狼尾草根系对阿特拉津长期胁迫的氧化应激响应

通过盆栽实验研究了抗性植物狼尾草根部丙二醛(MDA)、脯氨酸(Pro)、抗坏血酸(As A)含量及超氧化物歧化酶(SOD)、谷胱甘肽还原酶(GR)等氧化应激生理指标对不同浓度阿特拉津长期(48 d)胁迫的响应规律。结果表明:当阿特拉津胁迫浓度分别高于20 mg·kg~(-1)和50 mg·kg~(-1)时,狼尾草根系的MDA与Pro含量较对照组显著升高(P0.05);随着阿特拉津胁迫浓度的增加,狼尾草根部SOD和GR活性呈先升高后降低的趋势,其中当阿特拉津胁迫浓度为20 mg·kg~(-1)时,SOD和GR活性达到最大值;供试植物根系中As A含量与阿特拉津胁迫浓度呈正相关。综上,中低浓度(≤20 mg·kg~(-1))阿特拉津处理没有对狼尾草的根系产生明显的氧化胁迫效应,狼尾草根系的上述抗氧化应激生理指标对于发挥阿特拉津抗性起着重要的作用。     

沉水植物对阿特拉津胁迫的毒理响应

为揭示在阿特拉津胁迫下沉水植物生长及其与谷胱甘肽代谢途径的关系,通过培养实验研究了沉水植物菹草(Potamogeton crispus)和穗花狐尾藻(Myriophyllum spicatum)对0、0.5、1.0和2.0 mg·kg~(-1)阿特拉津的吸收特性,并对不同培养时期沉水植物的鲜重、总谷胱甘肽含量(T-GSH,即还原型谷胱甘肽GSH和氧化型谷胱甘肽GSSG之和)、GSH/GSSG比值及其形态变化、谷胱甘肽还原酶(GR)活性和谷胱甘肽-S-转移酶(GST)活性进行了测定。结果表明:沉积物阿特拉津初始浓度越高,植物体内阿特拉津浓度也越高。在培养60 d内,添加的阿特拉津对2种沉水植物的生长均产生显著抑制作用(P0.05)。在阿特拉津胁迫60 d后,各处理植物体内GSH/GSSG比值有所回升,其GR和GST活性均高于空白对照组。处理组植物体内GR和GST活性在30 d时达到最高值。与此同时,GSH脱去谷氨酸后能与阿特拉津形成共轭物。以上结果提示,≤2 mg·kg~(-1)阿特拉津在培养前60 d内会对植物生长产生抑制,但在90 d时植物会从伤害中恢复过来。沉水植物体内的谷胱甘肽在GR和GST作用下,对阿特拉津及其产生的活性氧具有一定去除作用,并通过控制酶活使植物体保持一定的GSH含量;另一方面,GSH可以与阿特拉津结合形成新的共轭物,以此缓解阿特拉津对沉水植物的毒害。     

Pb、Zn及其交互作用对蜈蚣草抗氧化酶及叶绿素含量的影响

采用水培实验的方法,研究了Pb、Zn及其交互作用对蜈蚣草抗氧化酶及叶绿素含量的影响.实验结果显示,Pb浓度在0—50 mg·L-1时,蜈蚣草叶绿素含量随Zn浓度增加逐渐升高、MDA含量逐渐降低,Pb、Zn交互作用可促进植株叶绿素合成.Pb浓度在100—400 mg·L-1时,Pb、Zn交互作用则降低叶绿素含量;在Pb浓度400 mg·L-1时,Pb、Zn交互作用显著增加MDA含量.实验结果还显示,在Pb浓度固定时,蜈蚣草叶片SOD、CAT的活性随Zn浓度增加呈现先上升后下降的趋势;POD随着Zn处理浓度的增加持续增加.在Zn浓度一定时,蜈蚣草叶片SOD、CAT、POD的活性随Pb浓度增加先上升后下降.由此可见,在低Pb、Zn浓度下,Pb、Zn交互作用表现为协同作用;在高Pb、Zn浓度下,Pb、Zn交互作用表现为拮抗作用.     

