 3.18 mm·d^-1. The minimum values occurred in the sowing and seeding stages, the phasic evapotranspiration was 10.70 mm, and the average daily evapotranspiration rate was 1.07 mm·d^-1. In summary, the amount of evapotranspiration was 487.14 mm during the whole growing period, and the average crop coefficient was 0.42. The results of evapotranspiration and crop coefficients of cotton at different stages provide a scientific basis not only for rating and timing of irrigation of cotton at different growth stages but also for field water management.

Harmful effect of salt dust on cotton leaves in Aibi Lake basin, Northwest China.

ZHANG Zhao-yong1,2, JILILI·Abuduwailil1**, JIANG Feng-qing1， LIU Dong-wei3

2015, 34(4):  982-990. 

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Using a field monitoring experiment, we analyzed the hazard effects of salt dust deposition on the photosynthetic characteristics, salt ion contents, and cell physiological functions of cotton leaves in Aibi Lake basin. The results showed that salt dust deposition led to increases in Na⁺, Cl^-, and SO₄^2- contents and a decrease in K⁺ content in cotton leaves, which influenced the absorption of nutrition elements by cotton leaves and made the leaves suffering from salt ion poisoning. Salt dust deposition significantly blocked the cotton leaf stomata and affected the photosynthetic indexes such as net photosynthetic rate, respiratory rate, light use efficiency, water use efficiency, transpiration, and the temperature of cotton leaves. Moreover, the salt dust deposition significantly increased the malondialdehyde content but decreased the chlorophyll and carotenoid contents in cotton leaves. Cotton leaves adjusted the loss of cell solvent by increasing the contents of the soluble sugar and proline and by increasing the activities of enzymes in antioxidant system to remove the harmful matters such as the reactive oxygen species, thereby reducing the damage caused by salt dust deposition and maintaining normal physiological functions of leaves.

Enhanced effects of exogenous nitric oxide on salt tolerance of Avena nuda L. seedlings.

LIU Jian-xin**, WANG Jin-cheng, WANG Rui-juan, JIA Hai-yan

2015, 34(4):  991-996. 

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A naked oat (Avena nuda L.) cultivar, ‘Dingyou No. 6’ was selected as material to investigate the effects of exogenous NO donor, sodium nitroprusside (SNP), on the growth, active oxygen metabolism and osmotic substances accumulation in leaves of naked oat seedlings under 100 mmol·L^-1 NaCl using nutrient solution cultivation. The results showed that 5 μmol·L^-1 SNP significantly alleviated the inhibitory effect of salt stress on the growth of naked oat seedlings. Besides, exogenous SNP not only significantly increased the activities of superoxide dismutase, peroxidase, ascorbate peroxidase, but also increased the contents of glutathione, ascorbic acid, soluble sugar, soluble protein and proline as well as the K⁺/Na⁺ ratio. Furthermore, SNP significantly decreased the contents of malondialdehyde, hydrogen peroxide, superoxide anion and free amino acid and catalase (CAT) activity in leaves of naked oat seedlings under NaCl stress. Exogenous NO could alleviate the oxidative damage and growth inhibition of naked oat seedlings under salt stress via improving antioxidant ability and osmotica accumulation as well as keeping balance between K⁺ and Na⁺ under NaCl stress, and consequently improve the salt tolerance of plants.

Effects of enhanced UV-B radiation on important physiological indices of leaves of foxtail millet (Setaria italica (L.) Beauv) under different nitrogen supplies.

FANG Xing1,2, ZHONG Zhang-cheng2**

2015, 34(4):  997-1003. 

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The aim of the present study is to investigate the responses of the contents of leaf chlorophyll, soluble substances and UV-B absorbing compounds of foxtail millet (Setaria italica (L.) Beauv.) at flowering stage to enhanced UV-B radiation treatment and whether the possible effect varied with nitrogen supply. The plants of foxtail millet were fertilized at two different nitrogen supply levels (1.88 and 15 mmol·L^-1) from the beginning of jointing stage and stressed by an enhanced UV-B radiation treatment (14.7 μW·cm^-2) from the beginning of heading stage. The results showed that chlorophyll content and soluble protein content decreased evidently, while UV-B absorbing compounds content increased in leaves of foxtail millet under the lower nitrogen supply level compared to the group under the higher nitrogen supply level during the treatment period, with or without enhanced UV-B radiation. Chlorophyll content from the beginning to middle of flowering stage and soluble protein content at the beginning of flowering stage in leaves of foxtail millet under the higher nitrogen supply level were more sensitive to the enhanced UV-B radiation treatment than under the lower nitrogen supply level. Leaf soluble sugar content was not sensitive to the enhanced UV-B radiation treatment, whereas it was significantly affected by nitrogen supply level from the middle to the end of flowering stage. The study indicated that the lower nitrogen supply level could improve the resistance of plants against UV-B radiation by promoting the accumulation of UV-B absorbing compounds in leaves of foxtail millet at flowering stage; however, a reasonable range of nitrogen supply level should be adopted to balance the requirements between reproductive growth and improvement of the resistance to UV-B radiation.

Effects of mulching in fallow period on soil moisture and yield components of dryland wheat.

ZHANG Jin-zhao, SUN Min, GAO Zhi-qiang**, DENG Yan, REN Ai-xia, YANG Zhen-ping, HAO Xing-yu, ZONG Yu-zheng

2015, 34(4):  1004-1012. 

