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    10 November 2009, Volume 28 Issue 11
    Articles
    Effects of enclosure on vegetation characteristics and spatial heterogeneity of Caragana mirophylla  community in Horqin Sandy land.
    JIANG De-Meng;LI Meng;JIA Tian-Min-Xiong;TANG Yi
    2009, 28(11):  2159-2164. 
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    This paper studied the vegetation characteristics and smallscale spatial heterogeneity of Caragana mirophylla community in Horqin Sandy Land in northeast Inner Mongolia of China under grazing and under 6 and 12 years enclosure, aimed to assess the effects of grazing and enclosure on vegetation restora tion. In the sampling plots of grazing and different years enclosure, the species composition of  C. mirophylla community all dominated by annual herbaceous plants. The species richness in grazed plot and in the plots enclosed for 6 and 12 years was 22, 19, and 20, respectively, with no significant difference. In the plots enclosed for 6 and 12 years, the plant density was (124.46±5.22) plants·m-2  and (203.05±10.38) plants·m-2,  respectively, being significantly higher than that in grazed plot, which suggested that enclosure was an effective method to accelerate the vegetation restoration in Sandy Land. The Shannon-Wiener  index, Simpson species diversity, and Pielou evenness in enclosed plots were lower than those in grazed plot, and decreased with increasing enclosure duration.  The small scale spatial heterogeneity of vegetation in enclosed plots was smaller than that in grazed plot. The longer the enclosure duration, the smaller the spatial heterogeneity was.
    Seed germination characteristics and their significance in artificial propagation of native species Anneslea fragrans.
    SHEN Shi-Kang;WANG Ti-Hua
    2009, 28(11):  2165-2170. 
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    This paper studied the seed germination characteristics of native species Anneslea fragrans in Southern China under the conditions of aril removal, dehydration, PEG osmotic stress, and different light and temperature. Aril removal benefited the seed germination of  A. fragrans. Fresh harvested seeds had higher moisture content (65.6%), and dehydration gave significant impact on their germination. The germination rate decreased with increasing dehydration duration, and the seed viability was completely lost after 48 h continuous dehydration. Soaking in 5%-30% PEG solution for 24 h decreased the seed germination rate significantly, indicating that  A. fragrans seed germination was sensitive to osmotic stress. Light had little effects on the seed germination. The optimal temperature range for the seed germination was 20 ℃-25 ℃, while high temperature inhibited the seed germination. Based on the responses of the seed germination to the test factors, some suggestions were made on the artificial propagation of  A. fragrans.
    Effects of sea water salinity and mother tree size on the seed germination and seedling early growth of Pinus thunbergii coastal rotection forest.
    HAN An-Han;MAO Pei-Li;LIU Su-Jing;WANG Guang-Mei;ZHANG Zhi-Dong;XUE Qin-Zhao
    2009, 28(11):  2171-2176. 
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    Pinus thunbergii is the main forestation tree species of coastal protection forests in northern Shandong Peninsula of China. Its seed germination and seedling early growth were studied under the conditions of different water salinity (0, 0.02, 0.04, and 0.08 mol·L-1) and mother tree sizes. With increasing sea water salinity, the seed germination rate, root  and plumule length, and the dry weights of root and plumule decreased significantly. Mother tree size had little effects on the seed germination rate, but affected the root and plumule length and the plumule dry weight significantly. The interaction of sea water salinity and mother tree size affected the root and plumule length significantly, but less affected the germination rate and the dry weights of root and plumule.
    Irrigation water requirement by winter wheat in Huanghuai Plain: Affecting factors and characteristics in different climatic years.
    FANG Wen-Song;LIU Rong-Hua;SHU Zi-Xi;MA Zhi-Gong;LI Shu-Yan;HU Peng-Peng
    2009, 28(11):  2177-2182. 
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    By using the last 46--54 years precipitation data from 80 meteorological stations and the 0-100 cm soil water content data at 10 stations in the Huanghuai Plain, the relationships between the irrigation water requirement and water requirement by winter wheat, and between the precipitation in winter wheat growth season and the soil water content at planting time were analyzed, based on t
    he principles of farmland water balance. In the meantime, the characteristics of irrigation water requirement by winter wheat in ifferent climatic years were studied. In the study area, the isoline of irrigation water requirement by winter wheat was basically in latitudinal distribution, with the requirement increased gradually from south to north. In normal years, the zero isoline was located in Xuchang-Fugou-Zhecheng-Luyi-Bozhou-Xiaoxian-Xuzhou. Along this line, the water requirement by winter wheat was in balance with water supply, and no or less irrigation was required. However, in the north of this line, irrigation should be made, with the irrigation amount increased northward, being about 60-100 mm and 100-190 mm and irrigating 1-2 times or 2 times. In the south of this line, no irrigation was required. In the years of plentiful precipitation, the zero isoline moved northward by 0.5-1.0 latitude, and the irrigation
     area and irrigation amount decreased obviously; while in the years of short precipitation, the zero isoline moved southward by 1.0-1.5 latitude, and the irrigation area and irrigation amount increased obviously.
    Plant communities in newly created wetlands in water level fluctuation zone of Three Gorges Reservoir after flooding to 156 m height.
    WANG Jiang;YUAN Xin-Zhong;LIU Gong;WANG Jian-Xiu
    2009, 28(11):  2183-2188. 
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    After flooding to 156 m height, a wide area of wetlands emerged in the water level fluctuation zone of Three Gorges Reservoir. From July to September 2008, an investigation was made on the plant communities beside Baijia stream, the first order tributary of Pengxi River in Kaixian County of Chongqing. There were 33 species of wetland vascular plants, among which,  Paspalum paspaloides, Typha latifolia, Scirpus juncoides, S. triqueter, Polygonum longisetum were the dominant. The plant communities in study area were divided into eight associations. An obvious zonal distribution was observed at the lateral side of Baijia stream from riparian to 156 m altitude. There were three plant zones,  i.e., floodplain annual herb zone,  X. sibiricum zone, and P. paspaloides zone. With increasing elevation, the aboveground biomass showed a singlepeak pattern. During the period with lower water level, the increase of soil water content accelerated the growth of wetland plants. P. paspaloides was most dominant in the low lying area of second terraces of Baijia stream, and X. sibiricum widely distributed on the sloping field between the first and second terraces of the stream. The variations of soil water content and microgeomorphic pattern significantly affected the distribution of plant communities in water level fluctuation zone.