锌对汞胁迫下小麦幼苗生理特性的影响

通过沙基培养方法研究不同浓度锌(Zn)对汞(Hg)胁迫下小麦幼苗叶绿素相对含量(SPAD)、丙二醛(MDA)与脯氨酸的积累及抗氧化酶活性等的影响.结果表明:单独Hg(10 mg L-1)胁迫下,小麦幼苗叶绿素含量降低,超氧化物歧化酶(SOD)与过氧化氢酶(CAT)活性受到抑制,MDA与脯氨酸含量升高.加入10 mg L-1Zn后,叶绿素含量比Hg单独胁迫升高了5.6%,MDA含量降低了32.4%,表明该浓度Zn在一定程度上缓解了Hg对小麦幼苗的毒害;Zn浓度高于10 mg L-1的处理中,叶绿素含量逐渐降低,MDA则呈升高趋势,表明随Zn浓度升高,Zn对Hg毒害的缓解作用逐渐降低.低浓度Zn(10~20 mg L-1)提高了Hg胁迫下小麦幼苗SOD与CAT活性,其活性随Zn浓度升高逐渐增加,20mg L-1Zn处理下,两种酶活性比Hg单独胁迫分别升高了103.3%与71.0%,高浓度Zn(50~100 mg L-1)处理下,两种酶活性则呈下降趋势,表明Zn对Hg胁迫下两种酶活性的促进作用逐渐减弱.在试验设置的Zn浓度范围内,脯氨酸含量均低于Hg单独胁迫,并且低于对照,说明外加Zn抑制了脯氨酸的生成.综上所述,10~20 mg L-1的Zn可以在一定程度上缓解10 mg L-1Hg对小麦幼苗造成的毒害.     

镉胁迫对小白菜（Brassica campestris L.）抗氧化机理的影响

采用水培的方法,研究了不同Cd2 水平(0、1、2.5、5、10、15mg·L-1)对小白菜(Brassica campestris L.)抗氧化酶(SOD、POD、CAT)活性、非酶物质(SH、GSH、PCs)含晕以及生长的影响.结果表明,小白菜叶片和根系SOD活性随Cd处理质量浓度的增加呈降低的变化趋势,POD、CAT活性以及MDA含量随Cd处理质量浓度的增加而增加.小白菜的生物量、根长、株高、叶绿素质量分数随Cd处理质量浓度的增加显著降低(P<0.05),表明Cd抑制了小白菜的生长,破坏了叶绿素的合成.小白菜地上、地下部镉质量分数均随Cd处理质量浓度的增加而显著增加(P<0.05).当Cd处理质量浓度为15 mg·L-1,小白菜地上、地下部镉质量分数分别达到637.5、1 663.0 mg·kg-1,表明小白菜对Cd有良好的富集效果.小白菜根系与叶片中SH、GSH和PCs含量均随Cd处理质量浓度增加而增加的变化趋势,表明SH、GSH和PCs在解毒小白菜Cd毒害中起着重要作用.     