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In order to explore the technology for soil water storage and yield improvement of dryland wheat by mulching, an experiment was carried out in Wenxi County, Shanxi Province from 2011 to 2012. The effects of mulching methods and time on water storage and yield formation of dryland wheat were studied through whole mulching, half mulching and no mulching at 30 and 60 days after wheat harvest. The results showed that the soil water storage from sowing stage to booting stage significantly increased by mulching. Especially, the soil water storage of 140-200 cm layer at sowing stage, 160-300 cm layer at wintering stage and turning green stage, 80-160 cm layer at elongation stage, 0-120 cm and 200-300 cm layers at booting stage increased obviously. The overall effect of whole mulching at 30 days after wheat harvest was best. The tiller number increased from wintering stage to booting stage, and dry matter significantly increased at mature stage. The ear number was significantly improved, with an increase of 3%-14%. Furthermore, the yield of wheat dramatically increased by 171-815 kg·hm^-2. The percentage of earbearing, economic coefficient, yield and its component factors with whole mulching were higher than those with half mulching, with a better effect for whole mulching at 30 days after wheat harvest. The results also showed that the soil water storage at sowing stage was closely related to ear number, grain number per spike and yield, especially for the deep water storage. Until the booting stage, the water storage of 200-300 cm layer was still closely associated with dry matter, ear number and yield. To sum up, early mulching during fallow period is beneficial to storing the rainfall, especially improving the water storage in deeper layers up to the depth of 300 cm; early mulching is also beneficial to building a reasonable community and enhancing the yield through improving the ear number, with a better effect for the whole mulching.

Effects of fungicide on interspecific competition between Flaveria bidentis and Amaranthus retroflexus in different planting densities.

LI Hui-yan1,2, CHEN Dong-qing1,2, WANG Hui1,2, YANG Dian-lin1,2, HUANGFU Chao-he1,2**

2015, 34(4):  1013-1018. 

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To examine the effects of AM fungi symbiosis on competition between Flaveria bidentis and native species, an interspecific competition experiment between F. bidentis and Amaranthus retroflexus was conducted with different planting proportions (1∶2, 1∶1, 2∶1) under the impact of fungicide. The results showed that F. bidentis is highly obligate mycotrophic, and the competition pattern depended on weather there was AM fungi symbioses. With the use of fungicide, the relative yield (RY) of F. bidentis was less than 1.0 regardless of its planting proportion, whereas that of A. retroflexus was above 1.0. Meanwhile, the relative yield total (RYT) of both species was less than 1.0 across all planting proportions. Thus, it was suggested that the F. bidentis and A. retroflexus might use the same resource and the latter was a stronger competitor. The symbiosis of AM fungi increased the content of nitrogen and phosphorus in F. bidentis plants by 1.1-1.6 times and 1.1-1.2 times, respectively. In conclusion, AM fungi symbiosis could benefit the invasion of F. bidentis by regulating the competition between invasive and native plants, possibly with potential fungalmediated chemical interaction. External environment might affect the symbiosis between F. bidentis and AM fungi, at the same time, mycohrrizal associations played significant roles in the invasion of F. bidentis by relieving the stress, such as interspecific competition.


 

Selectivity of Frankliniella occidentalis (Pergande) to six vegetables and chemical component changes of volatiles from infested vegetables.

GAO Hang, ZHI Jun-Jui**, ZHANG Jun, MOU Feng

2015, 34(4):  1019-1025. 

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To explore the host selectivity of western flower thrips (Frankliniella occidentalis, WFT) to vegetables and compare the differences among volatiles of healthy and WFTinfested host plants, the host selectivity of female thrips to six healthy and WFTinfested vegetables (cabbage, lettuce, cucumber, eggplant, celery, garlic) were determined by Y-tube olfactory, and volatiles were identified by SPME-GC/MS. Y-tube olfactory experiment results showed that the selective rate of WFT to WFTinfested garlic was only 23.3%, which indicated a significant negative response compared to clean air (P<0.01). However, when being offered a choice between other WFTinfested host odors and clean air, WFT didn’t show significant response to the odors of damaged host (P>0.05). There was no significant difference in WFT’s selectivity between healthy and WFTinfested plant of same host (P>0.05). Among pairings of WFTinfested plants, female thrips significantly preferred cabbage to celery and garlic (P<0.01), and the preference for lettuce over garlic was significant too (P<0.01). The difference between the preference to cucumber and garlic was significant (P<0.05). Compared with healthy hosts, the types of volatiles from WFTinfested plants were significantly increased, and the main changes were terpenoids and nitrides. For example, Npropylbenzamide, E-β-ocimene, (E,E)-α-farnesene were newly produced at relatively high levels in WFTinfested plants. No obvious changes in volatiles were found between healthy and WFTinfested celery and garlic, and the contents of β-myrcene and allyl disulfide were higher in celery. Our results indicated that volatiles had a great change after hosts were infested by thrips, which could provide a basis for further research on attractants and repellents.

Effects of mycorrhizal fungi on eggplant verticillium wilt and eggplant growth.

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

2015, 34(4):  1026-1030. 

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The effects of inoculating arbuscular mycorrhizae fungi (AMF) on the growth and verticillium wilt of eggplant were studied, with the possible mechanisms for induced disease resistance by AMF discussed. The results indicated that the AMF inoculation promoted the growth of eggplant plants. The disease incidence and disease severity index of eggplant plants inoculated by AMF were decreased significantly. In the combination of inoculation with AMF first and pathogen afterwards, the proline content and the relative electrical conductivity in eggplant leaf were lower, the root activity was higher, and POD, PPO and PAL activities were higher than those of inoculating pathogen alone. Our experiment confirmed that AMF had certain biocontrol effect on eggplant verticillium wilt. The resistance of plant against pathogen induced by AMF possibly resulted from improving plant nutritional status, thus activating the mechanism of plant disease resistance.