    Major hydro environmental factors affecting the community composition of wetland submerged plants in Beijing.
    YUAN Jing;CUI Guo-Fa;LEI Ting
    2009, 28(11):  2189-2196. 
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    In order to reveal the hydro environmental factors affecting the community composition of wetland submerged plants, and to approach the possibility of using certain submerged plant species or communities as the direct indicators in detecting hydroenvironment, a field investigation was conducted on nine freshwater wetlands in Beijing. The plant fresh mass, wetland hydrological parameters (flow rate and water depth), and water physical and chemical parameters (transparency, temperature, conductivity, pH, redox potential, total nitrogen, total phosphorus, and chemical oxygen demand) were measured, and DCCA ordination was made. Based on the ordination, and by using two way classification matrix, the fourteen wetland submerged plant species in Beijing were classified into ten groups. According to the comprehensive analysis on the measured variables, the factors affecting the community composition of the wetland submerged plants were flow rate, total nitrogen concentration, chemical oxygen demand, conductivity, and redox potential, among which, flow rate was the key. Different submerged plant communities had indicative significances for the wetland hydro environment. For example, the occurrence of  Myriophyllum spicatum + Potamongeton crispus community was an indicator for severe eutrophication, while that of  Batrachium pekinens community could be regarded as an indicator of better water quality.
    Phytoplankton and its relations with eutrophication of southern Taihu Lake.
    YUAN Ji-Lin;YIN Wen-Lin;CHEN Jin-Yu;ZHANG Ai-Ju;DIAO Han-Qu;XIE Jin-Yun
    2009, 28(11):  2197-2201. 
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    In August September 2008, an investigation was made on the phytoplankton in southern Taihu Lake, and the water quality at nine sampling sites was analyzed. A total of 47 phytoplankton species belonging to 28 genera and 7 phylums were collected, with 9 species of Cyanophyta, 13 species of Chlorophyta, 18 species of Diatoms, 3 species of Euglenophyta, 2 species of Cryptophyta, 1 specie of Chrysophyta, and 1 specie of Dinophyta. The phytoplankton density was 3.56×106-7.99×106 cells·L-1, Shannon Weaver index was 0.29-2.77, evenness was lower than 0.5, and trophic state index (TSIM) was higher than 64. Based on the evaluation of the dominant species composition, density, and ShannonWeaver index of phytoplankton, and of the TSIM, the southern Taihu Lake was considered at the stage of eutrophication.
    Flowering phenology of alpine meadow plant community in eastern Qinghai Tibetan Plateau.
    LI Xiang-Jian;GU Feng;ZHANG Zhi-Long;DU Guo-Zhen
    2009, 28(11):  2202-2207. 
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    Based on the observation on the flowering phenology in the whole growth season of 2008, the dynamics, patterns, and elationships among various parameters of flowering phenology of alpine meadow plant community in eastern Qinghai Tibetan Plateau were studied, and the  potential effects of above mentioned factors on the species coexistence of the plant community were approached. The flowering period of the plant community started from early May, came into peak period in the first ten days of August, and ended in early October, extending all over whole growth period. Different species had their different first flowering date, peak flowering period, and flowering duration, and their flowering phenological niches differentiated obviously. Most species had their peak flowering period centralized in July-August. There was a negative relationship between peak flowering period and flowering duration: the earlier the flowering, the longer the flowering duration. The differences in flowering phonology among the species were mainly determined by species per se characteristics and environmental conditions, but the flowering phenological pattern on community level was primarily controlled by abiotic factors.
    Effects of Ni stress on Agropyron elongatum seedlings growth and reactive oxygen species metabolism.
    LU Yan;HE Meng-Zhu;DIAO Cuan;LIU Yu-Bing;TAN Hui-Juan;LI Xin-Rong
    2009, 28(11):  2208-2212. 
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    Agropyron elongatum seedlings were exposed to different concentration Ni to study their growth and the changes in MDA and soluble protein contents and  SOD, POD and CAT activities in their shoots and roots, and the photosynthetic pigment content in their leaves. Low concentration (10 μmol·L-1) Ni had no significant inhibitory effects on the seedlings growth, but the growth indices decreased significantly with increasing Ni concentration, being more markedly for roots than for shoots. The leaf photosynthetic pigment content had a decreasing trend with increasing Ni concentration, while the MDA content in shoots and roots had significant positive correlation with Ni concentration. The soluble protein content in roots increased with increasing Ni concentration. Under low concentration (10 μmol·L-1) Ni, the SOD, POD and CAT activities all increased, and the protective enzyme system was well balanced. When the Ni concentration was increasing, the three enzyme activities were inhibited to different extents, and the balance of protective enzyme system was broken.
    Effects of doubled atmospheric CO2 concentration on nitrogen metabolism of transgenic Bt cotton under different nitrogen fertilization levels.
    GAO Hui-JingXIAO Nai-Wen;LI Dun-Sheng;CHEN Xiao-Yun;CHEN Fa-Jun;DI Bao-Beng
    2009, 28(11):  2213-2219. 
