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311.
PAHs pass through the cell wall and partition into organelles of arbuscular mycorrhizal roots of ryegrass 总被引:2,自引:0,他引:2
The subcellular process and distribution of polycyclic aromatic hydrocarbons (PAHs) in arbuscular mycorrhizal plants remains to be elucidated. This work used a greenhouse experiment to show that, accompanied by the apoplastic and symplastic water movement through the root, acenaphthene (ACE) as a representative PAH passed through the cell-wall boundary, dissolved in the cell solution, and partition organelles in arbuscular mycorrhizal roots of ryegrass (Lolium multiflorum Lam.). The observed concentrations of ACE in organelles were 0.6 to 4.4 times higher than in the cell walls. The cell wall and organelles were the dominant storage domains for ACE in the root, and the distribution of ACE in cells of mycorrhizal ryegrass roots was, in descending order, cell organelles (40.8-70.8%) > cell wall (19.7-3.8%) cell solution (9.6-20.5%). 相似文献
312.
Myong Hwan Sohn Kyung Won Seo Yong Seok Choi Sang Joon Lee Young Sil Kang Yang Soon Kang 《Marine Biology》2011,158(3):561-570
The marine dinoflagellate Cochlodinium polykrikoides is a harmful and highly motile algal species. To distinguish between the motility characteristics of solitary and chain-forming
cells, the swimming trajectories and speeds of solitary cells and 2- to 8-cell chains of C. polykrikoides were measured using a digital holographic particle tracking velocimetry (PTV) technique. C. polykrikoides cells exhibited helical swimming trajectories similar to other dinoflagellate species. The swimming speed increased as the
number of cells in the chain increased, from an average of 391 μm s−1 (solitary cells) to 856 μm s−1 (8-cell chain). The helix radius R and pitch P also increased as the number of cells in the chain increased. R increased from 9.24 μm (solitary cell) to 20.3 μm (8-cell chain) and P increased from 107 μm (solitary cell) to 164 μm (8-cell chain). The free thrust-generating motion of the transverse flagella
and large drag reduction in the chain-forming cells seemed to increase the swimming speed compared to solitary cells. The
measured swimming speeds agreed with those from field observations. The superior motility of chain-forming C. polykrikoides cells may be an important factor for its bloom, in addition to the factors reported previously. 相似文献
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Zinc metal and zinc sulfide were recovered by oxidative dissolution using Thiobacillus ferrooxidans, which is aerobic, autotrophic, and acidophilic bacteria. Thiobacillus ferrooxidans derive energy from oxidation of ferrous iron and elemental sulfur using molecular oxygen as an electron acceptor. From the 10, 000 mg/L of initial zinc concentration, 97% solubilization of zinc metal was obtained from coarse FeS2 due to microbial action. Also, about 70% metal solubilization occurred with fine sized materials in 58 days. The general trend observed for the ZnS systems was a decrease in pH with time. The pH drop is an indication that microorganisms are acclimating and producing acidic by-products. The iron oxidation state changes due to substrate containing coarse particle size FeS2 was shown. The shard drop of ratio of Fe(II)/Fe(Total) and sharp increase of ratio of Fe(III)/Fe(Total) was observed in 20 days after inoculation. Thus, microbial activity began more rapidly for the coarse particle size substrate than for the fine FeS2. 相似文献
316.
根据环境保护部环境工程评估中心公布的数据,中国环境影响评价机构现状特点是:环评机构的主要类型以科研院所占比例最大,其次是公司,最少的是高等院校;区域分布特点是东部多,西部少,经济发达地区多。经济欠发达地区少;评价范围特点是从事社会区域类别的环评机构最多,其次是化工石化医药类。同时,结合中国地区经济数据和市场化的要求,指出中国环评机构的数量与区域经济状况不对称,部分环评机构的评价范围与区域产业结构不匹配,环评机构市场化程度不高。最后,提出优化中国环境影响评价机构的建议。 相似文献
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318.
基于灰色理论的甲型H1N1流感传染人数预测模型研究 总被引:1,自引:0,他引:1
就我国甲型H1N1流感传染人数的预测运用灰色系统理论,建立了GM(1,1)模型和1阶残差修正模型GMε(1,1),并分别作了精度分析。研究了GMε(1,1)的变化趋势,提出了临界值和有效域概念。用MATLAB确定了模型参数及模型预测值。 相似文献
319.
用酶联免疫检测方法对苏州河沉积物PCDD/Fs进行分析,结果表明,PCDD/Fs水平在3.6~13.7TEQpg/gdw之间(平均值为8.4TEQpg/gdw)。PCDD/Fs含量的空间分布差异较大,中游含量高于上游和下游。对柱状沉积物的分析显示,沉积物PCDD/Fs含量在9.0~18.8TEQpg/gdw之间(平均值为13.8TEQpg/gdw),1996年前后达到峰值。通过对苏州河PCDD/Fs组成模式进行主分量分析发现,河流沉积物的PCDD/Fs为混合来源,其中污水排放的贡献较大。 相似文献
320.
城区内小型加油站的消防安全对策 总被引:1,自引:0,他引:1
通过对遵义市高庄(东)加油站进行实例分析,发现加油站安全管理体制不健全,违章作业表现突出,存在消防安全隐患;结合实例分析结果,得出城区内小型加油站的消防安全对策. 相似文献