 

Comparison of energy budget and digestive tract morphology in Hwamei Garrulax canorus between winter and summer.

WU Meng-si, ZHAO Li-dan, WANG Run-mei, ZHENG Wei-hong, LIU Jin-song**

2015, 34(4):  1031-1037. 

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Seasonal changes in the energy requirements of birds affect their ability to obtain and digest food. Increased food intake, hypertrophy of the gastrointestinal tract and the consequent increased absorption of nutrients may be viewed as responses by wintering birds to physical and biotic seasonal habitats. In the present study, seasonal changes in body mass, gross energy intake (GEI), fecal energy (FE), digestible energy intake (DEI), as well as length and mass of the digestive tract, were measured in Hwamei (Garrulax canorus) caught in the wild in Wenzhou, Zhejiang. Fourteen Hwamei birds were captured in mist nets in July of 2013 and January of 2014. Body mass was determined immediately upon capture with an electronic balance. The caloric contents of the dried food and feces were then determined using an oxygen bomb calorimeter. GEI, FE, DEI and digestibility were calculated. The digestive tract (stomach, small intestine and rectum) of each bird was measured and weighed. The stomach, small intestine and rectum were rinsed with saline to remove all gut contents and reweighed. These organs were then dried at 60 ℃ to a constant mass. As predicted, GEI and DEI were significantly higher in winter than in summer. The wet and dry masses of the total digestive tract, stomach and small intestine were greater in winter than in summer, and the magnitude of these parameters in both seasons was positively correlated with GEI and DEI. It is suggested that Hwamei is able to increase GEI and DEI to compensate for the higher daily energy expenditure in winter. Hwamei shows physiological adjustment in digestive tract size in winter to cope with significant increases in energy intake.

 

Niche characteristics of moth community in Manghe National Nature Reserve.

HOU Qin-wen1, BAI Hai-yan1,2**, TIE Jun1,2

2015, 34(4):  1038-1045. 

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To evaluate the relationship between moth community and environmental resources in Manghe National Nature Reserve, Shanxi Province, the niche and composition of moth community from different habitats were analyzed by using Levins niche breadth and Pianka niche overlap indexes. The results indicated that the moth specimens collected in the Reserve belong to 24 families, among which Pyralidae, Noctuidae, Tortricoidae and Geometridae are the dominant groups. The breadth of temporal niche was higher than that of spatial niche for moths and the degree of niche overlap varied with different groups. The temporal niche overlap value (0.913) and spatial niche overlap value (0.852) of Geometridae and Pyralidae were higher than those of the other communities. The temporal niche overlap value (0.772) of Sphingidae and Notodontidae was relatively high, but the spatial niche overlap value (0.218) was low. Except that the coefficient of temporal niche similarity between Sphingidae and Lymantriidae (0.247) and the coefficients of spatial niche similarity between Sphingidae and Saturniidae (0.258) and between Notodontidae and Sphingidae (0.226) were low, the coefficients of niche similarity among other groups of moths were relatively high. These results suggested the intense niche competition among main moth groups in the Reserve.

Soil microbial biomass and enzyme activities in Pinus massoniana forest infected by pine wood nematode.

SHI Cui-e1,2, GAO Yang2, WANG Yu-long2, XU Xiao-niu3, HUANG Bo2**

2015, 34(4):  1046-1051. 

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Bursaphelenchus xylophilusinfected Pinus massoniana forest soils were employed to investigate the effects of different infection rates of P. massoniana by pine wood nematode on soil physicochemical properties, microbial biomass and enzyme activities. The results showed that the contents of total carbon (TC), total phosphorus (TP), total potassium (TK), dissolved organic carbon (DOC), ammonium nitrogen (AN), nitrate nitrogen (NN) and available phosphorus (AP), and soil water content (SWC) increased with the aggravation of B. xylophilus infection in the forest soils. However, pH values, the contents of calcium (Ca), magnesium (Mg) and dissolved organic nitrogen (DON), microbial biomass carbon (MBC) or microbial biomass nitrogen (MBN) significantly decreased. Meanwhile, soil sucrase (SA), urease (UA), cellulose (CEA), and phenol oxidase (POA) activities tended to decline, whereas soil acid phosphatase (APA) and protease (PRA) activities were significantly elevated with the deterioration of B. xylophilus infection in the soils. In addition, the UA, SA, CEA and POA activities were negatively correlated with the soil physicochemical indicator of SWC, AN, NN, DOC, TP, TK, AP or TC, but were positively correlated with the soil pH, DON, Mg or Ca content, respectively. The APA and PRA activities were positively correlated with the indicator of SWC, AN, NN, DOC or TK, but negatively with the DON, pH, Mg or Ca content, respectively. The MBC and MBN were negatively correlated with the APA or PRA activity, but positively with the SA, CEA or POA activity, respectively. It was suggested that the B. xylophilus infection caused the changes of soil physicochemical properties as well as soil microbial community, microbial biomass and enzyme activities, which may be used to assess the soil quality in B. xylophilusinfected P. massoniana forest soils.

