香草醛和对羟基苯甲酸对杉木幼苗生理特性的影响

采用盆栽模拟实验 ,研究了不同浓度的香草醛和对羟基苯甲酸对杉木幼苗生理特性的影响 .结果表明 ,当浓度为 10mmol·L-1和 1mmol·L-1时显著抑制了杉木幼苗的叶绿素含量、光合作用、根系活力等生理指标 ,并且随着浓度的增加 ,对生理活性的抑制作用增大 .其中 ,用香草醛处理的杉木幼苗的净光合速率分别降低 37.0 %、2 5 .1% ;蒸腾速率分别降低 37.0 %、2 0 .3% ;气孔导度分别降低 4 6 .8%、33.7% ;根系活力分别降低 78.8%、5 1.6 % .连栽杉木林土壤中积累的香草醛、对羟基苯甲酸等酚类化合物能够对杉木幼苗产生化感作用 ,这是导致连栽杉木生产力降低的一个不可忽视的因素 .     

凤丹(Paeonia ostii T.)自毒物质的检测及其作用机制

药用牡丹的种植中存在明显的连作障碍现象,为探讨其机制,利用已萌发长根的凤丹(Paeonia ostii)种子对凤丹根际土壤和根的水浸提液进行了自毒化感检测;采用高效液相色谱法(HPLC)对种植4a的凤丹根际土壤及其根皮中的化感自毒物质进行了定性和定量分析;在此基础上,利用外源法研究了盆栽凤丹幼苗对5种检出物质(阿魏酸、肉桂酸、香草醛、香豆素和丹皮酚)及其混合物在3种不同浓度下对植株生长的影响和生理响应.结果表明:(1)连续种植4a的凤丹根际土壤和根浸提液对已萌发种子根的生长有显著的抑制作用(p＜0.05),显示凤丹根分泌物具有自毒化感的潜势;(2)HPLC分析表明在凤丹根际土壤中存在5种以上的酚酸类物质 (阿魏酸、肉桂酸、香草醛、香豆素和丹皮酚),其中阿魏酸、肉桂酸、香草醛、香豆素为前人已报道的化感物质;(3)在实验室条件下,所设浓度范围内,5种物质及其混合物对凤丹幼苗的高度、根长及地下和地上生物量均有明显影响,尤其对根长和地下生物量的影响最为明显(p＜0.05),此结果与连作移栽幼苗时,根部首先发黑死亡的现象相一致;(4)凤丹幼苗的根系活力和叶绿素含量在各处理中表现出相似性,即低浓度时根系活力和叶绿素含量高,高浓度时根系活力和叶绿素含量低,低浓度的阿魏酸和香草醛对幼苗根系活力和叶绿素合成有促进作用.此结果显示自毒物质可能是通过影响根系酶活性和叶绿素合成来影响群体中其它个体的生长.本实验的结果显示栽培4a的凤丹土壤水提液具有抑制自身种子根系生长的活性,此提示栽培凤丹连作障碍可能主要与自身分泌到土壤中的酚酸类物质的自毒作用有关.     

香草醛对杉木幼苗养分吸收的影响

 通过模拟实验研究了不同浓度的香草醛对杉木（Cunninghamia lanceolata）幼苗养分吸收和根系活力的影响,结果发现,当浓度为1 mmol·L-1时,香草醛能够显著抑制杉木幼苗对NO－3、NH+4、SO24-及HPO24-离子的吸收和根系活力（p<0.01）,而浓度为1×10-2 mmol·L-1时香草醛却促进了杉木幼苗对HPO24-离子的吸收（p<0.01）。这说明高浓度的香草醛能够通过化感作用对杉木幼苗产生影响,降低杉木幼苗的根系活力,进而减少了杉木幼苗对养分离子的吸收,从而影响了杉木幼苗的生长。     