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    By using open top chambers, this paper studied the physiological and ecological responses of transgenic Bt cotton cv. 33B and its parent line nontransgenic cotton cv. DP5415 in their growth potential and nitrogen metabolism to doubled CO2 concentration (750 μl·L-1 vs. 375 μl·L-1) and nitrogen fertilization level (200 mg N·kg-1 vs. 100 mg N·kg-1). Doubled CO2 concentration promoted the height and stem growth and the biomass production of the two cultivars significantly, whereas doubled N fertilization level only had significant positive effects on 33B. The leaf glutamine synthetase activity (GSA) of DP5415 decreased significantly under doubled CO2 concentration but increased significantly under doubled N fertilization level, while the GSA of 33B was significantly higher under doubled CO2 concentration and low nitrogen fertilization level. Both the doubled CO2 concentration and the doubled nitrogen fertilization level increased the leaf nitrate reductase activity (NRA) of 33B significantly, and the NRA of DP5415 also had a significant increase under doubled CO2 concentration. Doubled CO2 concentration had significant inhibitory effects on the leaf nitrite reductase activity (NiRA) of both 33B and DP5415. The NiRA of DP5415 decreased significantly under doubled CO2 concentration and N fertilization level. All the results suggested that under doubled CO2 concentration, N fertilization level had significant effects on the growth potential of transgenic Bt cotton but lesser effects on its nitrogen metabolism, compared with the control nontransgenic cotton. Therefore, in the planting of transgenic Bt cotton, especially under elevated CO2 condition, optimized N fertilization should be made.
    Effects of elevated O3 and CO2 on the antioxidant enzyme activities in Pinus tabulaeformis needles.
    LI Xiang;HE Xin-Yuan;CHEN Wei;XU Qing;YAN Kun
    2009, 28(11):  2220-2226. 
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    Four year old  Pinus tabulaeformis seedlings were planted in open topped chambers and treated with elevated O3 (80 nmol·mol-1) and/or CO2 (700 μmol·mol-1). After treated for three years, the malondialdehyde (MDA) content, reactive oxygen species, and antioxidant enzyme activities in the  current year needles were analyzed. In treatment elevated O3, the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and dehydroascorbate reductase (DHAR) increased significantly, being 43.1%, 18.9%, 283.5% and 142.6% higher than the control; and in treatments elevated CO2 and its combination with elevated O3, only APX and CAT activities were induced remarkably but still lower than those in treatment elevated O3. Elevated O3 increased the MDA content by 51.8%, whereas the combination of elevated O3 and CO2 reversed this increase efficiently. No significant differences were observed in the superoxide anion (O2) generating rate and H2O2 content among all treatments. All the results demonstrated that elevated O3 was able to effectively activate the antioxidant enzyme system in  P. tabulaeformis current year needles, while elevated CO2 could mitigate the negative effects of elevated O3 through the actions other than enhancing the antioxidant enzyme activities.
    Schima superba stem CO2 efflux and its relations to xylem sap flux density and xylem CO2 concentration.
    SHU Li-Wei;DIAO Beng;CA Ti-An;CENG Xiao-Beng;JU Lu-Liu
    2009, 28(11):  2227-2232. 
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    By using a Li 820 infra red CO2 gas analyzer, an in situ measurement of  Schima superba stem CO2 efflux was conducted for three consecutive days from 17 to 19 October 2008. In the meantime, the stem temperature, xylem sap efflux density, and xylem CO2 concentration were measured. The stem CO2 efflux had a diurnal variation of “S” pattern, and differed significantly with stem diameter. There was a significant exponential relationship between stem CO2 efflux and stem temperature (0.24<R2<0.78). The temperature coefficient (b) and regression coefficient (R2) were higher at nighttime than at daytime, and the Q10 value ranged from 2.01 to 2.79. The stem CO2 efflux correlated significantly with the xylem CO2 concentration, and the best regression curve was cubic (R2=0.48). Excluding the effects of stem temperature, the stem CO2 efflux showed a significant negative correlation with xylem sap flux density (r = -0.462). Therefore, only using simple temperature function to estimate stem CO2 efflux would yield a significant error, and xylem sap flux should be taken into consideration in the stem CO2 efflux estimation.
    A comparison of response curves of winter wheat photosynthesis to flag leaf intercellular and air CO2 concentrations.
    XIE Zi-Piao;XU Jiang
    2009, 28(11):  2233-2238. 
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    By using Li6400 portable photosynthesis system, the photosynthetic parameters of winter wheat (Triticum aestivum) during its heading stage in North China Plain were measured at air temperature 25 ℃ and 30 ℃ and at photosynthetically available radiation 1500 and 2000 mmol·m-2·s-1. The measured data were fitted with the modified rectangular hyperbola models of the photosynthetic responses to flag leaf intercellular CO2 concentration (A/Ci) and air CO2 concentration (A/Ca), aimed to approach the reasonability of the fitted results obtained from the models. The photosynthetic capacity and CO2 compensation point estimated by the modified A/Ci curve and A/Ca curve were nearly the same, but the photorespiration and initial carboxylation efficiency estimated by them were completely different. The difference between the two modified curves came from the calculated but not the real intercellular CO2 concentration. Modified A/Ca curve was more reasonable than the modified A/Ci curve, because the potorespiration rate estimated by the former was close to the measured value.
    Effects of long term fertilization on rice photosynthetic traits and water use efficiency.
    YUAN Ying-Gong;FAN Hou-Bao;HUANG Qian-Ru;LIAO Ying-Chun;HUANG Rong-Zhen
    2009, 28(11):  2239-2244. 
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    A field experiment has being conducted for 27 years in Jinxian County, Institute of Red Soil in Jiangxi Province (116°20′24″ E, 28°15′30″ N) to study the effects of fertilization on the rice photosynthetic traits and water use efficiency. Four treatments were installed, i.e., no fertilization (CK), chemical fertilization (N, NP, NPK), organic fertilization (M), and chemical and organic fertilization (NPKM). Longterm fertilization, especially treatment NPKM, increased the flag leaf chlorophyll content, net photosynthetic rate, stomatal conductance, transpiration rate, and water use efficiency of rice at its all growth stages and the rice yield, and decreased the flag leaf intercellular CO2 concentration. With the growth of rice, the chlorophyll content, net photosynthetic rate, stomatal conductance, and transpiration rate decreased, but the intercellular CO2 concentration increased. The water use efficiency was the greatest at full heading stage. There were significant positive correlations between the chlorophyll content and net photosynthetic rate at various growth stages and the rice yield. Long-term fertilization, especially the combined chemical and organic fertilization, was favorable to the rice growth and development, water use efficiency, and yield production in red soil region.