Protozoan population distribution and its homogeneity in Shijiu Lake.

ZHENG Jin-xiu, CHI Shi-yun, LI Dan, ZHOU Lian-feng, HU Ju-xiang**

2015, 34(4):  1052-1059. 

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Shijiu Lake is located in the middle and lower reaches of the Yangtze River. It is one of the few freshwater lakes linking to the Yangtze River. A survey was carried out in Shijiu Lake and its tributaries in autumn (normal water season) and winter (dry season) in 2012 to explore the species composition and seasonal variation of the protozoa community. At the same time, similarity index was calculated to discuss the protozoa response to habitat homogeneity by comparing with adjacent Gucheng Lake. In total, 57 species of protozoa were collected, and the species number in dry season was less than in normal water season. The similarity indexes were in the grades Ⅰ-Ⅲ among different river sampling sites, namely, the protozoa structure was completely different or mildly similar. The similarity indexes among different lake sampling sites were in the grades ⅡⅣ, being very dissimilar to moderately similar. Species in rivers were very dissimilar in different seasons (0.050-0.267), while species in lake were mildly similar (0.250-0.375). That suggested that seasonal change of protozoan species in river was more obvious than in lake, and the heterogeneity of biological composition was also higher in river than in lake. Protozoa had a good response to water quality, and nitrogen and phosphorus nutrition played an important role in protozoa species composition and distribution. The comparison of Shijiu Lake with Gucheng Lake and other lakes in the middle and lower reaches of the Yangtze River showed that within a certain scale, habitat homogeneity would accelerate biological homogeneity with the increase of habitat scale. But beyond the landscape scale, the regional characteristics of protozoa would gradually emerge, even if habitat is in homogeneity, its biological composition may not be homogeneous. Besides, the biological similarity had a decreasing trend with the increase of distance.

Ecological distribution and its influencing factors of bacterioplankton in the typical tributaries of Three Gorges Reservoir.

WU Ya1, WANG Yu-chun2**, HU Ming-ming2, LIU De-fu3,4, HUANG Yu-ling2, LI Dun-hai5, CHEN Wen-zhong1, XU Tao1

2015, 34(4):  1060-1065. 

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The distribution of bacterioplankton in three typical tributaries (Zhuyi River, Meixi River and Caotang River) of Three Gorges Reservoir was investigated in summer of 2013. The correlation between the abundance of bacterioplankton and ecological factors was analyzed. The results showed that the abundances of bacterioplankton were significantly different in these rivers, ranging from 0.53×10⁵ to 10.55×10⁵ cells·mL^-1 with an average value of 2.71×10⁵ cells·mL^-1. The average abundance values were in order of Meixi River > Zhuyi River > Yangtze River > Caotang River. Vertical distribution of bacterioplankton biomass in three tributaries showed a similar change trend, being the highest in the surface water and the lowest on the bottom. The correlation analysis showed that DO, pH and chlorophyll-a had significant correlations with bacterioplankton abundance, indicating that these parameters are the main factors limiting the bacterioplankton abundance in this region. The waters surveyed were eutrophic according to bacterioplankton abundance.

 

Comparison of spring dominant zooplankton species in Chinese estuaries with different latitudes.

GAO Qian, XU Jia-yi, XU Zhao-li**, Chen Jia-jie

2015, 34(4):  1066-1071. 

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Based on the investigations in the Guanhe Estuary, Changjiang (Yangtze River) Estuary, Oujiang Estuary, Jiaojiang Estuary, Jiulongjiang Estuary and Beilun Estuary (covering 14 latitudes) in April or May of 2010 to 2012, the ecological features of dominant species of the zooplankton assembles in each estuary and underlying mechanisms were analyzed. The result indicated that Calanus sinicus was predominant in all the estuaries. Labidocera euchaeta was the dominant species in the Guhe, Changjiang and Jiaojiang estuaries. Sagitta crassa was the dominant species of Guanhe Estuary, and Tortanus vermiculus was only limited to the Changjiang Estuary. Both S. enflata and Penilia avirostris were the dominant species in the Beilun Estuary. The zooplankton communities of the estuaries were dominated by the warmtemperate species in spring. In addition, temperate species such as S. crassa was also the dominant species in the north (Guanhe Estuary). Warm water species including S. enflata and P. avirostris were the dominant species in the south (Beilun Estuary). All the dominant species are euryhaline.

Isolation, identification and grazing characteristics of a protozoan species Ocromonas sp.

YANG Xiao-jing, PENG Yu-fu, HUANG Xin, LIU Li**, FENG Yue, XIA Xue-shan

2015, 34(4):  1072-1077. 

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A protozoan with the algophagous capability was isolated from the water samples of Dianchi Lake. Based on the morphological and genetic characteristics, it was identified as Ochromonas sp. The main factors influencing the grazing properties of Ochromonas sp. including algae species, protozoa concentration, culture temperature, time, pH and phenol concentration were investigated. The results showed that Ochromonas sp. had a strong grazing capability on Microcystis wesenbergii. When Ochromonas sp. was cocultured with M. wesenbergii for 6 days, the removal rate of M. wesenbergii was above 90%. Meanwhile, the grazing effect was enhanced with the increase of the initial concentration of the protozoa, and the best grazing capability was found when the culture pH and temperature were 4-7 and 25-35 ℃, respectively. However, high concentration of phenol could inhibit and kill the Ochromonas sp. The Ochromonas sp. was easy to culture and it reproduced rapidly. Therefore, it could be applied to control the water bloom of M. wesenbergii.

