Table of Content

20 March 2009, Volume 20 Issue 03

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Articles

Caloric value and ash content of dominant plants in plantation communities in Heshan of Guangdong, China.

ZENG Xiao-ping;CAI Xi-an;ZHAO Ping;RAO Xing-quan

2009, 20(03):  485-492 . 

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Different parts of twenty dominant plant species in five plantation communities on the subtropical hilly lands in Heshan of Gunagdong as well as the li tters from three of the five plantation communities were sampled, and their gros s caloric value (GCV) and ash content were measured by using a PARR-12 81 oxygen bomb calorimeter and a muffle furnace. Based on the measurements, the ash-free caloric value (AFCV) of the samples was calculated, and the characteri stics of caloric value and ash content of the samples, according to plant part, individual, and plant growth form, were analyzed. The results showed that the GC V and AFCV of leaf, branch, stem wood, stem bark, and root were in the range of 107〖KG-*2〗-〖KG-*7〗2217 kJ·g-1 and 1389〖KG-*2〗-〖KG-*7〗2304 kJ·g-1, respectively. The GCV and AFCV of leaf were significantly higher than those of other parts (P<005), and the individual plant’s weighted m ean values of GCV and AFCV were in the range of 1424〖KG-*2〗-〖KG-*7〗194 3 and 1663〖KG-*2〗-〖KG-*7〗2099 kJ·g-1, respectively. The mean AFCV of plantation communities was in the order of tree layer (1955 kJ·g-1) >shrub layer (1946 kJ·g-1)>herb layer (1877 kJ·g-1), with indigenous coniferous tree (1986 kJ·g-1)>indigenous broad-leaved tre e (1955 kJ·g-1) > exotic eucalyptus (1918 kJ·g-1), while the m ean ash content was just the opposite. In Acacia mangium, coniferous, and  Schima plantation communities, the GCV and AFCV of litters were higher than those of various plant parts (P<001). The litter-falls in A. mangium and coniferous plantations had higher mean GCV and AFCV than the litters and fr esh leaves of tree layer, while the fresh leaves of tree layer in Schima plantat ion showed higher mean GCV and AFCV.

Effects of root-excision on trunk hydraulic traits and growth status of Ginkgo biloba.

SUN Shou-jia¹;CONG Ri-chen²;GU Run-ze²;GAO Jun-ping³

2009, 20(03):  493-499 . 

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The roots of 8-year-old Ginkgo biloba saplings were partially excised to three degrees to study the effects of root-excision on the trunk hydraulic traits and growth status of the saplings. The three degrees were severe, medium, and light (8∶〖KG-*2〗1, 10∶〖KG-*2〗1, and 12∶〖KG-*2〗1 of excised root diameter to base diameter of tree trunk, respectively). Physiological parameters including trunk ultrasound acoustic emission (UAE) signal, branch percentage loss of hydraulic conductance (PLC), sap flow flux, and leaf stomatal conductance, transpiration rate and water potential were measured periodically after root-excision. In all treatments, a great number of trunk UAE signal produced after a short time of root-excision, peaked at 6 h, and decreased gradually then. The intensity of the UAE signals increased with increasing root-excision degree. After root-excision, the branch PLC increased rapidly in the first 12 h but slowly after 24 h. The sap flow flux, leaf stomatal conductance, transpiration rate and water potential after root-excision decreased obviously, with significant differences among the three treatments. The cumulative number of UAE signals (cUAE) was significantly and positively correlated with branch embolism degree, while negatively correlated with sap flow flux and leaf water potential. The leaf area and new branch length of G. biloba in the next year after root-excision decreased significantly, and the decrement was increased with root-excision degree. Root-excision not only made the degrees of conduits cavitation and branch embolism increased, but also affected water transportation and leaf transpiration rate within a short period of time, which would in turn give an impact on G. biloba plant growth.

Growth process of Larix principis-rupprechtii stands with different density on south slope of Liupan Mountains.

WANG Jing¹;MO Fei²;DUAN Wen-biao¹;YU Peng-tao²;XIONG Wei²;WANG Yan-hui²;WANG Zhan-yin²;CAO Gong-xiang³

2009, 20(03):  500-506 . 

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By the method of sample trees stem analysis, this paper studied the growth process and diameter structure of 21-year-old Larix principis-rupprechtii plantations with the densities of 1200, 1500, and 2000 stems·hm-2 in the head-water area on the southern slope of Liupan Mountain in Ningxia Hui Autonomous Region. The results showed that there were no significant differences in the growth status of L. principis-rupprechtii stands among the three densities when the stand age was less than 10 years. However, obvious differences were observed in the diameter and timber volume of individual trees and in the stand volume when the stand age was more than 10 years. The tree growth status in low-density stand was apparently better than that in medium- and high-density stands, but the height growth had no significant difference among the three densities. There was a significant difference in the skewness coefficient (Sk) of diameter distribution among the stands with different density, being higher (Sk=0338) in high-density stand than in medium-density stand (Sk=0072) and low-density stand (Sk=0015). The diameter distribution in high-density stand deviated from normal distribution, with a zenith tending to left, while that in medium- and low-density stands approached a normal distribution, with a more reasonable density structure. The kurtosis coefficient (K=1691) of medium-density stand was higher than that of high-density stand (K=1532) and low-density stand (K=0665), indicating a lower degree of polarization of tree growth in medium-density stand than in other two stands. The reasonable remaining density of 21-year-old L. principis-rupprechtii plantations was suggested to be 1200 stems·hm-2.

Relationships between Sabina przewalskii radial growth and climatic factors at upper timberlines in eastern mountainous region of Qaidam Basin.

ZHENG Yong-hong^1,2,4;ZHU Hai-feng¹;ZHANG Yong-xiang^2,3;SHAO Xue-mei¹

2009, 20(03):  507-512 . 

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Based on the investigation data of Sabina przewalskii tree-ring width at six sites at upper timberlines in eastern mountainous region of Qaidam Basin, the standard tree-ring chronologies of S. przewalskii were established. Cluster analysis indicated that there existed geographical differences in the radial growth of S. przewalskii among the sites. Higher similarity was observed between two northern sites, and among four central and southern sites. Climatic factors had different effects on the radial growth of S. przewalskii of the two clusters. The radial growth of S. przewalskii was positively correlated with the precipitation in current year’s June at northern sites, and with the air temperature in previous year’s November and current year’s July at central and southern sites.

Changes of soil nutrient contents after prescribed burning of forestland in Heshan City， Guangdong Province.

SUN Yu-xin^1,2;WU Jian-ping^1,2;ZHOU Li-xia¹;LIN Yong-biao¹;FU Sheng-lei¹

2009, 20(03):  513-517 . 

