Table of Content

20 January 2009, Volume 20 Issue 01

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Articles

C and N allocation patterns in planted forests and their release patterns during leaf litter decomposition in subalpine area of west Sichuan.

LIU Zeng-wen¹;DUAN Er-jun¹;PAN Kai-wen²;ZHANG Li-ping¹; DU Hong-xia¹

2009, 20(01):  1-6 . 

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With the planted forest ecosystems of Cercidiphyllum japonicum, Betula utilis, Pinus yunnansinsis, and Picea asperata in subalpine area of west Sichua n as test objects, their total biomass and the C and N contents in soils and tre e organs were determined. The results showed that the allocation of C in tree or gans had less correlation with the age of the organs, while that of N and C/N ra tio had closer relationship with the age. The N content in young organs was high er than that in aged ones, whereas the C/N ratio was higher in aged organs than in young organs, and higher in the leaf litters of needle-leaved forests than i n those of broad-leaved forests. There was an obvious enrichment of C and N in the topsoil of test forests. The accumulated amounts of C and N in the whole pla nted forest ecosystem, including tree, litter, and 0〖KG-*2〗-〖KG-*7〗40 cm soil layer, were 17675〖KG-*2〗-〖KG-*7〗22805 t·hm-2 and 1106〖KG-*2 〗-〖KG-*7〗1654 t·hm-2, respectively, and the nutrients allocation rat io between soil-litter and tree was (19〖KG-*2〗-〖KG-*7〗33)∶〖KG-*2〗1 for C an d (156〖KG-*2〗-〖KG-*7〗415)∶〖KG-*2〗1 for N. Needle-leaved forests functioned as a stronger “C-sink” than broad-leaved forests. The decomposition rate of the l eaf litters in needle-leaved forests was larger than that in broad-leaved fore sts, with the turnover rate being 22〖KG-*2〗-〖KG-*7〗37 years and 39〖KG -*2〗-〖KG-*7〗42 years, respectively. During the decomposition of leaf litter, the C in all of the four forests released at super -speed, with the turnover rate being 19〖KG-*2〗-〖KG-*7〗34 years. As for N, it also released at super-speed in C. japonicum and B. utilis forest s, with the turnover rate being 19〖KG-*2〗-〖KG-*7〗32 years, but released a t low speed in P. yunnansinsis and P. asperata forests, with the turnove r rate being 67〖KG-*2〗-〖KG-*7〗85 years.

Effects of simulated warming on the growth, leaf phenology, and leaf traits of Salix eriostachya in sub-alpine timberline ecotone of Western Sichuan, China.

XU Zhen-feng¹;HU Ting-xing¹;ZHANG Li¹;ZHANG Yuan-bin²;XIAN Jun-ren¹;WANG Kai-yun^2,3

2009, 20(01):  7-12 . 

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By using open-top chamber (OTC), the effects of simulated warming on the growth , leaf phenology, and leaf traits of Salix eriostachya in sub-alpine timber line ecotone of Western Sichuan were studied. The results showed that comparing with the control, the mean air temperature at 12 m above the ground through out S. eriostachya growth season in OTC increased by 29 ℃, while the soil temperature at the depth of 5 cm only increased by 04 ℃. The temperature inc rease in OTC made S. eriostachya budding advanced and defoliation postpon ed obviously, and the leaf life-span longer. The leaf and branch growth rates a s well as the specific leaf area in OTC increased obviously, whereas the leaf ni trogen concentration decreased significantly. In OTC, the stomata conductance, n et photosynthetic rate, photorespiration, and dark respiration rate of S. erio stachya all exhibited an increasing trend. It was suggested that S. eriostac hya had stronger capability to adapt to warming, and, under the background of future global climate change, the elevation of S. eriostachya distribution i n the timberline ecotone would be likely to ascend.

Effects of tree height on whole-tree water use of Acacia mangium.

LIU Xiao-jing¹;ZHAO Ping¹;WANG Quan²;CAI Xi-an¹;ZENG Xiao-ping¹

2009, 20(01):  13-19 . 

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By using Granier’s thermal dissipation probe, the sap flow of 14 sample trees i n a 22-year old Acacia mangium forest in hilly land of South China was continuo usly measured in 2004. Environmental factors including the photosynthetically active radiation, air temperature, and air humidity above canopy and the water content in 0〖KG-*2〗- 〖KG-*7〗30 cm soil layer were monitored simultaneously. Combining with the tree morp hological features and sap flux density, the whole-tree transpiration, canopy s tomatal conductance, and ratio of leaf area to sapwood area were calculated by s implified Whitehead and Jarvis equation, and the effects of tree height on these three parameters were analyzed. The results indicated that under sufficient soi l water supply, the whole-tree transpiration increased in a quadratic polynomial way with tree height (P<001), and the diurnal variation of canopy stomatal conductance was of one-peak pattern. Within the measured range of photosynthetically activ e radiation, taller A. mangium trees had higher reference canopy stomatal conduc tance and higher sensitivity of canopy stomatal conductance to vapor pressure de ficit, compared with the shorter ones. The ratio of leaf area to sapwood a rea was (1837±0048) m2·cm-2, and increased in power function with tree height. A. mangium had no obvious hydraulic limitation and compensation eff ect with its increasing tree height.

Patch diversity and spatial structure of wild Thymus quinquecostatus.

QUAN Jun-ping^1,2;PENG Feng³;HE Shu-lan³;ZHENG Yu-hong³;JIANG Yu-mei³;LI Nai-wei³;ZHANG Ming-xia³;XIA Bing³

2009, 20(01):  20-26 . 

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With the combination of ISSR (inter-simple sequence repeats), SRAP (sequence-r elated amplified polymorphism) and spatial autocorrelation, the genetic diversit y and spatial structure per unit patch of three Huaiyuan populations of Thymus quinquecostatus in southeast China were analyzed. The results showed that there e xisted higher levels of genetic and clonal diversity among the patches within th e wild T. quinquecostatus populations, with the percentage of polymorphic lo c being 7575%, Nei’s gene diversity being 02537, Shannon’s information ind ex being 03811, percent of genetype (G/N) being 061, Simpson index (D) bein g 096, and Fager index (E) being 091. Analysis of molecular variance (AMOVA) showed that only 965% of genetic variation resided among the populations, whi le 9035% of it resided among the individuals within the populations. No genoty pe patches in common were observed among the three populations. The spatial dist ribution of the same patches showed a concentrated distribution about 0〖KG-*2〗 -〖KG-*7〗25 m, and that of different patches showed an inlaid distribution. Exc ept for some locations that showed par correlations in the Huaiyuan populations of T. quinquecostatus, most locations lacked in spatial structure according to spatial autocorrelation analysis. The possible mechanism causing the establis hment of the patches of T. quinquecostatus populations was due to seed dispe rsing, and the following clonal reproduction played important roles in patch dev elopment and population expanding.

