高温胁迫对14C—水杨酸在葡萄苗中运转分配的影响

用38度高温和27度正常温度分别处理14C－SA标记的葡萄幼苗叶片1,3,6,12h,发现常温下14C－SA向外运转的很少,而高温下向外运转的更少。高温处理和常温对照的14C－SA都既向上运输又向下运输,以向下运输为主,但无向上运输还是向下运输,高温下要比常温下运输的少一些,在常温下1,3,6h,14C-SA以根系分配的最多,12h以茎中分配最多,而在高温处理下1,3h以根中分配最多,6,12h则以茎中分配最多。高温处理和常温对照下都对离引入叶越近的茎段和叶片（除引入叶）,14C－SA含量越高。     

高温胁迫对14C-水杨酸在葡萄苗中运转分配的影响

用38℃高温和27℃正常温度分别处理14C-SA标记的葡萄幼苗叶片1,3,6,12h,发现常温下14C-SA向外运转的很少,而高温下向外运转的更少。高温处 理和常温对照的14C-SA都既向上运输又向下运输,以向下运输为主,但无论向上运输还是向下运输,高温下要比常温下运输的少一些。在常温下1,3,6h,14C-SA 以根系分配的最多,12h以茎中分配最多,而在高温处理下1,3h以根中分配最多,6,12h则以茎中分配最多。高温处理和常温对照下都是离引入叶越近的茎 段和叶片(除引入叶),14C-SA含量越高。     

不同高温胁迫对白桦幼苗几个生理生化指标和电阻抗图谱参数的影响

以白桦1年生实生苗为试材,分别用37℃与42℃高温处理2、4、8、12、24 h,以常温处理(白天25℃、12 h/夜间15℃、12 h)苗木为对照,对其叶片叶绿素含量、根系活力、可溶性糖含量、超氧化物歧化酶(SOD)活性、超氧阴离子(O·-2)含量、丙二醛(MDA)含量、蛋白质含量和电阻抗进行测定,研究其抗热性.结果表明:37℃处理的叶片中叶绿素含量低于对照,SOD活性和MDA含量高于对照;42℃处理的叶片中叶绿素含量、根系活力、可溶性蛋白含量、MDA含量和弛豫时间τ低于对照,SOD含量和胞外电阻(re)高于对照;并且42℃处理的叶片中叶绿素、可溶性糖、SOD活性高于37℃处理,而可溶性蛋白、(O·-2)、MDA含量和根系活力较37℃处理低.37℃下,胞内电阻(ri)与MDA含量呈显著正相关(r=0.68),β系数与可溶性糖含量呈显著负相关(r=-0.75),胞内电阻(ri)与可溶性蛋白含量呈显著正相关(r=0.75);42℃下,胞外电阻(re)与可溶性糖含量成显著正相关(r=0.91),胞内电阻(ri)与SOD活性成显著负相关(r=-0.51).37℃与42℃处理下的电阻抗图谱参数差异显著,胞外电阻(re)、胞内电阻(ri)、弛豫时间τ和β系数变化规律不一致.研究发现,42℃是高温胁迫下诱导白桦幼苗抗热性的更理想条件;用电阻抗图谱法研究白桦幼苗的抗热性是可行的.     

局部灼伤对小麦幼苗外源茉莉酸吸收与运转的影响

采用示踪技术探索了3H-JA的运输和分配规律及其受伤害胁迫的影响.外源3H-JA能够在小麦幼苗体内向上和向下运输,局部灼伤其运输与分配都发生了改变.从小麦根系饲喂的3H-JA,在植株内的分布量依序为根＞茎＞叶,时间较长(4h)时分配于心叶的3H-JA大大增加.当叶片受到局部灼伤时3H-JA向地上部的输出量减少;但局部灼伤可加快由心叶饲喂的3H-JA的向下运输,改变3H-JA在小麦幼苗各部位的分配比率.心叶饲喂短时间(5min)时,3H-JA主要积累在受到伤胁迫的展开叶(第2叶)中.向展开叶(第2叶)饲喂的3H-JA向下运输的速率高于向上运输的速率.推测JA运输及分配的变化可能在植株的防御反应中起重要作用.     