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A comparative study was conducted to analyze the changes of soil nutrient contents in Eucalyptus forestland and in shrubland after three years of prescribed burning. In Eucalyptus forestland, soil organic carbon, total nitrogen, available potassium contents and soil pH decreased significantly; soil available phosphorus and exchangeable magnesium contents, net nitrogen mineralization rate and ammonification rate also decreased but showed no significant difference. In shrubland, soil exchangeable calcium content increased significantly, but the contents of other nutrients had no significant change. The main reason of the lower soil net nitrogen mineralization rate in Eucalyptus forest could be the decrease of available substrates and the uptake of larger amount of soil nutrients by the fast growth of Eucalyptus. The soil nutrients in shrubland had a quick restoration rate after burning.

Vertical distribution patterns of soil organic carbon and total nitrogen and related affecting factors along northern slope of Qilian Mountains.

ZHANG Peng;ZHANG Tao;CHEN Nian-lai

2009, 20(03):  518-524 . 

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With the shady and sunny northern slopes of Qilian Mountains along an altitude gradient from 2600 m to 3600 m as test objectives, this paper studied t he vertical distribution patterns of surface soil (0〖KG-*2〗-〖KG-*7〗20 cm) or ganic carbon (SOC) and total nitrogen (TN), and their relations to the altitude, landform, and vege tation. The results indicated that SOC and TN contents were significantly hi gher on shady than on sunny slope, and all increased with increasing altitude. The SOC and TN contents under different vegetation types were in the order of alpi ne bush >Picea crassifolia forest>alpine meadow>Sabina przewalskii fores t, and alpine bush >alpine meadow>P. crassifolia forest>S. przewalskii f orest, respectively. SOC had significant positive correlations with altitude , annual precipitation, soil moisture, and soil TN, and significant negative cor relations with soil pH and annual temperature. Soil C/N ratio along the gradient was within the range of 67〖KG-*2〗-〖KG-*7〗233, being favorable to the nu trient release dur ing organic matter decomposition. Among the factors affecting SOC, the annua l temperature, precipitation, and soil moisture content constituted the first pr incipal component, and soil C/N ratio constituted the second principal component . These two principal components accounted for 71% of the variance of SOC co ntent, suggesting that climate factors controlled the vertical distribution patt erns of SOC and TN along the altitude gradient.

Periodic fluctuation features of air temperature, precipitation, and aboveground net primary production of alpine meadow ecosystem on Qinghai-Tibetan Plateau.

ZHANG Fa-wei¹;LI Hong-qin²;LI Ying-nian¹;LI Yi-kang¹;LIN Li¹

2009, 20(03):  525-530 . 

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With Mexican Hat function as mother function, a wavelet analysis was conducted on the periodic fluctuation features of air temperature, precipitation, and aboveground net primary production (ANPP) in the Alpine Meadow Ecosystem Research Station, Chinese Academy of Sciences from 1980 to 2007. The results showed that there was a main period of 13 years for the annual fluctuations of air temperature, precipitation, and ANPP. A secondary period of 2 years for the annual fluctuations of air temperature and ANPP had lesser influence, whereas that of 4 years for the annual fluctuation of precipitation had greater effect. Lagged correlation analysis indicated that the annual fluctuation of ANNP was mainly controlled by the air temperature in a 20 years scale and had a weak 5〖KG-*2〗-〖KG-*7〗9 years lag effect, but there was a less correlation between ANPP and precipitation.

Effects of urbanization on soil nitrogen supply in Pinus elliottii plantations.

YU Ming-quan^1,2;YUAN Ping-cheng¹;CHEN Fu-sheng³;HU Xiao-fei³;DU Tian-zhen¹

2009, 20(03):  531-536 . 

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With the Pinus elliottii plantations along an urban-rural gradient in Nanchang City as test objectives, and by using ion-exchange resin (IER) bag, thi s paper studied the seasonal dynamics of soil available nitrogen in the plantati ons, and analyzed the effects of urbanization on soil nitrogen supply. The resul ts showed that the soil nitrogen supply in the plantations had an obvious season al fluctuation. Soil NH4+-N concentration was significantly higher in autum n and winter than in spring and summer, while soil NO3--N concentration, mi neral N concentration, and relative nitrification rate were in adverse (P＜0 05). The seasonal dynamics of soil available nitrogen was basically consistent with the growth rhythm of P. elliottii. The soil nitrogen availability and relative nitrification ratio along the gradient differed greatly, being signific antly higher in urban than in rural area (P＜005). Urbanization accelerate d soil N mineralization and nitrification, enhanced soil nitrogen supply capacit y, and increased soil NO3--N content. It was suggested that in the construc tion of urban forest, the plants with high N demand, especially with high NO3 -- N absorption capacity, should be introduced to mitigate the soil available N loss and its induced environmental pollution.

Litter decomposition of dominant plant species in successional stages in mid-subtropical zone.

SONG Xin-zhang¹;JIANG Hong^1,2;YU Shu-quan¹;MA Yuan-dan²;ZHOU Guo-mo¹;DOU Rong-peng¹;GUO Pei-pei¹

2009, 20(03):  537-542 . 

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The litters of seven tree species representing the dominant plant species in three main successional stages in subtropical China, i.e., Pinus massoniana in early successional forests, Schima superba and Cinnamanun camphora in transitional forests, and Castanopsis eyeri, Cyclobalanopsis gracilis, Cyclobalanopsis glauca, and Michelia chapensis in late successional forests, were collected, and their decomposition rates were measured with litterbags. The results showed that M. chapensls and C. gracilis had the highest litter decomposition rate (k=112 and 089, respectively), followed by C. camphora and S. superba (k=061 and 055, respectively), and P. massoniana (k=051), indicating that there was a trend of litter decomposition rate being increased with succession stage. Litter decomposition rate had significant correlations with the litter’s initial P, N, and lignin contents, lignin/N ratio (P<001), and C/N ratio (P<005), suggesting that the initial P, N, and lignin contents and lignin/N ratio of leaf litter could be the good indictors of litter decomposition rate.

Effects of salt stress on mulberry seedlings growth, leaf water status, and ion distribution in various organs.

SUN Jing-bo;SUN Guang-yu;LIU Xiao-dong;HU Yan-bo;ZHAO Yu-sen

2009, 20(03):  543-548 . 