Changes of plant community structure and species diversity in degradation process of Shouqu wetland of Yellow River.

HOU Yuan;GUO Zheng-gang;LONG Rui-jun

2009, 20(01):  27-32 . 

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Shouqu wetland of Yellow River plays important roles in the ecological security of the lower reaches of Yellow River. By the method of replacing time series with spatial sequence, an investigation was made on the changes of plant species diversity in the process of the natural degradation of the wetland. A co mparison was also made to study the effects of artificial drainage on the plant species diversity. The results indicated that in the degradation process of Shou qu wetland, i.e., from swamp to swamp meadow, to alpine meadow, and to steppe me adow, the dominant plants followed the pattern of hygrophytes being gradually re placed by mesophytes and xerophytes, richness index and diversity index were inc reasing while dominance index was decreasing, and evenness index decreased first and increased then. The species diversity had an overall increasing trend. Afte r artificial drainage, the proportion of poisonous weeds in the plant community increased, resulting in the increase of richness index and diversity index, slig ht decrease of evenness index and dominance index, and gradual decrease of Soren sen index. Artificial drainage made the habitat drying, which provided a chance for some mesophytes to invade, resulting in the increase of diversity index and richness index and the decrease of evenness index. On the whole, artificial drai nage increased the plant diversity in the community, but the increase accompanie d with increasing poisonous weeds, and thus, led the Shouqu wetland degraded int o weed type wetland.

Invasion and its effects of xerarch halophytes in reclaimed tidal wetlands.

GONG Jin-nan;WANG Kai-yun;ZHANG Chao;MA Yong-liang

2009, 20(01):  33-39 . 

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With the reclaimed tidal wetland of Chongming Dongtan in Shanghai as a case, and based on the landscape pattern analysis of colored infrared aerial ph otographs and field survey, this paper studied the invasion of xerarch halophyte s and its effects on the original reed community in the wetland after artificial drainage. The results showed that in the test reclaimed tidal wetland area, the xerarch halophyte community with Tripolium vulgare as edificator was spreading from northeast to southwest at a high speed of 143 m per year, with the original reed patch reduced and broken sharply, causing a 227 times increase in patch d ensity index and a 13 times increase in shape index. After the growth seasons in 2006 and 2007, the biomass of T. vulgare in the plant community reached a s high as 27838 g·m-2，occupying 98% of the total, and the importance v alue reached 88%. At the mean time, the biomass and importance value of original reed decreased 98% and 83%, respectively. The invasion process of xerarch haloph ytes was meaningfully correlated with the moisture content and salinity in 0-20 cm soil layer. To effectively control the rapid invasion of xerarch halophytes, the mechanisms of their invasion and the strategies of ra tional and dynamic drainage management should be deeply studied.

Effects of cadmium stress on the growth and physiological characteristics of Lonicera japonica.

LIU Zhou-li^1,2;HE Xing-yuan¹;CHEN Wei¹

2009, 20(01):  40-44 . 

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By using hydroponics, the growth and physiological characteristics of Lonicera japonica at different concentrations (0, 5, 10, 25, and 50 mg·L-1) of cadmium (Cd) were studied. The results showed that compared with the control, Cd stress had lesser effects on the growth of L. japonica. Within the range of test Cd concentrations, L. japonica biomass had less difference (P>00 5) with the control, and at low concentration of Cd (5 mg·L-1), the total biomass and the biomasses of leaf and root were increased by 125%, 288 and 2 33%, respectively, illustrating that L. japonica had stronger resistance a gainst Cd. Under low concentration Cd stress, the water content and soluble prot ein content in plant organs had some decrease, while the malondialdehyde (MDA) c ontent in root and leaf increased by 5190% and 2307%, respectively, leaf chl orophyll and carotenoid contents increased by 1587% and 2489%, respectively, and superoxide dismutase (SOD) activity increased significantly. With increasin g Cd concentration, the chlorophyll and carotenoid contents and SOD activity dec reased to some extent.

Effects of vegetation restoration on soil microbial biomass carbon and nitrogen in hilly areas of Loess Plateau.

HU Chan-juan^1,2;FU Bo-jie¹;JIN Tian-tian^1,2;LIU Guo-hua¹

2009, 20(01):  45-50 . 

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Aimed to explore the effects of different vegetations and of the years of vegeta tion restoration on soil microbial biomass carbon and nitrogen, a comparative st udy was conducted, with the 5 year old Robinia pseudoacacia, Hippophae reamno ide and Prunus armeniaca plantations and the 5, 15 and 25 years old R. pseudoacacia plantation in the Yangjuangou catchment of Yanan City of Shaa nxi Province, a typical hilly area of the Loess Plateau, as test objects. The re sults showed that among the three 5-year old plantations, H. reamnoides pl antation had the highest soil organic carbon (SOC) and total nitrogen (TN) conte nts, while R. pseudoacacia plantation had the highest soil microbial biomass carbon (MBC) (9956 mg·kg-1) and nitrogen (MBN) (2881 mg·kg-1) . The MBC was in the order of R. pseudoacacia>H. reamnoides>P. armeniaca, an d that of MBN was of R. pseudoacacia>P. armeniaca>H. reamnoides. The MBC/SOC was in the order of R. pseudoacacia>H.reamnoides>P. armeniaca, and that of MBN/TN was of R. pseudoacacia>P. armeniaca>H. reamnoides, with the differenc es being significant (P<005). With the increasing years of vegetation rest oration, the soil pH in R. pseudoacacia plantation decreased, while the SOC, TN, electricity conductance (EC), MBC, and MBN all had an increasing trend, whi ch illustrated that in the hilly area of Loess Plateau, planting R. pseudoacac ia was more beneficial to the increase of soil MBC and MBN, and, with the incr easing years of this planting, soil MBC, MBN, SOC and TN tended to be increasing.

Relationships of soil microbial biomass with soil environmental factors in Tarim Desert highway shelter-forest.

JIN Zheng-zhong^1,2;LEI Jia-qiang¹;XU Xin-wen¹;LI Sheng-yu¹;FAN Jing-long¹;ZHAO Si-feng³;ZHOU Hong-wei⁴;GU Feng⁴

2009, 20(01):  51-57 . 

