Table of Content

18 January 2007, Volume 18 Issue 01

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Articles

Compatible biomass estimation models of natural forests in Changbai Mountains based on forest inventory

XING Yan-qiu;WANG Li-hai

2007, 18(01):  1-8 . 

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Forest biomass estimation is the groundwork of analyzing carbon cycle and its dynamics in terrestrial ecosystems, but the current estimation models had the problem of un-compatibility between total forest biomass and its components. Taking the Wangqing natural forest area in Jilin Province as a case, the compatible concept of building forest biomass models based on forest inventory was brought forward. A series of compatible biomass estimation models,taking stem volume as one of the independent variables, were established by using simultaneous equations. The accuracy of the models in estimating the biomass of coniferous forest, broad-leaved forest, and mixed forest was all higher than 95%, suggesting that these models basically solved the problem of un-compatibility between total forest biomass and its components.

Species diversity and interspecific association in development sequence of Hippophae rhamnoides plantations in loess hilly region

GUO Lian-jin^1,2; ZHANG Wen-hui¹;LIU Guo-bin³

2007, 18(01):  9-15 . 

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Based on field investigation, this paper analyzed the characteristics of species diversity and interspecific association at different development stages of Hippophae rhamnoides plantations. The results showed that the species diversities of shrub layer, grass layer, and whole community of H. rhamnoides plantations were all fluctuated in “S” shape. At different development stages, the species richness and diversity were higher in grass layer than in shrub layer. The shrub species diversity was lower on bare land, but increased gradually with development stage. Shrub evenness index was higher in 13-year forest stand, while grass diversity index was higher in 3-year plantation, lower in 8-year plantation, and higher in 25-year plantation. The positive and negative absolute values of interspecific association between H. rhamnoides and other principal species changed in parabola shape, and the notable degree and the interspecific association intensity were weaker in 13-year plantation, showing that the species substitution rate was slower, competition was less, and community composition and its structure were relatively stable. To improve ecological environment, the H. rhamnoides plantations younger than 13 years old should be given priority to protection, while for those of 25 years old, moderate thinning should be made to promote the regeneration.

Photosynthetic physiological adaptabilities of Pinus tabulaeformis and Robinia pseudoacacia in the Loess Plateau

ZHENG Shu-xia^1，2;SHANGGUAN Zhou-ping^1，2

2007, 18(01):  16-22 . 

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With Yangling, Yongshou, Fuxian, Ansai, Mizhi and Shenmu, the six counties from the south to the north in the Loess Plateau as study sites, this paper studied the photosynthetic characteristics and leaf traits of Pinus tabulaeformis and Robinia pseudoacacia. The results showed that among the six sites, there were significant differences in the photosynthetic rate (P_n), photosynthetic nitrogen use efficiency (PNUE), water use efficiency (WUE), leaf mass per area (LMA), nitrogen content (N_mass), and chlorophyll content (Chl) of P. tabulaeformis and R. pseudoacacia, suggesting that the photosynthetic capacity and leaf traits of the two species differed with sites. From the south to the north, the P_n, PNUE and WUE of P. tabulaeformis increased slightly while those of R. pseudoacacia decreased significantly, indicating that in drought habitat, P. tabulaeformis could still maintain high photosynthetic capacity, but the photosynthetic capacity of R. pseudoacacia was greatly restrained. Also from the south to the north, the LMA of P. tabulaeformis and R. pseudoacacia had a slight increasing trend, while N_mass and Chl decreased slightly. The variation ranges of the three parameters were greater for R. pseudoacacia than for P. tabulaeformis, indicating that P. tabulaeformis had stronger drought-tolerant capability than R. pseudoacacia, which was not only exhibited in physiological metabolism, but also in leaf morphological acclimation. The correlation analysis between photosynthetic parameters and leaf traits of P. tabulaeformis and R. pseudoacacia in the six sites showed that there was a significant negative correlation between LMA and N_mass. The P_n and PNUE of both test species had no correlations with LMA and N_mass, but had significant positive correlation with Chl. The WUE of the species was negatively correlated with LMA, but positively correlated with N_mass.

Effects of light intensity on seed germination and seedling early growth of Shorea wantianshuea 

YAN Xing-fu^1,2;CAO Min¹

2007, 18(01):  23-29 . 

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With shading experiment, this paper studied the seed germination and seedling early growth of Shorea wantianshuea, a representative species in Xishuangbanna seasonal rain forest under different light intensity and forest habitat. The results showed that both 100% light and deepest shading did not facilitate the germination of S. wantianshuea seed, while medium shading accelerated the seed germination. Gap center was more appropriate to the seed germination than gap edge and under-canopy. The seeds in gap center had the highest germination rate and rapid germination. Under partially shading, the seedling height, diameter of basal stem, and leaf area per seedling were in their peak, while the root-shoot ratio decreased with increasing shading and achieved its maximum under 100% light. The specific leaf area increased with increasing shading in a certain range, and peaked under 42% light. Gap center was beneficial to the early seedling growth, with all growth parameters except rootshoot ratio peaked there. The effects of environmental factors, mainly light intensity and quality, on the seed germination and seedling growth of S. wantianshuea were discussed.

Transpiration of banana plant measured by Granier method

LIU Hai-jun¹;SHABTAI Cohen²; JOSEF Tanny²;HUANG Guan-hua¹

2007, 18(01):  35-40 . 

