纳米TiO_2对杉木种子萌发和幼苗生长及生理的影响

本文以杉木种子和纳米TiO_2为实验材料,研究不同浓度(50、100、500、1000 mg·L-1)纳米TiO_2溶液对杉木种子萌发、幼苗生长及生理特性的影响,探究纳米材料对林木种子萌发及幼苗生长发育的调节作用。结果显示:纳米TiO_2溶液对杉木种子发芽率、发芽势、发芽指数、活力指数均有促进作用,促进作用随处理浓度的增加呈现先增强后减弱的趋势,且100 mg·L~(-1)溶液处理对种子发芽指标提高效果最佳,分别比对照增加66%、92%、71%和299%;杉木幼苗的鲜重和根长均在100 mg·L~(-1)时达到最大值,分别比对照显著增加35%和143%。500 mg·L~(-1)纳米TiO_2溶液处理显著提高了CAT、SOD和POD活性,分别比对照提高108%、488%、182%,但降低了MDA含量(降低82%)。研究表明,适当浓度纳米TiO_2溶液处理不但能有效促进杉木种子萌发与幼苗生长,而且能改善幼苗的生理功能,可能会增强其对逆境的适应能力。     

Flor-essence对小麦种子萌发和幼苗生长的影响

研究不同浓度Flor-essence对小麦种子萌发及幼苗生长的影响,以开拓其在植物生长调节剂领域的新应用。通过室内水培试验,分别设定50、100、150、200和250 mg/L 5组不同浓度的Flor-essence溶液处理,测定小麦种子发芽和植株生长的相关指标,同时选取清水(0 mg/L Flor-essence)和0.015 mg/L的油菜素内酯(BR)作对照。结果显示,与对照相比,不同浓度Floressence浸种均促进了小麦种子的萌发和生长,小麦的发芽势、发芽率、发芽指数、根长、株高、鲜重、干重、叶绿素含量和根冠比均有不同程度提高。不同浓度处理中,以200和250 mg/L处理的幼苗发芽情况最好;以150 mg/L处理的株高最高;以200 mg/L处理的根长最长、根冠比最大;以250 mg/L处理的鲜重、干重和叶绿素含量最高。利用Flor-essence浸种可促进小麦种子萌发和幼苗生长,且浓度为150-250 mg/L Flor-essence更能够在不同程度上促进小麦苗期的生长。     

侧柏不同器官水提取物对油松种子萌发和幼苗生长的他感效应

研究了侧柏（Platycladus orientalis）根、枝、叶、果实不同浓度水提取物及枝叶挥发油对油松种子萌发和幼苗生长的他感效应。结果表明：侧柏各器官及挥发油都含有化感物质,均对油松种子萌发及幼苗生长表现出“高抑低促”效应,而且低浓度时的促进作用明显强于高浓度时的抑制作用。与对照相比,在浓度为2 mg·mL^-1时,侧柏根水提取物对油松幼苗根长和鲜重的促进能力最强,其根长和鲜重分别比对照提高了79.78%和376.60%;侧柏叶水提取物对油松幼苗苗高促进能力最强,比对照提高了102.41%;侧柏枝水提取物对油松种子发芽的促进能力最强,发芽率比对照提高了65.63%。而在浓度为30 mg·mL^-1时,除了侧柏根和枝水提取物对油松种子萌发（87.50%）和鲜重（85.11%）表现出明显的抑制作用外,其它提取物对油松幼苗根长和苗高生长的抑制作用均不明显。侧柏枝叶挥发油对油松种子萌发,幼苗生长均表现为促进作用,特别对油松种子萌发具有显著的促进作用,其促进率达70.37%。说明侧柏和油松混交,可能有利于油松树木生长及生产力的提高。     