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〖WT5HZ〗Abstract: 〖WT5BZ〗 By using correlation analysis, this paper studied the relationships of soil micr obial quantity and biomass with soil physical and chemical factors and enzyme ac tivities in highway shelter-forests of Tarim Desert, aimed to approach the inte ractions between microbes and environmental factors in aeolian sandy soil of ext remely arid area. The results showed that soil microbial quantity and biomass in the shelter-forests had an increasing trend with the decrease of soil bulk den sity and particle size (R<-0.84) and the increase of soil moisture content and p orosity (R>0.85), with the correlation between soil microbial biomass and soil b ulk density as the key. Soil microbial quantity and biomass were positively corr elated with soil nutrient contents, mainly caused by the correlations of soil ac tinomycetes and microbial biomass C and P with soil available nutrients. Greater differences (R=051〖KG-*2〗-〖KG-*7〗091) were observed in the correlations of soil enzyme ac tivities with soil microbial quantity and biomass, which was mainly determ ined by the correlations of soil invertase and phosphatase activities with soil actinomycetes and microbial biomass C. The increase of soil salt content was not favorable to the accumulation of soil microbial biomass (R<-071), and there w as a higher positive correlation (R>063) between soil microbial amount and bio mass. In practice, good soil condition should be established in the forestlands of arid area for the development of soil microbes and the promotion of soil matt er cycling.

Relationships between Horqin meadow NDVI and meteorological factors.

QU Cui-ping^1,2;GUAN De-xin¹;WANG An-zhi¹;JIN Chang-jie¹;WU Jia-bing¹;WANG Ji-jun^1,2;NI Pan^1,2;YUAN Feng-hui¹

2009, 20(01):  58-64 . 

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Based on the 2000〖KG-*2〗-〖KG-*7〗2006 MODIS 8-day composite NDVI and day -by-day meteorological data, the seasonal and inter-annual variations o f Horqin meadow NDVI as well as the relationships between the NDVI and r elevant meteorological factors were studied. The results showed that as for the seasonal variation, Horqin meadow NDVI was more related to water vapor press ure than to precipitation. Cumulated temperature and cumulated precipitation tog ether affected the inter-annual turning-green period significantly, and the pr ecipitation in growth season (June and July), compared with that in whole year, had more obvious effects on the annual maximal NDVI. The analysis of time lag effect indicated that water vapor pressure had a persistent (about 12 days) prominent effect on the NDVI. The time lag effect of mean air temperature was 11-15 days, and the cumulated dual effect of the temperature a nd precipitation was 36-52 days.

Impact of heavy snow storm and freezing rain disasters on soil fauna in Chinese fir plantation in southern China.

YAN Shao-kui¹;ZHANG Wei-dong¹;LIU Yan-xin¹;FU Sheng-lei²;LI Yuan-liang¹;WANG Si-long¹

2009, 20(01):  65-70 . 

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In January 2008, southern China suffered an unusual heavy snowstorm an d freezing rain over a large area for almost a month long. This catastrophic eve nt was the worst one in past 50 years, which brought the area a serious impact o n the infrastructure, ecology, and environment. To understand the long-term imp act of this catastrophic event on the forest ecosystems in this area, a field in vestigation was conducted on the soil fauna in a pure Chinese fir plantation and a mixed Chinese fir plantation-alder plantation in Huitong County of Hunan Pro vince on March 23, 2008, the date 40 days after the heavy snowstorm and freezing rain. With the abundance and community composition as the main parameters and t he monitoring data from the two plantations on March 23, 2007 as the reference, the flexibility and resistance of soil fauna to the disturbances of the catastro phic event was preliminarily evaluated. The results showed that there was a sign ificant deviation of soil fauna communities in the two plantations from the refe rence. An outbreak increase in microfauna nematode abundance was found from 122 169 ind·m-2 to 1183439 ind·m-2 in pure Chinese fir plantation and from 254359 ind·m-2 to 845730 ind·m-2 in mixed Chinese fir plantation-alder plantation, while a 270% and 856% decrease of macrofau na abundance was found in the two plantations, respectively, compared with the r eference. Mesofauna abundance also had a significant decrease in litter layer bu t not in soil. The abundance recovery displayed a trend from quick rate for micr ofauna to slow rate for macrofauna, w hich indicated that the soil fauna functional groups, in terms of body size, cou ld be used as a vulnerable indicator in evaluating disturbance event and post-d isturbance recovery. By using community ordinations, no shift in soil fauna comm unity composition was detected 40 days after the catastrophic event, suggesting that the community composition of soil invertebrate had a high resistance to cat astrophic snowstorm and freezing rain disturbances.

Responses of tree-ring width of Cinnamomum camphora to climate change in Dagangshan forest area of Jiangxi Province.

WANG Bing¹;GAO Peng²;GUO Hao¹;LENG Ling¹

2009, 20(01):  71-76 . 

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By using ARSTAN software to wipe off the growth trend of tree-ring width and transform the series into index form, the tree chronology of Cinnamomum camphora in Dagangshan forest area of Jiangxi Province was built, and the responses of the tree-ring width of C. camphora to climate change in study area were studied. The results showed that the built tree chronology included abundant environmental climatic information, which could be used in dendrochronological research. In study area, the tree-ring width of C. camphora was positively correlated to the mean monthly temperature in growth season, especially to that of April and May (P<005). The correlation of the tree-ring width with monthly prec ipitation was more complicated, being significant negative with the precipitatio n in current May (P<001) and last December (P<005), while significan t positive with that in current June and August (P<005). The tree-ring wi dth had a good correlation with the humidity index of current May, June, August, and September. Temperature and precipitation had obvious integrative effects on the tree-ring width of C. camphora in Dagangshan forest area of Jiangxi Province.

Precision of spatial interpolation for forest duff layer depth based on secondary variable.

LIU Zhi-hua^1,2;CHANG Yu¹;HE Hong-shi^1,3;CHEN Hong-wei^1,2

2009, 20(01):  77-83 . 

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Based on geostatistical method, three algorithms of spatial interpolat ion with elevation as a secondary variable, i.e., simple kriging with varying lo cal means (SKlm), kriging with an external drift (KED), and cokriging (COK), wer e used to calculate the precision of spatial interpolation for the forest duff l ayer depth, and cross validation was conducted. The results showed that among th e three algorithms, KED gave the highest precision because of its taking into ac count both the spatial variation among variables and the factors affecting local spatial change, SKlm did not yield expected precision because of the weaker corre lation between elevation and forest duff layer depth, while COK directly used th e variable elevation to estimate forest duff layer depth but many unexpected res ults yielded for the boundary area due to insufficient samplings. Comparing with the method of inverse distance weighting (IDW), only KED had a higher precision of interpolation, while for SKlm and COK, their interpolation precision was lower, suggesting that when a secondary variable was used for geostatistical interpola tion, the correlation between primary and secondary variables was of significanc e in increasing the precision of interpolation.

