Table of Content

10 March 2009, Volume 28 Issue 03

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Articles

Effects of spatial pattern and species combination on the performance of three plant species.

ZHANG Zuo-liang;MA Yin-shan;ZHAO Chuan;LI Chuan-long;ZHANG Shi-ting

2009, 28(03):  377-383 . 

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Taking the common three plant species with different seed size (two an nuals Galeopsis bifida and Chenopodium foetidum and a biennial Swertia tetraptera) in abandoned fields of eastern Tibetan Plateau as test materials, this paper studied their performance under effects of different spatial pattern (aggregated vs. random distribution, and low vs. high density) and species combination (mon oculture vs. mix-culture). The results showed that spatial pattern and species c ombination had no significant effects on the emergence rate, but affected the co mpetition hierarchy of the three species to some degree. Large-seed species G . bifida exhibited dominance in interspecific competition, small-seed species C. foetidum benefited from intraspecific aggregated pattern, while S. tet raptera, whose seed size was between that of G. bifida and C. foetidum , showed complexity in interspecific competition. For C. foetidum, its seedl ing mortality rate in aggregated pattern was lower, and its aboveground biomass was significantly higher in aggregated pattern than in random pattern. For G. bifida, its seedling mortality rate in aggregated pattern was higher, and its aboveground biomass was signif icantly lower in high density and aggregated pattern. The seedling mortality rat e of G. bifida was higher and its aboveground biomass was lower in monocultu re t han in mix-culture. For C. foetidum, its seedling mortality rate was higher in m ix-culture with S. tetraptera than in monoculture, but there was no signifi cant difference in its aboveground biomass among different species combination. For S. tetraptera, its seedling mortality rate was the lowest in mix-culture with G. bifida, but the highest in mix-culture with G. bifida and C. foetidum.

Effects of slope aspect on plant community characteristics of Vetiveria zizanioides slope-protection land.

LIU Jin-gen;XUE Jian-hui

2009, 28(03):  384-388 . 

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Base on 2-year consecutive investigation from June 2005 to October 2006, the effects of different slope aspects on the early-stage succession characteristics of plant communities on Vetiveria zizanioides slope-protection land were studied. The results showed that in the earliest period, the main plants settled on the slope-protection land were of Gramineae, Compositae and Leguminosae, with their species number occupying 5909%〖KG-*2〗-〖KG-*7〗9286% of the total. Since the second year of V. zizanioides planting, the characteristics of the plant communities on sunny and shady slopes began to differ. V. zizanioides population had obviously higher species dominance on sunny slope than on shady slope, and kept increasing on sunny slope but represented a declining trend on shady slope. The species dominance of V. zizanioides population was significantly negatively correlated with the richness, diversity index, and evenness index of the plant communities, but positively correlated with the community ecological dominance index.

Physiological adaptation and ion regulation of three leguminous species seeds at their germination stage to saline environment.

WANG Xiao-shan; ZHAO Guo-qi, LIU Da-lin, LIU Gao-jun

2009, 28(03):  389-393 . 

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To understand the adaptability and ion regulation mechanisms of Medi cago sativa, Melilotus officinalis, and Astragalus adsurgens seeds at thei r germination stage to saline environment, the seeds were treated with different concentrations of NaCl, and their germination rate and recovery germination rat e were determined. In the meantime, the changes of main ions contents in seed em bryos and the water uptake by the embryos at 400 mmol·L-1 of NaCl were in vestigated. At 50 mmol·L-1 of NaCl, the final germination rate of M. sativa seeds was obviously inhibited and decreased; while at 300 mmol·L-1 of NaCl, the final seed germination rate of M. officinalis was obviously hi gher than that of M. sativa and A. adsurgens, and the initiation of seed germination process of A. adsurgens was 5 days later than that of M. sati va and M. officinalis. M. sativa seeds rarely germinated at 400 mmol·L -1 of NaCl. After treated with 400 mmol·L-1 of NaCl for 1, 2, and 4 days, the water uptake by the seeds of test three species was obviou sly inhibited. The recovery seed germination rate of M. sativa was lower tha n that of the other two species, and the seed embryos of M. sativa accumulat ed more Na+ but leaked out more K+ and Ca2+. In saline environment, th e impact on the seed germination of the three species was due to osmotic stress and ion toxicity, but the physiological adaptation mechanisms differed with diff erent leguminous species seeds.

Edge effect of road in Dinghushan forests.

ZHOU Ting;PENG Shao-lin;LIN Zhen-guang

2009, 28(03):  433-437 . 

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This paper studied the edge effect of road in the forests in Dinghusha n Natural Reserve of Guangdong Province, and approached the effects of road in f orests on forest ecosystem. Four 30 m×5 m transects with a distance of 0, 10, 2 0, and 30 m from the both sides of a 6-m-wide winding mountain road were insta lled to conduct vegetation investigation and soil analysis. The results showed that t he total tree biomass in the transects adjacent the road was slightly higher tha n that of the inner forest communities, showing a positive edge effect, while th e soil acidity and total nitrogen content in downgrade transects showed a negati ve edge effect. Neither species diversity nor soil moisture content exhibited ob vious edge effect. As a whole, road construction had definite negative effects o n the integrality of forest ecosystem, producing artificial linear gaps and gene rating edge effect in the characteristics of vegetation and soil. The edge effec t caused by forest road should be considered in the management of Natural Reserv e.

