镉、铜和锌胁迫下黑藻活性氧的产生及抗氧化酶活性的变化研究

研究了不同Cd、Cu、Zn处理浓度对黑藻体内活性氧()产生及对抗氧化酶(SOD、POD、CAT)活性的分子毒理学效应以探讨高等水生植物抗氧化酶对重金属胁迫的反应。结果表明,三种重金属都不同程度地加快了产生速率;Cu使SOD、POD、CAT活性下降;Cd也都减弱了SOD和POD活性,而CAT活性在0.5—5mg/L处理浓度时增加;Zn对SOD活性也为抑制作用,当浓度为0.5—5mg/L时POD和CAT活性都上升。关联度分析发现Cd、Cu和Zn胁迫下黑藻起主要保护作用的分别为SOD、POD和CAT,而SOD最易受到影响。Cd、Cu处理下的叶绿素含量也都呈下降趋势,而0.5—5mg/L的Zn浓度刺激了叶绿素合成。所有Zn处理、0.5mg/L的Cu处理和0.5—1mg/L的Cd处理的叶绿素a/b值都大于对照值。除了Cu使可溶性蛋白含量减少外,0.5—5mg/L的Zn和0.5—1mg/L的Cd都使其含量增加。综合起来,Cu的毒性最强,其次为Cd,Zn最弱。致死阈浓度分别为:Cu:0.5—1mg/L;Cd:1—2mg/L;Zn:5—6mg/L。SOD是评价重金属对沉水植物毒性效应的灵敏指标。黑藻对水环境Cu污染反应敏感。       

镉胁迫对金银花叶片含水量及微量元素吸收积累的影响

采用土培试验方法,研究了不同浓度镉(Cd)胁迫下金银花的叶片含水量和体内微量元素含量的变化。结果表明:随着Cd处理浓度的增加,叶片含水量呈先上升后下降的变化趋势。在100和200mg·kg-1Cd处理下,叶片含水量分别为70.4%和65.3%,与对照相比虽有所降低,但并未表现出显著差异。从整体上看,Cd胁迫促进了根中Fe含量增加,而Mn、Cu和Zn含量均有所下降;与对照相比,叶中Cu含量降低,Fe、Mn和Zn含量均在低浓度Cd处理下增加,随着Cd处理浓度的增加而降低。     

铜递进胁迫对芦竹生理指标、富集能力的影响

通过测定叶片中叶绿素含量、过氧化氢酶（CAT）、过氧化物酶（POD）和超氧化物歧化酶（SOD）活性、丙二醛（MDA）含量、脯氨酸含量及质膜透性,研究了不同浓度铜胁迫对芦竹幼苗植株的生理指标及富集能力的影响。结果表明：随铜处理浓度的增大,叶片中叶绿素含量、POD、SOD和CAT活性均呈先升高后降低的趋势,当铜处理浓度在100mg·kg^-1时,叶绿素含量、CAT活性达到最大值,而POD、SOD活性在200mg·kg^-1处理时达到最大值。MDA含量、脯氨酸含量及质膜透性均随铜浓度增大而升高,当铜处理浓度在800mg·kg^-1时,叶片中的MDA含量、脯氨酸含量及质膜透性达到最大值。检测芦竹中铜含量的分布规律为根（地下部分）〉茎、叶（地上部分）,当铜处理浓度未达800mg·kg^-1时,转运系数小于1,富集系数大于1。结果表明芦竹对铜污染土壤具有一定耐受力。     

镉胁迫对秋华柳根系活力及其Ca、Mg、Mn、Zn、Fe积累的影响

以秋华柳为试验材料,采用水培试验方式,设置CK(0 mg·L^-1 Cd²⁺)、T₁(2 mg·L^-1 Cd²⁺)、T₂(10 mg·L^-1Cd²⁺)、T₃(20 mg·L^-1Cd²⁺)、T₄(50 mg·L^-1Cd²⁺)5种镉处理浓度,通过对秋华柳根系活力,叶、韧皮部、木质部和根部的镉含量,以及Ca、Mg、Mn、Zn、Fe 5种常规金属元素含量的测定,研究了不同浓度镉胁迫下秋华柳根系活力及Ca、Mg、Mn、Zn、Fe 等金属元素含量的变化.结果表明:1)秋华柳根系活力随着镉处理浓度的增加而逐渐下降,当镉浓度≥10 mg·L^-1时,根系活力与对照相比显著下降.2)随着镉处理浓度的增加,秋华柳叶中Fe的积累受到显著抑制;韧皮部Mg、Mn、Fe的积累受到显著抑制;木质部Ca、Mg、Mn、Zn、Fe 等5种常规金属元素的积累无显著性差异;根部5种常规金属元素的吸收和积累受到显著抑制,表现出镉对其他金属元素积累的拮抗作用.其中,50 mg·L^-1的镉胁迫下,根部Zn的积累量降幅最大,受Cd的抑制最明显.3)各处理组Fe的转移系数与对照相比均无显著性差异;Ca、Mg、Mn、Zn的转移系数均高于对照,且在一定的镉处理水平上差异显著.4)镉胁迫下,秋华柳根部镉的积累量与Ca的积累量呈显著负相关,与其他4种常规金属元素的积累量呈极显著负相关,说明根部常规金属元素的变化可作为秋华柳受镉毒害程度的指示之一.     