Change characteristics of climate and water resources in west Liaohe River Plain.

YANG Heng-shan¹;LIU Jiang²;LIANG Huai-yu¹

2009, 20(01):  84-90 . 

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Based on the 1951〖KG-*2〗-〖KG-*7〗2007 observation data of precipitation and temperature from To ngliao, Kailu, and Zhalute meteorological stations as well as the related hydrol ogic data from Tongliao hydrological survey bureau and water affairs bureau, the change characteristics of the climate and water resources in west Liaohe River Plain were studied. The results showed that in 1951〖KG-*2〗-〖KG-*7〗2007, the precipitation in its periodical changes in study area had a decreasing trend. Th e tendency rate of precipitation was -132 mm·（10 a）-1, and the instability of precipitation was increased. The runoff of four inbound rivers including Xil amulun all decreased, with the mean annual runoff in 2001〖KG-*2〗-〖KG-*7〗2007 being only 228% of that in 1990〖KG-*2〗-〖KG-*7〗1994. From 1951 to 2007, th e runoff of west Liaohe River decreased, and the days of its zero flow increased . Since 2001, the River had been zero flow. The groundwater overdraft area and t he funnel area in Keerqin Region in 2006 increased by 85 times and 15.5 times, respectively, compared with those in 1978; and the average groundwater level in Keerqin Region, Kailu County, and Naiman Banner in 2006 increased by 376 m, 2 77 m, and 193 m, respectively, compared with that in 1980. Since the 1970s, the number of electromechanical well in study area was increasing, irrigation amount had a fluctuated rise, and the proportion of agricultural water consumption had different extent decrease. Therefore, to exploit and use the water resources in atmosphere, to popularize water-saving irrigation technologies, and to make a reasonable arrangement of industrial structure were the effective measures in re alizing the sustainable utilization of water resources in west Liaohe River Plai n.

Responses of soil humidity on Songnen Plain to climate change in 1980-2005.

JIANG Li-xia;LI Shuai;JI Yang-hui;ZHU Hai-xia;YAN Ping;WANG Ping; WANG Chen-yi;HAN Jun-jie

2009, 20(01):  91-97 . 

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Based on the 1980〖KG-*2〗-〖KG-*7〗2005 observation data of ten-day soil humid ity, monthly air temperature, and monthly precipitation during crop growth perio d (from May to September) from 16 agro-meteorological stations on Songnen Plain , the spatiotemporal variation of surface soil (0〖KG-*2〗-〖KG-*7〗30 cm) humid ity and its responses to the air temperature and precipitation in study area wer e analyzed by using statistical method. The results showed that on Songnen Plain , the surface soil humidity during crop growth period in 1980〖KG-*2〗-〖KG-*7〗 2005 had a decreasing trend, and tended to be aridified, especially in the west and south parts of the Plain. Before the 1990s, the surface soil on the Plain was r elatively humid, but thereafter, the humidity kept decreasing, and partial dryne ss occurred. In the study period, the mean air temperature during crop growth pe riod had a periodical increase before 1992, with a small fluctuation in a cycle of 6 years, but increased obviously after then. The precipitation during crop gr owth period had a larger inter-annual variation, with a cycle of 4〖KG-*2〗-〖K G-*7〗5 years. The surface soil humidity during crop growth period was significa ntly negatively correlated to air temperature and positively correlated to preci pitation. Both air temperature and precipitation were the main climatic factors affecting the variation of surface soil humidity on Songnen Pl ain.

Spatial heterogeneity of surface soil moisture content in dry season in Mulun National Natural Reserve in Karst area.

SONG Tong-qing^1,2;PENG Wan-xia^1,2,3;ZENG Fu-ping^1,2;OUYANG Zi-wen^1,2,3;WU Hai-yong^1,2,4

2009, 20(01):  98-104 . 

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By the methods of classical statistics and geostatistics, the spatial heterogene ity of surface soil (0〖KG-*2〗-〖KG-*7〗5 cm and 5〖KG-*2〗-〖KG-*7〗10 cm laye rs) moisture content in dry season in the typical sloping fields and depressions in Mulun National Natural Reserve in Karst area were studied. The results indic ated that in study area, the surface soil moisture content in dry season was sti ll higher, and showed a fine semivariogram structure as a whole. The spatial distribution of moisture cont ent in 0〖KG-*2〗-〖KG-*7〗5 cm and 5〖KG-*2〗-〖KG-*7〗10 cm soil layers, both for sloping fields and for depressio ns, fitted exponential model well. Under the same stand conditions, the moisture content in the two soil layers had the similar spatial structure and distributi on pattern; while under different stand conditions, there existed obvious differ ence in the same soil layer. The spatial pattern of surface soil moisture conten t in sloping fields was characterized by medium spatial autocorrelation, clear p atches with well continuum, relatively slow variation of Moran’s I index, while that in depressions was characterized by strong spatial autocorrelation, larger variation of Moran’s I index, and more fragmented patches. Therefore, topograp hy, micro-physiognomy, precipitation, human disturbance, and especially vegetat ion were the most important factors affecting the spatial pattern of soil moistu re content in the Mulun National Natural Reserve, and to preserve primary forest should have favorable effect on the regulation of the spatial heterogeneity of soil moisture content in the Reserve.

Influence of climate change on mosaic landscape of sand land-wetland in middle-east Inner Mongolia.

LI Xing-hua^1,2;HAN Fang¹;ZHANG Cun-hou¹;NA Ri-su¹;LIU Peng-tao¹

2009, 20(01):  105-112 . 

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By using wavelet transform and remote sensing techniques, the influence of clima te change on the unique mosaic landscape of sand land-wetland in middle-east I nner Mongolia in 1961-2005 was studied. The results showed tha t in 1961-2005, the annual air temperature in study area had a n increment of 032 ℃·(10 a)-1, the annual precipitation fluctuated with a cycle of 30 years and of 15 years, and the annual average wind speed decreased by 026 m·s-1·（10 a）-1. In the southeast part of study area, which located in the places between Hunshandake sand land and Keerqin Deserts, there w as a district, in which, the climatic characteristics did not change evidently. Until 2010, the study area would still have an increasing air temperature, lesse r precipitation, and decreasing wind speed. Under the influence of warming and drying, the total area of Hunshandake sand land and the wetland a round reduced year after year, and, with the vegetation degradation on sand land , wetland shrunk and lake dried up, moving sand land enlarged ceaselessly, whil e immovable and semi-moving sand lands reduced obviously.