不同pH的酚酸溶液对杉木及萝卜幼苗生长的影响

通过四因素五水平的二次回归正交旋转试验设计 ,研究 pH值、肉桂酸、对羟基苯甲酸、香草醛四个因素对杉木和萝卜幼苗生长的影响。结果表明 ,杉木幼苗的鲜重生长随酚酸溶液的pH值的增大而增加 ,而随肉桂酸、对羟基苯甲酸和香草醛浓度的增大而减小。比较 3种不同酚类物质对杉木幼苗生长的影响 ,肉桂酸对杉木幼苗生长的影响 >对羟基苯甲酸 >香草醛 ,且 pH值与肉桂酸之间 ;肉桂酸与香草醛之间 ;对羟基苯甲酸与香草醛之间的交互作用都达到显著水平。萝卜幼苗生长对不同pH的酚酸溶液的反应与杉木幼苗相类似 ,随酚酸溶液的pH值的增大而增加 ,而随肉桂酸、对羟基苯甲酸和香草醛浓度的增大而减小。但对羟基苯甲酸对萝卜幼苗生长的影响 >肉桂酸 >香草醛 ,酚酸溶液的 pH值与所有 3种酚酸之间的交互作用都达到显著水平 ;肉桂酸与香草醛的交互作用对萝卜幼苗生长的影响也达到F0 0 1水平显著。     

土壤不同镉水平对马缨丹生长及其抗氧化酶活性的影响

采用盆栽试验方法,分别设置0(对照,不添加镉)、30、60、90、120、150、180、210mg·kg-1共8个土壤镉处理水平,研究土壤不同镉水平对马缨丹(Lantana comara L.)生长及其抗氧化酶活性的影响,以探讨马缨丹对镉胁迫的生理响应机制。结果显示:(1)随着土壤镉处理浓度的升高,马缨丹干重呈先升高后降低的趋势,30mg·kg-1镉处理能促进植株的生长,而浓度高于60mg·kg-1时显著抑制马缨丹的生长。(2)马缨丹叶片和根系中O-·2产生速率、H2O2和MDA含量及电解质渗漏率均随土壤镉处理浓度的升高和胁迫时间的延长逐渐升高,胁迫90d时,叶片和根系中O-·2产生速率、H2O2和MDA含量及电解质渗漏率分别在镉浓度高于60和30mg·kg-1时显著低于对照。(3)叶片和根系抗氧化酶SOD、POD、APX和CAT活性随着土壤镉处理浓度的增加大体呈先升高后降低的趋势,并在镉浓度分别高于90和60mg·kg-1时,叶片和根系抗氧化酶活性显著低于对照。研究表明,低浓度镉处理土壤能促进马缨丹植株生长,而高浓度镉处理土壤显著降低了马缨丹体内抗氧化酶活性,导致活性氧大量积累,引起严重的膜脂过氧化伤害,从而显著抑制马缨丹植株的生长。     

外源毒素对林地土壤养分的影响

杉木 (Ｃｕｎｎｉｎｇｈａｍｉａｌａｎｃｅｏｌａｔａ)人工林连栽导致地力退化是一个不争的事实[5] 。近年来许多研究表明 ,杉木连栽后的地力退化与植物化感作用有关[8,12 ,15,16] 。香草醛、对羟基苯甲酸是土壤中毒物质 ,早在 2 0世纪 6 0年代周崇莲等人在研究杉木连栽土壤氧化代谢能力时发现三耕土中香草醛的氧化代谢能力比头耕土高 ,为头耕土的 143% ,这证明三耕土中含有较多的土壤中毒物质[3 ] 。马越强等人的研究表明酚醛类化感物质会影响杉木种子发芽、幼苗生长和光合效率[1] ,Ｈｕａｎｇ等[12 ] 发现杉木根系水浸液中含有香草醛和对…     