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Banana plant is the highest herbaceous plant in the world. Because of the height, it’s inconvenient to measure the transpiration (T_r) of banana plant in direct way. Some indirect methods such as soil water balance method or FAO 56 Crop Coefficient are commonly used to measure or calculate the T_r, but the obtained results are easily influenced by soil texture and water content, climatic condition, and agronomic practice. In the present paper, Granier method was used to measure the sap flow (SF) at the corm of banana in a greenhouse from November 15 to October 5, 2005, with the T_r measured by gravimetric method compared. The results showed that the daily SF measured by Granier method was about 4% lower than the daily T_r measured by gravimetric method, and the SF rate lagged the T_r rate about one hour. Granier method was not sensitive enough to measure SF when the daily T_r was less than 0.05 L·m^-2 active leaf area. Granier probes could work properly 2-3 days after installation, and the measurement error of Granier method could be much reduced when more sets of probes were installed and the mean values of SF rate were taken.

Seasonal dynamics of ecosystem services of grassland in Qinghai-Tibetan Plateau

YU Ge^1,2; LU Chun-xia¹; XIE Gao-di¹

2007, 18(01):  47-51 . 

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Based on the theory of ecosystem services and by using RS and GIS techniques, the ecosystem services of grassland in QinghaiTibetan Plateau were analyzed and evaluated, with growth season as time unit. The results showed that the service of supplying biomass presented an up-down-up trend, and the peaks appeared in May and September. Its main affecting factors were PAR, soil moisture condition, and underground biomass. The service of carbon accumulation and oxygen release also presented updownup trend, which was related to the supplied biomass and its formation. As for the services of holding soil nutrients and water, the former had a peak in May, while the latter presented staggered variation due to the different water consumption characters of herbages at their different growth stages.

Effects of high field temperature on summer maize grain yield and quality

ZHANG Ji-wang;DONG Shu-ting;WANG Kong-jun;HU Chang-hao;LIU Peng

2007, 18(01):  52-56 . 

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A field study with two summer maize cultivars ND108 and YD13 showed that increased field temperature (3 ℃) at the stage from male tetrad to maturity had significant effects on their grain yield and quality. The grain yield of ND108 and YD13 decreased by 46.6% and 45.1%, grain crude protein content increased by 11.6% and 2.02%, ether extract content decreased by 38.9% and 9.6%, starch (mainly amylopection) content decreased by 7.0% and 8.4%, and lysine content decreased by 58.9% and 51.2%, respectively.

Characteristics of CO₂, CH₄ and N₂O emissions from winter-fallowed paddy fields in hilly area of South China

LIU Hui^1,2;ZHAO Ping¹;SUN Gu-chou¹;LIN Yong-biao¹;RAO Xing-quan¹;WANG Yue-si³

2007, 18(01):  57-62 . 

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With closed static chamber and modified gas chromatograph (HP5890Ⅱ), the in situ measurements were made on the CO₂, CH₄ and N₂O emissions from winter-fallowed paddy fields in the hilly area of South China. Gas samples were taken simultaneously from the fields with and without rice stubble. The results showed that both of the fields had the peak value of CO₂ flux in the late afternoon. In the fields with and without rice stubble, the CH₄ flux was positive in the day time while negative in the night, and the N₂O flux in the day time was 1.79 and 1.58 times as much as that in the night, respectively. The diurnal average CO₂ flux in the field with rice stubble was significantly higher than that in bare field (P＜0.05). Correlation analysis demonstrated that the CO₂ flux in winter-fallowed paddy fields had significant correlations with soil temperature, aboveground temperature, and air temperature, suggesting that temperature was the main factor affecting the CO₂ emission from rice field after harvesting. During the observation time (from 2003-11-10 to 2004-01-18), the average CO₂, CH₄ and N₂O fluxes in the field with rice stubble were (180.69 ± 21.21)mg·m^-2·h^-1,(-0.04±0.01)mg·m^-2·h^-1 and (21.26±19.31)μg·m^-2·h^-1, respectively. Compared with bare field, the CO₂ flux in the field with rice stubble was 13.06% higher, CH₄ absorption increased by 50%, while N₂O flux was 60.75% lower. It was concluded that the winterfallowed paddy field in hilly area of South China was the source of atmospheric CO₂ and N₂O, and the sink of atmospheric CH₄.

Heat stress characteristics of photosystem Ⅱ in eggplant

WANG Mei¹;GAO Zhi-kui¹;HUANG Rui-hong¹;WANG Hui-ying¹;ZHANG Wen-li¹;GAO Rong-fu²

2007, 18(01):  63-68 . 

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With lower-and higher heat-resistant varieties of eggplant (Solanum melongena L.) HeibeiⅠand Heibei Ⅱ as test materials, and by using Plant Efficiency Analyzer (PEA) from Hansatech, this paper measured the fast chlorophyll a fluorescence transient and its parameters. The results showed that PS Ⅱ construction became more sensitive to heat stress when ambient temperature was higher than 40 ℃. The F_o went up slowly, and F_v/F_m and ΔF/F_m′came down dramatically. Heibei Ⅱ had a longer semi-attenuation temperature of F_v/F_m (T₅₀) and ΔF/F_m′(t₅₀) than Heibei Ⅰ. Under strong heat stress (5 min at 48 ℃ or 20-30 min at 44 ℃), the K-step in relation to the inactivation of oxygen-evolving complex appeared in fluorescence rise at about 700 μs, and the regular O-J-I-P transient was transformed to O-K-J-I-P one. The K-phase of HeibeiⅠand Heibei Ⅱappeared when the treatment time was up to 20 and 30 minutes at 44 ℃, respectively. In comparing with 35 ℃heat treatment, the DI_o/RC in the parameters of Strasser′s specific energy fluxes model was increased by a great extent under 48 ℃ or more heat stress, reflecting a strong safeguard of energy dissipation to PS Ⅱ. When the temperature of heat stress increased from 35 ℃ to 52 ℃, the F_vi/F_v of PS Ⅱ silent reaction centers of HeibeiⅠand Heibei Ⅱ increased remarkably.