Ecological sensitivity of Jingnanxia-Heishanxia reach of Yellow River.

LIU Yao-long;WANG Jun;XU Shi-yuan;XIE Cui-na;CHEN Jing-jing;YE Ming-wu

2009, 20(01):  113-120 . 

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Aiming at the ecological problems such as soil erosion, desertification, and sal inization in the Jingnanxia-Heishanxia reach of Yellow River, the single-facto rial ecological problem’s sensitivity and the comprehensive ecological s ensitivity of the reach were analyzed by GIS spatial analysis, grid computing an d superposition, and RS image feature extraction. The results showed that the re gions with medium- and high ecological sensitivities almost covered the whole s tudy area, including the Wufo Town of Jingtai County, the Beiwan Town, Wulan Tow n, Mitan Town, Dongwan Town, and Santan Town of Jingyuan County, and the area be tween Doucheng and Hongliutan of Pingchuan District. The high, medium, and low s ensitive areas should be accordingly programmed as forbidden, medium, and deep c onstructing areas. During the development process of regional hydropower, effect ive measures should be adopted to protect the ecological environment to achieve the sustainable development of the drainage area.

Effects of land use/cover change on runoff sediment discharge in typical watershed in Loess gullied-hilly region of China.

ZHANG Xiao-ming¹;CAO Wen-hong¹;YU Xin-xiao²;ZHANG Man-liang³;WANG Xiang-dong¹;ZHU Bi-sheng¹

2009, 20(01):  121-127 . 

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By using the measurement technique of dynamic hydrological process and the estim ation method of landscape ecology, this paper studied the effects of 1986〖KG-*2 〗-〖KG-*7〗2004 land use/cover change (LUCC) on the runoff sediment discharge i n the Luoyugou watershed in Tianshui of Gansu Province in third sub-region of L oess Plateau. The results showed that the LUCC in Luoyugou watershed had signifi cant effects on the annual sediment yield. In 1995〖KG-*2〗-〖KG-*7〗2004, the s ediment discharge was reduced by approximately 630%, compared with that in 198 6〖KG-*2〗-〖KG-*7〗1994, and the reduction effect was more significant with inc reasing annual precipitation. The effects of LUCC on sediment discharge demonstr ated seasonal fluctuation characteristic. Relative to that in 1986〖KG-*2〗-〖KG -*7〗1994, the reduction effect of sediment discharge in 1995〖KG-*2〗-〖KG-*7〗 2004 was more concentrated in the period from May to October, and, the more the monthly precipitation, the more the reduction of monthly average sediment discha rge in 1995〖KG-*2〗-〖KG-*7〗2004 than in 1986〖KG-*2〗-〖KG-*7〗1994. The anal ysis on precipitation and flood peak discharge frequency indicated that under th e same frequency distribution of precipitation intensity, the average sediment c oncentration in any recurrence period in Luoyugou watershed was smaller in 1995 〖KG-*2〗-〖KG-*7〗2004 than in 1986〖KG-*2〗-〖KG-*7〗1994.

Effects of different root zone irrigation modes on apple seedlings hydraulic resistance.

YANG Qi-liang;ZHANG Fu-cang

2009, 20(01):  128-134 . 

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This paper studied the effects of different root zone irrigation modes (alternate partial drip irrigation, ADI; fixed partial drip irrigation, FDI; and conventional drip irrigation, CDI) and their watering amount on the whole-plant and its components hydraulic resistance and the stomata conductance and leaf area of apple seedlings. The results showed that both the irrigation mode and the watering amount had significant effects on the apple seedlings hydraulic resistance (R). Under the same irrigation modes, the root resistance (Rr) of apple seedlings was increased, but the shoot resistance (Rs) was decreased with decreasing watering amount; and under the same watering amounts, ADI and FDI increased the leaf and petiole resistance (Rl+p), but decreased the whole-plant resistance (Rt), Rr, Rs, and lateral branch and master rod resistance (Rlb+mr), compared with CDI. Under the irrigation quota of 20 mm and 30 mm, the Rl+p of ADI was 106% and 063% higher than that of CDI, respectively; and with the prerequisite of saving 33% of irrigation water, the average Rl+p of ADI and FDI was increased by 1965% and 2434%, while the average Rlb+mr was decreased by 483% and 1497%, respectively, compared with those of CDI. ADI and FDI effectively decreased stomata conductance and leaf area and increased Rl+p, and thus, decreased leaf blade luxurious transpiration dehydration while increased plant water use efficiency. By decreasing Rr and Rlb+mr, the ADI and FDI improved apple seedlings water regulation function and drought-resistant capability.

Dynamic characteristics of leaf area index and allocation characters of ecological resources for different yielding spring maize populations.

HOU Yu-hong¹;CHEN Chuan-yong²;GUO Zhi-qiang¹;HOU Li-bai¹;ZHANG Bin³;ZHAO Ming²

2009, 20(01):  135-142 . 

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By using 3-year field experimental results and related meteorological observation data, the dynamic characteristics of leaf area index (LAI) and the allocation characters of ecological resources for different yielding spring maiz e (Zea Mays L.) population in Huadian of Jilin Province were studied. The resul ts showed that the dynamic characteristics of relative LAI, with the relative gr owth days of test population, relative effective accumulated temperature, relat ive sunshine hours and relative rainfall as independent variables, fitted r ational formula y=(a+bx)/(1+cx+dx2), and the regression equation of maize yiel d with the ratios of growth days before and after silking (x1), effective accu mulated temperature before and after silking (x2), rainfall before and after s ilking (x3), and sunshine hours before and after silking (x4) was y=546519 +1781064x1-2323614x2+409341x3+628737x4 (R2=08187，P<001) , with the effects of these ecological factors on yield being in the sequence of x1>x2>x3>x4 according to the absolute values of partial regression coef ficients. In super high yielding (1549986 kg·hm-2) spring maize populat ion, the allocation ratios of x1, x2, x3, and x4 were 143, 141, 14 4, and 140, respectively. Therefore, in Northeast China, appropriate early sow ing of spring maize to prolong its growth days with more rainfall and sunshine h ours before silking could attain high yielding, and high or super high yield cou ld be achieved when the allocation ratios of x1, x2, x3, and x4 were all about 14.

Characteristics of paddy field nitrogen leakage and runoff in rice-duck farming system.

