Table of Content

10 January 2009, Volume 28 Issue 01

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Articles

Dynamic characteristics of litterfalls in four forest types of Changbai Mountains, China.

LIU Ying^1,2;HAN Shi-jie²;LIN Lu¹

2009, 28(01):  7-11 . 

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By the method of litterfall trap, and from May 2003 to September 2004, an investigation was made on the dynamic charcteristics of the litterfalls in four typical forests along a vertical vegetation zone on the north slope of Changbai Mountains. In the meanwhile, the annual nutrient return of the litterfalls was calculated through nutrient content anlysis. The results showed that different forest types in Changbai Mountains had differnt litter-falling rhythm and different litter composition. Though the seasonal pattern of the litter-falling rhythm was of one-peak, the peak values for the forests appeared at different periods of time. The annual litter-falling amount and the litter composition differed obviously among different forest types and among different periods of time in the same forest type. Broadleaved Korean pine forest had the largest annual litter-falling amount (about 490 g·m^-2), followed by Korean pine-spruce fir forest, Betula ermanii-spruce fir forest, and B. ermanii forest. There was a significant negative correlation between annual litter-falling amount and altitude. The amount of nutrient return from the litterfalls in the four forests was C>ash>N>K>P, and the total amount of the nutrient return was decreased with increasing altitude.

Effects of shading on the photosynthesis and chlorophyll content of Bidens pilosa.

YE Zi-piao¹;ZHAO Ze-hai²

2009, 28(01):  19-22 . 

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A pot experiment was conducted to study the effects of shading on the photosynthetic parameters of Bidens pilosa. The results showed that shading increased the content of chlorophyll a+b, but had less effect on the ratio of chlorophyll a/b. Under high light, the maximum net photosynthetic rate and saturation irradiance of B. pilosa were 3.79 times and 2.71 times of those under shading, respectively. The initial slope of light-response curve of B.pilosa was larger under shading than under high light, while the apparent quantum yield was in adverse. The net photosynthetic rate of B. pilosa under shading was higher than that under high light when the irradiance was below 100 μmol·m^-2·s^-1, and decreased with increasing irradiance when the irradiance was above 650 μmol·m^-2·s^-1. Under high light, the net photosynthetic rate decreased with increasing irradiance only when the irradiance was about 1780 μmol·m^-2·s^-1. It was suggested that shading was an important limiting factor for the growth of B. pilosa.

Effects of nitrogen fertilization on fine root biomass and morphology of Fraxinus mandshurica and Larix gmelinii: A study with in-growth core approach.

LIU Jin-liang¹; MEI Li²; GU Jia-cun¹; QUAN Xian-kui¹; WANG Zheng-quan¹

2009, 28(01):  1-6 . 

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Fine root biomass plays an important role in the carbon cycling of forest ecosystem, and fine root morphology (e.g., diameter, length, and specific length) is one of the main factors affecting fine root absorbing function. However, fine root biomass and morphology are generally controlled by soil resource availability. In 2003 and 2004, by using in-growth core approach, different order fine root samples were collected from the 17 year-old Fraxinus mandshurica and Larix gmelinii plantations at the Maoershan Experiment Station of Northeast Forestry University, and the effects of nitrogen (N) fertilization on the fine root biomass, morphology, and N content of the two tree species were studied. The results showed that N fertilization had significant (P<0.05) negative effects on the biomass of the 1st-3rd order roots of F. mandshurica and L. gmelinii, the diameter of the 2nd-4th order roots of F. mandshurica and the 3rd order roots of L. gmelinii, and the specific root length of the 1st-4th order roots of F. mandshurica and the 1st order roots of L.gmelinii, but had no significant effects on root length. N fertilization only increased the N content of the 1st-2nd order roots of F. mandshurica significantly (P<0.05). It was suggested that the fine root biomass, morphology, and N content of test tree species were correlated with soil resource availability, but the responses of the two species to N fertilization were differed.

Effects of elevated temperature on reproductive phenology and growth of Allium xichuanense and Anemone rivularis in timberline ecotone.

LI Xiao-yan^1,2;ZHANG Yuan-bin¹;PAN Kai-wen¹;SUN Cheng-ren²;WANG Kai-yun³;Wang Jin-chuang¹;QI Dong-ming²

2009, 28(01):  12-18 . 