    Historical eutrophication in Wuli Bay of Taihu Lake, China based on carbon isotope record.
    LI Jun;XIAO Hua-Yun;SHU Zhao-Zhou;WANG Shi-Lu;WANG Mei-Li
    2009, 28(11):  2245-2249. 
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    Through the analysis of total organic carbon, total nitrogen, and total phosphorus concentrations in surface sediment cores from Wuli Bay of Taihu Lake, the historical record of phosphate input in the Bay was studied, and in combining with the analysis of carbon isotope value of bulk sedimentary organic matter, the evolution process of the primary productivity and eutrophication in the Bay was revealed. The carbon isotope value of the sediment total organic C was -26.6‰ on average, with a variation between -27.0‰ and -26.3‰. It was decreased with depth up to the lowest value at 5 cm, subsequently increased gradually up to the highest value at 12 cm, and then fluctuated downward with the depth, which suggested that the evolvement of eutrophication, productivity, and primary producer was associated with the increasing phosphorus input from human activities. Moreover, the concentrations of total phosphorus and the C/N atomic ratios of total organic carbon to total nitrogen recorded the succession process of aquatic plant community from float grass to float grass + algae to algae.
    Effects of copper and cadmium on leguminous plant growth and nutrient uptake.
    HAN Xiao-Shu, CAO Cheng-Wei, TAO Jin-Dong, GAO Fei-Fei
    2009, 28(11):  2250-2256. 
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    Aimed to understand the growth status and nutrient uptake of leguminous plants under soil copper or cadmium contamination, a pot experiment with Medicago sativa, Trifolium pretense, and Astragalus adsurgens was conducted, with their plant height, root length, plant biomass, and N, P, K, Cu and Cd contents in leaf and stem measured. The application amounts of Cu2+ and Cd2+ we
    re 0, 400, 800, and 1200 mg·kg-1, and 0, 1, 10, and 20 mg·kg-1, respectively. All the test three leguminous plants had strong capability of absorbing Cu and Cd. The Cu and Cd contents in their roots, stems, and leaves, except the Cu content in T. pratense leaf, were significantly positively correlated with the application amounts of Cu2+and Cd2+ Under the application of Cd2+, all the three leguminous plants grew normally. When the application amount of Cu2+was ≤1200 mg·kg-1, T. pratense grew normally, while the growth of M. sativa was significantly inhibited. The growth of A. adsurgens was inhibited when the application amount of Cu2+ was ≥ 800 mg·kg-1. An application amount of ≤1200 mg·kg-1 of Cu2+ promoted the N, P and K absorption of M. sativa, but applying ≤ 800 mg·kg-1 of Cu2+ had little effects on the N, P and K absorption of  T. pretense. The N, P and K contents of  A. adsurgens increased when the application amount of Cu2+ was ≤400 mg·kg-1,but decreased significantly when the Cu2+ application amount was ≥800 mg·kg-1. When the application amount of Cd2+ was ≤20 mg·kg-1, the N, P and K contents in M. sativa and T. pratense stems and leaves and in A. adsurgens stem increased, while those in A. adsurgens leaf decreased. As a whole, the three leguminous plants all had certain tolerance to Cu2+ and Cd2+ stresses, especially T. pratense to Cu2+ and M. sativa to Cd2+.
    Acute toxicity effects of bisphenol A and p-nitrophenol to Misgurnus anguillicadatus.
    LEI Xin;LI Zong-Jiang;LIAN Zhen-Min;YAN Zhi-Lian;BAI Chong-Tan
    2009, 28(11):  2257-2261. 
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    By the methods of single factor toxicity test and histological observation, this paper studied the acute toxicity of bisphenol A (BPA) and p-nitrophenol (p-NP) to Misgurnus anguillicadatus and the histological changes of M. anguillicadatus gill. The median lethal concentration (LC50) and safe concentration (SC) were calculated. The LC50 of BPA for 24, 48, 72, and 96 hours were 8.32, 8.02, 6.97 and 6.43 mg·L-1, respectively, and the SC was 2.24 mg·L-1; while the mean LC50 values of p-NP for 24, 48, 72, and 96 hours were 19.14, 17.58, 16.98, and 14.69 mg·L-1, respectively, and the SC was 4.40 mg·L-1. After exposed to BPA and p-NP, the cells of branchial leaflets fell off, and the branchial leaflets became thin. Both BPA and p-NP had high toxicity to M. anguillicadatus, and BPA had higher toxicity than p-NP. With the increasing concentration and exposure time of BPA and p-NP, their toxicity effects to M. anguillicadatus increased, and the damage on gill of  M. anguillicadatus was more severe.
    Genetic diversity of three cultured Pinctada fucata populations based on microsatellite loci analysis.
    LI Xiao-Ning;ZHANG Dian-Chang;SHU Cai-Yan;SU Tian-Feng;JIANG Shi-Gui
    2009, 28(11):  2262-2268. 
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    By using eight microsatellite loci (M1, M2, M3, M4, M5, M6, M7 and M8), the genetic diversity of three Pinctada fucata populations from the pearl farms in Xuwen of Guangdong and Beihai of Guangxi, and from the experimental base of South China Sea Fisheries Research Institute in Hainan was studied. A total of fifty eight alleles of these eight microsatellite loci were detected, among which, the observed allele number was 2-9, average effective allele number was 3.72-5.06, average observed population heterozygosity was 0.41-0.56, and average observed expected heterozygosity was 0.67-0.75. All the three populations had a polymorphic information content (PIC) of 0.62-0.70, suggesting their high polymorphism (PIC>0.5). Among the three populations, the cultured population from the experimental base of South China Sea Fisheries Institute had the highest polymorphism, and that from Beihai of Guangxi had the lowest one. These results provided useful information for the selective breeding and germplast conservation of P. fucata
    Controlling effect of tobacco endophyte against tobacco root-knot nematode disease.