 

Histopathology in gill, liver and kidney tissues of Nile tilapia (Oreochromis niloticus) exposed to “Mie fei ling”, a structurally specific drug.

MA Guang-ming1,2, GU Dang-en1，3, MU Xi-dong1，3, LUO du1，3, ZHU Yun-jie1,2, LUO J

2015, 34(4):  1078-1084. 

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An acute toxic experiment of “Mie fei ling” on Nile tilapia (body weight: 34.65±5.69 g) was conducted to study the histopathology changes in gill, liver and kidney tissues and the mechanism of specific poison effect on Nile tilapia was explained. Results showed that the 24, 48, 72 and 96 hLC₅₀ values of “Mie fei ling” on Nile tilapia were 0.148, 0.103, 0.048 and 0.032 mg·L^-1, respectively. Necrosis, desquamation, fusion, shortening and curling of secondary lamellae, and secretion of mucous cells were observed in gill tissues after exposed to “Mie fei ling”. Hepatic lesions in the fish exposed to “Mie fei ling” were characterized by hypertrophy of hepatocytes, vacuolar degeneration, nuclear pycnosis, congestion and cloudy degeneration of hepatocyte. Tubular degenerations and congestion were observed in the kidney tissues of fish after the exposure. The degree of tissue damage by “Mie fei ling” was in order of gill>liver>kidney. Therefore, the main cause of death of Nile tilapia exposed to “Mie fei ling” was likely due to its harm on tissues.

Effects of extreme temperatures on survival, food consumption, growth, and gonad traits of the sea urchin Glyptocidaris crenularis.

SUN Ping, CHANG Ya-qing**, ZHAO Chong, WEI Hang-jing

2015, 34(4):  1085-1090. 

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The effects of extreme temperatures on survival, food consumption, growth, and gonad traits of the sea uchins Glyptocidaris crenularis were studied. Two treatments and one control group were involved. The control group was set at 19-23 ℃, and 30 ℃ and -2 ℃ were set as the two extreme temperature levels. Each group had three replicates, with each replicate consisting of 60 individuals. The experiment duration was 56 days. The results showed that the mortality rate of G. crenularis reached 100% within 2 days when G. crenularis were exposed to 30 ℃. The average food consumption (5.19±1.31 g·ind^-1) of G. crenularis at 30 ℃ was significantly lower than that in the control group (15.15±1.58 g·ind^-1) (P<0.01). No significant difference was found for the survival rate of G. crenularis between the low temperature and the control groups (P>0.05), although the food consumption (0.18±0.04 g·ind^-1) of G. crenularis at -2 ℃ was significantly lower than that in the control group (10.90±0.33 g·ind^-1) (P<0.01). The average body weight of G. crenularis in the low temperature group was significantly lower than that in the control group after 56 days. Wet lantern weight, lantern index, wet shell weight, wet gonad weight, dry shell weigh and shell index of individuals in the low temperature group were all significantly lower than those in the control group (P<0.01). Dry gonad weight and dry lantern weight were significantly lower than those in the control group (P<0.05). However, no significant difference was found in gonad index (P>0.05). Maximum pressure endurance of G. crenularis shell was significantly different between the low temperature and the control groups (P<0.01). These findings indicate that G. crenularis can not survive at extreme high temperature (30 ℃); at the extreme low temperature (-2 ℃), most of G. crenularis can survive during the experiment, while food consumption, growth and gonad weight are significantly reduced.

Spatial pattern and impact factors of soil fertility in West Lake Scenic Area.

AN Kang1, XIE Xiao-ping1**, ZHANG Hai-zhen2, ZHOU Hong2

2015, 34(4):  1091-1096. 

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Soil fertility comprehensively reflects soil properties and is the most sensitive dynamic indicator for integrated soil conditions. The spatial pattern of soil fertility may be impacted by different factors at different spatial scales. The spatial pattern and its impacting factors of soil fertility in West Lake Scenic Area were studied by grid sampling and the modified Nemerow formula was applied to quantitatively calculate soil fertility. The results showed that acidic soils (pH<6.5) dominated in West Lake Scenic Area. The average contents of soil organic matter and available P were at the 1st level of the soil nutrient classification standard in the second national general survey of China, while the average soil total N reached the 2nd level. Spatially, the integrated soil fertility in the north and south parts of West Lake Scenic Area was higher than in the northwest and southwest parts. Land use types, vegetation types and ecosystem types had significant effects on the spatial distribution of soil fertility. The soil integrated fertility index ranked in terms of land use types, vegetation types and ecosystem types, respectively as follows: residential area > traffic area > agricultural land > scenic greening space > mountain forest land, Quercus serrata var. brevipetiolata > Osmanthus fragrans > Cinnamomum camphora > Camellia sinensis > Phyllostachys edulis > Cyclobalanopsis glauca > Staphylea forrestii > Schima superba, and lawn > evergreen broadleaved forest > evergreen mixed forest. As a whole, greening landscape had higher soil fertility than agricultural soil and natural soil.

Land-use dynamic change  of Jinchang City in the last 28 years and simulation prediction.

LI Li, LIU Pu-xing**, YAO Yu-long

2015, 34(4):  1097-1104. 

