Effects of cadmium on the activities of photosystems of Chlorella pyrenoidosa and the protective role of cyclic electron flow

Cadmium (Cd) shows high toxicity to aquatic microalgae. Many studies showed that Cd inhibited activities of photosystem II (PSII) but the effects of heavy metals on photosystem I (PSI) and cyclic electron flow (CEF) were still controversial and unclear. The effects of CdCl₂ on the activities of PSI, PSII and CEF in Chlorella pyrenoidosa was measured simultaneously in the present study. In presence of 200 μM of Cd, ultrastructure of some cells was strongly modified. Cd exposure led to decrease of the activities of photosynthetic oxygen evolution and respiration. PSII was more sensitive to Cd treatment than PSI. Cd treatment showed significant inhibition on the photochemical quantum yield and electron transport rate of PSII. Cd increased the quantum yield of non-light-induced non-photochemical fluorescence quenching, indicating the damage of PSII. The activity of PSI showed tolerance to Cd treatment with concentration less than 100 μM in the experiment. Linear electron flow (LEF) made significant contribution to the photochemical quantum yield of PSI of the untreated cells, but decreased with increasing Cd concentration. The contribution of CEF to the yield of PSI increased with increasing Cd concentration. The activation of CEF after exposure to Cd played an essential role for the protection of PSI.     

毛细管柱气相色谱法测定水质五氯酚

用乙酸酐衍生,正己烷液一液萃取,毛细管柱气相色谱-电子捕获检测器对地表水、废水中五氯酚进行了测定,确定五氯酚浓度范围在5．0—500μg/L之间时,样品的测定精度、回收率及方法检出限均能满足要求。     

16种蛇鳞的微皮纹分析

对16种蛇鳞的扫描电镜观察表明,蛇类鳞片微皮纹的基本结构是由d约05μm横行排列的小孔和介于小孔间向后延伸的指状突构成背鳞的微皮纹结构有种的特异性同一种蛇的原动物、蛇蜕和药材标本相同部位的鳞片具有相同的微皮纹特征因此蛇鳞的微皮纹特征亦可作为蛇类药材的鉴别依据之一,并以背鳞的微皮纹特征为依据,编制了16种蛇背鳞微皮纹特征检索表。     

镉、铅在玉米幼苗中的积累和迁移--X射线显微分析

用扫描电镜-X射线能谱仪及原子吸收分光光度计,测定经不同浓度镉、铅处理的玉米根、叶中镉、铅的积累。结果表明,铅的积累为皮层>中柱;木质部薄壁组织>导管。镉则相反。铅主要以非共质体途径在根内横向迁移,镉主要以共质体途径在根内横向迁移。原于吸收分光光度计测定表明,镉、铅主要在玉米根内沉积,镉铅复合作用促进了玉米根叶对镉、铅的吸收,镉比铅更易为玉米吸收且更易从根向叶迁移。     

活性红m-3BE的辐照降解研究

利用电子加速器产生的高能电子束为辐照源,对较高浓度的活性染料活性红m3BE进行了辐射降解研究,探讨了H2O2加入量、吸收剂量对辐照降解结果的影响和辐照前后溶液pH值的变化。结果表明,电子束辐射能有效降解活性红m3BE,脱色效果显著,脱色率达100%,化学需氧量(COD)去除率可达47%,经2.3kGy剂量辐照后溶液的pH值已有明显下降。H2O2加入量、吸收剂量均与活性红m3BE的降解效率有关,溶液pH值的变化可能有利于提高废水的可生物降解性。实验证实,利用电子束辐射降解技术处理染料废水是一种可行的方案。     

PACS的形态及电导特性研究

借助于透射电镜技术观察了ＰＡＣＳ的聚合形态考察了电导率随碱化度（γ），加入的Ａｌ＾３＋／ＳＯ＾２－４摩尔比及熟化时间的变化情况，研究了熟化时间对ＰＡＣＳ电中和能力及絮凝效果的影响。实验结果表明，ＳＯ＾２－４的加入可提高聚合氯化铝的聚合度，ＰＡＣＳ聚合物的聚合度随着γ的提高及熟化时间的增长而增大，ＰＡＣＳ的电和和能力随着熟化时间的延长而下降，ＰＡＣＳ溶液（Ａｌ＾２＋含量为０．１８ｍｏｌ／Ｌ）的电导在     

用透射电镜研究聚硅氯化铝混凝剂的结构形貌

用透射电镜观察比较了聚硅氯化铝（PASC）与聚合氯化铝（PAC）混凝剂的结构形貌，探讨了碱化度（B）、Al/Si摩尔比、及制备工艺对PASC结构形貌的影响，研究结果表明，PASC较PAC具有更大的聚集度和枝化度，PASC的聚集度随B值的升高和Al/Si摩尔比的降低而增大，共聚法制备的PASC较复合法制备的PASC具有更大的聚集度。     

强电离放电产生臭氧等离子体过程及其应用研究

电子从强电场 (>30 0Td)放电过程中取得的平均能量大于 8.4eV ;促使氧分子分解、分解电离成高浓度的氧原子、氧原子离子 ,从而产生高浓度 (>2 0 0 g/Nm3 )臭氧 ,实现了用电离放电电场的物理量控制臭氧产生浓度、产生效率及臭氧分解速率 ,并实现臭氧产生装置小型化。极大地拓宽了臭氧在环境工程领域上的应用     

短程反硝化聚磷的反硝化特征研究

研究了温度、pH值、电子供体种类及电子受体种类对反硝化的影响.试验结果表明,(1)在相同试验条件下,亚硝酸型反硝化与硝酸型反硝化的速率与硝态氮的浓度有关.在温度为25℃、pH为7的条件下,基质浓度＜300mg/L时短程反硝化速率较快;基质浓度≥300 mg/L时,以NO3-为基质的反硝化速率较大.(2)具有大量碳源储存物(PHB)的细菌可实现快速的内源性反硝化脱氮,而处于饥饿状态的细菌的内源性反硝化效率极低.     

Toxic e ects of fluoranthene and copper on marine diatom Phaeodactylum tricornutum

To investigate the effects of polycyclic aromatic hydrocarbons (PAHs) and metals on the population reproduction,antioxidative defense system and cell ultrastructure of the marine diatom,fluoranthene and Cu2 were selected to test their toxicity to Phaeodactylum tricorntum,in the laboratory.The results indicated that both fluoranthene and Cu2 inhibited population reproduction of P.tricorntum.When the algal cells were exposed to fluoranthene or Cu2 for 72 h,ultrastructure damage in the cells was observed un...