    YANG You-Cai, HUANG Xiao-Hui, GONG Li, CENG Jiang, TAN Zhou-Jin
    2009, 28(11):  2269-2272. 
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    Several tobacco endophyte strains were screened out, and their controlling effect against tobacco root-knot nematodes was studied with pot experiment. The fermentation broth of endophytic bacteria was more effective than the bacterial thallus, while that of endophytic actinomycetes was less effective than the actinomycete fermentation broth. All test endophytes promoted tobacco growth, and the promotion effect of their thalli was better than that of their fermentation broths. Endophytic bacterial strain H3 was the best in controlling tobacco root-knot nematode disease, with 91.68% controlling effect and a disease index of 4.16, much better than the treatments CK and avermectin. Moreover, the morphological feature of tobacco plant treated with H3 was better than that treated with avermectin.
    Allelopathic effects of diisobutyl adipate on pepper seed germination and Fusarium oxysporum f. sp. vasinfectum.
    ZHOU Bao-Li;HANG Jian;LIU Na;AO Ting;U Bo;XIE Xue-Ling
    2009, 28(11):  2273-2278. 
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    By the methods of laboratory incubation and bioassay, a simulation test was conducted to study the allelopathic effects of different concentration diisobutyl adipate on pepper seed germination and its seedling growth and Fusarium oxysporum f. sp. vasinfectum. For the pepper seed germination and seedling growth, diisobutyl adipate exhibited allelopathic promotion at low concentration, but allelopathic inhibition at high concentration. There existed greater differences in the allelopathic effects of diisobutyl adipate on the seed germination and seedling growth of pepper and eggplant. The promotion effects of low concentration diisobutyl adipate on pepper were stronger than those on eggplant, while the inhibition effects of high concentration diisobutyl adipate on pepper were weaker than those on eggplant. All test concentration diisobutyl adipate had significant inhibition effects on the mycelium growth of Fusarium oxysporum f. sp. vasinfectum, and the effects increased with increasing diisobutyl adipate concentration, being the strongest (an inhibitory rate of 10.75%) at 1 mnol·L-1. Field text indicated that diisobutyl adipate at all test concentrations enhanced the disease resistance of pepper seedlings. The best effect was observed at 1 mmol·L-1 of diisobutyl adipate, with the disease index decreased by 49.88%, compared to the control.
    Effects of different tillage modes on rain-fed farmland soil microbial biomass and crop indices in Inner Mongolia.
    SUN Jian;LIU Miao;LI Li-Jun;LIU Jing-Hui;KENNETH Dean Sayre
    2009, 28(11):  2279-2285. 
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    This paper studied the dynamic changes of soil microbial biomass and crop indices on a degraded rain-fed maize field in the Qingshuihe County of Inner Mongolia under no tillage with low stubble (NL), no tillage with high stubble (NH), no tillage with low stubble and residues (NLS), no tillage with high stubble and residues (NHS), and conventional tillage (CT). No tillage increased the soil microbial biomass C, N, and P, with the sequence of treatments NHS>NLS>NH>NL>CT. Except that the soil microbial biomass C in CT had an increase in 10-20 cm soil layer, the soil microbial biomass C, N, and P in all treatments decreased with soil depth. The soil microbial biomass C, N, and P had the same seasonal pattern, being the highest in July, secondly in June, and the lowest in October. The LAI in whole growth period varied in unimodal form, while the plant height and dry matter accumulation were in “S” form. All the crop indices followed the order of NHS>NLS>NH>NL>CT. Soil microbial biomass, its P in particular, had positive correlations with crop indices. Our results revealed the advantages of no tillage on rainfed farmlands in Inner Mongolia.
    Soil respiration of winter wheat fields in North China Plain.
    DENG Ai-Juan;SHEN Shuang-He;ZHANG Xue-Song;LI Yong-Xiu;XIE Die-Song
    2009, 28(11):  2286-2292. 
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    By using LI-8100 and LI-6400-09, the soil CO2 flux of a winter wheat field in North China Plain was determined from April to June 2008, with its change patterns and affecting factors analyzed. The soil respiration had a single peak diurnal variation, with the maximum at 12:30-14:30 and the minimum at 5:00-6:30, and the respiration rate was higher in sunny days than in cloudy or overcast days. There was a significant negative correlation between the CO2 concentrations at all canopy heights and the soil respiration rate at daytime, but a significant positive correlation at night. The soil respiration rate presented a seasonal variation similar to the soil temperature at 5 cm depth, and had a significant exponential relationship with the soil temperature. Significant correlation was also found between the soil respiration rate and soil humidity when the soil moisture content was within the range of field capacity. Soil humidity less than 30% would limit the soil respiration, inducing a decrease of soil CO2 flux. A multiple exponential regression model of soil temperature and moisture could better explain the variation of soil respiration, especially when the soil temperature was below 15 ℃.
    Change characteristics of soil salt content in different landscape units in arid region.
    WANG Yu-Gang;ZHENG Xin-Jun;LI Pan
    2009, 28(11):  2293-2298. 
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    Aiming at the problem of soil salinization in inland river basin, a case study was conducted in the Sangong River catchment of Xinjiang, China. The characteristics and dominant affecting factors of salt accumulation in 0-10 cm and 10-20 cm soil layers in two hydro geological zones, i.e., alluvial-proluvial delta and alluvial plain, were studied in a growth season (from May to October), and the precipitation, evaporation, groundwater table, and irrigation were also taken into account. The soil salt content was obviously lower in alluvial-proluvial delta than in alluvial plain, but its coefficient of variation in the two zones was all higher than 100%, indicating a great variability. The soil salt accumulation in-irrigated landscape in the two zones had a similar decreasing trend, but that in nonirrigated landscape had greater difference, with a decreased soil salinization in alluvial-proluvial delta, and an increased soil salinization in alluvial plain. In alluvial-proluvial delta, the salt contents in 0-10 cm and 10-20 cm soil layers had a close relationship (P<0.01), and there was a clear process of salt leaching by precipitation and irrigation, leading to the decrease of soil salt content. In alluvial plain, the salt accumulation in 0-10 cm soil layer in non-irrigated landscape was promoted by evaporation, and that in 10-20 cm soil layer was co-affected by the salt content in 0-10 cm soil layer and the groundwater table.