Seasonal variation and its main affecting factors of soil microbial biomass under different vegetations along an elevation gradient in Wuyi Mountains of China.

HE Rong^1,3;WANG Guo-bing¹;WANG Jia-she²;XU Bo-feng³; WANG Ke-ji³;FANG Yan-hong²;SHI Zheng^1,4;RUAN Hong-hua¹

2009, 28(03):  394-399 . 

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Seasonal variation of soil microbial biomass plays an important role in the carbon cycle of terrestrial ecosystem. To understand this variation and its main affecting factors along an elevation gradient in mid-subtropical Wuyi Mo u ntains, four plant communities at different elevation, i.e., evergreen broadleaf forest at 500 m, coniferous forest at 1200 m, dwarf forest at 1800 m, and alpin e meadow at 2100 m were selected as study sites. The study from June 2005 to June 2006 showed that there was an obvious seasonal variation of soil microbial bioma ss along the elevation gradient, and the variation under the four plant communit ies had the same trend, being maintained at a high level in early spring but at a low level in summer. Soil microbial biomass had significant correlations with soil available organic carbon and soil moisture, but less correlations with soil temperature, soil total organic carbon and nitrogen, and plant litterfall input , suggesting that soil available organic carbon and soil moisture were the main factors controlling the seasonal variation of soil microbial biomass in the fore sts of Wuyi Mountains.

Litterfall decomposition in four forest types in Changbai Mountains of China.

LIU Ying¹;WU Yao-xiang²;HAN Shi-jie³;LIN Lu¹

2009, 28(03):  400-404 . 

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By the method of in situ litterfall lessening, the litterfall decompos ition in four forest types (broadleaf-Korean pine forest, Korean pine and spruc e-fir mixed forest, Betula ermanii and spruce-fir mixed forest, and B. e rmanii forest) on the north slope of Changbai Mountains Nature Reserve was stu died from May 2003 to September 2004. The results showed that Korean pine and sp ruce-fir mixed forest had the largest quantity of standing litterfall, followed by broadleaf-Korean pine forest, B. ermanii and spruce-fir mixed forest, and B. ermanii forest. There existed an exponential relationship between lit terfall decomposition rate and time. The annual decomposition rate of the litter fall in different forest types ranged from 25% to 47%, being the largest in broa dleaf-Korean pine forest, followed by in B. ermanii forest, Korean pine and spruce-fir mixed forest, and B. ermanii and spruce-fir mixed forest, and the time for decomposing 95% of the litterfall took about 18 to 39 years. In the same forest types, the annual decomposition rate of different plant components diff ered obviously, generally with broad leaf being the largest and conifer being th e least.

Effects of different concentration sea water on chicory seedlings growth and physiological characteristics.

SUN Lei;LONG Xiao-hua;LI Hong-yan;LIU Zhao-pu

2009, 28(03):  405-410 . 

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Growing salinity-tolerance plants is one of the effective measures for the rational use and exploitation of coastal land resources. With sand culture in greenhouse, this paper studied the effects of different concentration seawate r on the biomass, ion absorption and distribution, chlorophyll content, and phot osynthesis of chicory seedlings. Comparing with the control, treating with 10% s eawater had less effect on the biomass, chlorophyll content, and photosynthesis of chicory seedlings, suggesting that 10% seawater did not significantly restrai n the growth of chicory seedlings, while treating with 20%, 30%, and 40% seawate r decreased the biomass, chlorophyll content, photosynthesis, stomatal conductan ce, and transpiration rate significantly, indicating that higher concentration s eawater inhibited the growth of chicory seedlings and lowered their carbon assim ilation capacity. The Na+ and Cl- contents in seedlings shoot and root increa 〖JP2〗sed with increasing seawater concentration, while the K+ content was the highest under the stress of 20% seawater. Like Na+ and Cl-, the K+ accumulation in ro ot kept increasing with the increase of seawater concentration. All of the results su ggested that chicories seedlings had definite salinity-tolerance, and could be planted with the irrigation of low concentration seawater or saline water.

Biodegradation of phenanthrene, anthracene and n-hexadecane in petroleum-contaminated soil.

ZHAO Xiao-xiu;ZHAO Hui-min;QUAN Xie;CHEN Shuo;ZHAO Ya-zhi

2009, 28(03):  456-460 . 