Effects of potassium application rate and time on the uptake and utilization of nitrogen and potassium by winter wheat

YU Zhen-wen¹;LIANG Xiao-fang¹;LI Yan-qi²;WANG Xue²

2007, 18(01):  69-74 . 

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The study with ¹⁵N tracing techniques showed that basal application of K did not increase the N and K accumulation in wheat plant when the available K content in 0～20 cm soil layer was 118.5 mg·kg^-1, but increased the accumulation significantly when the soil available K content was 79.0 mg·kg^-1.When the fertilizer K was 1/2 basal-applied and 1/2 top-dressed at elongation stage, the absorbed fertilizer N and soil N by plant as well as the residual N of top-dressed N in soil were increased with increasing K application rate,while the fertilizer N loss decreased. Compared with basal application, the split application of K increased the accumulated amount, uptake efficiency, and productive efficiency of N and K significantly. When the K application rate was 135 kg·hm^-2, split application of K promoted the absorption of top-dressed and soil N by plant, and increased the residual N of top-dressed N in soil. The results also showed that K application increased the grain yield and its protein and wet gluten contents. At the same K application rate, split application had better effect than basal application, and treatment K45+45 (45 kg·hm^-2 as basal and 45 kg·hm^-2 top-dressed) showed the best effect. Applying excessive K tended to decrease wheat yield and its quality.

Effects of free-air CO₂ enrichment (FACE) on yield formation of wheat

YNAG Lian-xin¹;LI Shi-feng¹;WANG Yu-long¹;HUANG Jian-ye¹;YANG Hong-jian¹;DONG Gui-chun¹;ZHU Jian-guo²;LIU Gang²

2007, 18(01):  75-80 . 

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To investigate the effects of predicted higher CO₂ levels on the growth duration, plant height, yield, and yield components of wheat (Triticum aestivum L.), a free-air CO₂ enrichment (FACE) experiment with weak gluten variety Ningmai 9 was conducted at Anzhen of Wuxi in Jiang-su Province in 2001-2002 and 2002-2003 growth seasons. The target ［CO₂］ in FACE plots was 200 μl·L^-1 above that in ambient air. Three levels of N were supplied, i . e., 90 kg·hm^-2 (2001-2002) and 125 kg·hm^-2 (2002-2003) (low level, LN), 180 kg·hm^-2(2002-2003) (medium level, MN), and 250 kg·hm^-2 (high level, HN).The durations from sowing to heading and from heading to maturity and the whole growth period of wheat in FACE plots shortened 1.3, 1.3 and 2.6 days, respectively, compared with the control. FACE increased the plant height (+4.0%) significantly, due to the increases of panicle length and of the first and second internode lengths. FACE also greatly increased the grain yield by an average of 24.6%. Across the two years, there was a positive ［CO₂］×N interaction for grain yield, with a yield increase of 15.2%, 21.4% and 35.4% at LN, MN and HN, respectively. The ears per square meter in FACE plots was increased by an average of 17.8%, mainly due to the increase of maximum tiller number per unit ground area rather than that of the percentage of productive tiller (panicle bearing). In addition,FACE increased the grain number per ear(+2.9%)and the individual grain mass (+4.8%).

Allelopathy of garlic root exudates on different receiver vegetables

ZHOU Yan-li;CHENG Zhi-hui;MENG Huan-wen

2007, 18(01):  81-86 . 

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By the method of tissue culture under sterilized condition, this paper studied the allelopathy of garlic root exudates on lettuce, hot pepper, radish,cucumber, Chinese cabbage, and tomato. The results showed that garlic root exudates had no evident effects on the germination rate, germination index, shoot height, and protective enzyme system of test crops, but significantly increased the root length, aboveground fresh mass, and root fresh mass of lettuce, with the RIs being +0.163, +0.106, +0.318, respectively. The exudates also increased the root length of Chinese cabbage, with a RI of +0.120. For other test crops, no significant difference was observed between the treatments and the control. Garlic root exudates significantly increased the chlorophyll content and root activity of the receiver vegetables. The strongest promotion effects were found on chlorophyll content in radish, with RI being +0.282, and on root activity of cucumber, with RI being +0.184. The exudates promoted the nutrient absorption of all the receiver vegetables.

Effects of elevated CO₂ on photoinhibition of strawberry leaves under different nitrogen levels

XU Kai^1,2;GUO Yan-ping¹;ZHANG Shang-long¹;WU Hui-min²

2007, 18(01):  87-93 . 

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By using PAM-2000 portable chlorophyll fluorometer and HCM-1000 photosynthesis measurement system, this paper measured the initial fluorescence (F_o), maximal photochemical efficiency of PSII (F_v/F_m), maximal fluorescence (F_m), amount of inactive PSⅡ reaction centers (F_i-F_o), proportion of Q_B-non-reducing PSⅡ reaction centers［(F_i-F_o)/(F_p-F_o)］, and net photosynthetic rate (P_n) of strawberry leaves under conditions of elevated CO₂ (700 μl·L^-1) and ambient CO₂ (390 μl·L^-1) at three levels of nitrogen application (12, 4 and 0.4 mmol·L^-1). The results showed that there was a significant joint effect between CO₂ and N on the photoinhibition of strawberry leaves. Under elevated CO₂ condition, the P_n in treatment 12 mmol N·L^-1 increased by 62.7%, while that in treatments 4 and 0.4 mmol N·L^-1 decreased by 7.4% and 21.3%, respectively. When exposed to high light and subsequently recovered in dark for 4 hours, the strawberry leaves in treatment 12 mmol N·L^-1 showed less changes of F_m and F_v/F_m in elevated CO₂ than in ambient CO₂, while those in treatments 4 and 0.4 mmol N·L^-1 were in adverse, suggesting that for the strawberry leaves in elevated CO₂, nitrogen deficiency could result in an acclimatized decrease of photosynthesis and an increase of photoinhibition.