    Behavioral patterns of 5-month old Aohan fine-wool male lambs under stall-feeding.
    YAN Le-Yan;YUE Du-Bing;LUO Hai-Ling;ZONG Ze-Jun
    2009, 28(11):  2299-2304. 
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    By the methods of focal sampling and all occurrence recording, a continuous observation on the behaviors of 5-month old Aohan fine-wool male lambs under stall-feeding was conducted day and night in an experimental sheep farm in August 2007. The male lambs spent (519.37 ±14.27) min·d-1 for ruminating, (326.43±5.44) min·d-1 for eating, (94.67±10.41) min·d-1 for moving, (98.18±12.97) min·d-1 for standing, and (357.69±14.91) min·d-1  for resting. A diurnal rhythm was observed in the behaviors of the lambs, i.e., the time for eating and ruminating was longer at night than at daytime, while that for moving, resting, and standing was longer at daytime than at night. In the whole day, the time ratio for ruminating to for eating was 1.59:1.00, and the total number of ruminated cuds was 581.83±45.57. Understanding the behaviors of the male lambs would help to the improvement of management practices for rearing Aohan fine-wool sheep under stall-feeding.
    Vegetation landscape pattern and its fragmentation on southern slope of Qilian Mountain.
    SHANG Cui-Wen;ZHANG Hai-Feng;CHEN Yin-Ping;YAOXue-Ling;WANG Li-Juan;XIAO Du-Ning
    2009, 28(11):  2305-2310. 
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    Based on the forest form map and investigation data of Zhamashi forest area, and by using GIS, appropriate landscape pattern indices were chosen to study the basic characteristics of vegetation landscape pattern on the southern slope of Qilian Mountain, with the landscape fragmentation evaluated. In the study area, grass and shrub were the main vegetation types, and the landscape matrix had degraded to bare land. The patch densities of all vegetation types were far larger than that of bare land, and their mean fractal dimension was lower than that of bear land. All of these characters emphasized the highly fragmented condition of the vegetation landscape in this area. The total edge densities and fragment indices of grassland and shrub land were higher than those of other vegetation types, reflecting that the natural vegetation was mainly affected by grazing. The forests were more dispersed in small areas, and the landscape structure of Picea crassifollia forest was heavily destroyed, being induced that the heterogeneity became lower and the patch shape tended to single, suggesting a high fragmentation degree. Other forest types were centralized in a certain habitat and less disturbed by human activities, suggesting a lower fragmentation degree.
    Estimation of vegetation net primary productivity on North Shaanxi Loess Plateau.
    SONG Fu-Jiang;KANG Mu-Yi;CHEN Ya-Ru;YANG Peng;LIU Yang;WANG Jiang
    2009, 28(11):  2311-2318. 
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    Based on the data from MODIS (Moderate-resolution Imaging Spectroradiometer) and meteorological observatories, and by using improved CASA (Carnegie-Ames-Stanford Approach) model, the vegetation net primary productivity (NPP) and its spatiotemporal distribution on the North Shaanxi Loess Plateau in 2005 were simulated and analyzed. Comparing with the traditional CASA model which only uses a universal mean annual maximum light use efficiency (LUE), the estimated regional NPP by the improved CASA model was more precise, because this improved model used the LUE parameters of different vegetation covers. The detailed land cover classification also contributed to the increase of the precision via introducing the time-series Normalized Different Vegetation Index (NDVI) and ground survey data to modify and adjust the original classification system based on vegetation map (1:1000000). The testing of the simulation results from different models with the ground survey data in North Shaanxi showed that the estimation by the modified CASA model was much closer to the real survey data, implying the potential practical significance of this model in estimating the vegetation NPP in North Shaanxi Loess Plateau and its adjacent areas. In 2005, the NPP in North Shaanxi was estimated as 4.76×1013 g C, accounting for about 1.5% of China’s terrestrial total NPP, and the mean NPP was 447.3 g C·m -2·a-1, being much higher than that of China’s terrestrial vegetation (323.8 g C·m-2·a-1) in 1982-2000. The spatial distribution pattern of the vegetation NPP showed an apparently declining trend from the southeast to the northwest, with the highest value of 1087 g C·m-2·a-1 occurred in the broadleaved and conifer mixed forests of Huanglong Mountain in southeast part of the region. The mean NPP of desert vegetation in the whole region was the lowest, only about 205.0 g C·m-2·a-1. An obvious seasonal variation of the NPP was observed. The NPP in growth season (from April to October) took about 91.5% of the total in the year, and the peak occurred in mid-July to mid-August, amounting to 37.8% of the total.
    Spatiotemporal characteristics and related affecting factors of grassland net primary productivity in western Jilin Province.
    LUO Ling;WANG Zong-Meng;SONG Kai-Shan;ZHANG Bai;LIU Dian-Wei
    2009, 28(11):  2319-2325. 
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    By using the annual net primary productivity (NPP) data from 2000-2006 MOD17A3 dataset and the GIS technique, the spatiotemporal characteristics of grassland NPP in western Jilin Province were studied, with the related affecting factors analyzed. During the past seven years, the mean grassland NPP in this province was 232.14 g C·m-2·a-1, and the grassland area with a NPP of 200-300 g C·m-2·a-1 accounted for 59.47% of the total. 77.60% of the grassland had an increasing NPP, and the grassland area with a remarkable increase of NPP accounted or 15.0% of the total. Water condition was the main cntrolling factor for grass growth, and residential points had far more effects than roads, especially within 2 km from grassland, on the NPP.