茄子自毒物质对辣椒种子萌发及枯萎菌的化感效应

运用模拟的方式,采用生物测定和室内培养的方法,研究了两种茄子自毒物质香草醛和肉桂酸各浓度对辣椒种子萌发和幼苗生长的化感效应,及其对辣椒枯萎菌菌丝生长的影响.结果表明:这两种自毒物质对辣椒种子萌发和幼苗生长具有低浓度促进,高浓度抑制的化感效应.香草醛和肉桂酸对辣椒和茄子种子的化感效应存在较大差异,辣椒种子受这两种自毒物质的抑制强度明显弱于茄子种子.香草醛和肉桂酸对辣椒枯萎菌菌丝生长表现为各浓度(0.1, 0.5, 1, 4mmol/L)下均具有抑制作用,作用强度随着浓度增加而增强,肉桂酸低浓度时对菌丝生长的抑制作用即达到显著水平.     

阿魏酸和肉桂酸对杉木种子发芽的效应

杉木〔Ｃｕｎｎｉｎｇｈａｍｉａｌａｎｃｅｏｌａｔａ (Ｌａｍｂ .)Ｈｏｏｋ .〕连栽导致地力衰退问题 ,国内大多从提高土壤肥力和完善栽培制度方面进行研究[1 ] ,对化感自毒物质的毒害作用却注意不够。据报道杉木根桩与周围土壤酚类物质对杉木存在自毒作用[2 ] ,但除酚剂 (乙烯吡咯啉酮Ｋ30 0 )能降低杉木及其林下土壤的这种自毒作用[3 ] ,这暗示杉木叶、根等器官中含有酚类化感物质 ;香草醛 (ｖａｎｉｌｌｉｎ)对杉木幼苗生长也具有毒害作用[4] 。阿魏酸 (ｆｅｒｕｌｉｃａｃｉｄ)、肉桂酸 (ｃｉｎｎａｍｉｃａｃｉｄ)和香草醛同属于化感…     

酚类物质对杉木幼苗15N养分吸收、分配的影响

 应用15N同位素示踪技术,通过盆栽实验研究了香草醛和对羟基苯甲酸对杉木（Cunninghamia lanceolata）幼苗N素养分吸收、分配的影响,结果发现香草醛及其与对羟基苯甲酸的混合物（浓度比1∶1）明显抑制了杉木幼苗的生长和对15NO3-离子的吸收,10 mmol·L-1的香草醛使杉木幼苗根、茎、叶生物量分别下降了25.3%、13.5%、5.7%,15N吸收量分别减少了38.5%、48.1%、46.5%;10 mmol·L-1的混合物使杉木幼苗根、茎、叶生物量分别下降了33.5%、36.0%、21     

硒镉处理对萝卜硒镉吸收的影响及其交互作用

采用盆栽试验的方法,研究不同含量的硒、镉单一和复合作用对萝卜生长及其对硒、镉吸收的影响。结果表明:适量的硒(2.5~5.0 mg·kg-1)可以促进萝卜的生长,表现为萝卜发芽率提高43%、叶片SPAD值提高22%、生物量增加50%;镉单一污染时,镉显著抑制萝卜的生长(P0.05);土壤中硒的浓度低于1.5 mg·kg-1时对镉含量5.0 mg·kg-1具有拮抗作用,同时可以促进萝卜的生长;萝卜中硒的浓度随着土壤中硒的添加量的增加而增加,对硒的富集效果明显,且地下部分对硒的吸收能力大于地上部分;土壤中硒浓度5.0 mg·kg-1时,5.0 mg·kg-1镉的存在不影响萝卜对硒的吸收;当土壤中硒的浓度为5.0~10.0 mg·kg-1时,镉的存在虽然影响萝卜对硒的吸收,但萝卜中硒的含量仍处于稳定积累状态;而当土壤中硒浓度≥10.0 mg·kg-1时,镉的存在会抑制萝卜对硒的吸收,且这种作用表现为地上部分强于地下部分;硒能显著降低萝卜对镉的吸收,且这种作用表现为地下部分强于地上部分。因此,在轻度镉污染的土壤中种植富硒萝卜,既能生产营养安全的富硒食品,又可实现污染农田的再利用。     

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.