外源甲醇对油菜种子萌发和幼苗生长的影响

以中国南、北2个主要栽培品种‘玉油二号’和‘秦油二号’油菜种子为供试材料,采用溶液培养方法研究了0~2 000mmol·L-1甲醇溶液处理下,油菜种子萌发、幼苗生长特征及其相关生理生化指标的变化。结果表明:(1)10~1 000mmol·L-1甲醇处理的油菜种子萌发指标(发芽率、发芽势、发芽指数、活力指数)和幼苗生长指标(幼芽及幼根长度、鲜重、根冠比)均比对照显著增加,而甲醇溶液浓度为2 000mmol·L-1时油菜种子萌发和幼苗生长受到显著抑制;两个油菜品种种子萌发和幼苗生长在甲醇溶液处理下均表现为相同的变化趋势,但也存在品种的差异,‘秦油二号’生长受影响程度低于‘玉油二号’。(2)随着甲醇溶液浓度的增加,油菜种子萌发指标和幼苗生长指标表现出先增加后降低的趋势,并在甲醇溶液浓度为100mmol·L-1时均达到最大值,继续高于此浓度后促进作用即减弱以至消失,甚至产生抑制作用。(3)随着甲醇处理溶液浓度的增加,油菜幼苗叶片的叶绿素含量呈先增后降的趋势,而同期叶片的MDA和过氧化氢含量却呈先降后升的相反趋势,且均在相同的100mmol·L-1浓度下分别达到最大或者最低值。研究认为,适宜浓度的甲醇溶液能够促进油菜种子萌发和幼苗生长。     

磷、铜及其相互作用对三叶草种子萌发与幼苗生长的影响

通过水培实验研究了施加P对Cu2 胁迫下三叶草种子萌发活力、幼苗生物量、光合色素含量以及电导率的影响.重金属Cu2 (0～20mg·L-1)显著抑制了三叶草种子萌发和幼苗生长.但当施加0.06%的P后,明显提高了cu2 胁迫下的三叶草种子萌发率,促进了幼苗的生长,生物量、光合色素含量显著增加,同时幼苗叶片细胞膜透性极显著下降.可见,外施一定量P能缓解过量Cu2 对三叶草的毒害.     

青霉素对老化香瓜种子萌发和酶活性的影响

以人工老化的香瓜种子为材料,用浸种预处理的方法,研究不同浓度青霉素对老化香瓜种子萌发及酶活性的生理生化效应,摸索了种子吸涨时间,萌发时间,萌发率,可溶性糖,可溶性蛋白含量及POD和SOD活性随青霉素浓度变化的特点和规律,结果表明：200～300mg/L青霉素可显著促进种子吸胀,缩短萌发时间：300～400mg/L青霉素处理可显著提高发芽率,发芽率和发芽指数的提高均达到极显著水平;300mg/L浓度对膜系统的稳定性最强,300～400mg/L浓度范围内,SOD,POD活性最高,故300mg/L青霉素是促进老化香瓜种子萌发和幼苗生长的最佳处理浓度。     

CdCl2对豌豆种子萌发和幼苗生长的影响

以豌豆为实验材料,采用水培方法研究了Cd2 单盐胁迫对豌豆种子萌发与生长的影响。结果显示:(1)Cd2 质量浓度≤1 mg/L时,促进种子萌发,Cd2 质量浓度达到5 mg/L时抑制种子的萌发。(2)随Cd2 质量浓度的增加Cd2 对幼苗根生长的抑制作用逐渐增强;Cd2 质量浓度≤5 mg/L时,促进茎的生长,≥10 mg/L时,抑制茎的生长;且Cd2 对幼苗根生长的抑制作用大于茎。(3)低浓度Cd2 能促进幼苗叶绿素合成,当Cd2 质量浓度高于1 mg/L时,则对幼苗叶绿素合成有抑制作用,且随Cd2 质量浓度增加叶绿素含量逐渐下降。(4)Cd2 诱发的胚根细胞核、染色体畸变率随着Cd2 质量浓度增加而增大。(5)过氧化物酶(POD)同工酶的活性随着Cd2 质量浓度升高而明显增强,Cd2 质量浓度为1 mg/L时POD活性最强,但当Cd2 质量浓度达10 mg/L时,POD的灰度值明显下降。     