    Characteristics of climate change in Horqin Sandy Land in past 56 years.
    JU Cui-Beng;GUANDe-Xin;WANGAn-Zhi;JINChang-Jie;YUAN Feng-Hui;TUN Jia-Bing;NI Pan
    2009, 28(11):  2326-2332. 
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    ased on the 1951-2006 air temperature and precipitation data from seven meteorological stations in Horqin Sandy Land, the past 56-year climate change characteristics in this semi-arid area with vulnerable eco-environment and severe land desertification were analyzed. From 1951 to 2006, the mean annual air temperature in this area increased by 0.28 ℃·10 a-1, much higher than the global average value of 0.13 ℃·10 a-1 in recent 50 years. The increasing trend of the temperature appeared in all four seasons, but was only significant in winter and spring (P<0.01), with an increasing rate of 0.46 ℃·10 a-1and 0.39 ℃·10 a-1, respectively. Both the maximum and the minimum mean annual temperatures increased significantly (P<0.01), and the increasing rate was about 0.17 ℃·10 a-1 and 0.42 ℃·10 a-1, respectively. The annual precipitation fluctuated among years, with no obvious change trend at yearly and seasonal scales, while the precipitation days decreased significantly at yearly scale (1.3 d·10 a-1) but not at seasonal scale. No obvious change patterns were observed in the precipitation intensity both in yearly and seasonal scales. The annual light-rain days decreased significant (P<0.05) in a rate of 1.0 d·10 a-1.
    Change trends of forest fire danger in Yunnan Province in 1957-2007.
    DIAO Feng-Jun;SHU Li-Fu;TIAN Xiao-Rui;WANG Meng-Yu
    2009, 28(11):  2333-2338. 
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    Climate warming has already made great impact on forest fires. Based on the daily meteorological data (temperature, precipitation, relative humidity, and wind speed), and by using the Canadian Fire Weather Index calculation formula, the daily forest fire weather indices (FWIs) of Yunnan Province in 1957-2007 were calculated, and through the statistical analysis of FWIs, the forest fire trends in this province over the past 50 years were studied. In the past 50 years, the forest fire season in Yunnan Province was from previous year November to current year June, lasting 8 months. Fire data (fire numbers, burned area, and burned forest area) had significant relationships with fire weather indices. The average daily duff moisture code (DMC) in whole fire season and the seasonal severity rating (SSR) were the good indices to evaluate the fire danger conditions among different fire seasons. The forest fire danger in Yunnan Province in 1957-2007 showed two change trends. One showed a clear cyclical change and a weak upward trend, i.e., the fire danger conditions in 1991-2007 was slightly severer than that in 1961-1990; and the another was that the fluctuation of forest fire danger conditions among different fire seasons decreased in 1991-2007, and the number of abnormal severe fire seasons was less than that in 1961-1990.
    Climate suitability and its change trend of double-cropping rice in Huaihe River Basin.
    LAI Chun-Jia, QIAN Fu-Sui, DUAN Hai-Lai, SONG Qiu-Hong
    2009, 28(11):  2339-2346. 
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    Based on the 1961-2005 meteorological data from thirty three stations in Huaihe River basin, and by using fuzzy mathematics and spatial interpolation methods, the climate suitability of double-cropping rice in this basin were studied. Temperature and recipitation were the key climate factors affecting the growth of doublecropping rice, and the climate suitability of both early and late rice had strong regional characters. The climate suitability of early rice decreased from central plain area to east coast and west mountain area, whereas that of late rice decreased from south area to north area. Temperature suitability increased at a rate of 0.01 (10a)-1, suggesting that temperature had positive effects on the growth and development of double-cropping rice in Huaihe River Basin. Sunlight suitability decreased at a rate higher than 0.02 (10a)-1. The overall climate suitability had a decreasing trend.
    Effects of urban land expansion on urban thermal environment.
    DENG Yu-Jiao;KUANG Yao-Qiu;CHAN Hai-Bin;WANG Cha-Chun
    2009, 28(11):  2347-2352. 
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    Taking the rapidly urbanized Dongguan City of Guangdong as a case, and by using Landsat/TM and ETM+ data, the land surface temperature (LST) was retrieved via mono-window algorithm. A standardized method for treating the LST was proposed, and three thermal environment indices (relative thermal effect index, heat contribution index, and cold contribution index) were built to quantitatively study the effects of urban land expansion on urban thermal environment. In 1990-2005, the urban land area in Dongguan had a rapid expansion, and the high temperature zone expanded from island-shape to belt-shape and then to lamina-shape. The relative thermal effect index of urban land decreased after an initial increase, being 0.6 in 1990, 1.0 in 2000, and 0.6 in 2005. The heat contribution index increased persistently, which was 4.5% in 1990, 38.4% in 2000, and 62.9% in 2005, and the cold contribution index increased gradually, which was 1.2% in 1990, 1.8% in 2000, and 6.8% in 2005.
    Spatiotemporal dynamics of coastal landscape pattern of Shanghai during its rapid urbanization.
    LI Rong;LI Dun-Xiang;LI Cheng;QIN Hai;XU Meng-Ce;ZHANG Ting
    2009, 28(11):  2353-2359. 
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    Coastal zone’s landscape dynamics is recognized as one of the important aspects of integrated coastal management. In this paper, the land use datasets derived from time series aerial images were employed to study the coastal landscape dynamics of Shanghai from 1994 to 2005, the period of rapid urbanization. During this period, human disturbances caused landscape fragmentation and isolation, and increased landscape diversity. The area of main landscape (agricultural land) continued to decrease, its dominance declined, and became more fragmentation; while the areas of artificial landscapes reflecting urbanization (e.g., lands for industry, traffic, public facility, and residence) increased, becoming the second dominant landscape type. The increasing area of other land uses (mainly constructing sites) implied that this coastal zone was still undergoing rapid urbanization. Central government policies, local government decision-making, rapid urbanization of Shanghai, and coastal big-scale development programs such as Pudong International Airport, Yangshan International Harbor, and Shanghai Chemical Industry Park were the main driving forces for these coastal landscape changes. Based on the analysis of the ecological consequences of this rapid urbanization, some suggestions for integrated management were made to promote the sustainable development of Shanghai coastal zone.