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A simulation test was conducted to study the biodegradation of aromati c hydrocarbons (phenanthrene and anthracene) and aliphatic hydrocarbon (n-hexad ecane) by indigenous microorganisms when the test hydrocarbons were existed indi vidually or in coexistence in soil. The results indicated that the biodegradatio n of test hydrocarbons followed first-order kinetics. The biodegradation rate c onstant of phenanthrene, anthracene, and n-hexadecane existed individually in s oil was 00283, 00226 and 00096 d-1, respectively. When co-existed with phenanthrene, n-hexadecane could serve as a co-metabolic substrate and pr omote the biodegradation of phenanthrene, making the half life of phenanthrene r educed by 44%, comparing with that when phenanthrene existed individually. In th e meanwhile, n-hexadecane oxygenase was induced by phenanthrene. The increase o f the induced oxygenase activity promoted the degradation of n-hexadecane, and reduced the half life of n-hexadecane by 49%, comparing with that when n-hexad ecane existed individually. Contrarily, the coexistence of phenanthrene and anth racene promoted the biodegradation of phenanthrene but inhibited that of anthrac ene.

Comparison of diaspore shape, size, and mass of main desert plants in the lower reaches of Tarim River of Xinjiang, China.

ZHAO Xin-feng^1,3,5;ZHU Yan-fen⁴;XU Hai-liang^1,2,3;YE Mao⁴;LI Yuan^1,3,5

2009, 28(03):  411-416 . 

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A comparative study was conducted on the shape, size, and mass of diaspores of 21 main desert plants in the lower reaches of Tarim River. The diaspores includ ed 17 kinds of seeds and 4 kinds of fruits. Their shape was measured by three-d imension variance, size was measured by the sum of three-dimension, and mass was measured by 100-seed mass method. The diaspore shape of test plants varie d greatly, with that of Fabaceae being nearly spherical, and of Compositae great er deviating spherical (variance>005). Diaspore mass also had greater differ ence. There was a definite consistency between the trend of diaspore size and mass. The mean mass of perennial herb’s diaspore was 18% heavier than that of shrub and semi-shrub’s diaspore, though the perennial herb had le sser species than shrub and semi-shrub. Nine of the 21 main desert plants had p ersistent seed bank. 100% of Tamaricaceae and 100% of Compositae plants had papp us which is of significance for the dispersal and settling down of the diaspore.

Dynamic changes of plant population niche in succession series of evergreen broad-leaved forest in Daming Mountain of Guanxi.

YE Duo¹;WEN Yuan-guang²;DENG Rong-yan²;LIANG Hong-wen²;ZHU Hong-guang²;HUANG Mian³

2009, 28(03):  417-423 . 

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With the plant communities in four (15, 30, 60 and 160 years) successi on series of evergreen broad-leaved forest in Daming Mountain of Guangxi as tes t objects, this paper studied the dynamic changes of the importance value, niche breadth, and niche overlap of dominant populations in the process of succession. The results showed that Cunninghamia lanceolata, Castanopsis fabri, Huodendro n biaristatum, and Beilschmiedia fordii were the dominant populations in t he commu nities of the four succession series, respectively. These populations had the wi dest niche breadth, and played important function. In each succession series, th e species with wider niche breadth had larger niche overlap among themselves and with other species. The species with lower importance value but wider niche bre adth might become the dominant species in the next succession series. Some speci es had narrower niche breadth but larger niche overlap, due to the habitat fragm entation and spatial heterogeneity. In the whole succession series, the mean val ues of populations niche breadth and niche overlap all decreased gradually at ea rlier succession stages but increased slightly at the latest stage, suggesting t hat with the development of succession, the species competition and the changes of natural resources led to a definite niche differentiation, decrease of niche overlap, and formation of stable community structure.

The effects of disturbance on forest structure and diversity at different altitudes in Garhwal Himalaya

Munesh KUMAR¹; Chandra Mohan SHARMA²; Govind Singh RAJWAR³

2009, 28(03):  424-432 . 

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The effects of disturbance on forest structure and diversity along an altitudinal gradient in the temperate, sub-tropical, and tropical regions of Garhwal Himalaya were assessed. Each region was further categorized into undisturbed (UD), mildly disturbed (MD), and highly disturbed (HD) sites on the basis of magnitude of disturbance in these forests. On UD sites of temperate, sub-tropical and tropical regions, Quercus leucotrichophora, Anogeissus latifolia and Holoptelea integrifolia were the dominant tree species respectively. The highest values of tree density (1028 ind·hm^-2) and total basal cover at breast height (31.70 m² ·hm^-2) were recorded for UD site of temperate region, whereas maximum species diversity (3.128) and equitability (14.09) values were observed for HD site of tropical region. The structure and composition of the forests were greatly affected by the degree of disturbance.

Cadmium accumulation and its relationship with sulfur content in three crops.

FENG Qian^1,2;TAI Pei-dong¹;LI Pei-jun¹;FU Sha-sha^1,2;GUO Yan-li^1,2;ZHANG Yin-qiu^1,2

2009, 28(03):  461-465 . 