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Taking the seedlings of mulberry (Morus alba) varieties Qiuyu and Tailai from Heilongjiang Province as test materials, this paper studied their growth, leaf water relations, and ion distribution in various organs under the stress of different salt concentration. The results showed that salt stress decreased the plant height and dry mass of the seedlings obviously, and the dry mass of young leaves was more affected than that of old leaves. With increasing salt stress, leaf water potential, osmotic potential, pressure potential, and relative water content decreased markedly, while the Na+ concentration in root and stem had an obvious increase. When the soil NaCl concentration was 150 mmol·L-1 or higher, the Na+ concentration in leaf, stem, and root reached saturated. Salt stress markedly decreased the K+ and Ca2+ concentrations in leaf, stem, and root as well as the Mg2+ concentration in leaf and stem, but had lesser effects on the Mg2+ concentration in root. The decrease of leaf Ca2+, K+, and Mg2+ concentrations under salt stress caused the ion deficiency in plant and limited plant growth, while the regionalized distribution of Na+ in root, stem, and older leaf could be one of the salt tolerance mechanisms of test varieties.

Effects of exogenous spermidine and spermine on Celastrus orbiculatus antioxidant system under soil NaHCO₃ stress.

LIU Qiang;WANG Qing-cheng;XU Jing;SUN Jing

2009, 20(03):  549-554 . 

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This paper studied the effects of foliar spraying spermidine and sperm ine on the leaf antioxidant system of Celastrus orbiculatus under soil NaHCO 3 stress. The results showed that under the stress, spraying spermidine and sp ermine could significantly decrease the leaf O2〖SX(B-*3〗-〖〗·〖SX)〗 production rate, H2O2 and MDA contents, and electrolyte leakage of C. orbiculatus (P<005). Spra ying spermidine increased the leaf SOD, CAT, POD and APX activities and GSH, CAR and Pro contents obviously, but had no effect on leaf AsA content. Spraying sp ermine also increased leaf POD and APX activities and GSH, CAR and Pro contents obviously, but had lesser effect on leaf SOD activity and AsA content, and even , caused a significant decrease in leaf CAT activity. In the meantime, spermidin e and spermine effectively improved the growth of C. orbiculatus seedlings. It was suggested that under soil NaHCO3 stress, exogenous spermidine and sperm ine could improve the functions of membrane protective system and decrease the O 2〖SX(B-*3〗-〖〗·〖SX)〗 accumulation in C. orbiculatus leaves, an d consequently, increase the C. orbiculatus tolerance to NaHCO3 exposure.

Soil moisture dynamics of artificial Caragana microphylla shrubs at different topographical sites in Horqin sandy land.

HUANG Gang;ZHAO Xue-yong;HUANG Ying-xin;SU Yan-gui

2009, 20(03):  555-561 . 

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Based on the investigation data of vegetation and soil moisture regime of Caragana microphylla shrubs widely distributed in Horqin sandy land, the spatiotemporal variations of soil moisture regime and soil water storage of artificial sand-fixing C. microphylla shrubs at different topographical sites in the sandy land were studied, and the evapotranspiration was measured by water balance method. The results showed that the soil moisture content of the shrubs was the highest in the lowland of dunes, followed by in the middle, and in the crest of the dunes, and increased with increasing depth. No water stress occurred during the growth season of the shrubs. Soil moisture content of the shrubs was highly related to precipitation event, and the relationship of soil moisture content with precipitation was higher in deep soil layer (50-180 cm) than in shallow soil layer (0-50 cm). The variation coefficient of soil moisture content was also higher in deep layer than in shallow layer. Soil water storage was increasing in the whole growth season of the shrubs, which meant that the accumulation of soil water occurred in this area. The evapotranspiriation of the shrubs occupied above 64% of the precipitation.

Effects of water stress on photosynthetic parameters of Phragmites australis in estuarine wetland of Yellow River Delta.

XIE Tao;YANG Zhi-feng

2009, 20(03):  562-568 . 

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A pot experiment was conducted to study the effects of soil water cont ent on the net photosynthetic rate (Pn), transpiration rate (Tr), st omatal conductance (Gs), intercellular CO2 concentration (Ci), wat er use efficiency (WUE), and light use efficiency (LUE) of fresh water s wamp Phragmites australis from estuarine wetland of Yellow River Delta, with the appropriate soil water condition approached. The results showed that the P n, LUE, Tr , and WUE of fresh water swamp P. australis had o bvious response thresholds on the alteration of soil water content. Waterlogged status was not the optimal water condition for fresh water swamp P. australis . To maintain the normal growth of fresh water swamp P. australis during i ts fast growth period, soil volumetric water content (Wv ) should be above 257% (i.e., relative water content Wr>666%), opt imal Wv should be 369% (i.e., Wr=956%), and the most deficie nt degree of Wv should be about 215% (i.e., Wr=557%). Stomat al limitation was the main tolerance mechanism of fresh water swamp P. austral is under water deficit. Under drought condition, the maximum net photosyntheti c rate (Pn max) and apparen t quantum yield (AQY) of fresh water swamp P. australis declined obvious ly. In the meanwhile, fresh water swamp P. australis could reduce its dark r espiration (Rd) to decrease the consumption of photosynthetic products, an d improve its water use efficiency (WUE) to keep high photosynthetic rate.

Photosynthetic fluorescence characteristics of floating-leaved and submersed macrophytes commonly found in Taihu Lake.

SONG Yu-zhi¹;CAI Wei¹;QIN Bo-qiang²

2009, 20(03):  569-573 . 

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Some aquatic macrophytes commonly found in Taihu Lake, including Trapa bispinosa, Nymphyoides peltatum, Vallisneria natans, and Hydrilla verticillata were collected, and their maximal quantum yield of photosystemⅡ(Fv/Fm) as well as the rapid light curves (RLCs) under conditions of light adaptation and dark adaptation were measured in situ by using a submersible and pulse-amplitude modulated fluorometer (Diving-PAM). The results showed that floating-leaved plants T. bispinosa and N. peltatum had higher potential maximum photosynthetic capacity than submerged macrophytes V. natans and H. verticillata. The measured maximal quantum yield of T. bispinosa, N. peltatum, V. natans, and H. verticillata was 0837, 0831, 0684, and 0764, respectively. Both the maximal relative electron transport rate and the half saturation point of light intensity of T. bispinosa and N. peltatum were higher than those of V. natans and H. verticillata, especially under the condition of light adaptation.

Niches of seven bryophyte species in Hani peat land of Changbai Mountains.

CHEN Xu^1,3;BU Zhao-jun^1,2;WANG Sheng-zhong^1,2;LI Hong-kai¹;ZHAO Hong-yan^1,2

2009, 20(03):  574-578 . 