Desorption characteristics of inorganic nitrogen in vegetable garden soil and their effects on soil NO₃^- N loss potential

YAN Ming-juan¹;ZHANG Ming-qing¹;CHEN Zi-chong¹;LI Juan¹;LIN Qiong¹;WU Qi-tang²;XIONG De-zhong³

2007, 18(01):  94-100 . 

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With pot experiment and soil nitrogen desorption model, this paper studied the characteristics of nitrogen desorption in vegetable garden soil, and their effects on the NO₃^--N concentration of soil leachate. The results showed that soil leachate NO₃^--N concentration had a non-linear relationship with the parameters Q, Cli and C₁/λ of soil nitrogen, but the relationship became linear when these eigenvalues were relatively low. A conception of bi-curve cross point was put forward to assess the soil NO₃^--N loss potential. When the eigenvalues were higher than the bi-curve cross point X₀, the NO₃^--N concentration in soil leachate would be increased rapidly in non-linear form, while on the contrary, the increase would be maintained at a lower level.

Nutrient contents and microbial populations of aeolian sandy soil in Sanjiangyuan region of Qinghai Province

LIN Chao-feng¹;CHEN Zhan-quan³;XUE Quan-hong¹;LAI Hang-xian¹;CHEN Lai-sheng³;ZHANG Deng-shan³

2007, 18(01):  101-106 . 

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Sanjiangyuan region (the headstream of three rivers) in Qinghai Province of China is the highest and largest inland alpine wetland in the world. The study on the nutrient contents and microbial populations of aeolian sandy soils in this region showed that soil organic matter content increased with the evolution of aeolian sand dunes from un-stabilized to stabilized state, being 5.9 and 3.8 times higher in stabilized sand dune than in mobile and semi-stabilized sand dunes, respectively. Soil nitrogen and phosphorus contents increased in line with the amount of organic matter, while potassium content and pH value varied slightly. The microbial populations changed markedly with the development of vegetation, fixing of mobile sand, and increase of soil nutrients. The quantities of soil bacteria, fungi and actinomycetes were 4.0 and 2.8 times, 19.6 and 6.3 times, and 12.4 and 2.6 times higher in stabilized and semi-stabilized sand dunes than in mobile sand dune, respectively, indicating that soil microbial bio-diversity was increased with the evolution of aeolian sand dunes from mobile to stabilized state. In addition, the quantities of soil microbes were closely correlated with the contents of soil organic matter, total nitrogen, and available nitrogen and phosphorus, but not correlated with soil total phosphorus, total and available potassium, or pH value.

High effective phosphate-solubilizing bacteria: Their isolation and promoting effect on corn seedling growth

ZHU Pei-miao;YANG Xing-ming;XU Yang-chun;OUYANG Hong;SHEN Qi-rong

2007, 18(01):  107-112 . 

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By using modified PVK plate method, 44 strains of phosphate-solubilizing bacteria (PSB) were isolated from the root surface of wild plants growing well in calcareous soil. After 7-day incubation in a liquid medium NBRIP, the total P in the cultures of strains K₃ and K₉ reached 643.2 μg·ml^-1 and 608.5 μg·ml^-1, and soluble P was 584.8 μg·ml^-1 and 606.4 μg·ml^-1, respectively. About 12.9% of tricalcium phosphate was dissolved, being 9.5 times higher than CK. Pot experiment showed that the plant height, stem diameter, and dry mass of corn seedling were significantly higher in PSB treatments than in CK. Applying PSB agent with manure as a carrier could significantly increase the seedling’s dry mass, in comparing with applying PSB agent alone. The strains K₃ and K₉ were identified as Pseudomonas.

Effects of planting density and nitrogen application rate on soil microbial activity under wheat/forage rape multiple cropping

YANG Rui-ji^1,2; MA Hai-ling²;YANG Qi-feng³;NIU Jun-yi²

2007, 18(01):  113-117 . 

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A field experiment was conducted to study the effects of planting density and nitrogen application rate on the topsoil (0-15 cm) microbial activity under wheat/forage rape multiple cropping. The results showed that multiple-cropping forage rape with wheat could significantly increase soil microbial biomass C (C_mic), soil microbial biomass N (N_mic), soil bacteria number (SBN), soil fungi number (SFN) and soil actinomyces number (SAN), but decrease soil microbial biomass C/N (C_mic/N_mic). The C_mic/N_mic and SBN increased with increasing planting density of forage rape, while N_mic and SAN were in adverse. SFN increased significantly with increasing nitrogen application rate, but C_mic and N_mic decreased first, increased then, and decreased again, with the highest in treatment 1 000 kg·hm^-2 N. Also with increasing nitrogen application rate, the SFN and SAN during harvest stage of forage rape decreased first and increased then, while the SAN during seedling stage increased first and decreased then. Soil microbial activities at rape harvest stage were all higher than those at seedling stage, except for SAN in treatment 600 kg·hm^-2 N. SBN and SAN were positively correlated with C_mic and N_mic, but negatively correlated with C_mic/N_mic. No significant correlation was observed between SFN and C_mic, and SMBN and C_mic/N_mic.

Biodegradation of landfill leachate in soil

FU Mei-yun^1,2;ZHOU Li-xiang¹

2007, 18(01):  118-122 . 