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A field experiment was conducted to study the cadmium (Cd) accumulatio n and its relationship with sulfur content in the leaves and stems of Helianthus annuus, Zea mays, and Glycine max at the soil Cd concentration of 2 and 5 mg·kg-1. The results showed that from seedling stage to mature stage, there was a significant positive correlation between Cd accumulation and sulfur content in H. annuus and Z. mays stems but no correlation in their leave s, indicating that sulfur played an important role in plant Cd translocation. Th e seed Cd content was in the order of H. annuus>G. max>Z. ma ys when the soil Cd concentration was 2 mg·kg-1, and G. max>H. annuus>Z. mays when the soil Cd concentration was 5 mg·kg-1. Maize seed had the least Cd content, being 001 and 003 mg·kg-1 at soi l Cd concentration of 2 and 5 mg·kg-1, respectively, smaller than the lim ited value of national food standard of China.

Effects of shading at grain-filling stage on the growth and Q enzyme activity of rice grain.

FU Guan-fu¹;LI Hua²;TAO Long-xing¹;ZHANG Xiu-fu¹;WANG Dan-ying¹

2009, 28(03):  438-444 . 

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With rice varieties “Xieyou 9308” and “Xiushui 110” as test materi als, this paper analyzed the effects of non-shading, shading at whole grain-fi lling stage, and shading at part phases of grain-filling stage on the dynamics of grain- filling, and studied the grain growth and its relations with grain ch alkiness degree and amylose content under weak light stress. In shading treatmen ts, the final grain mass and the maximal grain-filling rate (GRmax) of the two varieties decreased significantly with increasing shading intensity (P<0.05). Sh ading at whole grain-filling stage had no general pattern in its effects on the average grain-filling rate, relative initial grain-filling power, and effecti ve filling time; while shading at 15 days or 30 days after flowering decreased t he average grain-filling rate but increased the relative initial grain-filling power and effective filling time with the increase of shading intensity (P< 005). In the treatment of shading at whole grain-filling stage, the Q enzyme activity, seed-setting rate, kernel mass, and amylose content of rice grain dec reased, and the chalkiness degree increased with increasing shading intensity; w hile in the treatments of shading at 15 days or 30 days after flowering, these p arameters had no general change pattern. Shading at part phases of grain-fillin g stage had less effects on the seed-setting rate, kernel mass, chalkiness deg ree, and amylose content of rice variety “Xieyou 9308”, but greater effects on those of “Xiushui 110”, suggesting that “Xieyou 9308” had higher shade-tol erance than “Xiushui 110”.

Wetland restoration in Sanjiang Plain based on hydrology and land cover.

HUANG Ni^1,2;LIU Dian-wei¹;WANG Zong-ming¹;ZHANG Bai¹;SONG Kai-shan¹

2009, 28(03):  509-515 . 

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By using RS and GIS techniques and the data of land cover and soil rel ative humidity in 2005, the regions to be preserved and those suitable for wetla nd restoration in Sanjiang Plain were ascertained, and the site selection model for the wetland restoration was established via the introduction of proximity cr iterion and patch size criterion. In the meantime, the potential grades of the r estoration were analyzed, and the sites’ spatial position and priorities for th e restoration were determined. The results showed that in the present wetland re storation regions, farmlands, especially those with high soil relative humidity, were the main sources for wetland restoration. The area of first-grade restoration region was 529261 hm2, accounting for 486% of the total area of Sanjiang Plain. Because of its low terrain and plentiful water, this region had great potential of restoring to wetland, and was the region of implementing wet land restoration in recent years. The area of second-grade restoration region was 73724 hm2, accounting for 068% of the total. This region had larg er patch area, and was not far from the extant wetland and water body. If it cou ld be restored to wetland, this region would contribute more to the further incr ease of the connectivity among wetland patches and the decrease of habitat fragm entation, being able to be used for wetland restoration in mid- and long terms. Third-grade restoration region was widely distributed in the Plain, ac counting for 2111% of the total. Considering of the importance of Sanjiang Pla in as the commodity grain and bean base in China and the present economic develo pment level, this region didn’t need to implement wetland restoration at presen t.

Landscape pattern of avian habitats in Macau.

ZHANG Min¹;ZOU Fa-sheng¹;LEONG Kun-fong²;CHEONG Kuai-tat²

2009, 28(03):  483-489 . 

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Under the support of RS and GIS techniques and by using the TM image of 2006, the basic feature and regional difference of avian habitat patterns in Macau were analyzed by Fragstats 33, and the habitat factors with important effects on the avian, such as landscape fragmentation, connectivity, and heterogeneity, were discussed. The results indicated that there was a greater difference in the avian habitat patterns between Macau Peninsula and Coloane and Taipa outlying island, which was highly correlated with urbanization level. In Macau Peninsula, construction land was the matrix, green land was little and fragmented, and the landscape diversity and heterogeneity were low; while in Coloane and Taipa outlying island, woodland was the matrix, the construction land and bare land in its central area were in large patches, and different types of habitat were evenly scattered and had higher connectivity. On the whole, the general pattern of avian habitats in Coloane and Taipa outlying island was better than that in Macau Peninsula. 72 avian species including 48 land bird species and 24 water bird species were recorded in Macau Peninsula, and 146 avian species including 94 land bird species and 52 water bird species were recorded in Coloane and Taipa outlying island. Avian survey data indicated that habitat pattern had definite effects on the avian species, diversity, and evenness. In the regions of Zhujiang River estuary, Macau played an important role in the bird migration and wetland conservation. To meet the habitat requirements of various kinds of birds in Macau, attentions should be paid on the improvement of landscape diversity and heterogeneity and the protection of important avian habitats in the process of urbanization.