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Based on field investigation and by using Levins and Pianka formula, the niches of seven bryophyte species in Hani Peatland of Changbai Mountains were studied. The results showed that the average niche breadth in nine environmental factors (total nitrogen, total phosphorous, K+ and Ca2+ in peat, pH，and electrical conductivity of surface water, tree coverage, shrub coverage, and depth to water table) of the seven species decreased in the order of Aulacomnium palustre＞Sphagnum fallax＞S. magellanicum＞S. capillifolium=Polytrichum juniperinum＞S. palustre＞S. fuscum. S. fuscum tended to be niche-specific species, while A. palustre tended to be niche-general species. Among the nine environmental factors, surface water electrical conductivity had the highest mean overlap value, while depth to water table, tree coverage, surface water pH, and shrub coverage had the lowest one, being the main environmental factors affecting the distribution of bryophytes. Most bryophyte species differentiated in their niches in the factors of depth to water table, tree coverage, surface water pH, and shrub coverage; while a few bryophyte species had higher overlap value in all of the test environmental factors due to their collaboration relationships in water use. This higher overlap value could offer indirect evidence of interspecific competition of bryophytes.

Maintenance capacity of plant community diversity of wetlands in patch scale.

SUN Xian-bin^1,2;LIU Hong-yu¹;ZHANG Xiao-hong¹;HU Jun-na¹

2009, 20(03):  579-585 . 

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Based on GIS and principal component analysis method, this paper analyzed the relationships between the patch characteristics and the plant community diversity in the patches of wetlands in Naoli River Watershed in 1950, 1967, 1983 and 2000. The results showed that in 1950〖KG-*2〗-〖KG-*7〗2000, the average patch size of the wetlands and the number of the patches that had the capacity of maintaining more than two types of wetland plant community decreased dramatically, and the minimum patch size was 101 km2. Both the plant community diversity index and the number of plant community types had significant positive correlations with the patch size of the wetlands. The larger the patch size, the higher maintenance capacity of plant community diversity. With the decrease of patch size, the patch fragmentation index and patch fragmental dimension increased, while the patch shape index and the plant community diversity index in the patches decreased. With the increase of patch spatial separation, the plant community diversity index in the patches decreased. Principal component analysis indicated that patch size was the most important factor affecting the plant community diversity of wetlands, followed by patch fragmentation and separation.

Regulation effect of calcium and salicylic acid on defense enzyme activities in tomato leaves under sub-high temperature stress.

LI Tian-lai;LI Miao;SUN Zhou-ping

2009, 20(03):  586-590 . 

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In order to investigate the regulation effect of Ca2+ and salicylic acid (SA) on the sub-high temperature resistance of tomato plants, the plants were treated with sub-high temperature (35 ℃) at day time during their 1st inflorescence flowering, and CaCl2 (10 mmol·L-1) and SA (02 mmol·L-1) were foliar sprayed to study the variations of the activities of defense enzymes (SOD, POD, and CAT) and the content of soluble protein in tomato leaves, taking spraying clear water under 25 ℃ at day time as the control. The results showed that under the sub-high temperature stress, the SOD, CAT and POD activities in tomato leaves were decreased by 1482%, 3184%, and 2634%, respectively, while spraying CaCl2 (10 mmol·L-1) and SA (02 mmol·L-1) decreased the leaf MDA content and increased the leaf SOD, POD and CAT activities and soluble protein content, compared with the control, indicating that Ca2+ and SA had positive regulation effect on the defense enzyme activities in tomato leaves, which could protect the photosynthetic system of tomato under the sub-high temperature stress to a certain degree.

Effects of grafting on photosynthesis of sweet pepper seedlings under low temperature and weak light intensity.

ZHENG Nan^1,2;WANG Mei-ling^1,2;WANG Hong-tao^1,2;AI Xi-zhen^1,2

2009, 20(03):  591-596 . 

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Sweet pepper ‘Chifengtexuan’ seedlings were grafted onto ‘Weishi’ and ‘Buyeding’ rootstocks, treated with low temperature (8 ℃/ 5 ℃) and weak light intensity (100 μmol·m-2·s-1) for 7 days, and then recovered under normal conditions (25 ℃/18 ℃, PFD 550〖KG-*2〗-〖KG-*7〗600 μmol·m-2·s-1) for 3 days to study the variations of their gas exchange parameters, carboxylation efficiency, and fluorescence parameters, with the own-rooted ‘Chifengtexuan’ seedlings as the control. The results showed that on the 3rd day of low temperature and weak light intensity stress, the photosynthetic rate (Pn), stomatal conductance (Gs), and carboxylation efficiency (CE) of both own-rooted and grafted seedling leaves decreased more than 50%, and after then, the Pn and Gs tended to stable while CE decreased continually. The intercellular CO2 concentration (Ci) declined first, but enhanced after the 4th day of the stress. Low temperature and weak light intensity decreased the maximal photochemical efficiency of PSⅡ in darkness (Fv/Fm), actual photochemical efficiency of PSⅡ during illumination (ФPSⅡ) and electron transport rate (ETR), but increased the initial fluorescence (Fo), which implied that the stress caused definite damage of photosynthetic apparatus. However, the damage diminished after 3 days of recovery. Comparing with those of own-rooted seedlings, the Pn, Gs, CE, ФPSⅡ, and Fv/Fm of grafted seedlings increased to various degrees, and Fo decreased markedly during the stress. It was concluded that grafting could promote the photosynthetic function, and alleviate the effects of low temperature and weak light intensity on the photosynthesis of sweet pepper seedlings.

Effects of endophytic Paenibacillus polymyxa S-7 on photosynthesis, yield,and quality of sugar beet.

SHI Ying-wu^1,2; LOU Kai²; LI Chun¹;YANG Liang¹; WANG Xing-qin¹; LIU Wen-yu¹

2009, 20(03):  597-602 . 

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This study showed that inoculation of endophytic Paenibacillus polym yxa S-7 could significantly (P<005) promote the photosynthesis of sugar beet. After the inoculation, the leaf net photosynthetic rate (Pn), stoma tal limitation (Ls), stomatal conductance (Gs), and transpiration r ate (Tr) increased by 1611%, 2382%, 4191%, and 3480%, respectively , while the stomatal intercellular CO2 concentration (Ci) decreased by 2 1. 09%. Inoculation of endophytic P. polymyxa S-7 could also increase sugar be et yield and its quality significantly (P<005), with the tuberous root bio mass and its sugar content increased by 2563% and 1746%, respectively. It wa s concluded that endophytic P. polymyxa S-7 not only affected the photosynt hetic parameters, but also promoted the yield and quality of sugar beet.

Effects of alcohol extracts from three kinds of biomass energy plant tissues on biological activity of Bemisia tabaci.

ZHOU Fu-cai¹;ZHOU Gui-sheng²;LI Chuan-ming¹;YANG Yi-zhong¹;QIN Pei³

2009, 20(03):  603-608 . 