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By using open-top chamber (OTC), the short-term effects of simulated warming on the reproductive phenology and growth of two perennial herbaceous species Allium xichuanense and Anemone rivularis in subalpine timberline ecotone of Western Sichuan were investigated. The results showed that warming made the dates of initial flowering, maximum flowering, and bud- shooting advanced obviously, and prolonged the duration of flowering and increased the blossoming rate. Warming also advanced the fruit phenology of A. rivularis and promoted the growth of A. xichuanense and A.rivularis. However, no significant effects were observed on the plant height and organ biomass by the end of growth season. It is suggested that A.xichuanense and A. rivularis had stronger plasticity in response to simulated warming, and could easily adapt to the intending global warming.

Roles of urban lawn system in controlling rainfall-induced runoff nitrogen pollution.

SUN Shu-ming^1,2;SHAN Bao-qing¹;PENG Wan-jiang³

2009, 28(01):  23-26 . 

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To control the rainfall-induced runoff pollution in the urban sightseeing areas of Wuhan, a lawn system was constructed in the Deer Yard of Wuhan Zoo. In this paper, the roles of the lawn system in controlling rainfall-induced runoff nitrogen pollution and in reserving rainfall nitrogen were studied. The results showed that the concentrations of total nitrogen (TN), total dissolved nitrogen (DN), and ammonium nitrogen (NH₄⁺-N) in pretreated rainfall-induced runoff decreased by 16.0%, 13.9%, and 75.6%, respectively. The retention rates of influent nitrogen by the lawn system were >90% of NH₄⁺-N, >65% of TN and DN, and> 5% of nitrate nitrogen (NO₃^--N). Hydraulic loading rate affected the effluent TN concentration and its removal rate significantly. When the influent TN concentration was nearly the same while hydraulic loading rate increased from 3.3 to 8.3 cm·d^-1, the removal rate of TN decreased from 28.0% to 19.8%. Lawn width also affected the concentrations of effluent N pollutants. With the increase of lawn width, the effluent NH₄⁺-N concentration decreased, while NO₃^--N concentration increased. The DN concentration was the lowest at 10 m of lawn width. At the meantime of purifying rainfall-induced runoff, lawn system increased the nutrients re-use and rainwater recycling, and saved the cost of lawn maintenance.

Simulation of Beta vulgaris climatic productivity and its planting climatic zoning in Heilongjiang Province.

GAO Yong-gang¹;NAN Rui²;GU Hong¹;YU Ying-nan¹;WANG Ping¹

2009, 28(01):  27-31 . 

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By using the 1975-2004 day-by-day observation data from 81 meteorological stations in Heilongjiang Province and the corresponding interpolated grids data, and based on WOFOST model, the climatic productivity of Beta vulgaris was simulated. The spatial characteristics of this productivity and the climatic affecting factors were analyzed. The results showed that the climatic productivity of early and mid mature varieties of B. vulgaris was increased from north to south in the central and east parts and decreased from north to south in the west part of the Province, while the climatic productivity of late mature variety was increased from north to south in the central-east and east parts, decreased from north to south in the west part, and was at middle level in the central-west part of the Province. The spatial distribution of the chief climatic factors had important effects on the climatic productivity of B.vulgaris. Taking the climatic productivity anomaly percent, variation coefficient of actual yield, and four climatic factors (average air temperature at branch and leaf exuberating phase, average air temperature at sugar accumulating phase, rainfall at root expanding phase, and daily air temperature difference between maximum and minimum at sugar accumulating phase) in the major growth phases closely related with climatic productivity as the parameters, and using dynamic clustering analysis, the possible planting areas of early, mid, and late mature varieties of B. vulgaris in Heilongjiang Province were zoned into 8, 7, and 6 planting climatic areas, respectively.

Roles of birds in seed dispersal of Phoebe hunanensis in Spirit Valley forest of Nanjing.

LI Xin-hua;DONG Yi-xiao;XU Shi-qing;HUANG Bei

2009, 28(01):  32-37 . 