Cd2+胁迫对竹叶眼子菜的毒理学效应分析

以不同浓度Cd2 处理5 d的竹叶眼子菜为实验材料,分析了叶片的光合色素、抗氧化系统、丙二醛(MDA)、可溶性糖、可溶性蛋白等生理生化指标的应答反应,并用透射电镜观察了叶细胞超微结构的变化.随着Cd2 处理浓度的增加,叶绿素含量和超氧化物歧化酶(SOD)活性下降,而MDA和可溶性糖含量上升;过氧化氢酶(CAT)、过氧化物酶(POD)活性和抗坏血酸(ASA)、还原型谷胱甘肽(GSH)含量分别在2 mg L-1和4 mg L-1时达到峰值;可溶性蛋白含量下降,相对分子质量(Mr)为52.1×103、42.9×103、27.4×103和14.1×103的多肽合成量逐渐减少,但Mr为18.1×103的多肽的合成量增加;叶绿体膨大、解体;线粒体嵴突肿胀、空泡化;核仁分散、核膜断裂、核质散出.结果表明: Cd2 对竹叶眼子菜的光合结构、细胞保护系统以及细胞结构的完整性等都产生明显破坏作用,最终将导致植物死亡.其中SOD、叶绿素和蛋白生物合成各指标的反应较灵敏,可作为水体Cd2 污染的监测指标. Cd2 对竹叶眼子菜的半效应浓度为2.97 mg L-1.图8参27     

4,4'-二氨基二苯基甲烷对浮萍(Lemna minor L.)毒性作用

以浮萍(Lemna minor L.)为受试生物,通过研究不同浓度(0、0.6、1.8、5.4、16.2和48.6 mg·L-1)的4,4'-二氨基二苯基甲烷(4,4'-methylenedianiline,MDA)对浮萍生长、叶绿素含量、PSⅡ最大光化学效应(Fv/Fm)、质膜透性及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性的影响,初步探讨MDA对水生植物浮萍的毒性作用.实验结果表明,在7d暴露时间下,MDA对浮萍叶片数、叶片数生长率、叶片干质量和叶面积都有显著的抑制作用,且抑制程度与MDA的浓度呈正相关.其对浮萍叶片数生长抑制的7d半数效应浓度(7 d-ECs0)为26.7 mg·L-1,95％置信限为22.3 ～ 32.1 mg·L-1;对浮萍叶片数产量抑制的7 d-EC50为0.62 mg-L-1,95％置信限为0.53～0.74 mg-L-1;对浮萍总叶面积及干质量产量抑制的7 d-EC50＜0.6 mg·L-1.MDA处理导致浮萍总叶绿素含量和Fv/Fm下降,而浮萍质膜透性显著增加.低浓度MDA对浮萍SOD、POD和CAT酶活性无显著影响,但随着MDA浓度的升高SOD、POD和CAT酶活性显著升高,当MDA浓度达到48.6 mg· L-1时,抑制POD和CAT酶活性.以上结果表明,MDA能够直接损伤质膜,干扰叶绿体功能并抑制光合活性,而氧化损伤是质膜损伤引起的继发性应激,继而引起膜脂质过氧化,加剧质膜损伤,从而进一步抑制浮萍的生长.     

1,2,4-三氯苯对铜钱草染毒的毒性响应及其机理

以水培铜钱草为材料,研究1,2,4-三氯苯(1,2,4-TCB)染毒引起植株叶绿素、类胡萝卜素和可溶性蛋白含量等生理指标的毒性响应,并从叶片丙二醛(MDA)含量及各种抗氧化酶(超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD))的改变探讨了1,2,4-TCB的毒性作用机理.结果表明,1,2,4-TCB(5、10 mg.L-1)处理后,铜钱草叶片各种生理代谢指标与1,2,4-TCB处理之间呈现一定浓度-效应和时间-效应关系,但与对照组间无显著的统计学差异.叶绿素含量、叶绿素a/b和可溶性蛋白均随着1,2,4-TCB处理时间延长先升高后降低;MDA含量随处理时间延长先升高后降低,随浓度增加而增加;SOD和POD活性随处理时间和浓度增加先升高后降低;CAT活性变化不明显.在10 mg.L-11,2,4-TCB处理4—6 d时,各种抗氧化酶活性均达到最大.高浓度1,2,4-TCB(15、20 mg.L-1)处理铜钱草的抗氧化酶活性与对照组相比,均显著降低,且各处理组间也呈现统计学差异.     