Autotoxicity and phenolic acids content in soils with different planting interval years of Rehmannia glutinosa.

DU Jia-fang¹;YIN Wen-jia¹;ZHANG Zhong-yi^1,2;HOU Jian¹;HUANG Jian¹;LI Juan¹

2009, 28(03):  445-450 . 

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Field replanting bioassay was conducted on the soils having planted wi th Rehmannia glutinosa for 2, 4, 6, and 8 years. The soils were repl anted with R. glutinosa, and 5 phenolic acids (coumalic acid, 4-hydroxybenz oic acid, venillic acid, syringic acid and ferulic acid) closed related to allel opathetic effects in the replanted soils were analyzed by using high pressure li quid chromatography (HPLC). The results showed that on the soils with increasing planting interval years of R. glutinosa, the root tube dry mass and volume and the leaf dry mass of replanted R. glutinosa increased since seeding stag e then, while the contents of test five phenolic acids in the replanted soils de creased accordingly. The total contents of test five monohydric phenolic acids i n the replanted soils having been planted with R. glutinosa for 2, 4, 6, and 8 years was 1503, 1323, 0700, and 0340 μg·g-1, respectively, an d the content of ferulic acid, 4-hydroxybenzoic acid, and coumalic acid in soil water extract had significant negative correlation with filed planting bioassay results. As a whole, the early and middle growth stages of R. glutinosa sho uld be the crucial periods for the allelopathetic effects of R. glutinous.

Peroxidase activity and MDA content of endangered species Davidia involucrata.

ZHU Li-jun^1，2;SU Zhi-xian¹;HU Jing-yao¹;SU Rui-jun¹

2009, 28(03):  451-455 . 

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To understand the eco-physiological adaptability of Davidia involucrata, th e peroxidase (POD) activity and MDA content of D. involucrata leaves of dif ferent age class and at different leaf layer and leaf position were analyzed by the method of colorimetry. The results showed that the D. involucrata leaves of different age class but at the same growth phase had different POD activity and MDA content. With increasing leaf position, the POD activity of the leaves o f same age class and at the same leaf layer had a decrease after an initial incr ease, while the MDA content was increasing. The POD activity and MDA content of the leaves at same leaf position but at different leaf layer and those at differ ent leaf position but at same leaf layer also varied. Growth phase had greater e ffects on the leaf POD activity and MDA content. With the growth and senescence of leaf, the POD activity and MDA content of the leaves of same age class and at same leaf position increased gradually. The POD activity and MDA content of D . involucrata leaves were affected by both biological and non-biological fact ors, and varied with leaf age class, leaf position, and leaf layer.

Effects of the first feeding timing on the growth and survival of Russian sturgeon (Acipenser gueldenstaedtii) larvae.

ZHANG Tao¹;ZHUANG Ping¹;ZHANG Long-zhen¹;XIA Yong-tao²;GAO Lu-jiao¹;WANG Bin²;TIAN Mei-ping³

2009, 28(03):  466-470 . 

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The effects of the first feeding timing on the growth and survival of artificially breeding Russian sturgeon Acipenser gueldenstaedtii larvae at the age of 6, 8, 10, 12, 14, 16, 18, 20, and 22 days were examined at 174 ℃ under laboratory conditions. The larvae started first feeding at the age of 9〖KG-*2〗-〖KG-*7〗10 days; while before this age, feeding did not provide any advantage. Up to two days delay of the first feeding affected the growth and survival of larvae significantly. The survival rate of the larvae was significant lower when the first feeding timing was at the age of 18 days than at the age of 6〖KG-*2〗-〖KG-*7〗16 days, and no larvae could survive when the first feeding timing was at the age of 24 days. The larvae achieved the point of no return (PNR) at the age of 23〖KG-*2〗-〖KG-*7〗24 days when the exogenous feeding could not be set. Under artificial breeding conditions, feeding larvae should be started within 14 days after the first feeding timing to avoid the potential starvation mortality and get better growth.

Morphological changes of embryo and yolk sac larvae of barred knifejaw (Oplegnathus fascltus) under salinity stress.

SHI Zhao-hong¹;PENG Shi-ming¹;YIN Yan-qiang²;LUO Hai-zhong³;NI Meng-lin³

2009, 28(03):  471-476 . 