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To test the feasibility of using raw extracts from the tissues of biomass energy plants Ricinus communi and Kosteletzkya virginica as plant protection agents, the alcohol extracts from R. communi seed and leaf and from K. virginica leaf were used to treat adult Bemisia tabaci by spraying. The glutathione S-transferase and carboxylesterase activities in B. tabaci body were measured after treated for 4 h, 24 h, 48 h, 72 h, and 96 h, and the olfaction responses of B. tabaci to the alcohol extracts were detected with a Y-tube olfactomet. All the three alcohol extracts obviously inhibited the glutathione S-transferase and carboxylesterase activities in a concentration-dependent manner. The inhibitory effect of the 250-times diluted alcohol extracts on the two enzyme activities was equivalent to that of 3000 times-diluted 18% avermectins. In addition, the 250-times diluted alcohol extracts had obvious repellent effect on B. tabaci, with the repellent coefficient of the alcohol extracts from R. communi seed and leaf and from K, virginica leaf being 1000%, 967%, and 794%, respectively. All of these suggested that the test three alcohol extracts had repellent and other biological effects on B. tabaci.

Effects of increasing surface ozone concentration on spikelet formation of hybrid rice cultivars.

YANG Kai-fang¹;YANG Lian-xin¹;WANG Yun-xia¹;SHI Guang-yue¹;LAI Shang-kun¹;ZHU Jian-guo²;Kazuhiko Kobayashi³;WANG Yu-long¹

2009, 20(03):  609-614 . 

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To investigate the effects of high ozone concentration on spikelet formation of hybrid rice cultivars, an experiment using a unique free air ozone concentration enrichment (ozone-FACE) system was conducted in 2007. Two hybrid rice cultivars, Shanyou 63 (SY63) and Liangyoupeijiu (LYPJ), were grown at ambient and elevated (target at 50% above ambient) ozone concentration. The results showed that compared with ambient ozone concentration, elevated ozone reduced the spikelet number per panicle by 28 and 34 (relative decrease of 15% and 13%) for SY63 and LYPJ, respectively. This reduction in spikelet number per panicle was mainly contributed to the significant decrease in spikelet number on secondary branches (SB), while only minor response was detected for the spikelet number on primary branches (PB), resulting in an increase in percentage of primary branch spikelets and a decrease in percentage of secondary branch spikelets under ozone exposure. In terms of spikelet formation, the large ozone-induced reduction in spikelet number per panicle of the two hybrid cultivars was entirely due to the suppression of spikelet differentiation per panicle (especially that on SB), while the degenerated spikelets per panicle decreased rather than increased under ozone exposure. It was suggested that corresponding measures should be adopted to mitigate the detrimental effects of ozone on the spikelet differentiation to minimize yield loss under increasing surface ozone concentration.

Effects of farmland use type and winter irrigation on nitrate accumulation in sandy farmland soil.

YANG Rong^1,2;SU Yong-zhong^1,2

2009, 20(03):  615-623 . 

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With the sandy farmland in the marginal oasis in middle reaches of Heihe River Basin, Northwest China as test object, this paper studied soil NO3--N accumulation and leaching under effects of different farmland use type and winter irrigation. The results showed that the mean NO3--N concentration in 0〖KG-*2〗-〖KG-*7〗300 cm soil profile in different farmlands ranged from 127 mg·kg-1 to 8360 mg·kg-1. Soil NO3--N concentration was higher in 0〖KG-*2〗-〖KG-*7〗40 cm and 135〖KG-*2〗-〖KG-*7〗300 cm layers, but lower in 40〖KG-*2〗-〖KG-*7〗135 cm layer. Greenhouse vegetable field had a significantly higher soil NO3--N concentration than the other farmland use types. The accumulated amount of soil NO3--N decreased in the order of greenhouse vegetable field>tomato field>cotton field>seed maize field>maize-wheat rotation field>maize-wheat stripe intercropping field>alfalfa field>jujube plantation. The NO3--N accumulation in 0〖KG-*2〗-〖KG-*7〗300 cm soil profile in greenhouse vegetable filed reached 217145 kg·hm-2, which would be a serious menace to groundwater quality, followed by tomato field and cotton field. Lesser accumulation of soil NO3--N was found in seed maize field, maize-wheat intercropping field, maize-wheat rotation field, alfalfa field, and jujube plantation, but its pollution potential would not be neglected. After winter irrigation, soil NO3--N concentration decreased in 0〖KG-*2〗-〖KG-*7〗80 cm layer but increased in 80〖KG-*2〗-〖KG-*7〗300 cm layer, indicating that winter irrigation caused NO3--N leaching into deeper soil depth. The leached amount of soil NO3--N to deeper layers increased with increasing amount of winter irrigation. To mitigate soil NO3--N leaching and groundwater contamination, a comprehensive consideration should be made on the rational arrangement of farmland use type, proper decrease of planting N-accumulated crops, and reasonable winter irrigation.

Effects of organic-inorganic mixed fertilizers on rice yield and nitrogen use efficiency.

ZHANG Xiao-li;MENG Lin;WANG Qiu-jun;LUO Jia;HUANG Qi-wei;XU Yang-chun;YANG Xing-ming;SHEN Qi-rong

2009, 20(03):  624-630 . 

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A field experiment was carried to study the effects of organic-inorganic mixed fertilizers on rice yield, nitrogen (N) use efficiency, soil N supply, and soil microbial diversity. Rapeseed cake compost (RCC), pig manure compost (PMC), and Chinese medicine residue compost (MRC) were mixed with chemical N, P and K fertilizers. All the treatments except CK received the same rate of N. The results showed that all N fertilizer application treatments had higher rice yield (79188〖KG-*2〗-〖KG-*7〗94492 kg·hm-2) than the control (69479 kg·hm-2). Compared with that of chemical fertilizers (CF) treatment (79188 kg·hm-2), the yield of the three organic-inorganic mixed fertilizers treatments ranged in 85320〖KG-*2〗-〖KG-*7〗94492 kg·hm-2, and the increment was 77%〖KG-*2〗-〖KG-*7〗193%. Compared with treatment CF, the treatments of organic-inorganic mixed fertilizers were significantly higher in N accumulation, N transportation efficiency, N recovery rate, agronomic N use efficiency, and physiological N use efficiency. These mixed fertilizers treatments promoted rice N uptake and improved soil N supply, and thus, increased N use efficiency, compared with treatments CF and CK. Neighbor joining analysis indicated that soil bacterial communities in the five treatments could be classified into three categories, i.e., CF and CK, PMC and MRC, and RCC, implying that the application of exogenous organic materials could affect soil bacterial communities, while applying chemical fertilizers had little effect on them.

Effects of different fertilization modes on vegetable growth, fertilizer nitrogen utilization, and nitrogen loss from vegetable field.