    Research progress on Merremia boisiana.
    WANG Ba-Sun;BANG Shao-Lin;LI Dai-Jiang;ZHOU Ting
    2009, 28(11):  2360-2365. 
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    Recent researches demonstrated that Merremia boisiana is a photophilou s heliophyte liana rather than a sciophyte, which has a wide ecological adaptabi lity a nd contains the allelochemicals, one of invasion mechanisms of invasive species. In China, M. boisiana had a distribution in Yunnan, Guangxi, and Guangdong Pro vinc es, but its distribution in Fujian Province has not been confirmed. Guangzhou City and its vicinity are becoming a new distribution area of M. boisiana due to i ts northward invasion from Hainan under global warming. However, M. boisiana is not really a kind of tropical plants, but one of the tropical and subtropical el ements. The tropic of cancer is the north boundary of M. boisiana distributi on, and thereby, there is a high possibility that M. boisiana is a latent lo cal species activated by global warming. M. boisiana causes widespread disas ter in its holotype locality (Vietnam) and its original distribution center (Hai nan Province), which is not consistent with the existing viewpoint that the inva sive species cannot spread to be a disaster owing to the natural enemies in orig in, while suggests that there are no fatal natural enemies in the origin. The widel y spreading to be a disaster is originated from the intrinsic ecosystem being de stroyed by disturbances, which causes the worsened, broken, and heterogeneous ha bitat. The reduced community biodiversity and functional group diversity intensi fy the invasive possibility of exotic communities and provide chance for invasiv e species. Therefore, the viewpoint that the invasion of M. boisiana is non-selective should be modified, and the prevention measures of M. boisiana remain to be break through. Integrative control should be the first choice. Addit ionally, protecting the natural ecosystem from disturbance, and reconstructing a nd optimizing the destroyed ecosystem would be the necessary strategies and meas ures.
    Plant-microorganism combined remediation of heavy metals-contaminated soils: Its research progress.
    NIU Zhi-Xin;SUN Li-Na;SUN Tie-Hang
    2009, 28(11):  2366-2373. 
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    Bioremediation is one of the important means in controlling soil heavy metals pollution, which has the advantages of environmentally friendly and cost-effective, and attracted much attention around the world. This paper discussed the principles and forms of plant-microorganism combined remediation, and introduced the research progress on the behaviors of heavy metals in soils, the physiological and biochemical characteristics of plants, and the changes in rhizosphere environment under the remediation. Some perspectives for future research were proposed.
    Iron plaques on wetland plant root surface: A review.
    TAO Hai-Xin;XIE Zhi-Hong
    2009, 28(11):  2374-2380. 
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    Wetland plants have a series of physiological and anatomical characteristics to adapt flooding habitat, e.g., their root aerenchyma and oxygen penetrating capability can make the rhizospheric micro-environment be under oxidation condition, resulting in the formation of Fe/Mn plaques on root surface. Soil Fe and Mn and the microenvironment oxidation condition are the two important prerequisites for the formation of the Fe/Mn plaques. The plaques are mainly composed of Fe-and-Mn-oxides and their hydrates, which can alter the forms of heavy metals and nutrients in rhizospheric micro-environment via the actions absorption-desorption, oxidation-reduction, and organic-inorganic chelation, etc., and thereby, affect the bioavailability and the migration of pollutants and nutrients in wetland soil-plant system. This paper reviewed the researches about the formation and composition of Fe/Mn plaques on wetland plant root surface, and the effects of the plaques on the heavy metals and nutrients uptake by wetland plants. Some problems worthy to be further approached were discussed.
    Research advances on ecological benefit evaluation index system of ecological restoration for controlling water and soil loss.
    MA Jian;XU Xin-Xiu
    2009, 28(11):  2381-2386. 
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    To establish a rational evaluation index system is the basis of scientifically evaluating the benefit of ecological restoration for controlling regional water and soil loss. Based on the analysis of current researches on ecological benefit evaluation index system of ecological restoration for controlling water and soil loss, and the latest research achievements, it was suggested that besides the benefit of water and soil conservation, the monitoring and evaluation of vegetation structure, biological diversity, and ecological processes should be strengthened to make that the benefit evaluation of  ecological estoration for water and soil loss can be conducted on ecosystem health level.
    Landscape ecological classification: Its concept and research progress.
    YANG Jiu-Chun;ZHANG Shu-Wen
    2009, 28(11):  2387-2392. 
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    Landscape ecological classification (LEC), through establishing hierarchical classification system, can comprehensively reflect the spatial heterogeneties and their associations of definite regional landscape, and reveal its spatial structural characteristics and ecological functions, being the basis of landscape evaluation, landscape planning, and landscape management. In this paper, the concept of LEC was paraphrased, and the research progress of LEC was reviewed and analyzed from the aspects of framing classification systems, selecting indices, improving classification methods, mapping landscape ecotypes, and applications. The problems of LEC research and its development trend were pointed out.
    Hypotheses of alpine timberline formation mechanism: A review.
    SONG Hong-Chao;CHENG Rong;SUN Shou-Qin
    2009, 28(11):  2393-2402. 
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    As a sensitive transitional zone between forest and tundra, timberline has always been considered by ecologists to be an ecologically fragile zone, an amplifier of outside interference signals, and a global climate change early warning zone. Since the 1980s, many studies have been made on the effects of global climate change on alpine timberline, mainly addressed the relationships of the upper limits of timberline with altitude and latitude, and in particular, the responses of timberline location to global warming. Several hypotheses were proposed to examine the timberline formation of various tree species affected by environmental factors. This paper summarized these hypotheses, and discussed some potential studies in the future.