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Based on the fourperiod remote sensing images of Landsat TM/ETM⁺ and Landsat-8 TIRS in 1987, 1999, 2006 and 2014, combined with RS and GIS technology, the landuse vector data were obtained. Additionally, the CAMarkov model was employed to simulate the spatial pattern and development tendency of the land use in Jinchang City with IDRISI Selva 17.0 software. The results showed that the builtup land, forest land and cropland presented an increasing trend over the past 28 years in the study area. The built-up land was increased prominently by 96.98%, and mainly located in towns, industrymining sites and the areas neighboring traffic lines, which were influenced intensively by human activities. However, the unused land, grassland and waterbody showed a decreasing trend, and the unused land and grassland decreased by 5.13% and 4.32%, respectively. The most significant conversions were found from the unused land to built-up land, grassland to unused land, and waterbody to unused land. In the next 16 years, the landuse change in Jinchang would roughly keep its previous trends, but the change amplitude would increase. The area of built-up land, forest land, cropland and waterbody would increase, while that of the unused land would decrease and would be highly developed. The area of grassland would decrease and the degradation would be obvious. Therefore, it is particularly important to protect the grassland for ecological environment and windbreak and sand fixation.


 

Health status and influencing factors of coral reef ecosystems in Houhai waters, Sanya, Hainan Province.

LI Yuan-chao1, YANG Yi1, ZHENG Xin-qing2**, CHEN Shi-quan1

2015, 34(4):  1105-1112. 

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Several parameters including species biodiversity, coverage, diseases, and recruitment of corals were investigated in Houhai waters, Sanya, Hainan, by the manta tow and line intercept transect methods to assess the health status of coral reef ecosystems, and the main factors affecting the health status of coral reef ecosystems were analyzed. The results showed that there were 54 species of scleractinia corals in Houhai waters and the mean coverage of corals reached more than 50%. Few coral diseases and low mortality were observed. The recruitment of corals was very high, up to 4.5 ind·m^-2. The condition index of coral reef ecosystems ranged from 1.75 to 2.27, indicating that the coral reef ecosystems in Houhai waters were in a healthy status. Analysis showed that seagrass bed and seaweed in the shallow area, abundant grazers and the upwelling in summer should be mainly responsible for the healthy status of coral reef ecosystems. Massive seagrass and seaweed distributed in shallow water can absorb the landsourced nutrients and stop the eutrophic water directly into coral reefs in Houhai waters. Abundant grazers such as Diadema setosum mediate the competitive interaction between reefbuilding corals and seaweeds, preventing the seaweed from threatening the growth of corals and preempting the space for coral settlements. The existence of the upwelling in summer maintains the suitable water temperature in Houhai water in summer, avoiding the coral bleaching. Accordingly, the interactions of multiple factors ensure the health of the coral reef ecosystem in Houhai waters.

Final ecosystem services valuation of Bosten Lake.

JIANG Bo, CHEN Yuan-yuan, RAO En-ming, ZHANG Lu, OUYANG Zhi-yun**

2015, 34(4):  1113-1120. 

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As the biggest inland freshwater lake in China, Bosten Lake provides important ecosystem services to the arid area that is poor in water resources. Ecosystem services valuation of Bosten Lake can reveal the direct contribution of Bosten Lake to human welfare using visible economic data, thus creating economic incentives (e.g. ecological compensation) to protect Bosten Lake. In this paper, we established the final ecosystem services valuation system based on the interactions between regional water resources and socioeconomic conditions. We then evaluated the ecological economic value from nine final ecosystem services provided by Bosten Lake in 2012 using market price method, replacement cost method, individual travel cost method, and contingent valuation method. The total estimated value of the ecosystem services from Bosten Lake was 91.89×10⁸ Yuan RMB in 2012, among which the values of runoff regulation, and recreation and tourism were 77.60×10⁸ and 8.44×10⁸ Yuan, respectively, accounting for 93.63% of the total value evaluated. According to the valuation, the nine final ecosystem services were ranked in a descending order as: runoff regulation, recreation and tourism, oxygen release, raw material products, carbon sequestration, aquatic products, non-use value, water resources provision, and water purification. The evaluation results reflect the multiple contributions of Bosten Lake to the sustainability of regional socioeconomic development, which will help increase awareness on the multiple ecosystem services from Bosten Lake, and inform managers on creating ecological compensation mechanisms. The evaluation methods and evaluation parameters in this study will also provide guidance to establish monitoring programs to study the influence of alternative ways of water resources allocation on human wellbeing, and provide important directions on coordinating multiple contradictories among ecology, economy, and society in the processes of water resources development.

Water quality and water environmental capacity for the small subsidence lakes in the Huainan and Huaibei coal mine areas, Anhui Province.

ZHANG Lei, YI Qi-tao**, LI Hui, XU Xin, WANG Xiao-meng

2015, 34(4):  1121-1128. 

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Underground mining activities have resulted in largescale land subsidence and submergence in the Huainan and Huaibei coal mine areas, Anhui Province. As a result, it produces landscapes of many small lakes in the coal mine areas. At present, the characteristics of water quality in this type of lakes are not clear, which is urgent for their scientific planning and management. Six lakes, among which three are in the Huainan mining areas (HNPJ, HNXQ and HNGQ) and three in the Huaibei mining areas (HBDH, HBZH and HBNH), were selected as research areas. Different evaluation methods for water quality were employed to determine the water quality goals and functions of such type of lakes based on field monitoring data. Then a mixing model was chosen for calculation of water environmental capacity of each lake. The results showed that the lakes in the Huainan mining area can be classified as the Grade Ⅲ according to the national water quality criteria, while HBZH and HBNH mainly belong to the Grade Ⅱ. In order to maintain the water quality to meet the Grade Ⅲ criteria, the lakes in the Huainan mining area requires nitrogen control by cutting down 8.3 and 37.4 t·a^-1 of TN for HNPJ and HNXQ, respectively. COD is a major concern for the Huaibei mining area, and reductions of 25.8 and 87.7 t·a^-1 of COD from HBDH and HBZH are necessary to achieve the water quality goals of Grade Ⅳ and Grade Ⅲ, respectively.