HUANG Dong-feng^1,2;WANG Guo²;LI Wei-hua¹; QIU Xiao-xuan¹

2009, 20(03):  631-638 . 

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A field experiment with Chinese cabbage, water spinach, and three-colored amaranth cropped three times in one year was conducted to study the effects of seven fertilization modes, i.e., none fertilization, basal application of chemical fertilizers, 1/2 basal application and 1/2 top-dressing of chemical fertilizers, basal application of chemical fertilizers and dicyandiamide, 1/2 basal application and 1/2 top-dressing of chemical fertilizers and dicyandiamide, 1/2 basal application and 1/2 top-dressing of chemical fertilizers and organic manure, and basal application of organic manure, on the plant height, yield, nitrogen accumulation, and fertilizer nitrogen utilization of the vegetables, and the loss of NO3--N and NH4+-N from vegetable field under natural rainfall condition. The results showed that comparing with none fertilization, the fertilization modes ‘1/2 basal application and 1/2 top-dressing of chemical fertilizers and organic manure’ and ‘basal application of chemical fertilizers and dicyandiamide’ improved the agronomic properties of test vegetables, increased their yields by 103%〖KG-*2〗-〖KG-*7〗219% and 93%〖KG-*2〗-〖KG-*7〗226%, and nitrogen accumulation by 153%〖KG-*2〗-〖KG-*7〗216% and 231%〖KG-*2〗-〖KG-*7〗320%, respectively, and enhanced fertilizer nitrogen utilization rate. They also decreased the surface runoff loss of NO3--N and NH4+-N by 481% and 465%, respectively, compared with the mode ‘basal application of chemical fertilizers’, and hence, reduced the risk of agricultural non-point pollution. Therefore, these two fertilization modes could be popularized in vegetable production.

Assessment of eco-environmental vulnerability of Hainan Island, China.

HUANG Bao-rong¹;OUYANG Zhi-yun²;ZHANG Hui-zhi³;ZHANG Li-hua¹;ZHENG Hua²

2009, 20(03):  639-646 . 

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Based on the assessment method of environmental vulnerability constructed by SOPAC and UNEP, this paper constructed an indicator system from three sub-themes including hazard, resistance, and damage to assess the eco-environmental vulnerability of Hainan Island. The results showed that Hainan Island was suffering a middling level eco-environmental hazard, and the main hazards came from some intensive human activities such as intensive agriculture, mass tourism, mining, and a mass of solid wastes thrown by islanders and tourists. Some geographical characters such as larger land area, larger altitude range, integrated geographical form, and abundant habitat types endowed Hainan Island higher resistance to environmental hazards. However, disturbed by historical accumulative artificial and natural hazards, the Island ecosystem had showed serious ecological damage, such as soil degradation and biodiversity loss. Comprehensively considered hazard, resistance, damage, and degradation, the comprehensive environmental vulnerability of the Island was at a middling level. Some indicators showed lower vulnerability, but some showed higher vulnerability.

Ecological benefits of planting winter rapeseed in western China.

WANG Xue-fang^1,2;SUN Wan-cang¹;LI Fang³;KANG Yan-li¹;PU Yuan-yuan¹;LIU Hong-xia¹;ZENG Chao-wu¹;FAN Chong-xiu²

2009, 20(03):  647-652 . 

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To evaluate the ecological benefits of popularizing winter rapeseed planting in western China, a wind tunnel simulation test was conducted with four kinds of farmland surface, i.e., winter rapeseed, winter wheat, wheat stubble, and bare field just after spring sowing, collected from west Gansu in April. The results showed that winter rapeseed surface had a roughness of 408 cm and a threshold wind velocity as high as 14 m·s-1, being more effective in blown sand control than the other three surfaces. Under the same experimental conditions, the wind erosion modulus and sand transportation rate of winter rapeseed surface were only 41% and 485% of those of the bare field just after spring sowing, and the losses of soil organic matter, alkali-hydrolyzed N, available P and K, catalase, urease, alkaline phosphatase, invertase, and microbes of winter rapeseed surface due to wind erosion were only 14%, 51%, 16%, 27%, 97%, 36%, 63%, 67% and 15% of those of the bare field, respectively. It was suggested that popularizing winter rapeseed planting in west China could control wind erosion, retain soil water and nutrients, increase multi-cropping index, and improve economic benefits of farmland. In addition, it could benefit the regional desertification control and ecological environment improvement.

Relations of landslide and debris flow hazards to environmental factors.

ZHANG Guo-ping;XU Jing;BI Bao-gui

2009, 20(03):  653-658 . 

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To clarify the relations of landslide and debris flow hazards to envir onmental factors is of significance to the prediction and evaluation of landslid e and debris flow hazards. Base on the latitudinal and longitudinal information of 18431 landslide and debris flow hazards in China, and the 1 km×1 km grid dat a of elevation, elevation difference, slope, slope aspect, vegetation type, and vegetation coverage, this paper analyzed the relations of landslide and debris f low hazards in this country to above-mentioned environmental factors by the ana lysis method of frequency ratio. The results showed that the landslide and debri s flow hazards in China more occurred in lower elevation areas of the first and second transitional zones. When the elevation difference within a 1 km×1 km gri d cell was about 300 m and the slope was around 30 degree, there was the greates t possibility of the occurrence of landslide and debris hazards. Mountain forest land and slope cropland were the two land types the hazards most easily occurre d. The occurrence frequency of the hazards was the highest when the vegetation c overage was about 80%〖KG-*2〗-〖KG-*7〗90%.

Edge influence of soil moisture at farmland-grassland boundary in agriculture-pasturage ecotone of Northern China.

LIU Hong-lai^1,3;ZHANG Wei-hua²;WANG Kun^1,3;ZHAO Na¹

2009, 20(03):  659-664 . 

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In the agriculture-pasturage ecotone of Northern China, a typical zone with linear boundary of cropland and grassland was chosen to investigate its soil moisture regime, and the moving split-window technique was adopted to study the edge influence of soil moisture at the boundary. The results showed that the edge influence was 10 m, from 6 m within grassland and 4 m within cropland, and was categorized as the acute change type boundary. Accordingly, the farmland-grassland landscape boundary could be divided into three functional zones, i.e., grassland zone, farmland zone, and compositional ecotone zone. Soil moisture content varied abruptly in the ecotone zone, but presented linear distribution in both grassland zone and farmland zone. The average soil moisture content in grassland was about 1 g·g-1 higher than that in farmland, which was mainly caused by the decreased capillary moisture capacity of farmland. Owing to the different vegetation cover, farmland and grassland had different transpiration and evaporation, which led to the diverse soil moisture regime, making soil water potential changed and water movement from one ecosystem to another possible.