YU Xiang^1,2;WANG Qiang-sheng¹;WANG Shao-hua¹;LIU Zheng-hui¹;WANG Xia-wen^1,2;DING Yan-feng¹

2009, 20(01):  143-148 . 

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A field experiment was conducted to study the characteristics of paddy field nitrogen (N) leakage and runoff under rice-duck farming (MRD), conventio nal farming (MR), and conventional farming with flooding (CK). Comparing with th at under MR, the paddy field under MRD had a notable decrease of N (especially N O3--N) concentration in its leaked liquid; but this concentration was tended to be increased, compared with that under CK. After 7〖KG-*2〗-〖KG-*7〗9 days o f fertilization, the NH4+-N and NO3--N concentrations in paddy field su rface water were higher under MRD than under MR. However, owing to the no draini ng and the higher band, the paddy field under MRD had a notable reduction of drainage, resulting in a marked decr ease of N runoff than that under MR. Comparing with MR, the paddy field under MR D had an addition of nitrogen supply from duck dung, a reduction of N leakage an d runoff, a lesser application of chemical nitrogen fertilizer, and more nitroge n uptake by rice plant. Both the reduction of N input and that of N output in ri ce-duck farming system were nearly equal in quantity.

Effects of air temperature on enzyme activities of cotton plants related to saccharide metabolism of cotton fiber.

ZHOU Qing^1,2;WANG You-hua¹;XU Nai-yin¹;ZHANG Chuan-xi¹; ZHOU Zhi-guo¹;CHEN Bing-lin¹

2009, 20(01):  149-156 . 

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Taking two cotton cultivars with different fiber strength (KC-1, aver age fiber strength 35 cN·tex-1; and AC-33B, average fiber strength 32 cN ·tex-1) as test materials, a field experiment with two planting dates (25 April and 25 May) was conducted in Nanjing of Jiangsu (lower reaches of Yangtze River Valley) and Xuzhou of Jiangsu (Yellow River Valley) to study the dynamic changes of plant sucra se, sucrose synthase, sucrose phosphate synthase, and β-1,3-glucanase activit ies during the development of cotton fiber at different air temperatures and the ir relationships with fiber length and strength. In the development period of fi ber elongation, sucrase and β-1,3-glucanase activities were higher; while du ring the period of fiber thickening, sucrose synthase and sucrose phosphate synt hase activities increased rapidly and were high, but sucrase and β-1,3-glucan ase activities had a rapid decrease. The higher sucrase activity in fiber elonga tion development period favored the fiber length development, while the rapid in crease of sucrose synthase and sucrose phosphate synthase and the rapid decrease of sucrase and β-1,3-glucanase activity favored the development of fiber str ength. For cotton variety KC-1, the sucrase and β-1,3-glucanase activities i n its early development period and the sucrose synthase and sucrose phosphate sy nthase activities in its middle and later development periods were all higher th an those of AC-33B. In this study, 233 ℃ was the optimal temperature for hig h strength fiber formation, and 233 ℃〖KG-*2〗-〖KG-*7〗255 ℃ was the opti mal temperature for long length fiber formation.

Effects of transgenic insect-resistant cotton root exudates on the growth of Verticillium dahliae Kleb.

LI Xiao-gang^1,2;LIU Biao²;LIU Dou-dou¹;HAN Zheng-min¹;ZHOU Ke-xin²;ZHENG Yang-ping²

2009, 20(01):  157-162 . 

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The decline of disease resistance of transgenic insect-resistant cotton has bec ome one of the important factors restricting China cotton production. With two t ransgenic insect-resistant cotton varieties and their parental conventi onal cotton lines as test materials, the effects of their root exudates on the s pore germination and mycelial growth of Verticillium dahliae Kleb were studi ed, and the components and contents of the amino acids and sugars in the exudate s were determined. Comparing with their parental lines, the two transgenic insec t-resistant varieties had a declined resistance against V. dahliae, and the ir root exudates had promotion effects on V. dahliae spore germination and mycel ial growth. The root exudates of transgenic cotton Zhong-41, compared with thos e of its parent line Zhong-23, contained two additional amino acids Met and Lys , and the contents of Asp, Glu, Ser, Ala, Val, Leu, and Tyr were significantly h igher. Though the components of amino acids in the root exudates of Simian-3 an d transgenic cotton GK-12 were the same, the Tyr, Val, and Leu contents in the root exudates of transgenic cotton GK-12 were significantly lower. Four kinds o f sugar were detected in the root exudates of Zhong-41, while only glucose was detected in the root exudates of Zhong-23. These four kinds of sugar were also detected in the root exudates of Simian-3 and GK12, but their contents differed significantly.

Supply-demand level and development capability of Harbin urban ecosystem.

CAI Chun-miao^1,2;SHANG Jin-cheng³

2009, 20(01):  163-169 . 

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To measure the supply-demand level and the development capability of u rban ecolsystem is the prerequisite in ensuring urban sustainable develop ment. By using the analysis model of ecological footprint and the improved model of urban ecological carrying capacity, the utilization rate and supply degree o f natural resources in Harbin City in 1998〖KG-*2〗-〖KG-*7〗2005 were quantitat ively studied, with the supply-demand level and development capability of the C ity’s ecosystem measured and analyzed comprehensively. The results show ed that in 1998〖KG-*2〗-〖KG-*7〗2005, the demand of Harbin urban ecosy stem was greater than its supply. Though the ecological deficit had an annual de crement of 245%, the contradiction between demand and supply of the ecosystem was still obvious. The diversity index of ecological footprint and the d evelopment capability both presented an overall uptrend, but the increment of th e latter was far greater than that of the former, which illustrated the enhancem ent of the development capability being based on the consumption of ecological r esources, and the urban development being of not sustainable. Social economic me asures should be adopted to coordinate the contradiction between demand and supp ly and to realize the sustainable development of Harbin City.

Dynamic coupling of ecological supporting capability and socioeconomic development of west Jilin Province.

WANG Ming-quan^1,2;WANG Jin-da¹;LIU Jing-shuang¹;GU Kang-kang^1,2

2009, 20(01):  170-176 . 