 

Assessment on traffic ecological footprint of typical megalopolises in China.

WANG Zhong-hang1, ZHOU Chuan-bin1**, WANG Ru-song1, LIN Ya-feng2, SUN Xiao1

2015, 34(4):  1129-1135. 

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The rapid urbanization in China has caused a series of urban ecological problems, including surge in the number of motor vehicles, traffic congestion, worsening of traffic
pollutant emissions and energy consumption. Ecological footprint can be used as an effective indicator to measure the pressure of ecological environment brought by the development of urban transports. In this article, six megacities including Beijing, Shanghai, Tianjin, Hangzhou, Shenyang and Chengdu were chosen as the study objects, and the ecological footprints of urban transports in the six megacities were calculated from 2005 to 2012. The results showed that ecological footprints of urban transports in the six megacities were all increasing, and the pressure of urban transportation on ecological environment was also increasing every year. The indirect ecological footprint of fossil energy played a major role in the growing ecological footprint of urban traffic. The rapid growth of motor vehicles and cars and their high using times led to the continuous increase of energy consumption, which was the main reason for the growth of urban traffic ecological footprint. Improved development of green travel on rail transportation and slow traffic can effectively reduce the number of selfdriving travels in megacities, optimize the traffic travel structure, and ease the ecoenvironment pressure of urban traffic.

Distribution and transfer of heavy metals in the mangrove wetland of Quanzhou Bay estuary.

LIU Bing-xing, YU Rui-lian**, HU Gong-ren, ZHANG Li-ling

2015, 34(4):  1136-1142. 

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The distribution, enrichment and migration characteristics of heavy metals in the mangroves of Aegiceras corniculatum and Kandelia candel collected from the mangrove wetland in Quanzhou Bay estuary were studied by means of determining the contents of acid extractable heavy metals in rhizosphere sediments and different parts of mangrove. The acid extractable contents of heavy metals in the rhizosphere sediments of both mangrove plants showed a sequence of Fe > Mn > Zn > Pb > Cu > Cr > Ni. In K. candel rhizosphere sediments, Cu, Zn, Pb, Ni and Cr presented positive correlation to each other. In A. corniculatum sediments, Cu and Zn showed a positive correlation, while Pb had no significant correlation to other metals. Most heavy metals in the roots of both mangrove plants showed positive correlations to their acid extractable contents in the rhizosphere sediments, while the heavy metals in the branches had no significant correlations to their acid extractable contents in the sediments. The enrichment capabilities of the two mangrove plants showed the same trend that Mn was the highest, followed by Cu and Zn. For both plants, Mn, Cu, Zn and Cr were mainly concentrated in leaves, while Pb, Fe and Ni mainly concentrated in roots. Mn showed the highest transfer ability from root to leaf in both plants.

A review on the research perspectives and methods for grassland vegetation biomass dynamics.

ZHANG Cai-qin1**, ZHANG Jun1, LI Xi-ruo2

2015, 34(4):  1143-1151. 

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Grassland biomass dynamics is a comprehensive reflection of community structure and function, and also an important research direction of ecology. The main interference factors that affect the grassland biomass dynamics were described and the relationships between the individual and population dynamics from qualitative and quantitative respects were demonstrated in this paper. The new concepts of composite biomass and composite growth dynamics based on the measurement indicators and estimation methods were given here, which may explain the influencing mechanism of the composite biomass dynamics for community productivity and stability. The research efforts on the interference effects of environmental factors on biomass dynamics and vegetation stability should be strengthened. In terms of major limiting factors or interference forms faced by specific communities, the research should cover the inner biological and ecological changes of the communities. The state variables studied should consider the comprehensive effects of multiple variables such as biomass and height. Revealing population and community biomass dynamic changes and their relationship with environmental factors at the individual level contributes to understanding the influencing mechanisms of environmental disturbances for plant community dynamics and stability, and thus providing a theoretical basis for the maintenance of grassland productivity.

A review on vegetation restoration of opencast coal mine areas in northern China.

YANG Qin-xue1, ZHAO Bing-qing2, GUO Dong-gang2**

2015, 34(4):  1152-1157. 

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Coal mining has destroyed the original natural attributes of land, leading to a series of ecological and environmental problems and forming a large number of abandoned mining lands. Restoring the damaged soil and vegetation is the key to the ecological reclamation of abandoned mining lands. Based on the relevant research results at home and abroad, we review the current research progress of vegetation restoration and existing problems in opencast coal mine areas in northern China. We then point out that longterm field monitoring and in situ research of soilvegetation systems are the important part of the future research, aiming to provide a scientific basis for reasonable management of opencast coal mine areas.

Research progress on effects of straw returning on soil potassium and its substitute for potassium fertilizer.

JIANG Chao-qiang1, ZHENG Qing-song2, ZU Chao-long1**

2015, 34(4):  1158-1165. 