阿特拉津对铜绿微囊藻和四尾栅藻生长的影响

在实验室内利用MA培养液培养,通过测定藻生长量和叶绿素a含量,研究不同浓度下的阿特拉津对铜绿微囊藻(Microcystis aeruginosa)和四尾栅藻(Scenedesmus quadricauda)生长的影响,并以藻细胞数表示的最大比生长率为指标,评价2种藻对阿特拉津的敏感性.结果表明,在0.001～5.000 mg·L-1质量浓度范围内,阿特拉津对铜绿微囊藻和四尾栅藻的生长表现出低浓度刺激、高浓度抑制的效应,且阿特拉津对四尾栅藻的刺激效应明显大于铜绿微囊藻.     

低浓度阿特拉津对鲫鱼谷胱甘肽-S转移酶(GSTs)活性的影响

研究不同作用时间和不同暴露浓度下阿特拉津对鲫鱼肝脏、肾脏和肌肉谷胱甘肽-S转移酶(GSTs)活性的影响.结果表明:阿特拉津对鲫鱼各个组织器官GSTs活性产生较强的影响.长期暴露下(24 d),阿特拉津对鲫鱼肝脏和肌肉GSTs活性基本表现为诱导作用,最大诱导率为110.81%和32.54%,且分别在0.1～5.0和1.0～10.0 mg·L-1质量浓度范围内存在剂量-效应关系;对鲫鱼肾脏GSTs活性具有抑制作用,最大抑制率为14.42%,且在所设质量浓度(0～10 mg·L-1)范围内均表现出剂量-效应关系.在10.0 mg·L-1质量浓度暴露下第6-14天内,阿特拉津与鲫鱼肝脏及肌肉GSTs活性间存在时间-效应关系;其他情况下,任何组织器官在试验期间均未表现出时间-效应关系.     

Alteration of photosystem II activity by atrazine on Chlamydomonas reinhardtii synchronized and asynchronized cell cycle cultures

Inhibition of photosystem II (PSII) activity by atrazine was investigated in the green alga Chlamydomonas reinhardtii during different states of the cell cycle. The algal cultures were maintained under continuous light or under light/dark cycle (16/8?h) to obtain homogenized cell cycle distribution. The cycle state of algal population was determined by the DNA content using flow cytometry and defined as newly divided cells before the initiation of DNA replication (G₀/G₁) and cells at the end of the replication cycle with fully duplicated DNA content (G₂/M). Under different synchronized states of the cell population, the photosynthetic activity was investigated after treatment at 10, 100, and 1000?µmol?L^?1 atrazine exposed for 24?h by using fluorescence parameters related to PSII activity measured with a plant efficiency analyzer and pulse-amplitude modulated methods. In this study, we found that the atrazine effect was different depending on cell cycle phases and the period of illumination. Algal cells under light–dark cycle showed inhibition of the PSII electron transport leading to an increase of heat energy dissipation by the PSII reaction center. Algal cells grown under continuous light was shown to be more resistant to atrazine than the cells grown under light–dark cycle.     

图像处理在弹琴蛙(Rana adenopleura)蝌蚪生物监测研究中的应用

利用图像处理方法对不同质量浓度的阿特拉津溶液(1mg／L、5mg／L、10mg／L、15me／L)中弹琴蛙(Rana ade-nopleura)蝌蚪行为进行了图像的识别及分析．根据实验结果，利用MATLAB语言编写了弹琴蛙蝌蚪在水族缸中具体分布型判定的程序，采用了负二项分布的参数κ值来反应不同溶液中蝌蚪聚集程度的差异，并作为该指示生物监测阿特拉津水体污染情况的一个指标．结果显示，该程序可如实反映不同污染水体中蝌蚪的聚集程度：经χ^2检验各种水体中蝌蚪均符合负二项分布，同时阿特拉津溶液中蝌蚪的κ值均小于空白对照和丙酮对照，表明阿特拉津溶液的浓度和蝌蚪的聚集程度相关．图9表1参14     

Investigation of the effects of humic acid and H 2 O 2 on the photocatalytic degradation of atrazine assisted by microwave