铅铬胁迫对小麦种子萌发及幼苗脯氨酸含量的影响北大核心CSCD

旨在探讨铅铬胁迫对小麦的毒害效应以及对幼苗脯氨酸的影响。用不同浓度的铅铬溶液处理小麦,研究铅铬单一及复合胁迫对小麦种子萌发及幼苗脯氨酸含量的影响。结果表明,铅铬单一及复合胁迫均使得小麦种子萌发率降低,幼苗株高、根长降低,鲜物质量和干物质量减少。铅铬处理1 d后,各处理组小麦体内的脯氨酸含量较对照都有升高,尤其是复合胁迫下100mg/L Pb+100 mg/L Cr处理组,其小麦脯氨酸含量较对照升高了32.81%。铅铬处理3、5和7 d后,100 mg/L Cr、50 mg/L Cr、200mg/L Pb+100 mg/L Cr、100 mg/L Pb+100 mg/L Cr这4个处理组的小麦脯氨酸含量较对照均显著升高,其它各处理组与对照相比差异不显著。铅铬胁迫抑制了小麦种子的萌发和幼苗生长,使得小麦体内脯氨酸含量升高,因此建议脯氨酸含量的变化可以作为监测植物铅铬胁迫的指标之一。     

铅铬胁迫对小麦种子萌发及幼苗脯氨酸含量的影响

旨在探讨铅铬胁迫对小麦的毒害效应以及对幼苗脯氨酸的影响。用不同浓度的铅铬溶液处理小麦,研究铅铬单一及复合胁迫对小麦种子萌发及幼苗脯氨酸含量的影响。结果表明,铅铬单一及复合胁迫均使得小麦种子萌发率降低,幼苗株高、根长降低,鲜物质量和干物质量减少。铅铬处理1 d后,各处理组小麦体内的脯氨酸含量较对照都有升高,尤其是复合胁迫下100mg/L Pb+100 mg/L Cr处理组,其小麦脯氨酸含量较对照升高了32.81%。铅铬处理3、5和7 d后,100 mg/L Cr、50 mg/L Cr、200mg/L Pb+100 mg/L Cr、100 mg/L Pb+100 mg/L Cr这4个处理组的小麦脯氨酸含量较对照均显著升高,其它各处理组与对照相比差异不显著。铅铬胁迫抑制了小麦种子的萌发和幼苗生长,使得小麦体内脯氨酸含量升高,因此建议脯氨酸含量的变化可以作为监测植物铅铬胁迫的指标之一。     

硝酸镧浸种对NaCl胁迫下柳枝稷种子萌发及幼苗生理特性的影响

为探讨镧对NaCl胁迫下柳枝稷种子萌发及幼苗生理特性的影响,该研究以柳枝稷(Panicum virgatum L.)种子为研究材料,通过不同浓度(0、0.05、0.1、0.5和1.0mmol/L)La(NO3)3溶液浸种24h处理后,添加100mmol/L NaCl溶液,以蒸馏水为对照,在种子发芽箱中培养并观察柳枝稷种子萌发和幼苗生长,测定幼苗叶片相对电导率、丙二醛、脯氨酸和叶绿素的含量。结果显示:(1)0.05mmol/L La(NO3)3浸种处理可缓解100mmol/L NaCl对种子发芽的影响。(2)不同处理对幼苗苗长无显著影响,0.1mmol/L La(NO3)3浸种显著增加了幼苗的鲜重和叶面积,当浓度≥0.5mmol/L时根长、根冠比、鲜重和叶面积受到抑制。(3)幼苗叶片相对电导率和脯氨酸含量随La(NO3)3浓度的增加呈先降低后增加的趋势,其中0.05和0.1mmol/L La(NO3)3浸种处理下效果较好,丙二醛含量随La(NO3)3浓度的增加持续降低,但各浓度处理间差异不显著,叶绿素含量在0.05mmol/L La(NO3)3浸种处理下较NaCl处理显著增加,当浓度≥0.5mmol/L随着浸种浓度的增加呈下降趋势。(4)不同指标间发芽势与发芽率、根长和叶绿素含量间呈极显著正相关关系,与根冠比、电导率和脯氨酸含量均呈极显著负相关关系,而与苗长不相关。研究表明,低浓度(0.05mmol/L)La(NO3)3可缓解NaCl胁迫对柳枝稷种子萌发及幼苗生长的影响,而高浓度(1.0mmol/L)的La(NO3)3则会加重NaCl的胁迫危害。     

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.     

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.     

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.     

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.     

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。     

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.