紫茎泽兰茎和叶片色素及叶绿素荧光相关参数对不同温度处理的响应差异

通过人工模拟低温(12 ℃)、常温(25 ℃)、高温(35 ℃)生境,对紫茎泽兰茎和叶片色素(叶绿素a,b,类胡萝卜素,花青素)含量和组成、叶绿素荧光参数包括最大荧光效率Fv/Fm、光系统II效率ФpsⅡ、光化学淬灭系数qP、非光化学淬灭系数NPQ、热耗散速率HDR进行了动态测定.结果表明:在低温和高温胁迫处理过程中,茎和叶片的色素含量和组成随时间变化趋势基本一致,但茎的变化幅度明显低于叶片.与此类似,茎和叶片叶绿素荧光参数在不同温度处理过程中的变化趋势一致,但是茎各指标的变化幅度普遍小于相应叶片的变化幅度:低温下,茎的ФpsⅡ和ETR较对照最大降低44%,而叶片降低超过60%;高温下,茎的ФpsⅡ和ETR较对照下降16%～57%;而叶片则下降50%～80%.其产生原因在于:在温度胁迫条件下,叶片获取光能用于光化学过程的份额(qP)大幅下降,用于热耗散的份额(NPQ)大幅上升,茎的情况相反,所获取光能用于光化学电子传递的份额较常温下更多、用于热耗散的减少,这使得茎的耗散速率(HDR)升高的幅度显著低于叶片的升高幅度(p<0 05).综合3个温度的测定结果,茎的叶绿素含量相当于叶片的1/3～1/6,茎的叶绿素a/b较叶片低20%左右,但是光合电子传导速率ETR与叶片相当,这使得茎的光合色素利用效率ETR/Chl远高于叶片.叶片和茎叶绿素荧光参数在不同温度处理下变化趋势一致、但叶片的变化幅度远大于茎的这一响应差异,使得在适宜温度下紫茎泽兰叶片光合对整体光合贡献增大,而在温度胁迫条件下茎的光合贡献增大,这种策略使得这一植物在适宜生境下通过叶片光合、快速生长迅速占据生境,而在逆境条件下茎等非同化器官光合贡献增加,有利于其在逆境中的保存.     

低温胁迫下西番莲叶片的生理反应及超微结构变化

以西番莲扦插苗为实验材料,比较预冷处理和常温处理(对照)情况下,西番莲叶片对-6℃低温胁迫的生理反应及叶肉细胞的超微结构变化,以探讨预冷处理对西番莲的抗寒作用及其机理。结果显示:(1)常温处理组在-6℃低温胁迫处理后,西番莲叶片的质膜相对透性、MDA含量随着低温处理时间的延长而逐渐增加,而预冷处理组这两个指标在处理期间都比常温处理组低;(2)常温处理组叶片H2O2含量在48h时达到峰值后出现下降,而预冷处理组的H2O2含量都低于对照,在48h时对照的H2O2含量比预冷锻炼的高1.14倍;(3)常温处理组的脯氨酸含量在24h内增加以后出现下降,而预冷处理组在处理期间逐渐增加且高于对照;(4)常温处理组的POD活性在12h时最高,CAT、SOD活性在24h时最高,以后出现下降。预冷处理组提高了3个酶的活性,其中POD在12h时是对照的2.73倍,CAT、SOD活性在24h时比对照分别提高18.7%和42.7%。(5)超微结构研究显示,预冷处理组在低温胁迫72h时虽出现叶绿体片层肿胀、核膜消失、质膜内陷等症状,但叶绿体伤害症状轻于常温处理。研究表明,低温预冷处理能够提高西番莲的抗寒性。     