A solution of atrazine in a TiO₂ suspension, an endocrine disruptor in natural water, was tentatively treated by microwave-assisted photocatalytic technique. The effects of mannitol, oxygen, humic acid, and hydrogen dioxide on the photodegradation rate were explored. The results could be deduced as follows: the photocatalytic degradation of atrazine fits the pseudo-first-order kinetic well with k = 0.0328 s⁻¹, and ·OH was identified as the dominant reactant. Photodegradation of atrazine was hindered in the presence of humic acid, and the retardation effect increased as the concentration of humic acid increased. H₂O₂ displayed a significant negative influence on atrazine photocatalysis efficiency. Based on intermediates identified with gas chromatography-mass spectrometry (GC-MS) and Liquid chromatography-mass spectrometry (LC-MS/MS) techniques, the main degradation routes of atrazine are proposed.     

Investigation of the effects of humic acid and H<Subscript>2</Subscript>O<Subscript>2</Subscript> on the photocatalytic degradation of atrazine assisted by microwave

A solution of atrazine in a TiO₂ suspension, an endocrine disruptor in natural water, was tentatively treated by microwave-assisted photocatalytic technique. The effects of mannitol, oxygen, humic acid, and hydrogen dioxide on the photodegradation rate were explored. The results could be deduced as follows: the photocatalytic degradation of atrazine fits the pseudo-first-order kinetic well with k = 0.0328 s^?1, and ·OH was identified as the dominant reactant. Photodegradation of atrazine was hindered in the presence of humic acid, and the retardation effect increased as the concentration of humic acid increased. H₂O₂ displayed a significant negative influence on atrazine photocatalysis efficiency. Based on intermediates identified with gas chromatography-mass spectrometry (GC-MS) and Liquid chromatography-mass spectrometry (LC-MS/MS) techniques, the main degradation routes of atrazine are proposed.     

Effect of short-term atrazine addition on the performance of an anaerobic/anoxic/oxic process

In this study, an anaerobic/anoxic/oxic (A²O) wastewater treatment process was implemented to treat domestic wastewater with short-term atrazine addition. The results provided an evaluation on the effects of an accidental pollution on the operation of a wastewater treatment plant (WWTP) in relation to Chemical Oxygen Demand (COD) and biological nutrient removal. Domestic wastewater with atrazine addition in 3 continuous days was treated when steady biological nutrient removal was achieved in the A²O process. The concentrations of atrazine were 15, 10, and 5 mg·L^?1 on days 1, 2 and 3, respectively. The results showed that atrazine addition did not affect the removal of COD. The specific NH₄ ⁺ oxidation rate and NO₃ ^? reduction rate decreased slightly due to the short-term atrazine addition. However, it did not affect the nitrogen removal due to the high nitrification and denitrification capacity of the system. Total nitrogen (TN) removal was steady, and more than 70% was removed during the period studied. The phosphorus removal rate was not affected by the short-term addition of atrazine under the applied experimental conditions. However, more poly-hydroxy-alkanoate (PHA) was generated and utilized during atrazine addition. The results of the oxygen uptake rate (OUR) showed that the respiration of nitrifiers decreased significantly, while the activity of carbon utilizers had no obvious change with the atrazine addition. Atrazine was not removed with the A²O process, even via absorption by the activated sludge in the process of the short-term addition of atrazine.     