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From September 2003 to November 2005, an investigation on the seed ingestion and dispersal of Phoebe hunanensis by birds was conducted in the Spirit Valley forest at the southern foot of Zhongshan Mountain of Nanjing, Jiangsu Province, East China. Five resident bird species Turdus merula, Garrulax perspicillatus, G. pectoralis, Urocissa erythrorhyncha, and Cyanopica cyana were observed to frequently ingest the fleshy drupes in P. hunanensis crown, and to help the seed dispersal by rejecting the drupes stone after ingestion. The germination of P. hunanensis seeds was not affected after the ingestion by birds, but the seedlings emergence rate of the rejected seeds was higher. The birds could disperse the seeds wider to the habitats favorable to the seed germination, seedling survival, and population establishment of P. hunanensis. Possibly due to the seed dispersal of P.hunanensis by birds, twenty seven mother trees initially introduced and cultivated at the edges of the Spirit Valley forest in 1961 had multiplied into thousands of saplings and young trees, which were successfully settled in the areas within a distance of about 300 m around the mother trees. As a result, the species composition of evergreen trees in the Spirit Valley forest became richer, and the succession and development of forest community in study area was promoted.

Behavioral responses of Xylotrechus rusticus L. to poplar bark volatiles.

CHENG Li-chao¹;CHI De-fu²;XIE Xing²;WANG Guang-li²

2009, 28(01):  45-50 . 

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The volatiles in the barks of ten poplar species, namely Populus×xiaozhuanica W. Y. Hsu et Liang cv. ‘Baicheng-2’, P. simonii Carr. ×P. nigra L., P. russkii Jabl., P. berolinensis Dipp., P. pseudo-simonii Kitag., P. pseudo-simonii Kitag. ×P. nigra L., P. ussuriensis Kom., P. stalintz Jabl., P. alba L. ×P. berolinensis Dipp., and P. simonii Carr., were steam-distillated, and their qualitative and quantitative analyses were made with gas chromatography-mass spectrometry (GC-MS). Salicylaldehyde, linolein acid, and 11,14,17-eicosatrienoic acid methyl ester were the common components in the volatiles. Different poplar species had greater differences in the components of their volatiles and in the relative contents of aldehyde, ester, and hydrocarbon. Phenol, camphor, and δ-cadinene were the specific components. The behavioral responses of male and female Xylotrechus rusticus L. to the volatiles at the doses of 20, 60, 90, 120, 150 and 180 μl were observed with Y-tube olfactometer, and it was indicated that male adults had significant differences in the choice rate to the volatiles at the doses of 120, 150, or 180 μl (P<0.05), while female adults had the differences at the doses of 60, 90, or 120 μl (P<0.05). The test of the behavioral responses of male and female X. rusticus to 200 μl volatiles of poplar barks and to 20 g scraps of different poplar species by using wind tunnel technique indicated that for the females, their choice rate to the scraps was significantly different (P<0.05), but the choice rate to the volatiles had no significant difference (P>0.05). For the males, the choice rate to the volatiles was significantly different (P<0.05), while the choice rate to the scraps had lesser difference (P>0.05). The potential active chemical substances and related poplar species were discussed, based on the significant differences in the choice rate of X. rusticus to the volatiles of different poplar barks.

Community characteristics of soil sarcodinid and flagellate in Taohuagou forest park in Xiaolongshan Mountains of Gansu.

SHEN Hai-xiang^1，2;MA Zheng-xue¹;MA Shang-sheng³;NING Ying-zhi¹;WANG Juan¹

2009, 28(01):  38-44 . 

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By means of non-flooded petri dish method and in vivo observation, the community characteristics of soil sarcodinid and flagellate in Taohuagou Forest Park (including Taohuagou and Puduxia scenic areas) and Fujiatan (an area with heavy human disturbance) in Xiaolongshan Mountains of Gansu province were studied from August 2004 to July 2007. A total of 75 species were identified. In Taohuagou Forest Park, there were 69 species belonging to 33 genera of 22 families from 10 orders in 4 classes, among which, 58 species were found in Taohuagou scenic area, and 33 species in Puduxia scenic area. In Fujiatan, 22 species were found. Chrysomnadida, Kinetoplastida, and Amoebida were the dominant orders, and Acanthamoeba astronyxis, A. polyphaga, Oikomonas termo, Bodo globosus, B. ovatus, and Spumella amoebina were the dominant species in Taohuagou Forest Park; while Euglenida, Chrysomnadida, and Kinetoplastida were the dominant orders, and B. ovatus was the dominant species in Fujiatan. The Gleason-Margalef species diversity index in Taohuagou and Puduxia scenic areas of Taohuagou Forest Park and in Fujiatan was 6.60, 4.00, and 3.20, respectively, and the Jaccard similarity index was 0.32 between Taohuagou scenic area and Puduxia scenic area, 0.18 between Taohuagou scenic area and Fujiatan, and 0.20 between Puduxia scenic area and Fujiatan. The results showed that in Taohuagou Forest Park, the species of soil sarcodinid and flagellate were abundant, including a large number of endemic and rare species, the community structure was complex, and the species composition was unique. It was indicated that there were great differences in species diversity and community structure of soil sarcodinid and flagellate between intact and disturbed environments.