钴在蚕豆中的积累分布及其对叶片光合作用和抗氧化酶活性的影响

以6叶期蚕豆(Vicia faba L.)幼苗为材料,用不同浓度钴(0、20、40、80、120mg·kg-1)土培处理14d,研究不同浓度钴处理对蚕豆体内钴的富集和分布特征,以及叶片光合色素含量、叶绿素荧光参数、光合作用参数、生长指标和POD、SOD、CAT活性的影响。结果显示:(1)蚕豆的根、茎、叶均能吸收一定量的钴,但不同器官间积累量有显著差异,并表现为根叶茎,且在不同钴浓度处理下根吸收量也存在显著差异。(2)不同浓度钴处理下,蚕豆叶片叶绿素(a、b)含量、气孔导度(Gs)、最大光化学效率(Fv/Fm)、PSⅡ潜在活性(Fv/F0)等参数与对照组相比表现出0~40mg·kg-1浓度下促进,40~120mg·kg-1浓度下抑制,而净光合速率(Pn)、胞间CO2浓度(Ci)以及光系统Ⅱ最小荧光(F0)、最大荧光(Fm)表现为在0~80mg·kg-1浓度下促进,80~120mg·kg-1浓度下抑制,蒸腾速率(Tr)和类胡萝卜素含量则在各浓度下一直表现为促进,并且以上光合作用相关参数与对照组相比都在40mg·kg-1浓度下促进作用达到最大。(3)蚕豆幼苗的根长、株高、生物量以及抗氧化酶POD、SOD和CAT活性均随着钴浓度增加表现出先升高后降低的趋势。研究表明,蚕豆的根、茎、叶均能积累钴,且吸收量有随土壤钴浓度增加而增加的趋势,但以根部的富集能力最强、积累量最大;低浓度钴可以诱导蚕豆中抗氧化酶活性增强,促进其叶片光合色素含量、光合作用效率提高和植株生长发育,而高浓度钴则表现出相反趋势,抑制蚕豆的光合效率和生长发育。     

铅、锌及其交互作用对鱼腥草(Houttuynia cordata)叶绿素含量及抗氧化酶系统的影响

采用营养液培养方法研究铅、锌及其交互作用对鱼腥草叶绿素含量及抗氧化酶系统的影响。实验结果显示，随着Pb浓度的增加，鱼腥草叶绿素含量逐渐降低但无显著变化。Zn在一定浓度下能提高鱼腥草叶绿素含量，而在高浓度Zn胁迫下，叶绿素含量急剧下降。鱼腥草叶片中SOD、POD和CAT3种酶活性都是随着Pb浓度的增加先上升后下降。随着Zn浓度的增加，SOD和CAT也是先上升后下降，POD则是逐渐上升。Pb—Zn交互作用增加了鱼腥草叶绿素含量，对SOD和POD活性具有抑制作用，对CAT活性影响不明显。同时研究结果还表明，单一Pb、Zn对鱼腥草叶绿素含量和抗氧化酶系统的影响大于Pb、Zn二者的共同作用，其中高浓度Zn对鱼腥草的伤害作用最大，而当溶液Pb处理浓度达到400mg／L时，鱼腥草仍能正常生长，说明鱼腥草具有较强的耐Pb能力。     

镉与锌复合污染对栝楼幼苗生理特性的影响

通过室内盆栽实验,研究镉(Cd)、锌(Zn)复合污染对栝楼(Trichosanthes kirilowii Maxim.)幼苗生理特性的影响.结果显示,随着Cd、Zn浓度的升高,叶绿素a、叶绿素b、总叶绿素、可溶性糖及紫外吸收物含量下降;超氧化物歧化酶(SOD)活性先升高再下降,过氧化物酶(POD)活性及类胡萝卜素含量呈升—降—升趋势;丙二醛(MDA)和可溶性蛋白含量分别呈S"型及倒N"型曲线变化.与对照相比,在不同浓度复合污染条件下,光合色素、可溶性糖、可溶性蛋白、紫外吸收物含量及SOD活性均有所下降,POD活性和MDA含量上升.研究表明,栝楼幼苗对Cd、Zn胁迫具有一定的耐受力,但高浓度Cd、Zn对幼苗正常生长有较为显著的抑制作用.     

