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341.
342.
单一重金属污染对水稻叶片光合特性的影响 总被引:14,自引:0,他引:14
以杂交稻协优818为材料,研究了Cu^2+、Hg^2+、Cd^2+ 3种重金属离子对水稻叶片光合特性的影响。试验结果表明:(1)Cu^2+在低浓度时BI起叶片叶绿素含量降低。而Hg^2+、Cd^2+在低浓度时。则导致叶绿素含量增加:高浓度时,3种重金属均BI起叶绿素含量降低。同时,低浓度时3种重金属离子均导致叶绿素a/b值升高:高浓度时则均引起叶绿素a/b值下降。(2)Cu^2+、Hg^2+、Cd^2+对水稻叶片叶绿素的吸收光谱均无明显影响,在活体条件下并未发生卟啉环中Mg^2+的置换。(3)Cu^2+、Hg^2+、Cd^2+均引起叶片希尔反应活力降低,即重金属污染明显影响光合作用。 相似文献
343.
A pot experiment was conducted to investigate the influence of elemental sulfur to contaminated soil on plant uptake by a heavy metal hyperaccumulator, Indian mustard( Brassica juncea ) and a field crop, winter wheat( Triticum. aestivum). Elemental sulfur(S) with different rates was carried out, they were 0(S0 ), 20(S20 ), 40(S40 ), 80(S80 ), and 160(S160 ) mmol/kg respectively. Extra pots with the same rates of S but without plants were used for soil sampling to monitor pH and CaCl2-extractable heavy metal changes. The results showed that S enhanced phytoextraction of Pb and Zn from contaminated soil. Application S effectively decreased soil pH down to 1.1 as the most at the rate of Sl60. The concentrations of CaCl2-extractable Pb and Zn in soil and uptake of Pb and Zn by the plants were increased with soil pH decreased. A good correlation between CaCl2-extractable Pb/Zn and soil pH was found( Rpb^2 = 0.847 and RZn^2 = 0,991, n = 25). With S application, soil CaCl2-extractable Pb and Zn concentrations, concentration of Pb and Zn in plants and the amount of removal by plant uptake were significanfly higher than those without S. Under the treatment of S160, the highest CaCl2-extmctable Pb and Zn were observed, they were 4.23 mg/kg and 0.40 mg/kg, 2.7 and 2.0 times as that of the control(So ) respectively. At the highest rates of S( Sl~0 ), both Indian mustard and winter wheat reached the highest uptake of Pb and Zn. The highest Pb concentrations in wheat and Indian mustard were 32.8 mg/kg and 537.0 mg/kg, all 1.8 times as that of the control, and the highest Zn concentrations in wheat and Indian mustard were 215.5 mg/kg and 404.0 mg/kg, 2.4 and 2.0 times as that of the control respectively. The highest removals of Pb and Zn from the contaminated soil were 0.41 rag/pot and 0.31 nag/pot by Indian mustard in the treatment of S160 through 50 days growth. 相似文献
344.
王星辉 《防灾科技学院学报》2005,7(4):117-118
本文对高职高专院校里在非外语专业开设及如何开展外语口译课程的教学工作进行了两方面的初步探讨。首先介绍了我国目前高校里的外语教学普遍以小班教学的模式,接着就如何在高校非外语专业学生中快速培养实用型的涉外口译人才而采用的另外一种教学模式,最后分别就其所在学校如何抓口译教材建设和抓课堂教学质量等方面工作并结合自己的教学实际进行了探讨。 相似文献
345.
Mohsen Soleimani Nasibeh Amini Babak Sadeghian Dongsheng Wang Liping Fang 《环境科学学报(英文版)》2018,30(10):166-175
The presence of heavy metals(HMs) in particulate matters(PMs) particularly fine particles such as PM_(2.5) poses potential risk to the health of human being. The purpose of this study was to analyze the contents of HMs in PM_(2.5) in the atmospheric monitoring stations in Isfahan city,Iran, in different seasons between March 2014 and March 2015 and their source identification using principle component analysis(PCA). The samples of PM_(2.5) were taken using a high volume sampler in 7 monitoring stations located throughout the city and industrial zones since March 2014 to March 2015. The HMs content of the samples was measured using ICP-MS.The results showed that the concentrations of As, Cd and Ni were in a range of 23–36, 1–12,and 5–76 ng/m~3 at all the stations which exceeded the US-EPA standards. Furthermore,the concentrations of Cr and Cu reached to 153 and 167 ng/m~3 in some stations which were also higher than the standard levels. Depending on the potential sources of HMs, their concentration in PM_(2.5) through the various seasons was different. PCA illustrated that the different potential sources of HMs in the atmosphere, showing that the most important sources of HMs originated from fossil fuel combustion, abrasion of vehicle tires, industrial activities(e.g., iron and steel industries) and dust storms. Management and control of air pollution of industrial plants and vehicles are suggested for decreasing the risk of the HMs in the region. 相似文献
346.
347.
研究表明,经济发展与环境退化之间经常呈现倒“U”型曲线关系,许多学者将其定义为环境库兹涅茨曲线(Environmental Kuznets Curves,EKC),并将其运用到对发展中国家和发达国家的“先污染,后治理”的发展模式的解释之中,但是环境库兹涅茨曲线假说本身并不完善。利用现有数据建立了针对CO2和水污染物COD排放量的中国的环境库兹涅茨曲线。同时对其未来走势进行预测,得出结论:近期内CO2排放量会随着经济的发展持续增加;而COD的排放量已经趋于稳定,只会有略微增加。 相似文献
348.
系统介绍了一种新的地下水污染治理技术——渗透性反应墙,阐述了可渗透反应墙的类型、活性材料的选取、反应机理,可渗透反应墙的构建、应用实例以及存在问题等,并展望了其今后还需深入研究的方向,认为其是一种非常有发展前景的环境污染修复技术。这将为在我国开展该方法的研究和应用打下基础。 相似文献
349.
根据加热炉炉管温度分布,提出了加热炉炉管剩余寿命评估方法:即炉管蠕变损伤后剩余寿命的评估和腐蚀损伤后剩余寿命的评估,采用此方法对在用加热炉进行了评估,并对评价结果进行了验证. 相似文献
350.
王利 《防灾科技学院学报》2005,7(2):84-85
大学生在校期间要确立正确的职业理想和明确的职业目标,要进行系统地自我分析和职业分析,根据自己的兴趣、特长来进行职业生涯设计。要加强职业需要的实践能力的锻炼,根据职业和社会发展的具体要求,将已有的知识科学地重组,构建合理的知识结构,为将来的职业发展打下良好的基础。 相似文献