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With aerobic and anaerobic incubation tests, this paper studied the biodegradation of three kind landfill leachates in acidic and calcareous soils. The leachates were collected from a landfill just receiving refuse (fresh sample) and the landfills having received refuse for 4-5 years (Tianjingwa sample) and 12 years (Shuige sample). The results showed that in the first seven days of incubation, these three landfill leachates degraded more quickly. Under aerobic condition, the apparent degradation rate of fresh sample, Tianjingwa sample and Shuige sample was 88.9%, 60.5% and 25.0% in acidic soil, and 96.6%, 80.4%, and 65.0% in calcareous soil, respectively. Seven days after, a lower degradation rate was observed. In same test soils, the shorter the landfilling age, the higher apparent degradation rate of the leachates was. Similar results were obtained under anaerobic condition, but the degradation rates were lower. The degradation of test landfill leachates fitted first-order kinetics model well, with a half-life of 12-16 days for fresh sample, and 20-30 days for Tianjingwa and Shuige samples. Once the leachates penetrated into soil, their degradation quickened greatly, suggesting that soil treatment of landfill leachate could have definite efficacy.

Effects of PCBs on Aegiceras corniculatum seedlings growth and membrane protective enzyme system

LIU Ya-yun^1,2;SUN Hong-bin¹;CHEN Gui-zhu¹

2007, 18(01):  123-128 . 

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With pot experiment, this paper studied the effects of PCBs (0, 180, 900, 1 800 and 2 700 μg·kg^-1) on the seedlings growth and the leaves chlorophyll content, MDA content, and membrane protective enzyme system of Aegiceras corniculatum. The results showed that PCBs had definite stimulative effects on the seedlings growth. The stem height, basal stem diameter, and stem volume were all increased with increasing PCBs concentration. Within the test range of PCBs, the chlorophyll content and chlorophyll a/b ratio maintained at a relatively stable and normal level. The decrement of chlorophyll content and the increment of chlorophyll a/b ratio were less than 25% and 10% of the control, respectively. With increasing PCBs concentration, SOD activity increased first and decreased then,while POD activity and MDA content were in adverse. It was suggested that A.corniculatum could endure and adapt definite concentrations of PCBs through physiological and biochemical mechanisms, being available to the phytoremediation of PCBs pollution.

Free radicals in Carassius auratus liver:Their generation and oxidative stress induced by 2,4,6-trichlorophenol

JI Liang-liang¹；LI Fa-yun¹；LUO Yi²；MA Xi-ping¹；CHEN Zhong-lin¹

2007, 18(01):  129-132 . 

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With electron paramagnetic resonance (EPR) technique, this paper studied the free radicals generation and oxidative stress in Carassius auratus liver after 4, 8, 12, 24 and 72 hours of 2,4,6-trichlorophenol (2,4,6-TCP) intraperitoneal injection. The results showed that 2,4,6-TCP significantly promoted the generation of free radicals in C. auratus liver. The superoxide dismutase (SOD) and glutathione-S-transferase (GST) activities were induced significantly, while catalase (CAT) activity was inhibited, and glutathione (GSH) content had little difference with the control. A significant increase was observed in the contents of oxidized glutathione (GSSG) and malondialdehyde (MDA).

Characteristics of multi-scale temporal-spatial distribution of urban heat island in Guangzhou

JIANG Xue-ding;XIA Bei-cheng;GUO Luo;LI Nan

2007, 18(01):  133-139 . 

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Hourly data were collected from 47 automatic weather stations in Guangzhou to calculate the Guangzhou urban heat island (UHI) intensity in January, April, July and October 2001. The Kriging interpolation showed that the spatial variation of Guangzhou UHI was closely correlated with underlying surface, man-made heat, atmospheric pollutant and weather system, and the analysis on the temporal variation from January 2001 to February 2002 by Morlet wavelet transform revealed that there were multi-scale UHI periods. The main time scales were daily,weekly and bimonthly periods, and the secondary time scale was trimestral period. Sea-land breeze, man-made heat, long wave radiation of earth surface, and heat exchanges on earth surface affected the daily period, human activities affected the weekly period, solar radiation and weather system affected the bimonthly period, while monsoon affected the trimestral period. This temporal-spatial variation of Guangzhou urban heat island was deeply affected by the coactions of weather system, long wave radiation, underlying surface, atmospheric pollutant, man-made heat, and heat exchanges on earth surface, etc.

Spatial correlation of active mounds locative distribution of Solenopsis invicta Buren polygyne populations

LU Yong-yue;LI Ning-dong;LIANG Guang-wen;ZENG Ling

2007, 18(01):  140-144 . 

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By using geostatistic method, this paper studied the spatial distribution patterns of the active mounds of Solenopsis invicta Buren polygyne populations in Wuchuan and Shenzhen, and built up the spherical models of the interval distances and semivariances of the mounds. The semivariograms were described at the two directions of east-west and south-north, which were obviously positively correlated to the interval distances, revealing that the active mounds in locative area were space-dependent. The ranges of the 5 spherical models constructed for 5 sampling plots in Wuchuan were 9.1 m, 7.6 m, 23.5 m, 7.5 m and 14.5 m, respectively, with an average of 12.4 m. The mounds of any two plots in this range were significantly correlated. There was a randomicity in the spatial distribution of active mounds, and the randomicity index (Nugget/Sill) was 0.7034, 0.9247, 0.4398, 1.1196 and 0.4624, respectively. In Shenzhen, the relationships between the interval distances and semivariances were described by 7 spherical models, and the ranges were 14.5 m, 11.2 m, 10.8 m, 17.6 m, 11.3 m, 9.9 m and 12.8 m, respectively, with an average of 12.6 m.

Secondary productivity of macrobenthos in Jiaozhou Bay

YUAN Wei^1,2;ZHANG Zhi-nan¹;YU Zi-shan¹

2007, 18(01):  145-150 . 