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To study the effects of salinity on the development of barred knifejaw (Oplegnathus fascltus) embryo and yolk sac larvae, the fertilized eggs of O. fascltus were put in seawater with different salinity, and their buoyancy, diameter, oil globule diameter, hatching rate, abnormality rate as well as the morphological changes and nutrient utilization of yolk sac larvae were observed. The results indicated that the fertilized eggs subsided in seawater at the salinity of 25 or lower, but floated on the seawater surface at the salinity of 30 or higher. Most embryos were buoyant at salinity 26. The larvae were hatched after 24〖KG-*2〗-〖KG-*7〗30 h in seawater at 225 ℃〖KG-*2〗-〖KG-*7〗240 ℃, and the hatching time was not significantly affected by salinity (P>005). Larvae could be hatched at the salinity from 20 to 50, but the hatching rate and abnormality rate were significantly affected by the changes of salinity. The suitable salinity for hatching was from 25 to 35, and the theoretical optimum salinity was from 285 to 305. Small fertilized eggs were obtained at higher salinity, and the post-embryonic larvae hatched at higher salinity water had the smaller volume of yolk sac. The total length and height of larvae reduced significantly with increasing salinity, whereas the diameter of oil globule was not affected by seawater salinity.

Behavioral responses of sea cucumber (Apostichopus japonicus) to different light intensity and settlement substratum color.

ZHANG Hui^1,2;WANG Yin-geng¹;RONG Xiao-jun¹;CAO Shan-mao²;CHEN Xia³

2009, 28(03):  477-482 . 

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The behavioral responses of sea cucumber (Apostichopus japonicus) to different light intensity (100, 50, 10, 5, and 1 lx) and settlement substratum color (red, gray, yellow, blue, white, black, and green) were examined by mean phototactic rate (MPR) and mean attractive rate (MAR) methods. The results showed that the MPR was significantly different (P<005) among strong light regions (100, 50, and 10 lx) (P<005), but was not between weak ones (5 and 1 lx). Under natural light and darkness, the MAR of same color settlement substrata had no significant difference; while under the same light intensity, the MAR of black and grey settlement substrata was superior to that of the others, being significantly different with that of blue and yellow settlement substrata and of the control (P<001). The attractive effect of different color settlement substrata was in the order of black>gray>red>green>white>blue>yellow. The above results suggested that the MPR of A. japonicus decreased with increasing light intensity, representing the photonegative response of the organism. Among the seven colors settlement substrata, the black, gray, and red ones had the higher MAR.

Hotspot analysis of settlement dynamics in urbanization process of Nanjing.

ZHANG Chi¹;LIU Mao-song¹;XU Chi¹;TANG Mao-lin²;SHI Qin¹

2009, 28(03):  503-508 . 

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Based on the multi-temporal Landsat TM images in 1988, 1998, 2003 and 2006, and by using neighborhood analysis, the top 5% areas with the quickest change rate of settlement percentage coverage in Nanjing in 3 periods of time in 1988〖KG-*2〗-〖KG-*7〗2006 were picked up as the hotspots, aimed to study the settlement dynamics in the urbanization process of the City. The results showed that with urban expansion, both the growth hotspots and the shrinking hotspots in Nanjing exhibited an overall outward-shifting tendency. The growth hotspots mostly located in the regions 6 km from the fringe of urban built-up areas, while the high-occurrence zone of shrinking hotspots was located in the regions 1 km from the fringe of the built-up areas. Moreover, the areas of the two kinds of hotspots declined with the distance along the urban-rural gradient. The intensity and range of the hotspots varied significantly among different directions, and tended to be influenced by the short-term urban development decisions. At some specific stages, the primary urban development zones generally presented in growth hotspots, which resulted in the temporal variation of hotspot-concentrated locations. The shrinking hotspots were concentrated in the areas experienced growth hotspots in previous periods, indicating that relatively extensive settlement reform and integration could occur after the rapid settlement growth in urbanization process.

Theoretical basis and construction methods of urban nature-approximating landscape architecture.

YANG Yu-ping^1,2;ZHOU Zhi-xiang¹

2009, 28(03):  516-522 . 

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Nature-approximating landscape architecture is not only a planning and construction idea of sustainable landscape architecture and one of the modes of ecologic al garden construction, but also the key measure to actualize resources-saving landscape architecture and the development trend of landscape architectu re. Based on the analysis of the problems in current garden construction in Chin a, the conception, connotation, and theoretical basis of nature-approximating l andscape architecture were expatiated, and the essential construction principles were brought forward. The methods of nature-approximating landscape architectu re design, implementation, and management were summarized in detail, and the pro blems in nature-approximating landscape architecture construction as well as th eir solving measures were analyzed and developed. This review would provide the basis for emphasizing the idea and promoting the research and construction of near nature landscape architecture.

Hierarchical structure of urban system in multi-cities of central Liaoning.

WANG Hou-jun^1,2;LI Xiao-yu¹;HE Xing-yuan¹;CHEN Wei¹; ZHANG Zu-lu²;GAO Yan-ni^1,3;TANG Ling^1,3

2009, 28(03):  490-496 . 

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Hierarchical structure is one of the main three structures in urban sy stem. Its characteristics can reflect the distribution patterns of cities in dif ferent scales and the degrees of concentration or dispersion of urban population , and also, can help us to understand the development stage of urban system. By using the theories and methods of urban primacy index, fractal, and urban gravit y transfer, the hierarchical structure of urban system in the multi-cities of c entral Liaoning were analyzed. The results showed that the multi-cities of cent ral Liaoning had a fractal hierarchical structure, their sizes were in primacy d istribution, and middle-size cities were fewer. The spatial distribution of cit y size tended to balance, but the development process had significant regional d ifference. From 1982 to 2005, the gravity of urban population had an overall sou thwestward transfer.