水杨酸对高温胁迫下半夏幼苗内源激素含量的影响

以半夏37℃高温倒苗过程中的叶片和块茎为材料,考察了不同浓度外源水杨酸(SA)处理的倒苗率,采用ELISA方法研究了0.5 mmol/L外源SA对半夏叶片和块茎中内源激素GA3、IAA、ABA、ZR和JA含量的影响.结果表明:随着高温胁迫时间的延长,半夏出现倒苗现象,并以0.5 mmol/L的SA处理后半夏倒苗率最低.倒苗过程中叶片和块茎中GA3、IAA、ZR含量逐渐下降.而ABA和JA含量显著上升.0.5 mmol/L SA处理条件下叶片中生长促进类激素GA3、IAA、ZR含量高于同期对照,生长抑制类激素ABA和JA含量低于同期对照;块茎中ABA、IAA和JA的含量低于同期对照.GA变化不明显,而ZR处理前期低于对照,后期高于对照.可见,一定浓度的外源SA可通过改变高温胁迫下半夏内源激素水平来促进其生长,延缓其倒苗.     

局部灼伤对小麦幼苗外源茉莉酸吸收与运转的影响

采用示踪技术探索了3H－JA的运输和分配规律及其受伤害胁迫的影响,外源3H－JA能够在小麦幼苗体内向上和向下运输,局部灼伤其运输与分配都发生了改变,从小麦根系饲喂的3H－JA,在植株内的分布量依序为根＞茎＞叶,时间较长（4h)时分配于心叶的3H0JA大大增加,当叶片受到局部灼伤时3H－JA向地上部的输出量减少,但局部灼伤可加快由心叶饲喂的3H－JA的向下运输,改变3H－JA在小麦幼苗各部位的分配比率。心叶饲喂短时间（5min)时,3H－JA主要积累在受到伤胁迫的展开叶（第2叶）中,向展开叶（第2叶）饲喂 的3H－JA向下运输的速率高于向上运输的速率。推测JA运输及分配的变化可能在植株的防御反应中起重要作用。     

高、低温胁迫对牡丹叶片PSⅡ功能和生理特性的影响

以牡丹‘肉芙蓉’离体叶片为试材,以25 ℃为对照,研究了强光(1400 μmol·m-2·s-1)下高温(40℃)和低温(15℃)处理对牡丹叶片PSⅡ光化学活性和生理特性的影响.结果表明:随处理时间的延长,各处理叶片的PSⅡ最大光化学效率(Fv/Fm)、PSⅡ实际光量子效率(φPsⅡ)和光下开放的PSⅡ反应中心激发能捕获效率(Fv’/Fm’)均持续降低.暗恢复4h后,对照和15℃处理叶片的Fv/Fm基本上完全恢复,而40℃处理叶片仅恢复到处理前的75.5％,即使15 h后也不能完全恢复;强光下40℃处理使PSⅠ和PSⅡ间的激发能分配严重偏离平衡状态.强光下40 ℃处理抑制了超氧化物歧化酶活性,加剧了O2、H2O2、丙二醛的产生,导致叶绿素和可溶性蛋白含量不断下降.说明强光下40℃高温胁迫对牡丹叶片光合机构造成了不可逆的破坏,而15℃低温处理对其光合机构的影响相对较弱.     

短期夜间低温后番茄光合作用及叶绿体超微结构的恢复效应

为明确短期夜间低温后番茄光合作用在常温下的恢复效应,研究了番茄幼苗经夜间15 ℃（对照）、12 ℃、9 ℃和6 ℃处理7 d后植株光合作用和叶绿体超微结构的变化.结果表明：短期夜间低温处理有利于恢复期番茄叶片的光合作用;12 ℃和9 ℃处理叶片叶绿素含量均可恢复至对照水平,6 ℃处理叶绿素含量则不可恢复;夜间低温处理并未严重抑制叶片气孔的形成,相反刺激了恢复期叶片气孔的形成与发育;6 ℃处理后叶绿体基粒片层排列较松散,片层数减少.恢复7 d时,夜间处理温度越低,叶绿体中淀粉粒越小、数量越少,基粒片层排列越整齐致密.另外,短期夜间低温处理促进了番茄植株叶片在恢复期的光合产物运输.     

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.