Species composition and abundance variation of protozoa in Dianshan Lake.

ZHENG Xiao-yan, WANG Li-qing

2009, 28(01):  51-57 . 

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By using the survey method for freshwater plankton, the species composition and abundance variation of protozoa in Dianshan Lake in Shanghai was investigated from 2004 to 2006, and the relationships between protozoan density, Margalef diversity index, and lake water eutrophication were studied. A total of 48 species belonging to 33 genera of 7 orders were identified, including 10 Sarcodina species and 38 Ciliata species. The dominant species were Tintinnidium fluviatile Stein, T. entzii Chiang, Strombidium viride Stein, Didinium balbiamii nanum Kahl, and Vorticella companula Ehrenberg, and the sum of the dominant species densities accounted for 69.8% of the total protozoan density. The annual average abundance of protozoa in 2004, 2005, and 2006 was 3365, 5298, and 2549 ind·L^-1, respectively, and the seasonal fluctuation in the annual average density of protozoa in the three years was shown as spring (7685 ind·L^-1) > winter (3241 ind·L^-1) > autumn (2153 ind·L^-1) > summer (1680 ind·L^-1). Two sampling sites (St2 and St5) near the villages had the higher densities of protozoa, and the horizontal distribution of protozoan density was consistent with that of modified Carlson trophic state index. The Margalef index ranged from 1.15 to 1.99, with an average of 1.45, which was closely related with water quality.

Total mercury content in seawater-cultured shellfish in Fujian Province and its health risk assessment.

LI Xiu-zhu

2009, 28(01):  58-63 . 

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The 1999-2004 quality monitoring data of seawater-cultured shellfish in 16 bays along Fujian coastal areas showed that in 152 samples of 15 kinds of shellfish, the total mercury content ranged from 0.002-0.035 mg·kg^-1. Comparing with the recent 20 years quality monitoring data of marine organisms in Fujian, the total mercury content in the shellfish was relatively low, being accorded with the China national standard of aquatic products for hygienic and safe evaluation, and the MRLS of mercury content in fish and shellfish ordered by the European Community and WHO. With the mercury intake from shellfish being 100 g per person per day as the base of estimation, the intake of mercury and methyl mercury from shellfish by the inhabitants along Fujian coastal areas was lower than the PTWI value recommended by WHO and the RfD value of methyl mercury regulated by US EPA, indicating that the health risk arising from the exposure to methyl mercury due to the consumption of aquatic products was very small.

Arsenate reduction characteristics and diversity analysis of arsenic-reducing bacteria enriched from an arsenic contaminated soil.

ZHANG Xue-xia; JIA Yong-feng;CHEN Liang;WANG Xin;XU Li-ying;ZHANG Xu-dong

2009, 28(01):  64-69 . 

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Arsenic (As)-resistance bacteria were enriched from an As-contaminated soil and cultured in anaerobic environment, aimed to study their arsenate reduction capability and microbial diversity. Within 21 h incubation, arsenate was completely reduced to arsenite; after 72 h incubation, yellow precipitates formed; and after 150 h incubation, about 65% of soluble arsenic was removed. SEM-EDS and XRD analyses revealed that the yellow precipitates were mainly of three kinds of AsS crystalloid. The microbial diversity in the culture was investigated by 16S rDNA-dependent molecular phylogeny, and a near-full-length 16S rDNA gene clone library was constructed. 197 clones were analyzed by using RFLP, and a total of 72 OTUs were obtained, among which, six OTUs occupied 51% of the volume. One clone from each of the six OTUs was selected for sequencing, and it was indicated that the enriched As-reducing bacteria belonged to Caloramator, Clostridium, and Bacillus.