Temporal variation and regional differences of ecosystem service value of Nanjing City.

GU Xiang¹; ZHOU Sheng-lu¹; ZHANG Hong-fu¹; LI Su-ju²; GENG Zhao²

2009, 28(03):  497-502 . 

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The changes of ecosystem service value affect the sustainable regional development, and the valuation of ecosystem service has been one of the hot topics in ecological study. By using per unit area ecosystem service value and eco-economic harmony index (EEH), this paper analyzed the temporal variation and regional differences of ecosystem service value of Nanjing. With the comparison in 2007 and in 1997, Nanjing City had six districts with the sub-zones of different per unit area ecosystem service value, while seven districts and counties having the same per unit area ecosystem service value sub-zones. In general, the regional per unit area ecosystem service value showed the features of counties > suburban areas > urban areas. In 1997〖KG-*2〗-〖KG-*7〗2007, the eleven districts and two counties of Nanjing City were of five different types of eco-economic harmony zones. Three districts and two counties belonged to eco-economic harmonious zones, while the other eight districts belonged to eco-economic inharmonious zones. The strategies of ecological construction adjustment in different districts and counties of Nanjing City were put forward, which could provide reference for the decision-making of the harmonious eco-economic development and regional sustainable development of the City.

Water conservation function and its measurement methods of forest ecosystem.

ZHANG Biao^1,2;LI Wen-hua¹;XIE Gao-di¹;XIAO Yu¹

2009, 28(03):  529-534 . 

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With the increasing demand for clean water, the water conservation of forest ecosystem has raised increasing concerns. This paper reviewed the researc h progress on the concept of water conservation, summarized its main manifestati ons, and introduced the measurement methods of water storage. The current studie s lack a comprehensive analysis of the water conservation function of forest eco system. Water conservation is a dynamic comprehensive concept, which develops wi th the advancements in forest hydrology research. The broad and narrow senses of water conservation could be found in recent literatures. The manifestations of water conservation in a broad sense cover the rainfall interception and storage, runoff regulation, precipitation increasing (in debate), and water purification , etc., while the actual manifestations of water conservation are closely linked to the study area, objectives, and scales. Currently, the methods for measuring the amount of conserved water include soil water storage capacity method, water balance method, annual runoff method, and multiple-factor regression analysis m ethod, etc., and all of them have their prerequisites and limitations. In practi ce, the measurement methods should be selected according to actual situations.

Degradation of watershed ecosystems in China: A review.

LI Chun-yan^1，2;DENG Yu-lin¹

2009, 28(03):  535-541 . 

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Watershed ecosystem is a macro-scale and integrated unit with the comp lexity in coupling of natural, social, and economic factors. Owing to its specia l development condition and evolution process, watershed ecosystem is intensivel y and chronically interfered by human activities. In recent years, the functiona l assessment of watershed ecosystem has been paid more attentions by researc hers, and especially, the degradation of different type watershed ecosystems has been widely studied at various temporal and spatial scales, giving a sound basi s for the integrated management of watershed ecosystems in China. This paper sum marized the research progress on the degradation of watershed ecosystems in Chin a, including evolution mechanism, diagnosis, classification, integrated assessme nt, and monitoring and early-warning, and analyzed the focuses and directions o f further studies.

Research advances in biological conservation corridor.

LI Zheng-ling¹;CHEN Ming-yong^2,3;WU Zhao-lu^1,2

2009, 28(03):  523-528 . 

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Biological conservation corridor (BCC) is an applied type of landscape ecological corridors. The basic concept, theoretical foundation, structure and role, quality and function, efficiency validation, construction, and management of BCC were introduced. There were more theoretical discussions than practices o n BCC, and the importance of community participation in BCC planning and design became common understanding but had lesser case study. A detailed analysis of Xish uangbanna BCC revealed the key roles of community participation in the BCC plann ing/design and practice. The co-management pattern of community participation w ould be the important way in BCC research and practice in the future.

Research progress in aquatic ecological function regionalization and its approach at watershed scale.

HUANG Yi;CAI Jia-liang;ZHENG Wei-shuang;ZHOU Feng;GUO Huai-cheng

2009, 28(03):  542-548 . 

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Sustained and intensive human activities have serious impact on the he alth and security of aquatic ecosystems. It is one of the keys to coordinate eco nomic development and ecological protection at watershed scale by discriminating aquatic ecological function, establishing aquatic ecological function regions, and rationally administrating water resources based on different functions. Thro ugh the analysis of the development in the concept, definition, characteristics, and approach of aquatic ecological function region at watershed scale (AEFRWS), this paper proposed the principles, indicators, and methods of AEFRWS regionali zation, and provided basic information for the establishment and improvement of the theories and approaches of AEFRWS in China.