锌和铁缺乏对枳生理指标、矿物质含量及叶片超微结构的影响

采用营养液培养法,研究了缺锌(0μmol·L-1 Zn2+)、缺铁(0μmol.L-1 Fe-EDTA)条件下柑橘砧木枳的生理胁迫反应.结果表明:1)锌、铁缺乏使枳生物量与根系活力均显著下降,叶片与根系中的SOD活性明显上升;叶片与根系中的POD活性在缺锌下显著增高,但在缺铁胁迫下显著降低;缺锌处理的根系CAT活性显著上升,但缺铁处理下的CAT活性与对照无显著差异.2)缺铁处理的根部K、Mg、P含量及缺锌处理的地上部K含量均显著降低;缺铁处理的根部和地上部Zn、Cu含量以及缺锌处理的根部Fe、Mn及地上部Mn含量均显著增高.3)叶肉细胞超微结构变化显著,缺铁胁迫下细胞器受损程度较重,如叶绿体、线粒体空泡化严重,叶绿体膜及类囊体片层模糊,质体小球明显增多,无淀粉粒;而缺锌处理时叶绿体基粒片层排列松散、数目明显减少,质体小球明显增多.     

两个桃树品种对土壤中不同镉水平的响应

以不同品种桃(Amygdlus persica(L.)Batsch)"大久保(Okubao)"和"丽春(Lichun)"为试材,研究了不同土壤镉水平下桃树对镉及矿质养分的吸收.结果表明:随着镉浓度增大,品种间镉、大量元素、微量元素的含量差异显著(P＜0.05);桃树器官中镉积累量为根＞茎＞叶＞果实;土壤中镉浓度为10 mg·kg-1时,大久保外果皮中镉积累量最大,较对照增加了226.78%,而丽春桃果实组织中镉积累量在处理前后没有明显变化;当土壤镉浓度超过20 mg·kg-1时,2品种均不能正常座果.土壤镉浓度为100 mg·kg-1,胁迫时间为9个月后,大久保桃树体死亡;土壤Cd浓度＜20 mg·kg-1时促进大量元素K、N、Ca、Mg 和微量元素Zn、Cu、Mn、Fe吸收,＞20 mg·kg-1时抑制其吸收,但丽春根和大久保茎中Fe 元素含量呈现持续上升趋势,且Cd 100 mg·kg-1时Fe的吸收值达最大.     

铅、锌及其交互作用对鱼腥草(Houttuynia cordata)叶绿素含量及抗氧化酶系统的影响

采用营养液培养方法研究铅、锌及其交互作用对鱼腥草叶绿素含量及抗氧化酶系统的影响。实验结果显示,随着Pb浓度的增加,鱼腥草叶绿素含量逐渐降低但无显著变化。Zn在一定浓度下能提高鱼腥草叶绿素含量,而在高浓度Zn胁迫下,叶绿素含量急剧下降。鱼腥草叶片中SOD、POD和CAT 3种酶活性都是随着Pb浓度的增加先上升后下降。随着Zn浓度的增加,SOD和CAT也是先上升后下降, POD则是逐渐上升。Pb-Zn交互作用增加了鱼腥草叶绿素含量,对SOD和POD活性具有抑制作用,对CAT活性影响不明显。同时研究结果还表明,单一Pb、Zn对鱼腥草叶绿素含量和抗氧化酶系统的影响大于Pb、Zn二者的共同作用,其中高浓度Zn对鱼腥草的伤害作用最大,而当溶液Pb处理浓度达到400mg/L时,鱼腥草仍能正常生长,说明鱼腥草具有较强的耐Pb能力。     

Definitions,measurements, and classifications of stimuli,situations, and environments

A review is presented of issues relevant to the definition, measurement, and classification of stimuli, situations, and environments. Problems such as the lack of adequate definitions of concepts, error and bias in measurement procedures, confusion between measurement of a concept and measurement of its behavioral effects, and the lack of agreement among alternative measures are emphasized. It is suggested that concepts be defined in terms of objective characteristics while allowing for the study of the transactional relationship between organism and environment. The work of the ethologists in defining stimuli while studying their relationship to different organismic states and situational contexts is emphasized in this regard. Following Brunswik, it is also suggested that wherever possible there be a representative sampling of variables in natural settings. Note from the editors: From time to time, Human Ecology will publish a review article. Our first in this series is a review by a psychologist of basic definitional and conceptual problems in environmental studies.This paper was prepared while the author was a Visiting Research Fellow at the Educational Testing Service. The support of ETS and my colleagues in the Division of Psychological Studies is gratefully acknowledged. The review was also supported in part by a grant from the Rutgers University Research Council.     