Comparative analysis of landscape dynamics in Kerqin sandy land areas with different desertification formation causes.

LI Jian-ying;CHANG Xue-li;ZHANG Ji-ping;CAI Ming-yu

2009, 28(01):  80-87 . 

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Based on 3S（GIS，RS，GPS）technique, a comparative analysis was made on the landscape dynamic changes in the Kerqin sandy land areas with different desertification formation causes. The results showed that in past 20 years, the desertified land in Baxiantong, where the desertification process was mainly affected by human activities, had a greater change extent, which represented in the transformation from mobile and semi-fixed sands to fixed sands and from fixed sands to cropland and woodland. In Weiliansu, where the desertification process was mainly affected by natural disturbance, the desertified land had smaller changes, and mainly manifested in the inter-transformation among different types of sands. In the areas dominated with human activities, the spatiotemporal pattern of fixed sand had significant changes, i.e., the association of fixed sand decreased in 1985-1995, reflecting the enhanced human disturbance, but increased in 1995-2005, reflecting the comparatively weaker human disturbance. In natural disturbance dominated areas, the spatiotemporal pattern of mobile sand changed obviously, with the fractal dimension index decreased and the area increased in 1985-1995 and the fractal dimension index further decreased but the increased area being restrained in 1995-2005, indicating that the effect of combating desertification was prominent during 1995-2005.

Long-term effects of fire suppression policy on forest landscape, fuels dynamics, and fire risks in Great Xing’an Mountains.

LIU Zhi-hua^1,2;CHANG Yu¹;HE Hong-shi¹;CHEN Hong-wei^1,2

2009, 28(01):  70-79 . 

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Since the 50 years implementation of strict fire suppression policy, the natural fire pattern in Great Xing’an Mountains changed greatly, and the species composition and age structure of the forests altered significantly. To understand the responses of the forests in Great Xing’an Mountains to the long term fire suppression could supply a sound basis for the sustainable development of forestry in this area. By using a spatially explicit landscape simulation model (LANDIS), the long-term (300 years) responses of forest landscape in Great Xing’an Mountains to the scenarios of natural fire (before 1950) and fire suppression (after 1950) were simulated, and the changes in fuel load, fire hazard, and forest tree species abundance under the two scenarios were compared. The simulation results showed that under fire suppression scenario, larch (Larix gmelinii) forest area increased significantly, while birch (Betula platyphylla) forest area was in adverse. Meanwhile, over-matured larch forest area increased, while young larch and birch forest areas decreased. Fire suppression prolonged the interval of fire, decreased the times of fire, increased the chance of catastrophic fire, and made the fire risk rapidly increased to a dangerous level. Under natural fire scenario, fire risk maintained at a relatively low level. Therefore, if the present strict fire suppression policy still implemented, extensive fuels management measures such as prescribed burning and coarse fuel load reduction should be adopted to decrease the occurrence chance of catastrophic fire. How to evaluate the effect of prescribed burning and coarse fuel load reduction in Great Xing’an Mountains, and to find the ways of keeping balance among fire suppression, maximal timber production, and sound ecological function, should be the issues to be urgently solved.

Distributions of total phosphorus, phosphorus fractions, and biogenic silica in Dianchi Lake and Hongfeng Lake sediments.

WU Feng-wei;WANG Fu-shun;WU Ming-hong;YIN Ran

2009, 28(01):  88-94 . 

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Sediment cores were taken from two lakes (Dianchi Lake and Hongfeng Lake) with different degree of eutrophication to analyze the contents of total phosphorus (TP), phosphorus (P) fractions, and biogenic silica, compare their profile distribution characteristics, and approach the relationships of these distribution characteristics with the evolution of eutrophication. The results showed that the residual-P and organic-P (Or-P) in Dianchi Lake accounted for 50.5%-80.8% of TP, being the main fractions of the TP, while the Or-P in Hongfeng Lake accounted for 53%-60.9% of TP, contributing more to the TP. The phosphorus fractions in the two lakes had a trend of decreasing with increasing sediment depth. The rapid increase of TP, Or-P, and Al-P contents in the two lakes and of residual-P in Dianchi Lake revealed that the P pollution of the lakes was mainly from the people’s living and production activities. The biogenic silica content in the sediments represented increasing from the bottom to the top, and decreasing in the top. The distribution characteristics of Or-P, Al-P, Fe-P, residual-P, and biogenic silica could better reflect the evolution and the present status of lake eutrophication.