Protection regionalization of Houshi Forest Park based on landscape sensitivity.

ZHOU Rui^1,2;LI Yue-hui¹;HU Yuan-man¹;ZHANG Jia-hui³;LIU Miao¹

2009, 20(03):  665-672 . 

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By using GIS technology, and selecting slope, relative distance to viewpoints, relative distance to tourism roads, visual probability of viewpoints, and visual probability of tourism roads as the indices, the landscape sensitivity of Houshi Forest Park was assessed, and an integrated assessment model was established. The AHP method was utilized to determine the weights of the indices, and further, to identify the integrated sensitivity class of the areas in the Park. Four classes of integrated sensitivity area were divided. Class I had an area of 29724 hm2, occupying 229% of the total area of the Park, which should be strictly protected to maintain natural landscape, and prohibited any exploitation or construction. Class II had an area of 35972 hm2, accounting for 278% of the total. The hills in this area should be kept from destroying to protect vegetation and water, but the simple byway and stone path could be built. Class III had an area reached up to 49580 hm2, occupying 383% of the total, which could be moderately exploited, and artificial landscape was advocated to beautify and set off natural landscape. Class IV had the smallest area (14280 hm2), accounting for 11% of the total, which had the greatest potential of exploitation, being possible to build large-scale integrated tourism facilities and travelling roads.

Influence of interpolation method and sampling number on spatial prediction accuracy of soil Olsen-P.

SUN Yi-xiang^1,2;WU Chuan-zhou³;ZHU Ke-bao³;CUI Zhen-ling¹;CHEN Xin-ping¹;ZHANG Fu-suo¹

2009, 20(03):  673-678 . 

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Different from the large scale farm management in Europe and America, the scattered farmland management in China made the spatial variability of soil nutrients at county scale in this country more challenging. Taking soil Olsen-P in Wuhu County as an example, the influence of interpolation method and sampling number on the spatial prediction accuracy of soil nutrients was evaluated systematically. The results showed that local polynomial method, ordinary kriging, simple kriging, and disjunctive kriging had higher spatial prediction accuracy than the other interpolation methods. Considering of its simplicity, ordinary kriging was recommended to evaluate the spatial variability of soil Olsen-P within a county. The spatial prediction accuracy would increase with increasing soil sampling number. Taking the spatial prediction accuracy and soil sampling cost into consideration, the optimal sampling number should be from 500 to 1000 to evaluate the spatial variability of soil Olsen-P at county scale.

Distribution characteristics of land use pattern on terrain gradient in Jiaodong mountainous areas at county level.

SI Jun-lang;QI Wei;QU Yan-bo;LI Le

2009, 20(03):  679-685 . 

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Based on RS and GIS techniques, and combining with digital terrain index and land use degree composite index, this paper studied the changes of land use pattern in Qixia City of Shandong Province form 1987 to 2003, and quantitatively analyzed the land use degree on terrain gradient. The results indicated that in the City, construction land had obvious advantageous on lower terrain niche, the advantageous terrain niche section of orchard increased by six terrain niche and distributed from aggregation to uniformity, while the advantageous terrain niche of crop land, forest land, grass land, water area, and unutilized land generally remained stable during the study period. According to the quantitative expression of land use degree on terrain gradient, terrain niche was divided into three sections, i.e., 1〖KG-*2〗-〖KG-*7〗15, 16〖KG-*2〗-〖KG-*7〗30, and 31〖KG-*2〗-〖KG-*7〗50, which occupied 4948%, 4358%, and 694% of the total study area, respectively.

Toxicity of Vitex negundo extract to aphids and its co-toxicity with imidacloprid.

JIANG En-shun^1,2;XUE Ming¹;LIU Yu-qing¹;WANG Yu-feng¹

2009, 20(03):  686-690 . 

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In this paper, the toxicity of Vitex negundo seed dichloromethane extract, imidacloprid, and omethoate to Aphis citricola, Aphis gossypii, and Myzus persicae was determined by impregnation method, and the co-toxicity of the seed extract and imidacloprid to A. gossypii as well as the repellent effect of the extract and test insecticides to M. persicae were tested by topical application of capillary tube and by selection in culture dish, respectively. The results showed that the LC50 of V. negundo seed dichloromethane extract to A. citricola, A. gossypii, and M. persicae was 33459, 36279, and 26858 mg·L-1, respectively, indicating that V. negundo seed dichloromethane extract was highly toxic to A. citricola and A. gossypii. The co-toxicity coefficient of the seed extract and imidacloprid was 17745 when the mixture was in 1000 ∶〖KG-*2〗1, showing an obvious synergism. The repellent effect of V. negundo seed dichloromethane extract and imidacloprid to M. persicae was 5575% and 3944%, and 6989% and 6543% after treated for 24 and 48 hours, respectively, while that of thiamethoxam and acetamiprid to M. persicae was 1652%〖KG-*2〗-〖KG-*7〗3368% after treated for 24 and 48 hours.

Hexachlorobenzene: Its aging characteristic in different soils and accumulation in earthworm.

GAO Hong-jian¹;JIANG Xin²

2009, 20(03):  691-695 . 

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A simulation experiment was conducted to study the aging characteristics of hexachlorobenzene (HCB) in different soils and its bioaccumulation in earthworm. The results indicated that the aging of HCB in soils displayed a biphasic characteristic, i.e., quicker in the first 60 days and slowing down since then. The aging of HCB mainly occurred in the first 60 days during its contact with soil, and its aging rate in soils followed the sequence of paddy soil>red soil>fluvo-aquic soil. The accumulated amount and accumulation rate of HCB in earthworm decreased with increasing aging time. Though the soil extractable HCB decreased with increasing aging time, earthworm still had a higher HCB accumulation (4576〖KG-*2〗-〖KG-*7〗9843 ng·g-1) in its body due to its high HCB accumulation ability (the bioaccumulation factor BAF was between 374 and 635), giving a potential risk to soil ecological safety.

Research advances in plant lead tolerance and detoxification mechanism.

HUANG Hua-gang^1,2;LI Ting-xuan¹;YANG Xiao-e²;ZHANG Xi-zhou¹;WU De-yong¹

2009, 20(03):  696-704 . 

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To have an overall understanding about the physiological mechanisms of plants in their lead (Pb) absorption, transportation, accumulation, and detoxif ication is the prerequisite of the phytoremediation of Pb-polluted soil. This paper reviewed the research advances in the mechanisms of plant Pb-adaptation and recovery, including the functions of cell wall and vacuole in Pb-inactivati on and sequestration in plant cells, the effects of plant root exudates on Pb bi oavailability, the roles of antioxidative enzymes dismutase (SOD), peroxidase (P OD), catalase (CAT), glutathione reductase (GR), and ascorbate peroxidase (APX), and of antioxidants phytochelatins (PCs) and glutathione in Pb detoxification, and the expression and function of metallothionein and Pb-specific genes. The further researches on the plant’s Pb-tolerance and detoxification mechanisms as well as the technologies for phytoremediation of Pb-contaminated environmen ts were prospected.