Exercise, dobutamine, and combined atropine, norepinephrine, and epinephrine compared

We compared the cardiovascular effects evoked in conscious dogs by 1) submaximal exercise; 2) infusion of dobutamine (40 micrograms X kg-1 X min-1); and 3) infusion of a combination of atropine (0.15 mg/kg), norepinephrine (0.19 micrograms X kg-1 X min-1), and epinephrine (0.05 micrograms X kg-1 X min-1). Myocardial O2 demand, as estimated by the double product (heart rate X systolic blood pressure), was similar during all three interventions. Cardiac output and heart rate increased significantly (P less than 0.05) during each of the three interventions. Arteriovenous O2 difference and total body O2 consumption, however, increased only during submaximal exercise. Although myocardial blood flow increased similarly during each of the three interventions, blood flow to skeletal muscle and the tongue increased only during exercise. Exercise and the combined infusion of atropine, norepinephrine, and epinephrine produced similar increases in blood flow to the diaphragm and similar decreases in blood flow to the stomach. These changes in blood flow were associated with appropriate changes in vascular resistance. Additionally, blood flow to the brain, kidney, adrenal glands, liver, and intestine did not change during any of the three interventions. Thus, in dogs, submaximal exercise, infusion of dobutamine, and infusion of a combination of atropine, norepinephrine, and epinephrine to evoke a given level of estimated myocardial O2 consumption produce similar increases in cardiac output, heart rate, and myocardial blood flow. In contrast, the changes in total body O2 consumption, arteriovenous O2 difference, regional blood flow, and regional vascular resistance that occur during each of these three interventions are different.     

Indians, Markets, and Rainforests: Theory, Methods, and Analysis

Indians, Markets, and Rainforests: Theory, Methods, and Analysis. Ricardo A. Godoy. New York: Columbia University Press, 2001. 274 pp.     

Synthesis,tautomerism, and antimicrobial,anti-HCV,anti-SSPE,antioxidant, and antitumor activities of arylazobenzosuberones

2-Dimethylaminomethylene-1-benzosuberone 1 was coupled with diazotized aniline derivatives to afford a series of the hitherto unreported 2-arylazo-1-benzosuberones 3a–i. The tautomeric structure and the effect of substituents on the tautomeric form (s) of the products 3a–i were discussed. Similar coupling of the enaminone 1 with diazonium salts of heterocyclic amines gave the respective fused azolotriazino-benzosuberones. Some of the newly synthesized compounds showed potent antimicrobial, anti-HCV, antioxidant, antitumor (as topoisomerase I inhibitors), and antimicrobial activities.     

Incorporating Science,Technology, Fairness,and Accountability in Environmental,Health, and Safety Decisions

The Precautionary Principle is in sharp political focus today because (1) the nature of scientific uncertainty is changing and (2) there is increasing pressure to base governmental action on more “rational” schemes, such as cost-benefit analysis and quantitative risk assessment, the former being an embodiment of ‘rational choice theory’ promoted by the Chicago school of law and economics. The Precautionary Principle has been criticized as being both too vague and too arbitrary to form a basis for rational decision making. The assumption underlying this criticism is that any scheme not based on cost-benefit analysis and risk assessment is both irrational and without secure foundation in either science or economics. This paper contests that view and makes explicit the rational tenets of the Precautionary Principle within an analytical framework as rigorous as uncertainties permit, and one that mirrors democratic values embodied in regulatory, compensatory, and common law. Unlike other formulations that reject risk assessment, this paper argues that risk assessment can be used within the formalism of tradeoff analysis—a more appropriate alternative to traditional cost-benefit analysis and one that satisfies the need for well-grounded public policy decision making. This paper will argue that the precautionary approach is the most appropriate basis for policy, even when large uncertainties do not exist, especially where the fairness of the distributions of costs and benefits of hazardous activities and products are a concern. Furthermore, it will offer an approach to making decisions within an analytic framework, based on equity and justice, to replace the economic paradigm of utilitarian cost-benefit analysis.