Vegetation water conservation effect in the Jinghe River basin: An analysis based on topography and soil type.

BI Xiao-li^1,2;GE Jian-ping²

2009, 28(01):  95-101 . 

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Vegetation water conservation effect is a hotspot of the researches on the Loess Plateau. The precious researches often ignored the heterogeneity of environmental factors, and conducted at small scale, supposing that the environment is homogenous. By using GIS techniques and giving consideration of the factors (landform and soil), the vegetation water conservation effect and its spatial distribution in the Jinghe River basin of the Loess Plateau were analyzed, with the standard set of vegetation-soil-slope complex at basin scale. The results showed that in the Jinghe River basin, the vegetation average annual water conservation effect was 3.92×10⁸ m³, accourting for 1/3 of the runoff. The total water conservation effect by the vegetations was grassland > farmland > forestland > shrub land, and the average water conservation effect per unit area was farmland > forestland > shrub land > grassland. Being different from previous studies, our study showed that soil played an important role in the vegetation water conservation effect based on grid Unit. As a result, this study could more objectively reflect the vegetation water conservation effect and its spatial distribution at basin scale.

Some basic issues in plant environmental stress research in China.

TAO Da-li; HE Xing-yuan

2009, 28(01):  102-107 . 

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Based on the long term experiences of the authors’ research and teaching in the field of plant environmental stress as well as the current situations of related researches in China, some relevant basic issues were discussed in this paper. These issues include the definition and quantification of environmental stress, the ‘direct sensing’ of plants to environmental stress, the resistance and sensitivity, tolerance and avoidance, adaptation, acclimation, and hardening of plants, the dosage-effect relationship of the stress, the diagnosis of plant injury and death, and the responses of plant cell membrane permeability and free radical-scavenging system to environmental stress. A better understanding on these issues would help to the researchers, especially young ones, to improve their experimental design and paper writing.

Flora transitiona and its biogeographical significance.

FENG Jian-meng¹; XU Cheng-dong²

2009, 28(01):  108-112 . 

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Based on field survey and document information, and combining with climate data, the biogeographical significance of flora transition and its correlations with climate factors were examined, and in terms of the biogeographical significance, the vegetation regionalization in eastern China was explored. The results showed that the ratio of tropic flora component to temperate flora component (T_trop/T_temp) had significant negative correlations with altitude and latitude, and thus, the flora transition could be estimated by the regressive equation among them. When the flora transition was constant, the altitude decreased against latitude. With increasing mean annual temperature, the flora transition increased first and decreased then, representing a hump-shaped pattern. Through the analysis of the relationship between flora transition and mean annual temperature, the boundaries between tropic rain forest and southern subtropical evergreen forest, between northern subtropical evergreen-deciduous mixed forest and warm temperate deciduous forest, and between cool temperate deciduous forest and temperate needle forest in eastern China were the south of 21.5°N and the north of 34°N-35°N and 47.5°N, with the mean annual temperature of 23.40 ℃, 12.45 ℃, and 1.51 ℃, respectively, which was consistent with the previous studies. This study provided a new idea and methodology in exploring the spatial variation of flora transition and the geographical distribution of vegetation in eastern China.

Responses of plant from individual to community level to grazing: A review.

MA Yin-shan, ZHANG Shi-ting

2009, 28(01):  113-121 . 

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The study of plant responses to grazing is an important part in probing the mechanisms of livestock-plant interaction and of grassland degradation, and to understand the species characteristics and dynamics as well as the species composition of plant community under the disturbance of grazing will provide a scientific basis for the establishment of grazing management policy-making system and the scientific management of natural grassland. In this paper, the research progress in the plant compensation and its mechanism, plant morphological plasticity, and plant community structure under the disturbance of grazing was summarized, and the further researches about the over-compensatory mechanism of different plant communities, the response pattern of plant to grazing, and the long-term effects of grazing to plant individual and community were prospected.

Diagnosis methods of N and P limitation to tree growth: A review.