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From September 2003 to September 2004, seven cruises bimonthly survey was conducted on the macrobenthos at five research stations in the Jiaozhou Bay,and the abundance, biomass, secondary productivity, and P/B value of the macrobenthos were studied by using Brey’s empirical formula. The results showed that the secondary productivity of the macrobenthos was averagely 47.34 g·m^-2·a^-1, and the mean P/B value was 0.58. Correlation analysis indicated that Chl-a was the important environmental factor affecting the secondary productivity. A comparative study on the southern Yellow Sea, Bohai Bay and other areas also proved that on local scale, Chl-a was the important factor affecting the secondary productivity of the benthic community, but on regional scale,water depth was more determinative, i . e ., this productivity was decreased with increasing water depth. The greatest contributor to the secondary productivity of macrobenthos in studied areas was Ruditapes philippinarum, the most important economic bivalve in the Jiaozhou Bay, and its population was dominated by the individuals with the ages of less than one year, one year, and two years.

Selective feeding of Calanus sinicus on harmful algal blooms species in East China Sea in spring

SUN Jun; WANG Xiao-dong; SONG Shu-qun

2007, 18(01):  151-157 . 

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From April 27^th to June 5^th 2005, the selective feeding of Calanus sinicus on harmful algal blooms (HABs) species was studied by in situ feeding experiments at six typical stations in a high frequency red tide occurring region of East China Sea. The results showed that the selective feeding behavior of C. sinicus was dependent on food density. It had an obvious food selectivity when the abundance of phytoplankton cell was low, but the selectivity changed from preference to discrimination at high phytoplankton cell abundance, with a threshold value of 329 cells·ml^-1. The selective feeding of C. sinicus was also dependent on food composition. It showed no selective feeding or discrimination on microzooplankton at most stations, but preferred to P.delicatissima and disliked Karenia mikimotoi at HABs occurring station, which induced the succession of phytoplankton community to K. mikimotoi blooming.

Macrobenthos in Jinping reach of Yalongjiang River and its main tributaries

QU Xiao-dong^1,2;CAO Ming¹;SHAO Mei-ling^1,2;LI Dao-feng¹;CAI Qing-hua¹

2007, 18(01):  158-162 . 

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In this paper, an investigation was made on the macrobenthos at 25 sites in the Jinping reach of Yalongjiang River and its main tributaries in May and November 2004, aimed to study the relationships between macrobenthos distribution and environmental factors. The results showed that the dominant species of macrobenthos was Baetis sp. (Baetidae, Ephemeroptera), with a relative abundance being 14.9% and 27.0% in May and November, respectively. Based on the species composition and their relative abundance, and by using two-way indictor species analysis (TWINSPAN) and detrended correspondence analysis (DCA), the macrobenthods was divided into four groups, according to the habitat types of the sites. Canonical correspondence analysis (CCA) on the relationships between macrobenthods community structure and environmental factors indicated that in May, elevation and water hardness and NH₄⁺-N content were the main environmental factors affecting macrobenthods distribution, while in November, elevation, water hardness, NH₄⁺-N and SiO₂ contents were the main ones.

Relationships among planktons DNA sequence diversity, water quality and fish diseases in Siniperca chuatsi ponds

WANG Ya-jun^1,2;WU Shu-qin¹;LIN Wen-hui¹;YANG Zhi-hui¹;WU Hui-min¹;SHI Cun-bin¹;PAN Hou-jun¹

2007, 18(01):  163-168 . 

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By using random amplified polymorphic DNA (RAPD) technique, this paper studied the α-diversity of plankton communities and its relationships with water quality and fish diseases in 7 Siniperca chuatsi ponds, as well as the effects of stocking density and a new culture model on the diversity and water quality. The results showed that there was a significant negative correlation between the DNA sequence diversity of plankton communities and water quality index, and high stocking density decreased the DNA sequence diversity and increased the water quality index. The new culture model with short culture period, low stocking density and high feeding stuff input had a greater damage on the water environment. Hierarchical cluster analysis indicated that there existed similarities in the DNA sequences of plankton communities and the physicochemical properties of water bodies in the ponds with fish diseases, which provided a possibility to predict the diseases occurrence in Siniperca chuatsi ponds.

Overcompensation effect of Pavlova viridis under ultraviolet (UV-B) stress

LIU Xiao-juan;DUAN Shun-shan;LI Ai-fen

2007, 18(01):  169-173 . 

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To examine the existence of overcompensation growth of microalgae, this paper studied the effects of UV-B stress on the production of bioactive substances during the overcompensation of Pavlova viridis. Six groups of UV-B treatments 18, 36, 54, 65, 86 and 108 J·m^-2 as well as the control were set up for this study. After the UV-B stress relieved, the treated groups and the control were simultaneously cultured for 12 days under the same inoculation density and normal culture conditions, and the parameters OD, biomass, chlorophylla, carotenoid, cellular protein and carbohydrate were measured. The results showed that under UV-B stress, the growth of P. viridis was inhibited significantly (P＜0.05), with a decrease of relative growth rate being 16.15%～60.00%, compared with the control. But, after the relief of UV-B stress, the growth rate during anaphase was significantly higher (P＜0.05) in UV-B treatments than in the control, indicating the occurrence of overcompensation growth. On the 12^th day of culture, the OD, biomass, chlorophyll a, carotenoid, cellular protein and carbohydrate in treated groups were 22.38%, 15.00%, 26.15%, 23.81%, 11.63% and 27.58% higher than those in the control, respectively. The overcompensation growth of P. viridis provided an effective way to exploit the bioactive substances of microalgae.

