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931.
932.
以生态脆弱带石羊河流域为实验区,利用遥感技术获取20世纪80年代以来3个时段遥感数据,探讨了快速高效地获得土地利用/土地覆盖变化(LUCC)信息技术方法和流程,分析了土地类型变化的信息特点和原因。 相似文献
933.
乌头种质资源形态学多态性研究初报 总被引:1,自引:0,他引:1
收集乌头种质资源,经种属鉴定,均来源于毛莨科植物乌头(Aconitum camichaeli Debx.),以南瓜叶、鹅掌叶、艾叶等3种变异类型为主。观察了全生育期间哥形态学特征,证实乌头种质资源的形态学多态性,其中南瓜叶乌头长势壮、叶面积大、叶片肥厚、茎粗、须根发达、子根数目多、形状规则、子根大,表现出良好的丰产性,可作为附子栽培的重点推广品种。这些形态学指标可直接用于3种乌头资源的早期鉴定,对附子种质资源评价和良种选育具有重要意义。 相似文献
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936.
以简并引物PCR获得的Cat酶基因片段探针,结合生物信息学方法,探明了耐辐射奇球菌(D.radiodu-rans)基因组中存在两个编码过氧化氢酶(Catalase,Cat)的基因:katA和B.katA和katB基因长2277bp和1611bp,各编码758和536个氨基酸,用pKK223-3表达载体连接katB基因,转入Cat酶缺陷型大肠杆菌(E. coliUM2)进行表达.katB基因表达产物具有Cat酶活性,电泳迁移位置与D.radiodurans CatB酶位置相符,并可重建E.coliUM2对低浓度H2O2损伤的耐受力。 相似文献
937.
Contributions of deposited particles to pine needle polycyclic aromatic hydrocarbons 总被引:4,自引:0,他引:4
Yang P Chen J Wang Z Qiao X Cai X Tian F Ge L 《Journal of environmental monitoring : JEM》2007,9(11):1248-1253
The contributions of deposited particles (P) to polycyclic aromatic hydrocarbon (PAH) levels in pine (Cedrus deodar) needles sampled from the Dalian region were evaluated by washing off the particles from pine needle surfaces. P values ranged from 4.4 +/- 2.2% for fluorene to 69.9 +/- 4.0% for indeno(1,2,3-cd)pyrene, and positively correlated with the logarithm of octanol-air partition coefficients (log K OA) of each PAH significantly. P and the total levels of 14 PAHs under study ( summation PAHs), that ranged from 490 to 3241 ng g(-1) dw (dry weight) with median value of 1521 ng g(-1) dw, were high for traffic areas, and low for residential or park areas, implying the significant contributions of PAHs in both gas and particle phases emitted by vehicles. However, PAH profiles in pine needles were not significantly altered by the washing, due to the low fractions (2-5%) of the 5- and 6-ring PAHs in summation PAHs. The high wind speed and frequently alternating wind directions in the Dalian spring could quicken the depuration processes of pine needle PAHs. Thus, the local meteorological conditions and source variations should be taken into account when using pine needles to implicate seasonal variations of atmospheric semi-volatile organic compounds. 相似文献
938.
The influence of storage on the morphology and physiology of phthalic acid-degrading aerobic granules 总被引:1,自引:0,他引:1
The precultured aerobic granules with special degradabilities could be used as a feasible bioseed for enhancement of aerobic granulation systems. In practice, the storage stability, physicochemical characteristics, and recovering efficiency of granules are crucial for a long-distance transportation and successful application. In this study, phthalic acid (PA)-degrading aerobic granules were cultivated and stored for 8 wk at 4 °C. The granular size, settling ability as well as structure integrity was found stable during the storage period. It was observed that the upper 1/3 part of granules stored in the reagent bottle turned to black color, while the lower 2/3 part granules did not significantly change color (brown–yellow) after the 8-wk storage. The black and brown–yellow color PA-degrading granules were manually separated and re-inoculated into two identical sequencing batch reactors for reviving the PA degradation capability. After a 7 d operation, both black and yellow granules restored their activities to the levels before storage, in terms of total organic carbon removal efficiency (100%), specific oxygen uptake rate (59 mg g VSS−1 h−1), and adenosine triphosphate content (0.016 mg g VSS−1). This study demonstrated that aerobic granules grown on a complex substrate could tolerate storage conditions and rapidly restored their bioactivities toward the target pollutant. The results also shed the light on the future application of precultured aerobic granules with unique functions for biodegradation and bioremediation purpose. 相似文献
939.
Fourteen surface sediment samples were collected from Lanzhou Reach of Yellow River, China in July 2005. The concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography equipped with a mass spectrometry detector (GC-MS). Total concentrations of the PAHs ranged from 464 to 2621 ng/g dry weight. Sediment samples with the highest PAH concentrations appeared at the downstream of Lanzhou City, where there was the biggest wastewater discharge pipeline from Lanzhou Oil Refinery Factory and Lanzhou Chemical Industry Company. Municipal sewage also contributed to the PAH contamination in the sediments. A correlation existed between the sediment organic carbon content (f(oc)) and the total PAH concentrations (r(2)=0.57), suggesting that sediment organic carbon content played an important role in controlling the PAHs levels in the sediments. According to the observed molecular indices, PAHs contamination in Lanzhou Reach of Yellow River originated both from the high-temperature pyrolytic processes and from the petrogenic source, showing a mixed PAH input pattern, which was also confirmed by the results of a principal component analysis (PCA). According to the numerical effect-based sediment quality guidelines (SQGs) of the United States, the levels of PAHs at most studied sites in Lanzhou Reach of Yellow River should not exert adverse biological effects. Although at some sites (such as S10, S12, etc.) one PAH may exceed the effects range low (ERL), individual PAH did not exceed the effects range median (ERM). The results indicated that sediments in all sites should have potential biological impact, but should have no impairment. 相似文献
940.