硅对受土壤中镉污染的白菜生长和抗胁迫能力的影响

在土培盆栽条件下,硅可提高白菜的地上部鲜重和茎鲜重,但根鲜重下降,叶鲜重略有下降。硅可抑制白菜吸收镉,在0.3、0.6、1.2mg·kg~(-1)镉水平下,施硅可显著降低白菜地上部的镉含量,并在一定程度上提高叶中过氧化物酶(POD)活性,但降低超氧化物歧化酶(SOD)活性。0.5、1.0 g·kg~(-1)硅可提高白菜的叶绿素含量和过氧化氢酶(CAT)活性,降低叶细胞膜透性,从而提高其对镉胁迫的耐受力。较高的硅浓度对植物有一定的毒性,叶绿素含量和CAT活性都下降,细胞膜透性也增加。     

亚硒酸钠和硒酸钠对小白菜生长生理特性的影响

以小白菜品种'秦白2号'为材料,采用盆栽试验研究了不同浓度亚硒酸钠[Se(IV)]和硒酸钠[Se(VI)]胁迫对小白菜生长生理特性的影响及其生理机制,为土壤硒污染修复及其合理开发利用提供理论依据.结果表明,Se(IV)≤10.0 mg·kg-1时,小白菜的叶长、叶宽显著下降,而生物量没有受到显著影响;Se(VI)≤1.0 mg·kg-1时,叶长、叶宽、生物量没有显著变化;更高浓度处理时,叶长、叶宽、生物量均随外源Se(IV)和Se(VI)处理浓度的增大而急速下降.Se(IV)≤40.0 mg·kg-1和Se(VI)≤20.0 mg·kg-1处理均对小白菜叶片叶绿素含量无显著影响,但更高浓度外源Se(IV)和Se(VI)却显著抑制了叶绿素合成.低浓度外源Se(IV)和Se(VI)均使小白菜叶片谷胱甘肽过氧化物酶(GSH-Px)活性上升,膜质过氧化物(MDA)含量下降,对超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性及脯氨酸含量无显著影响;高浓度硒使MDA含量、脯氨酸含量及SOD活性上升,而使GSH-Px活性和CAT活性下降;外源Se(IV)和Se(VI)均使过氧化物酶(POD)活性降低.研究发现,低浓度外源Se(IV)和Se(VI)均提高了小白菜的抗氧化作用,从而促进小白菜叶片叶绿素的合成和生长,高浓度时则相反;低浓度硒的抗氧化作用和高浓度硒的过氧化作用均以Se(VI)大于Se(IV).说明硒酸钠的有效性和毒害作用均大于亚硒酸钠.     

芘对小白菜幼苗生长和一些生理生化指标的影响

采用土培方法探讨芘对小白菜幼苗生长和若干生理生化指标影响的结果表明:芘对小白菜种子发芽率无影响,对幼苗株高、根长和叶面积显著抑制;芘处理的小白菜幼苗叶内叶绿素a、叶绿素b、叶绿素a b和类胡萝卜素含量显著下降;而丙二醛(MDA)含量和细胞质膜透性则显著提高,且质膜透性随着芘浓度的增加呈现升高一下降一升高的趋势;高浓度芘处理的小白菜幼苗叶内脯氨酸含量和过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)活性均极显著提高.     

模拟酸雨和铜复合污染对白花泡桐生理特性的影响及其解毒机制

采用盆栽方法,研究了模拟酸雨(pH分别为4.0、5.0)和Cu(0～200mg·kg-1)复合污染对白花泡桐生理特性的影响及其解毒机制.结果表明:未加Cu处理时,不同酸雨处理间,白花泡桐的叶绿素、类胡萝卜素、超氧阴离子、过氧化氢和丙二醛含量均差异不显著;100和200mg·kg-1Cu处理时,pH4.0处理的叶绿素和类胡萝卜素含量显著低于,而超氧阴离子、过氧化氢和丙二醛含量显著高于pH5.0处理.Cu处理的叶绿素a/b值明显高于未加Cu处理.随着酸雨酸度增加,叶片铜含量明显减少,而根部铜含量明显增加.pH5.0时,随Cu浓度增加,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性均持续增强,植物络合素和谷胱甘肽(GSH)总量均明显增加;而在pH4.0时,SOD、POD、CAT和APX活性呈先升后降,而GSH总量在Cu浓度为200mg·kg-1时明显下降.模拟酸雨加剧了高浓度Cu对白花泡桐的氧化胁迫.     