Utilization of tidal creek habitat by the nektons in a newly formed salt marsh at Yangtze River estuary.

QUAN Wei-min;NI Yong;SHI Li-yan;CHEN Ya-qu

2009, 28(03):  560-564 . 

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The nektons in an intertidal creek of a newly formed salt marsh at Yangtze River estuary were sampled by Fyke net to assess its habitat utilization of the salt marsh. A total of 20 nekton species were recorded in three investigations, including 15 fishes and 5 crustaceans. Among the nektons, freshwater species (10 species) were the most abundant ecological groups, followed by estuarine (6 species), migratory (3 species), and coastal species (1 species). In term of numeric abundance, the nektons were highly dominated by Exopalaemon annandalei (35.4%), Acanthogobius luridus (177%), Hemiculter leucisculus (177%), Saurogobio dumerili (92%), and Marobrachium nipponensis (46%). Most of the nektons sampled in this study were juveniles, suggesting that the newly formed salt marsh was the important nursery habitat for many fishes and crustaceans.

Research advances in soil magnesium pollution of magnesite mining area and related mechanisms.

FU Sha-sha^1,2;LI Pei-jun¹;FENG Qian^1,2;JIA Hong-yu¹;LI Xiao-jun¹; Verkhozina VA³

2009, 28(03):  549-555 . 

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Magnesium is a necessary element for plant growth. There are many repo rts concerning about magnesium as a nutrient, but a few about soil magnesium pol lution. This paper introduced the present status of soil magnesium pollution in magnesite mining area, discussed the mechanisms of the pollution based on the ph ysical and chemical behaviors of magnesium in soil, summarized the corresponding amelioration techniques, and approached the main problems and the prospects in related researches.

Effects of exogenous silicon on leaf structure and water-holding capacity of cucumber plant.

ZHOU Xiu-jie^1,2;ZHAO Hong-bo³;MA Cheng-cang¹;LI Qing-fang¹

2009, 28(03):  556-559 . 

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A pot experiment was conducted to study the effects of silicon (K2SiO3) supply on the leaf structure and water-holding capacity of cucumber plant. The results showed that silicon supply increased the leaf thickness by 303%〖KG-*2〗-〖KG-*7〗408%, epidermis thickness by 353%〖KG-*2〗-〖KG-*7〗723%, palisade tissue thickness by 569%〖KG-*2〗-〖KG-*7〗1152%, and cell tense ratio by 259%〖KG-*2〗-〖KG-*7〗711%, and decreased the specific leaf surface area by 476%〖KG-*2〗-〖KG-*7〗714% and sponge ratio by 226%〖KG-*2〗-〖KG-*7〗245%. As a result, the leaf transpiration of cucumber plant decreased by 258%〖KG-*2〗-〖KG-*7〗276%, and the leaf water content increased by 325%〖KG-*2〗-〖KG-*7〗362%. By the alteration of cucumber leaf structure, silicon decreased the leaf transpiration while increased the leaf water-holding capacity, and thus, enhanced the drought resistance of cucumber plant.

Landscape statistics and landscape sampling methods.

LI Xiao-li^1,2;ZHANG Jian-fang³;LIU Guo-bin²;XU Ming-xiang²

2009, 28(03):  565-571 . 

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In the study of large-scale landscape, adopting low resolution remote sensing data often causes the trouble of modifiable area unit, while scaling-u p technique can hardly assure the reliability of the conclusion. Landscape stati stics and its sampling technique, in which the basic principles and methods of s tatistics were applied to landscape ecology, would be a good way for solving the problems mentioned above, being available to the more accurate research on larg e-scale landscape with limited input. In this paper, some basic concepts of lan dscape statistics were introduced, and the principles and methods of landscape s ampling and statistical inference were discussed. The application scope, difficu lties, and development prospects in using landscape statistics were also approached.

Extraction and amplification of genomic DNA from formalin-fixed Coreius heterodon.

WANG Dan^1,2;TAN De-qing¹;TONG Jin-gou¹

2009, 28(03):  572-576 . 

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Coreius heterodon is an important commercial fish species in the upper and middle reaches of Yangtze River, and one of the appropriate fishes for the study of possible ecological effects of the Three Gorges Dam. However, the museum C. heterodon specimens were preserved in formalin. It is necessary to approach the methods of effectively extracting the genomic DNA from formalin-fixed C. heterodon, and the feasibility of using the extracted DNA in microsatellite- and mitochondrial analyses. In the present paper, the genomic DNA of ten formalin-fixed C. heterodon specimens was successfully extracted by the steps of removing the formaldehyde through improved gradual dehydration first and extracting the genomic DNA by the traditional phenol-chloroform method then. After primers designed, the PCR amplification was carried out, and a 205 bp of the control region of mtDNA from all of the ten specimens was successfully amplified. SSCP analysis indicated that no polymorphism was detected in this short fragment, and SSR also showed monomorphic. It was suggested that by using alcohol treatment, the formalin-fixed specimens of C. heterodon could be used as the potentially suitable biological materials in the studies of the possible changes of genetic diversity after large hydropower projects were constructed.