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Crop residue is an important organic resource, and its reasonable and effective use is getting more and more attention. Straw returning can not only increase crop yield, enhance soil organic carbon content, enrich soil fertility, but can also improve nutrient cycling and utilization, alleviate soil acidification, and reduce the application of chemical fertilizer. Nowadays, with better understanding of highly efficient utilization of resource, studies on the effects of straw returning on soil potassium in China and at abroad have made plentiful and substantial achievements. This review paper summarized recent researches on effects of straw returning on potassium mainly from three aspects including soil potassium, crop yield, and the equivalence between straw potassium and chemical potassium fertilizer. The findings are as follows: returning straw could increase the available potassium in soil by the release of potassium from the straw, especially at the early stage of decomposition while long-term straw returning might also promote the release of mineral potassium. Effective straw returning not only provides plenty of nitrogen, phosphorus and potassium for the soil, but also improves soil microbial conditions by supplying abundant carbon, and thus increases crop yield. The return rate of straw in China was currently less than 1/3, which was much less than that in Europe and America. There is still great potential to enhance the return rate of straw in China, which will gradually improve soil potassium and alleviate the contradiction of the lack of potassium resources in China. In order to enhance the return rate of straw residue and promote the circulation of potassium between the soil and crop, more researches should be focused on the reasonable incorporation of the straw returning with chemical potassium fertilizer, and the affecting mechanism of straw returning on soil potassium in both shortterm experiment and long-term monitoring.

A comprehensive review of warming experiments of grassland ecosystem in China.

QUAN Guo-ling, SHANG Zhan-huan**

2015, 34(4):  1166-1173. 

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The influence of global warming on terrestrial ecosystems has been one of the hot topics of scientific research in recent years. Grassland ecosystem is one of the most important terrestrial ecosystems and the research on responses of grassland ecosystems to global warming is particularly important. In this paper, the development of warming experiments in terrestrial ecosystems and its application in grassland ecosystems in China were discussed through reviewing the research findings in recent 10 years. Then the effects of global warming on subalpine meadow, alpine meadow, Leymus chinensis meadow and desert grassland in China were analyzed in respects of plant species and community, soil, ecological function and animals. The results showed that shortterm warming would benefit the growth of gramineous plants in meadows, while the importance of warming on plant biomass varied with the stage of plant growth. Warming would change the whole phenology of the plants and significantly reduce the soil moisture of L. chinensis meadow. Moderate climate warming could increase soil microbial biomass carbon and nitrogen and enhance the recycling of soil carbon and phosphorus in alpine meadow. Based on the discussions, several scientific issues for future research were put forward.

A review of diversity of freshwater picophytoplankton and its related research methods.

LI Sheng-nan1,2, ZHOU Jian1,2, WEI Li-jun1,2, KONG Fan-xiang1, SHI Xiao-li1**

2015, 34(4):  1174-1182. 

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Picophytoplanktons are distributed worldwide and are ubiquitous in all types of oceans and lakes. They are a fundamental component of aquatic ecosystems, especially in the microbial loop. Previous researches were mainly focused on marine picophytoplankton since their discovery in the 1970s, and only recently freshwater picophytoplankton has been received wide attention. Synechococcus and eukaryotic picophytoplankton are the main component of freshwater picophytoplankton discovered to date, while Prochlorococcus which is widespread in marine is rarely found in freshwater habitats. The eukaryotic component of picophytoplankton is of great diversity which comprises clusters from almost all algal phyla. However, Synechococcus found in lakes in China are mainly composed of phycocyaninrich cells. The abiotic and biotic factors affecting their diversity include nutrients, temperature, light and predation, and picophytoplankton in natural waters could be affected by multiple factors at the same time. Traditional methods including microscopy observation and pure culture techniques hampered the progress of picophytoplankton study, due to its tiny cell size, insufficient distinct morphological features for taxonomic discrimination and being unculturable for most picophytoplankton species. Major advances in picophytoplankton ecology and taxonomy benefited from the introduction of new techniques, including epifluorescence microscopy, flow cytometry and molecular biology techniques. In this paper, we presented the species of freshwater picophytoplankton described to date, and discussed how they are affected by abiotic and biotic factors. In the end, we focused on the techniques recently used in picophytoplankton research.

Comparison of four methods for extracting microbial DNA from mouse intestine.

WU Min-na**, WU Ya-qi, QU Yan, WEI Ji-dong， ZHONG Gen-shen

2015, 34(4):  1183-1188. 

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The total microbial DNA of mice feces was extracted by GITC (guandine thiocyanate) method, CTAB (hexadecyl trimethyl ammonium bromide) method, Tiangen and Omega fecal DNA extraction kits. The yield and purity of the extracted DNA were determined by spectrophotometer of NanoDrop 2000. The results showed that the DNA extracted by the commercial DNA extraction kits was of the highest purity but of lowest yield, while the DNA with highest yield and lowest purity was obtained by CTAB method. The DNA extracted from mice feces by using GITC method showed higher purity than that retrieved from CTAB method, and higher yield than that extracted by commercial DNA extraction kits. The bacterial richness and diversity were further compared among the four methods by using 16S rDNA-PCR-DGGE fingerprinting method. Results revealed that significantly higher bacterial richness and diversity were observed in the community extracted from GITC method than that from the other three methods. In conclusion, the GITC method developed in our lab had some advantages as a fecal DNA extraction protocol, with higher DNA quality and quantity, specifically, higher richness and diversity of intestinal microbiota, compared with CTAB method, Tiangen and Omega fecal DNA extraction kits.