铜胁迫下链格孢菌对白车轴草生理生化特性的影响

通过盆栽实验研究了Cu胁迫下接种链格孢菌(AlternariatenuisNees)对源自Cu污染区(记作种群Ⅰ)和非污染区(记作种群Ⅱ)白车轴草(TrifoliumrepensL)生理生化特性的影响。结果表明,两种群白车轴草在Cu处理后接种链格孢菌,0~1500mg·kg-1时叶片电导率、MDA含量均高于未接种组,且随浓度增加而升高,2000mg·kg-1时电导率低于未接种组,MDA含量降低但仍高于未接种组。两种群接种后叶绿素、蛋白质含量较未接种组下降,且随Cu浓度增加而降低,其中叶绿素含量与浓度呈显著或极显著负相关,种群Ⅰ和种群Ⅱ相关系数分别为-0.954*和-0.961**。链格孢菌使白车轴草SOD活性低浓度(0和500mg·kg-1)高于未接种组,高浓度则降低。接种后POD活性随Cu浓度增加先增后减,500mg·kg-1浓度下接种组POD高于未接种组,而在其他浓度下,显著低于未接种组。0~1000mg·kg-1时接种组CAT活性高于未接种组,随土壤Cu浓度增加先增后减。3种保护酶对胁迫的敏感性为POD>SOD>CAT。高浓度Cu(2000mg·kg-1)胁迫下,白车轴草保护酶系统的受损打破了体内活性氧产生与清除之间的正常平衡状态,积累了过量的活性氧,膜脂过氧化程度加重,对白车轴草产生毒害,且这种毒害在接种链格孢菌后表现更为严重。两种群白车轴草相比,种群Ⅰ植物在土壤Cu<2000mg·kg-1时可生存,感染链格孢菌后生长土壤Cu浓度应控制在1500mg·kg-1以内;种群Ⅱ在Cu胁迫浓度不超过1500mg·kg-1,链格孢菌和Cu双重胁迫时不超过1000mg·kg-1可生长。种群Ⅰ在Cu处理、链格孢菌单一或双重胁迫下表现的抗逆性较Ⅱ强。     

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。     

氯化胆碱对盐胁迫黄瓜幼苗渗透调节物质及活性氧代谢系统的影响

以盐敏感型黄瓜品种津春4号为材料,采用水培方法研究了叶面喷施不同浓度(0.5、1.0和1.5 mmol·L-1)氯化胆碱(CC)对NaCl胁迫(75 mmol·L-1)下黄瓜幼苗鲜重、叶片叶绿素、渗透调节物质含量及活性氧代谢系统的影响.结果表明:(1)单独CC处理可提高黄瓜叶片的叶绿素、可溶性糖和可溶性蛋白含量以及过氧化氢酶(CAT)与过氧化物酶(POD)活性,降低O2·-产生速率,但对植株鲜重及超氧化物岐化酶(SOD)活性影响不大;(2)NaCl胁迫处理增加了黄瓜幼苗叶片中可溶性糖和可溶性蛋白含量,增强了SOD、POD和CAT活性,提高了O2·-产生速率及丙二醛(MDA)的含量,但同时降低了叶绿素含量与植株鲜重;(3)盐胁迫前CC预处理可缓解黄瓜幼苗叶绿素含量和植株鲜重的下降、以及MDA含量和O2·-产生速率的上升趋势,且进一步提高了盐胁迫下黄瓜叶片中SOD、POD和CAT活性.因此,适宜浓度的氯化胆碱可显著提高盐胁迫下黄瓜叶片的抗氧化酶活性,提高清除活性氧的能力,缓解盐胁迫对黄瓜幼苗细胞膜的伤害,增强黄瓜幼苗的耐盐性.     

菇床废料对设施栽培土壤盐害下小白菜生长的影响

通过盆栽试验,研究了菇床废料对缓解设施栽培土壤次生盐渍化及小白菜盐胁迫的影响.结果表明:盐渍化土壤添加菇床废料(0～30 g·kg-1)栽培60 d后,土壤pH趋于中性,有机质和有效磷含量显著提高,水溶性盐总量的增加幅度小于不加菇床废料的对照土壤;当菇床废料添加量为10 g·kg-1时,土壤盐分增加幅度最小,说明适量添加菇床废料可以减少设施栽培土壤的盐分积累.加入菇床废料后,小白菜的种子发芽率、株高、鲜质量、叶绿素SPAD值和维生素C含量均有所提高,脯氨酸含量显著下降,说明菇床废料能改善小白菜生长环境,有效缓解盐胁迫对小白菜的危害.     

铬、硒对水稻幼苗生长和生理的影响

以单一铬(Cr6+0～200μmol·L1)及硒(Se0～200μmol·L1)、铬硒混合液(铬100μmol·L1,硒50μmol·L1)处理水稻幼苗,研究不同处理和浓度对水稻幼苗生长和生理特性影响。结果表明(1)单一铬处理,随着铬浓度增加,植株生长明显受到抑制,铬毒害表现为株高、鲜重和干重受抑制,叶片黄色、叶绿素含量下降,体内SOD、CAT活性下降,POD活性上升,膜透性增大;(2)单一硒处理,50μmol·L1促进植株生长,100μmol·L1和200μmol·L1则抑制植株生长;(3)铬硒混合处理结果反映,硒有减轻水稻铬毒害的作用,表现为:减轻铬胁迫对株高、鲜重和干重增加的抑制,提高叶绿素含量,提高SOD、CAT活性,降低POD活性和膜透性。     

镉胁迫下红树植物木榄幼苗的生理生化特性

用含CdCl2的Hoagland营养液处理了沙培中的木榄(Bruguiera gymnorrhiza)幼苗.2个月后对幼苗丙二醛(MDA)、叶绿素含量、过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性及其同工酶进行分析.结果表明,镉引起幼苗膜质过氧化,导致总叶绿素含量显著下降.镉主要影响迁移率大的阴离子型POD同工酶的活性.1 mmol·L-1镉显著抑制根中2条CAT同工酶RC-1和RC-2的活性.木榄根CAT和叶POD同工酶分析可作为红树林镉污染的监测手段之一.     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.