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131.
Assessing the impact of fungicide enostroburin application on bacterial
community in wheat phyllosphere 总被引:1,自引:0,他引:1
Likun Gu Zhihui Bai Bo Jin Qing Hu Huili Wang Guoqiang Zhuang Hongxun Zhang 《环境科学学报(英文版)》2010,22(1):134-141
Fungicides have been used extensively for controlling fungal pathogens of plants. However, little is known regarding the effects that fungicides upon the indigenous bacterial communities within the plant phyllosphere. The aims of this study were to assess the impact of fungicide enostroburin upon bacterial communities in wheat phyllosphere. Culture-independent methodologies of 16S rDNA clone library and 16S rDNA directed polymerase chain reaction with denaturing gradient gel electrophoresis (PCR-DGGE) were used for monitoring the change of bacterial community. The 16S rDNA clone library and PCR-DGGE analysis both confirmed the microbial community of wheat plant phyllosphere were predominantly of the γ-Proteobacteria phyla. Results from PCR-DGGE analysis indicated a significant change in bacterial community structure within the phyllosphere following fungicide enostroburin application. Bands sequenced within control cultures were predominantly of Pseudomonas genus, but those bands sequenced in the treated samples were predominantly strains of Pantoea genus and Pseudomonas genus. Of interest was the appearance of two DGGE bands following fungicide treatment, one of which had sequence similarities (98%) to Pantoea sp. which might be a competitor of plant pathogens. This study revealed the wheat phyllosphere bacterial community composition and a shift in the bacterial community following fungicide enostroburin application. 相似文献
132.
黑河下游的额济纳绿洲是我国西北地区重要的生态屏障,也是当地人民赖以生存的自然资源,然而由于种种原因,这片绿洲正在衰败并且有消亡的危险.胡杨是典型的潜水旱中生植物,它虽然有较强的耐大气干旱、耐盐碱能力,其生长发育与水分条件的优劣有着十分密切的关系.本文通过研究额济纳天然胡杨的叶水势、蒸腾速率、光合速率的变化规律,综合分析其水分利用效率与叶水势的相关关系,了解胡杨树体内水分运移关系,为揭示胡杨生存现状和合理利用水资源提供理论依据,为合理保护额济纳绿洲胡杨林提供科学支持. 相似文献
133.
134.
CUI Huxiong CHENG Tiantao YU Xingn CHEN Jianmin XU Yongfu FANG Wen 《环境科学学报(英文版)》2009,21(8):1103-1107
The variations of sulfate formation and optical coe cients during SO2 heterogeneous reactions on hematite surface under di erent
SO2 concentrations were examined using in situ di use reflectance infrared Fourier transform spectroscopy (DRIFTS) and ion
chromatograph (IC). Laboratory experiments revealed that within ambient SO2 of 0.51–18.6 ppmv, sulfate product, producing velocity,
absorption and backward scattering coe cients showed an increasing trend with SO2 concentration. Under given SO2 concentration,
the velocity of sulfate producing performed an evolution of initial increasing, midterm decreasing and final stabilizing. The reactive
uptake and Brunauer-Emmett-Teller (BET) uptake coe cients of heterogeneous reactions rose with SO2 and exhibited high reactivities.
Considering global warming, this result is important for the knowledge of heterogeneous reactions of SO2 on mineral particle surface
in the atmosphere and the assessment of their impacts on radiative forcing. 相似文献
135.
纳米TiO_2的溶胶-微波法合成及其光催化性能研究 总被引:1,自引:0,他引:1
以钛酸四正丁酯为原料,采用溶胶-凝胶法、溶胶-水热法及溶胶-微波法三种方法合成出纳米TiO2,借助XRD、UV-Vis吸收光谱等测试手段对其进行了表征,并以甲基橙为模型污染物,考察了样品的光催化性能。物相分析表明,所得样品均为锐钛矿相TiO2,与其它两种方法相比,溶胶-微波法合成的样品衍射峰明显宽化,强度明显降低,说明该法合成出纳米TiO2粒径较小;UV-Vis吸收光谱表明,溶胶-微波法合成的样品在可见光区和紫外光区对光均呈现更强的吸收,说明该法合成的粉末对光具有更高的利用率。光催化实验表明,溶胶-微波法合成样品的光催化活性高于另两种方法,紫外灯连续照射5h,甲基橙溶液脱色率为99.06%。此外,将该样品用于延安卷烟厂蒸叶车间废水的光催化氧化处理,效果较好,太阳光照射3d后COD去除率为77.4%。 相似文献
136.
137.
The article investigated the adsorption of Hg(II) on Macrocystis pyrifera and Undaria pinnatifida in monometallic system and in the presence of Zn(II), Cd(II) and Ni(II). 相似文献
138.
We report on the effects of forest management practices of understory removal and N-fixing species (Cassia alata) addition on soil
CO2 fluxes in an Eucalyptus urophylla plantation (EUp), Acacia crassicarpa plantation (ACp), 10-species-mixed plantation (Tp), and
30-species-mixed plantation (THp) using the static chamber method in southern China. Four forest management treatments, including
(1) understory removal (UR); (2) C. alata addition (CA); (3) understory removal and replacement with C. alata (UR+CA); and (4)
control without any disturbances (CK), were applied in the above four forest plantations with three replications for each treatment.
The results showed that soil CO2 fluxes rates remained at a high level during the rainy season (from April to September), followed by
a rapid decrease after October reaching a minimum in February. Soil CO2 fluxes were significantly higher (P < 0.01) in EUp (132.6
mg/(m2·hr)) and ACp (139.8 mg/(m2·hr)) than in Tp (94.0 mg/(m2·hr)) and THp (102.9 mg/(m2·hr)). Soil CO2 fluxes in UR and CA
were significantly higher (P < 0.01) among the four treatments, with values of 105.7, 120.4, 133.6 and 112.2 mg/(m2·hr) for UR+CA,
UR, CA and CK, respectively. Soil CO2 fluxes were positively correlated with soil temperature (P < 0.01), soil moisture (P < 0.01),
NO3?-N (P < 0.05), and litterfall (P < 0.01), indicating that all these factors might be important controlling variables for soil CO2
fluxes. This study sheds some light on our understanding of soil CO2 flux dynamics in forest plantations under various management
practices. 相似文献
139.
Leaf litterfall plays an important role in transporting atmospheric mercury to soil in forests area. 相似文献
140.