生物炭对土壤中阿特拉津吸附特征的影响

为探究生物炭对土壤中阿特拉津的吸附特征及影响因素,采用批处理实验研究了灭菌(T1)、5%秸秆生物炭+灭菌(T2)、未灭菌(T3)和5%秸秆生物炭+未灭菌(T4)条件下对土壤中阿特拉津吸附特征及土壤理化性质的影响.结果表明,在最初0—12 h内,不同处理下阿特拉津吸附量均随时间的延长而快速增加,而在12—96 h内增加较为缓慢并逐渐趋于平衡.在96 h时,T2和T4处理下阿特拉津最大吸附量分别达到46.22 mg·kg^-1和46.43 mg·kg^-1,而未添加生物炭的T1和T3处理则有所降低,分别为44.20 mg·kg^-1和43.09 mg·kg^-1.准二级动力学模型更好地拟合不同处理下土壤对阿特拉津吸附特征,T2和T4处理下吸附速率常数K分别为0.257 kg·mg^-1·h^-1和0.339 kg·mg^-1·h^-1,显著高于未添加生物炭处理的T1和T3处理(K分别为-0.083 kg·mg^-1·h^-1和-0.261 kg·mg^-1·h^-1).内扩散模型显示添加生物炭后,土壤对阿特拉津的吸附是一个由边界扩散、内部孔隙扩散等多因素控制的复杂化学过程.添加生物炭可显著提高土壤pH、有机碳、碱解氮、速效磷和速效钾含量,其中土壤有机碳含量与阿特拉津最大吸附量之间存在显著的正相关关系(P<0.05).由此可见,添加生物炭可以提高土壤对阿特拉津的固持能力,减少其淋溶迁移风险,从而达到修复阿特拉津污染土壤的目的.     

天津市污水以及再生水处理过程中的雌/孕激素干扰效应（Estrogen and Progesterone Interference Effect of Sewage and Reclaimed Water Treatment Process in Tianjin）

应用重组基因酵母检测了天津市4个污水处理厂以及2个再生水厂13个水样的雌/孕激素干扰效应.其中3个污水处理厂的进水检出了雌激素诱导活性,最高检测值为10.7ngEEQ·L-1;所有水样均未检测出孕激素诱导活性,但都检测出不同程度的孕激素抑制活性,其中检出了雌激素诱导活性的污水处理厂的进水具有相对较强的孕激素抑制活性.4个污水处理厂均不能完全去除孕激素抑制活性物质,去除率在44%～78%之间.微滤和臭氧氧化两种工艺结合对孕激素抑制活性物质的去除效率略优于MBR反应器.2个再生水厂出水加氯后孕激素抑制活性均有所增强.     

Exposure of ground water to alachlor,atrazine and metolachlor in maize areas of ribatejo and oeste (Portugal)

In irrigated maize areas of an important Portuguese agricultural area, Ribatejo and Oeste Region, alachlor, atrazine and metolachlor were detected in ground water.

During the study performed from 1996 to 1998 atrazine was the herbicide that showed the highest frequency of detection. In the 177 ground water samples collected 62% were contaminated with atrazine, 30% with alachlor and 12% with metolachlor. All these herbicides were detected both in ground water for human consumption and for irrigation, in some cases above 0.1 ug/L. The maximum levels quantified were 13μg/L for alachlor, 30μg/L for atrazine and 56 μg/L for metolachlor.

Seasonal variation of residues in ground water it is also presented through several examples of studies performed during the period 1991–1999.     

Plant Bioavailability of “natural” and “model” Humic acid‐bound [14c] Atrazine residues

The release of bound [14C] atrazine residues and their uptake by maize plants was investigated.

“Natural”; humic acids, extracted from a brown soil, and “model”; humic acids, prepared from catechol, both containing bound [14C] atrazine residues were incubated with plants in soil. After 21 days, the maize plants contained 0.7% (plants grown in soil mixed with “natural”; humic acids) to 1.7% (plants grown in soil mixed with “model”; humic acids) of the radioactivity originally introduced.

The roots contained 55 to 70% of the [14C] residues whereas the remainder was present in the shoots. A significant amount of the total [14C] residues (29 to 53%) became again bound in plant tissues, whereas the, majority of extractable [14C] residues was present in the form of conjugates.

The behaviour of “model”; humic acid‐bound residues was comparable to that of “natural”; humic acid‐bound residues or soil‐bound residues.