Algal control ability of allelopathically active submerged macrophytes: A review.

XIAO Xi;LOU Li-ping;LI Hua;CHEN Ying-xu

2009, 20(03):  705-712 . 

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The inhibitory effect of allelochemicals released by submerged macrophytes on ph ytoplankton is considered as one of the mechanisms that contribute to the stabil ization of clear-water status in shallow lakes. This paper reviewed t he research progress in the allelopathy of submerged macrophytes on algae from t he aspects of the occurrence frequency and coverage of allelopathically active s ubmerged macrophytes in lakes, and the kinds and allelopathical effects of the a llelochemicals released from the macrophytes. The previous researches indicated that allelopathically active submerged macrophyte species such as Myriophyllum , Ceratophyllum, and Elodea were efficient to control phytoplankton, espec ially when their biomass was high enough, and the dominant algae were sensitive species. The allelochemicals such as hydroxybenzene released by the submerged ma crophytes could inhibit the growth of algae. Different phytoplankton species exh ibited different sensitivity against allelochemicals, e.g., cyanobacteria and di atom were more sensitive than green algae, while epiphytic species were less sen sitive than phytoplankton. Environmental factors such as light, temperature, and nutrients could significantly affect the allelopathical effect of submerged mac rophytes. The research of the allelopathy of submerged macrophytes is still at i ts beginning, and further researches are needed on the effects of environmental factors on the allelopathy, extraction and identification of allelochemicals, se lective algal control mechanisms, and metabolism of the allelochmicals.

Land use pattern and its dynamic changes in Amur tiger distribution region.

LI Zhong-wen¹;WU Jian-guo^1,2;KOU Xiao-jun¹;TIAN Yu¹;WANG Tian-ming¹;MU Pu¹;GE Jian-ping¹

2009, 20(03):  713-724 . 

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Land use and land cover change has been the primary cause for the habitat loss and fragmentation in the distribution region of Amur tiger (Panthera tigris altaica). Based on the spatiotemporal changes of land use and land cover in the distribution region, as well as their effects on the population dynamics of Amur tiger, this paper analyzed the development process and its characteristics of the main land use types (agricultural land, forest land, and construction land) in this region, with the land use change history being divided chronically into three distinctive periods, i.e., ancient times (prior to 1860), modern times (1860〖KG-*2〗-〖KG-*7〗1949), and contemporary times (after 1949). The results showed that the sporadic land use in ancient times had no significant effects on the survival of Amur tiger, while the extensive and intensive land use after the 1860s was mainly responsible for the decrease of Amur tiger population and its living space. Since 1949, the Amur tiger distribution region has been divided into two parts, i.e., Northeast China and Russia Far East. The differences in land use pattern, policy, and intensity between these two parts led to different survival status of Amur tiger. The key driving forces for the land use change in Amur tiger distribution region were human population increase, policy change, and increased productivity.

Effects of elevated ozone on phenolic substances content and total antioxidative capacity of Quercus mongolica leaves.

ZHANG Guo-you^1,2;HE Xing-yuan¹;TANG Ling^1,2;YAN Kun^1,2;CHEN Wei^1,2;XU Sheng¹;LI Xiang^1,2

2009, 20(03):  725-728 . 

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An open-top chamber experiment was conducted to examine the effects o f elevated atmospheric O3 (80±8 nmol·mol-1) on the total phenols, flav onoid, condensed tannin, and MDA contents, and the total antioxidative capacity of Quercus mongolica leaves. Elevated O3 increased the contents of tota l phenols and condensed tannin by 4817% and 2677% (P<005), and the fla vonoid and MDA contents by 2466% and 526% (P>005), respectively. The t otal antioxidant capacity of Q. mogonlica leaves determined by DPPH method w as enhanced significantly (P<005), and had an obvious linear relationship with the contents of total phenols and condensed tannin.

Diversity of grasshopper community in lac plantation-farmland ecosystem.

LI Qiao¹;CHEN You-qing²;CHEN Yan-lin¹;CHEN Zhen¹

2009, 20(03):  729-735 . 

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The grasshopper communities in the paddy field, dry land, natural fore st, and plantation forest of lac plantation-farmland ecosystem in Lvchun County, Yunnan were investigated by sweep netting. A total of 1426 grasshoppers belonging to 33 species, 22 genena, and 5 families were captured. In the paddy f ield, dry land, natural forest, and plantation forest of the ecosystem, the spec ies richness S were 16333, 13000, 11000, and 12000, Margalef index was 2 873, 2266, 2335, and 2137, Shannon-Wiener index was 2034, 1976, 1 982, and 1488, Simpson index was 0196, 0189, 0174, and 0323, and Pielo u index was 0728, 0787, 0829, 0599, respectively. This ecosystem had a l ower diversity of grasshop per communities, and different land use habitats in the ecosystem had different species component and diversity. In paddy field, grasshopper had a higher divers ity than in dry land, but its evenness and stability were moderate; in natural f orest, the diversity was high and the stability was strong; while in plantation forest, the diversity was low and the stability was weak. There existed species exchange in different land use habitats in the ecosystem.

Differences in cadmium absorption and accumulation of Brassica varieties on cadmium-polluted soil.

CHEN Ying^1,2;LI Ting-qiang²;YANG Xiao-e²;JIN Ye-fei¹

2009, 20(03):  736-740 . 

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A pot experiment was conducted to study the differences in cadmium (Cd ) absorption and accumulation of sixty Brassica varieties on the soils added with different concentration of Cd. The results showed that when the soil Cd co ncentration was 06 mg·kg-1 and 12 mg·kg-1, the percentage of t est Brassica varieties whose Cd content exceeded the National Edible Standar d was 833% and 6667%, respectively, suggesting that Brassica was easy to be Cd-polluted. The shoot Cd content of all test varieties was below the National Edible Standard, and the biomass of the varieties Changgengbaicai,Shanghaiqing,Aijisuzhouqing,Qingyou 4,Aijiaokuipianheiyebaicai,Zhouyeheiyoudonger,Gaohuaqinggengbaicai,Zaoshenghuajing,Jinguanqingjiangbai,Xiawangqinggengcai, Lifengqinggengbaicai, and Hangzhouyoudonger was not affected. These 12 Brassica varieties could be planted on the soils with light Cd pollution.