ZHAO Qiong; ZENG De-hui

2009, 28(01):  122-128 . 

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To quickly and accurately diagnose nutrient limitation factors is indispensable for the study of nutrient limitation in forest ecosystem. Nitrogen (N) and phosphorus (P) are the two popular and major limitation nutrients in forest ecosystem. At present, the main diagnosis methods of N and P limitation to tree growth are fertilization experiment, foliar nutrition diagnosis, and root diagnosis. This paper reviewed the research progress on these methods, discussed the development trend of related researches, and emphasized the significances of the interactions between nutrient elements and the eco-physiological adaptability of plants to nutrient deficiency in the diagnosis of nutrient limitation.

Wastewater treatment with constructed mangrove wetland system: A review.

ZHENG Kang-zhen^1,2;CHEN Geng^1,2;ZHENG Xing-wen^1,2;CHEN Gui-zhu^1,2

2009, 28(01):  138-145 . 

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Mangroves are the diverse communities of tropical to subtropical trees and shrubs growing in inter-tidal zone. This particular zone endows the mangrove plants the capability of resisting and reducing contamination. However, there are still controversies about whether natural mangrove forests can be utilized to treat wastewater. According to the types of constructed mangrove wetlands, they are classified into three groups, i.e., simulated tide wetland system, constructed wetland wastewater treatment system, and integrated mangrove-aquiculture system. The first one simulates the tidal situation of true seashore; the second one resembles most of ordinary constructed wetlands; while the third one is the aquiculture pond planted with mangrove to remove organic matter and nutrients. Different types of the constructed wetlands are the evidences of the progress in research work, showing the gradual process from theory to practice. It is feasible and promising to use constructed mangrove wetlands for wastewater treatment.

Antifouling mechanisms of marine organisms and their application prospects.

CAO Wen-hao^1,2;YAN Tao^1,2;LIU Yong-hong¹;CHENG Zhi-qiang¹

2009, 28(01):  146-151 . 

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Adhesion of marine fouling organisms is unfavorable to human activities, while many sessile and motile organisms inhabited in marine environment can keep themselves clean by the physical and chemical means, such as tolerance, avoidance, low surface energy, and natural compounds etc., against fouling that are formed during their long-term evolution. In this paper, the antifouling mechanisms of marine organism were reviewed, and their application prospects were put forward. To understand these mechanisms would be beneficial to the research and development of new non-toxic antifouling products, and thus, to provide new ways to solve the fouling problems.

Molecular level study of the effects of UV-B radiation on plant: A review.

ZHONG Chu¹;CHEN Zong-yu¹;WANG Yi²;LIU Yan-zhong³

2009, 28(01):  129-137 . 

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The depletion of stratospheric ozone increases the ultraviolet-B (UV-B) radiation on the earth surface, which results in multiple effects on plant, including the effects on DNA, antioxidant enzymes system, photosystem Ⅱ, and biosynthesis of protectants such as flavonoids. UV-B radiation is also an important abiotic factor. In its long-term evolution process, plant gradually forms adaptation mechanisms on UV-B radiation, which can be considered as a kind of environmental signals about the regulation of a series of gene expression processes in plant itself. In this paper, the repair of UV-B-induced DNA damage and the changes in the gene expression of antioxidant enzymes and photosystem Ⅱ in response to UV-B, as well as the studies of UV-B signal transduction, were discussed, and some issues worthy to be further studied in the plant molecular biology of UV-B radiation were put forward.

Molluscicidal efficacy of three kinds of plants mixed with Streptomyces violaceoruber against snail Oncomelania hupensis.

MA An-ning¹;ZHANG Yun¹;KE Wen-shan²;NI Hong²

2009, 28(01):  158-161 . 

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To develop high-efficiency and low-toxicity plant molluscicides against snail (Oncomelania hupensis), the water extracts of Carpesium abrotanoides, Xanthium sibiricum, and Artemisia carvifolia were respectively mixed with Streptomyces violaceoruber solution, and the mollusicicidal efficacy of the liquid mixtures against O. hupensis was evaluated, with the comparison of corresponding granular mixtures. After 7-day exposure to the 1% liquid mixtures of C. abrotanoides and S. violaceoruber and of X. sibiricum and S. violaceoruber, the mortality of the snail was 17.6% (P=0.019) and 5.3% (P=0.362) lower than that exposed to the corresponding granular mixtures, respectively; while after 7-day exposure to the 1% liquid mixture of A. carvifolia and S. violaceoruber, the mortality was 6.7% (P=0.022) higher than that exposed to corresponding granular mixture. The granules of C. abrotanoides mixed with S. violaceoruber and of X. sibiricum mixed with S. violaceoruber had higher synergistic effects than the corresponding liquid mixtures.