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The coupling relations between ecological supporting capability ［F(x)］ and socioeconomic situation ［F(y)］ of west Jilin Province from 1986 to 2004 wer e analyzed by harmonious development model and scissor difference method. The re sults showed that in study period, the F(x) of west Jilin Province had a trend o f decreasing first and slightly increasing then, while F(y) had an overall expon ential increase. Influenced by natural and anthropogenic factors, both F(x) and F(y) had obvious vulnerability. The scissor difference α between F(x) an d F(y) declined from 493° in 1986 to 028° in 1996, and then increased to 1230° in 2004. During the period of 1995〖KG-*2〗-〖KG-*7〗2004, west Jilin Province g radually changed its traditional manner, i.e., from increasing F(y) with the rapid degradation of F(x) to the harmonious development of both F(x) an d F(y), and the coupling degree of F(x) and F(y) changed from elementary or crit ical inharmonious to barley or elementary harmonious. After 1995, the scissor difference α increased with higher velocity, and the harmonious degree C also fluctuated obviously, illustrating an intensive antagonism between F(x) and F(y). The study area was in the erupting period of various ecological problems, and at present, the high instability of elementary harmonious status still existed. Comparing wi th harmonious development model alone, its combination with scissor difference m ethod could reveal the coupling relations of F(x) and F(y) from the perspectives of development status and changing rate. This combination could reflect not onl y the equilibrium status but also the conflict intensity between F(x) and F(y), and give more comprehensive and profound analysis on the coupling relations betw een F(x) and F(y).

Water environment adaptability and ecological groups of Hydroidomedusae in East China Sea.

XU Zhao-li

2009, 20(01):  177-184 . 

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Based on the data of four seasonal oceanographic censuses in East Chin a Sea (23°30′〖KG-*2〗-〖KG-*7〗33°00′ N, 118°30′〖KG-*2〗-〖KG-*7〗128°00 ′ E) in 1997〖KG-*2〗-〖KG-*7〗2000, the optimal water temperature and salinity and the ecological groups of Hydroidomedusae were stud ied by curve fitting, mathematical model forming, and geographic distribution an alyzing. The results showed that Hydroidomedusae could live in the waters with d ifferent temperature and salinity. 15 species of Hydroidomedusae had an optimal water temperature of <20 ℃, 8 species at 20 ℃〖KG-*2〗-〖KG-*7〗25 ℃, 12 spec ies at 22.5 ℃〖KG-*2〗-〖KG-*7〗25 ℃, and 17 species at ≥25 ℃. 32 species of Hydroidomedusae had an optimal salinity o f 32〖KG-*2〗-〖KG-*7〗34, 13 species at 34, 6 species at 30〖KG-*2〗-〖KG-*7〗3 2, and only 2 species at <30. Th e weak adaptability of most Hydroidomedusae species to the variation of water sa linity made them have low density and limited distribution in East China Sea. Sugiura chengshanense and Clytia hemisphaerica were of nearshore warm temperate water species, Cunina octonaria and other 12 species were of offshore warm temperate water species, 8 species represented by Ectopleura latitaeniata were of nearshore subtropical water species, 5 species represented by Aglaura hemistoma showed some oceanic tropical features, while 25 species represented by Liriope tetraphylla were of offshore subtropical species. Some Hydroidomedusae species could b e used as an important bio-indicator of water mass in East China Sea.

Effects of temperature and light intensity on the growth and biochemical composition of Sargassum thunbergii.

JIANG Hong-bo^1,2;TIAN Xiang-li¹;DONG Shuang-lin¹;BAO Jie^1,2

2009, 20(01):  185-189 . 

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A two-factorial experiment was designed to study the effects of temp erature (10, 15, 20, and 25 ℃) and light intensity (20, 60, 100, 140, and 180 μE·m-2·s-1) on the growth and biochemical composition of Sargas sum thunbergii. The results showed that temperature, light intensity, and thei r interactions had significant effects on the growth of S. thunbergii. A hig her growth rate of S. thunbergii was observed at 15 ℃〖KG-*2〗-〖KG-*7〗20 ℃, and, with the increase of temperature, the light intensity for the maximum grow th rate of S. thunbergii had an increasing trend. At 10 ℃ and 15 ℃, higher li ght intensity had definite inhibition effect on the growth of S. thunbergii; while at 20 ℃ and 25 ℃, the growth rate was generally increased with increasing light intensity. Both temperature and light intensity had significant effects on the chlorophyll a and fucoxanthin contents of S. thunbergii, and the effect s of light intensity was greater than those of temperature. In general, the chlo rophyll a and fucoxanthin contents of S. thunbergii decreased significantly with increasing light intensity but increased with increasing temperature. The c arbohydrate content of S. thunbergii increased with increasing light intensi ty, while no significant difference was observed at different temperature. The p rotein content of S. thunbergii decreased with increasing light intensity, a nd was higher at 10 ℃ and 15 ℃ but tented to decrease with increasing temperature . The variation of light intensity and temperature induced the changes in the bi ochemical composition of S. thunbergii, and these changes could be an active physiological adjustment for the adaptation to the variation of environmental f actors, which was of ecological significance to the growth and survival of S. thunbergii.

Genetic diversity of duck breeds: A study with microsatellite markers.

XIAO Tian-fang^1,2;KE Liu-yu¹;ZHANG Li¹;JIANG Xiao-bing²

2009, 20(01):  190-196 . 

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Thirty two microsatellite markers were utilized to analyze the genetic diversity and germplasm characteristics of five Fujian native duck breeds (Jind ing duck, Liancheng white duck, Putian black duck, Shanma duck, and Muscovy duck) and two reference duck breeds (Beijing duck and Khaki Campbell duck). By using the marke rs, 371 alleles in test duck breeds were detected. The average allelic number pe r locus was 11719, average value of PIC was 0.522, average number of effec tive alleles was from 5141 to 6961, and average heterozygosity was from 05 12 to 0700. Based on Nei’s standard distance (DS) and DA genetic distance, a dendrogram was constructed by using the unweighted pair group method with arithmetic mean ( UPGMA). Jinding duck, Putian black duck, Liancheng white duck, Shanma duck, and Khaki Campbell duck were clustered into a group, and Beijing duck and Muscovy duck wer e clustered into another two groups, respectively. The dendrogram of DA and DS g enetic distances were accorded with the real relations among the seven duck bree ds.

Micronutrient cycling and its affecting factors in forest ecosystems.

JIANG Yong

2009, 20(01):  197-204 . 

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Micronutrient cycling in forest ecosystems is affected by soil conditi ons, litterfall turnover, throughfall properties, and some important ecological processes such as forest fire. This paper reviewed the related researches, with the focus on the micronutrient cycling in aboveground part of forest ecosystems and relevant affecting factors. In most forest ecosystems, litterfall and throug hfall were the important sources ensuring the balanced supply of micronutrients for growth forest, while forest fire, environmental pollution, and fertilization could also play important roles in the micronutrient cycling in some forest eco systems. Future studies on the micronutrient cycling in forest ecosystems should focus on the mechanisms governing micronutrient release from litterfall, the ef fects of global change and environmental pollution on the micronutrient cycling processes, and the balanced supply of micronutrients in restoration and reconstr uction of degraded ecosystems.