Relationships between copepods and Eriocheir sinensis larvae in ecological breeding ponds

ZHANG Qing-jing¹;LI Xiao-dong²;ZHU Hua¹;LIU Xu²;LI Yong-han³

2007, 18(01):  174-178 . 

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The study on the relationships between two copepod species Eurytemor affinis and Sinocalanus tenellus and Chinese mitten crab Eriocheir sinensis larvae in the ecological breeding ponds of E. sinensis larvae in Liaohe Delta district of Panjing City, Liaoning Province showed that E. affinis and S. tenellus had significant effects on the survival rate of first stage zoae (Z₁). The higher the density of the two copepod species, the lower the survival rate of Z₁ was (P＜0.01). Third stage zoae (Z₃) could prey on the copepods nauplii, and the feeding amount was increased with the increasing density of the nauplii (P＜0.01). Fifth stage zoae (Z₅) and megalopae could easily prey on E. affinis, but not on S. tenellus. The megalopae yield in the ecological breeding ponds was negatively correlated with the quantity of the copepods during early breeding stage of E. sinensis larvae, and there was a significant difference among the megalopae yields when different quantity of copepods existed (P＜0.01). Some measures for controlling and utilizing the copepods in ecological breeding ponds of E. sinensis larvae were put forward.

Spatial distribution and its environmental analysis of chironomid larvae in Fuxian Lake of Yunnan Province

XIONG Fei^1,2，3;LI Wen-chao¹;PAN Ji-zheng¹

2007, 18(01):  179-184 . 

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A field survey was made on the chironomid larvae in Fuxian Lake of Yunnan Province from June to July 2005. A total of 6 species belonging to 5 genera were collected, among which, Procladius choreus and Chironomous plumosus were the dominant species, with a sum of their relative density and of relative biomass being 94.9% and 97.5%, respectively. The average density of chironomid larvae in the lake was （275±333） ind·m^-2, and the average biomass was （0.642±0.763）g·m^-2. P. choreus distributed all over the lake, C. plumosus mainly distributed in the water area at the south of Mingxingyudong, while other species distributed locally. Micropsectra sp., a typical species distributing in deep oligotrophic water, had an average distribution water depth of 107.2 m. The density of chironomid larvae had a significant positive correlation with water depth, and increased in the sequences of sand or gravel bottom＜sand bottom＜mud bottom, and submerged macrophyte area＜no submerged macrophyte area. Compared with the survey data around 1980, the occurrence frequency and standing stock of chironomid larvae increased greatly, and the indicator species C. plumosus for eutrophic water appeared, indicating that the nutritional level of Fuxian Lake was being improved.

Nitrification-denitrification and N₂O emission of typical Calamagrostis angustifolia wetland soils in Sanjiang Plain

SUN Zhi-gao^1,2;LIU Jing-shuang¹;YANG Ji-song^1,2;LI Xin-hua^1,2;ZHOU Wang-ming^1,2

2007, 18(01):  185-192 . 

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With intact soil core and by using acetylene inhibition method, this paper measured the N₂O emission and denitrification rates of typical Calamagrostis angustifolia wetland soils in Sanjiang Plain, analyzed their relationships with environmental factors, and estimated the total amounts of N₂O emission and denitrification loss. The results showed that meadow marsh soil and humus marsh soil had a similar change range of N₂O emission rate (0.020-0.089 kg N·hm²·d^-1 and 0.012-0.033 kg N·hm²·d^-1, respectively), but the former had a much higher N₂O emission rate than the latter, and the difference was significant (P＜0.05). As for denitrification rate, its change range was 0.024-0.127 kg N·hm²·d^-1 for meadow marsh soil and 0.021-0.043 kg N·hm²·d^-1 for humus marsh soil. Meadow marsh soil also had a higher denitrification rate than humus marsh soil, but the difference was not significant (P＞0.05). In meadow marsh soil, nitrification played an important role in N₂O emission and nitrogen loss; while in humus marsh soil, denitrification was the main process inducing N₂O emission and nitrogen loss. For these two soils, nitrogenous compounds were not the important factor affecting nitrification-denitrification. In meadow marsh soil, temperature had more evident effect, where nitrification-denitrification had a significant positive correlation with the soil temperature at the depths of 5 cm, 10 cm and 15 cm (P＜0.05). Soil moisture condition was another important factor inducing the difference of N₂O emission and denitrification rates. In growth season, the amount of N₂O emission and denitrification loss was 5.216 kg N·hm^-2 and 6.166 kg N·hm^-2 for meadow marsh soil, and 3.196 kg N·hm^-2 and 4.407 kg N·hm^-2 for humus marsh soil, respectively. In the denitrification productions of meadow marsh soil and humus marsh soil, the maximum value of N₂O/N₂ ratio was 5.49 and 3.76, respectively, indicating that the proportion of N₂ in denitrification productions was higher in humus marsh soil than in meadow marsh soil, and the seasonal waterlogged condition could induce the decrease of N₂O/N₂ ratio.

Effects of exogenous metallothionein on thermoresistance and SOD gene expression of dairy cattle

ZHANG Bin¹;XUE Li-qun¹;LI Li-li²;DE Xing-hou³;CHEN Yu-guang¹;WANG Jie¹;PENG Hui-zhen²;XIAO Ding-fu¹

2007, 18(01):  193-198 . 