Current situation of grassland degradation and its management options in farming-pasturing ecotone in western Jilin Province and eastern Inner Mongolia.

TIAN Xun¹;YANG Yun-fei²

2009, 28(01):  152-157 . 

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The farming-pasturing ecotone in western Jilin Province and eastern Inner Mongolia is a transitional area of sub-humid and semi-arid climate, where natural grassland was severely degraded and showed saline-alkalization and desertification.Anthropogenic activity was the main cause of the grassland degradation, and larger population pressure and irrational land use were the dominant factors that accelerated this degradation.The management options for the degradation would be the carrying-out of ecosystem health diagnosis, protection of health grassland, restoration and reconstruction of damaged grassland, and establishment of scientific management system.

Potential distribution areas of Solanum rostratum in China: A prediction with GARP niche model.

ZHONG Gen-ping^1,2;SHENG Wen-jun²;WAN Fang-hao²;WANG Jing-jun¹

2009, 28(01):  162-166 . 

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In recent years, quarantine weed Solanum rostratum has being spread to North China. Based on the distribution characteristics of S. rostratum in its native and invaded areas, and by using 14 environmental variables, the potential distribution areas of S. rostratum in China were predicted by the Genetic Algorithm for Rule-set Prediction (GARP) niche model combining with Geographic Information System (GIS). The results from jackknife operation indicated that 7 environmental variables could improve the accuracy of the prediction. The one-tailed goodness-of-fit χ²-statistics was employed to test the significance of the model, which indicated that all of our predictions were highly significant. Moreover, the Receive Operation Curve (ROC) test by using leaving-aside data indicated the good performance of our model, and all the known distribution points in China were all correctly predicted. The potential distribution areas of S. rostratum included whole China except Tibet, Qinghai, and south Guangdong and Guangxi, and the Central, North, and East China had high suitability. S. rostratum would probably enter its hazard’s rapid-spread period, and the related departments should pay more attentions to this danger weed.

An experiential formula about the evapotranspiration of reference vegetation on northern slope of Great Hing’an Mountains.

BING Long-fei^1,2;LI Xiu-zhen¹;HU Yuan-man¹;WANG Xian-wei^1,2;LÜ Jiu-jun^1,2

2009, 28(01):  167-171 . 

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By the method of time series analysis, the evapotranspiration of reference vegetation in the small watersheds of continuous permafrost on the northern slope of Great Hing’an Mountains was approached. The results showed that the evapotranspiration of the reference vegetation, ET₀, had an obvious periodic fluctuation within a year, i.e., from relatively low at the beginning of the year to high before or after July, and declining to the lowest by the end of the year. The ET₀ had significant correlations with net radiation (R_n) and daylight hours (N), and the formula ET₀=0.260R_n-0.036N+0.422 was established, based on the two years meteorological data of Amur basin, which would benefit to the further studies on the eco-hydrological processes in the permafrost areas of northern Great Hing’an Mountains.

Conversion relationships between the chemical parameters in saturated and in 1∶5 soil/water extracts of saline and alkaline soils in Songnen Plain of Northeast China.

CHI Chun-ming^1,2;WANG Zhi-chun¹

2009, 28(01):  172-176 . 

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Ninety-four saline and alkaline soil samples were collected from the Songnen Plain of Northeast China, and their electrical conductivity (EC), sodium adsorption ratio (SAR), total cation concentration (TCC), and major cations (Na⁺, Ca²⁺, Mg²⁺, K⁺) concentrations in saturated and in 1∶5 soil/water extracts were determined. The EC, SAR, TCC, and Na⁺ concentration in saturated and in 1∶5 soil/water extracts had significant correlations, and the established regression equations could be used to convert these parameters in the two extracts. However, no correlations were observed between the K⁺, Ca²⁺ and Mg²⁺ concentrations in saturated and in 1∶5 soil/water extracts.