Carbon nanomaterials: their environmental behavior and effects on the transport and fate of pollutants in environment.

XU Lei;DUAN Lin;CHEN Wei

2009, 20(01):  205-212 . 

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Carbon nanomaterials are the excellent candidates for a variety of app lications, and thus, their research is a hotspot in recent years. The big amount production and utilization of carbon nanomaterials will inevitably lead to the release of these materials into environment, and may incur potential environment al and ecological risks. On the one hand, carbon nanomaterials themselves are to xic to living organisms; on the other hand, they have stronger adsorbing capabil ity on the pollutants in environment, and thus, affect the transport and fate of the pollutants. At present, the researches on the ecological risk of carbon nan omaterials are largely focused on their potential biotoxicity, while a few are on their environmental behavior and their effects on the transport and fate of p ollutants in the environment. This paper reviewed the researches on the sources, exposure pathways, and environmental behavior of carbon nanomaterials, and thei r potential effects on the transport and fate of pollutants in the environment. The significances of the research on the assessment of environmental and ecologi cal risks of nanomaterials were discussed.

Effects of grafting on cucumber leaf SOD and CAT gene expression and activities under low temperature stress.

GAO Jun-jie^1,2;QIN Ai-guo¹;YU Xian-chang¹

2009, 20(01):  213-217 . 

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This paper studied the relative expression of Mn-SOD, Cu/Zn-SOD and CAT mRNAs and the changes of SOD, Mn-SOD, Cu/Zn-SOD and CAT activities in grafted and own-rooted cucumber leaves under low temperature stress, and their relation s with the cold resistance of cucumber. For both grafted and own-rooted cucumbe r leaves, the relative expression of Mn-SOD and Cu/Zn-SOD mRNAs under low temp erature stress was respectively accordance with the changes of Mn-SOD and Cu/Zn -SOD activities, while the expression of CAT mRNA was not accordance with the c hange of CAT activity. The relative expression of Mn-SOD and Cu/Zn-SOD mRNAs a nd the activities of SOD, Mn-SOD and Cu/Zn-SOD in grafted cucumber leaves were higher than those in own-rooted cucumber leaves, while the MDA content and ele ctrolytic leakage were in adverse. The higher SOD activity regulated by the high er SOD mRNAs expression in grafted cucumber leaves might be the key factor of gr afted cucumber having a higher cold resistance to low temperature stress than ow n-rooted cucumber. The relative expression of CAT mRNA was slightly higher in f unctional leaves but lower in young leaves of grafted cucumber, while less diffe rence was observed in CAT activity, comparing with own-rooted cucumber, which i llustrated that low temperature stress had lesser effects on the relative expres sion of CAT mRNA and the activity of CAT in grafted cucumber leaves.

Effects of Hg contamination on paddy soil microbial and enzymatic activities.

JING Yan-de^1,2;HE Zhen-li^2,3;YANG Xiao-e²

2009, 20(01):  218-222 . 

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With pot experiment, the microbial and enzymatic activities in two paddy soils w ere investigated at different Hg2+ loadings. The results showed that a fter harvest, all measured microbiological and enzymological indices including m icrobial biomass carbon, respiration rate, and activities of urease, acid phosph atase, and dehydrogenase in test soils were increased under low Hg treatments (< 2 mg Hg·kg-1) while decreased under high Hg treatments (≥2 mg Hg·kg -1), except the basal respiration and metabolic quotient were partly increased with increasing Hg level. Among the test indices, soil microbial quotient was a microbiological index more sensitive to Hg contamination. The enzymatic activit y in test yellowish red soil was higher than that in test silty loam soil. ED 50 analysis indicated that Hg had a stronger ecological toxicity on soil ure ase in test silty loam soil and on acid phosphatase in test yellowish red soil.

Niche characteristics of common microalgae communities in prawn-aquaculture pond in terms of water temperature, salinity, nitrogen, and phosphorus resources.

LIANG Wei-feng^1,2;CHEN Su-wen¹;LI Zhuo-jia¹;CAO Yu-cheng¹;YANG Ying-ying¹

2009, 20(01):  223-227 . 

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A 4-factorial (water temperature, salinity, nitrogen, and phosphorus) experiment was designed to study the niche characteristics of four common micro algae communities in prawn-aquaculture pond. The results showed that the niche breadth was the greatest for Cryptomonas erosa in temperature and salinity r esources (0980 and 0988, respectively) and for Niztzschia closterium in nitr ogen and phosphorus resources (0990), but the smallest for Chlorella pyrenoidosa in all test resources, with an average value of 0926. As for niche overlap, it was the smallest for C. erosa and C. pyrenoidosa in temperature and sa linity resources (0809 and 0702, respectively) and for C. erosa and N. closterium in nitrogen and phosphorus resources (0829), but the greatest fo〖HJ*3〗 r C. pyrenoidosa and Nannichloropsis oculata in temperature, salinity, and nitro gen and phosphorus resources, with the values being 0986, 0974 and 0989, r espectively. All of these suggested that in prawn-aquaculture pond, C. erosa co uld be bred with any other three of the microalgae communities, while N. oculata and C. pyrenoidosa should not be bred together for their obvious competition on the resources.

Apoptosis of grass carp (Ctenopharngodon idellus) lymphocytes induced by the combination of microcystins and disinfection by-products in drinking water.

NI Wan-min¹;ZHANG Hang-jun^1,2;ZHANG Jian-ying¹;YAO Chao-ying³

2009, 20(01):  228-232 . 

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Aiming at the combined pollution of low dose microcystins (MCs) and di sinfection by-products (DBPs) in drinking water, the individual and combined cy totoxic effects of two MCs (MCLR and MCRR) and two DBP compounds (CHClBr2 and CH Cl2Br) on the apoptosis of isolated grass carp (Ctenopharngodon idellus) lymphoc ytes were examined by using in vitro bioassays. The results showed that after 2 hours exposure to the four pollutants within the range of test concentrations, t he apoptosis of isolated lymphocyte occurred, and there existed significant dose -effect relationship. The combined cytotoxic effects of 1 nmol·L-1 MCLR or MCRR and 1〖KG-*2〗-〖KG-*7〗100 nmol·L-1 CHClBr2 or CHCl2Br were all of additive, and the apoptosis percent was highly correlated with the exposure dose. It was suggested that the apoptosis percent of grass carp lymphocytes could be used as an effective indicator to evaluate the cytotoxicity caused by the co mbined pollution of MCs and DBPs.