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To approach the effects of exogenous metallothionein (Zn-MT) on the thermoresistance and SOD gene expression of dairy cattle, an experiment was conducted with 28 lactating cows, which were randomly allocated to groups A, B, C andD, and supplemented with 0, 6.0, 12.0 and 16.0 mg Zn-MT·capita^-1, respectively, by intravenous injection. The results showed that the pulse, breath rate, and serum MDA content of the cows in groups B, C and D were lower (P＜0.05 or P＜0.01), while their milk yield, serum- and milk MT contents, blood GSH-PX activity, erythrocyte SOD activity, and SOD gene expression level were higher (P＜0.05 or P＜0.01) than those in group A. All the test indices of the cows in groups C and D were superior (P＜0.05 or P＞0.05) than those in group B, but no significant difference (P＞0.05) was observed between groups C and D. Exogenous Zn-MT had the best effects on the thermoresistance and SOD gene expression of dairy cattle 30 days after injection. All of these suggested that exogenous Zn-MT should be a physiologically active substance effective to the thermoresistance and SOD mRNA expression of dairy cattle, and presented time- and dose-dependent effects.

Research progress on methane oxidation in landfill cover soil

WANG Yun-long;HAO Yong-jun;WU Wei-xiang;CHEN Ying-xu

2007, 18(01):  199-204 . 

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Methane is the second largest contributor after carbon dioxide to global warming, while landfill is considered as one of the major sources of methane emission, accounting for 1.5%-15% of the global methane sources. Methanotrophic microorganisms play an important role in regulating global methane content, and landfill cover soil is proved to have high capacity of methane oxidation. The study of methanotrophic microorganisms in landfill cover soil and their mechanisms in methane oxidation becomes one of the hot research fields in environmental science and applied microbiology. This review summarized the recent progress on the research of methanotrophic microorganisms, mechanisms and dynamics of microbial methane oxidation, co-metabolism of methane and trace landfill gases, and environmental factors affecting methane oxidation in landfill cover soil. Some perspectives for further research on methanotrophic microorganisms in landfill cover soil were discussed.

Research advances in diet selection mechanisms of grazing herbivores

WANG Ling;WANG De-li

2007, 18(01):  205-211 . 

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Diet selection is a complicated topic. This paper reviewed the multi-disciplinary research advances in the diet selection mechanisms of grazing herbivores. There were two hypotheses about the mechanisms. One assumed that the diet selection behaviors were inherited and innate, while the other supposed that they were from learning, including post-ingestive feedback, trial-and-error learning, social learning, spatial memory, visual cues, and skin-defense. Four hypotheses on diet selection strategies including RT, MVT, OFT and MTD of grazing herbivores were summarized, and the prospects of grazing herbivores diet selection study, such as spatial-scale of diet selection, physiological factors of digestion, and interactions of multiple affecting factors, were discussed.

Methodology and application of soil metagenomics

SHEN Ju-pei^1,2;ZHANG Li-mei¹;ZHENG Yuan-ming¹;ZHU Yong-guan¹;HE Ji-zheng¹

2007, 18(01):  212-218 . 

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Culturable microorganisms provide very limited information on soil microbial diversity, because only 0.1%-10% of soil microorganisms can be cultured under conventional laboratory conditions. A novel culture-independent approach, i . e ., metagenomic methodology, has been developed as an effective tool for the discovery of new natural products and microbial functions. Soil metagenomic methods, comprising isolation of soil DNA and construction and screening of clone libraries, enable to peep at more complete scenario of soil microbial communities, and thus, to better understand their interactions. This methodology is of great potential for use in the studies of soil microbial communities and their functional genes, and in the discovery of new biocatalysts for industry and pharmacy. This review summarized some advances of soil metagenomic study.

Effects of aniline and phenol on freshwater algae growth

CHEN Chuan-ping;ZHANG Ting-ting;HE Mei;WU An-ping;NIE Liu-wang

2007, 18(01):  219-223 . 

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By the methods of bioassay, this paper studied the effects of aniline or phenol on the growth of Chlorella pyrenoidosa and Scenedesmus obiquus. The results showed that these two compounds had evident effects on the growth of test algae species. For the same species, aniline was more toxic. Under the same concentration of the compounds, S. obiquus was more sensitive than C. pyrenoidosa. These two algae species could degrade or absorb parts of the compounds, and phenol in particular, when their concentrations were lower.

Characteristics of arthropod community in alpine cabbage fields

WANG Xiang-ping^1,2;ZHANG Zhong-ning²

2007, 18(01):  224-228 . 

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The study on the community structure of arthropod in the alpine cabbage fields of Hubei Province showed that the dominant pests were Brevicoryne brassicae, Mamestra brassicae and Plutella xylostella, while the dominant natural enemies were Diaeretiella rapae, Cotesia plutella,Erigonidum gramiaicolum and Syrphus corollae. The richness, diversity index, evenness index and dominance index of pest and natural enemy sub-communities all changed with time. The dominance index of pest sub-community was higher, while its diversity and evenness indices were lower than those of natural enemy sub-community. Based on fuzzy clustering analysis, the pest and natural enemy sub-communities of 14 time sequences were grouped into 4 and 3 sorts, respectively.

Relationships between eggplant leaf pubescent and its resistance to Polyphagotarsonemus latus

GUI Lian-you;GONG Xin-wen;MENG Guo-ling

2007, 18(01):  229-232 . 

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With 27 eggplant varieties as test objects, this paper studied the effects of their leaf pubescent on the field population density of Polyphagotarsonemus latus, its injury index on eggplant leaf, and population growth rate. The results showed that the density and length of leaf pubescent differed with eggplant varieties. For the same variety, leaf pubescence had a higher density but a shorter length on reverse side than on obverse side. Among the test varieties, 7 resistant varieties had a significantly higher mean pubescence density than 6 susceptive varieties on their reverse side leaf. The higher the pubescence density on reverse side eggplant leaf, the less field population density of P. latus and the lower injury index of eggplant leaf, suggesting a positive correlation between the pubescence density on reverse side eggplant leaf and the resistance of eggplant to P. latus.