温度对紫色不结球白菜外观和营养品质的影响

以紫色不结球白菜品种‘紫衣’为试验材料,利用人工气候箱,采用盆栽法,研究3个不同温度(5℃、25℃和35℃)条件对紫色不结球白菜叶片颜色和营养品质等指标的影响,为优质紫色不结球白菜设施栽培温度的选择提供依据。结果显示:(1)紫色不结球白菜在受到5℃低温处理时,叶片紫色会随着处理时间的延长而加深,最终呈深紫色;反之,当受到35℃高温时,叶片颜色逐渐变浅,直至叶片呈绿色,该现象与叶片中花青素含量的变化规律一致。(2)与正常25℃相比,紫色不结球白菜叶片中的还原糖、可溶性糖和总糖含量在受到高温胁迫(35℃)后逐渐降低,而在低温(5℃)处理下,先增后减,且高温降低幅度大于低温;可溶性蛋白、还原性抗坏血酸和氨基酸含量也随着高温胁迫的延长而降低,但低温处理下则逐渐增加;抗坏血酸-过氧化物酶活性(APX)、纤维素和硝酸盐含量在高温胁迫下逐渐增加,低温条件下则显著降低。研究发现,不同温度明显影响着紫色不结球白菜叶片紫色深浅,低温促进花青素积累,高温抑制或是加速花青素的降解;低温能促进叶片可溶性蛋白、抗坏血酸和氨基酸等品质指标的积累,同时降低纤维素含量,从而提高紫色不结球白菜的外观和营养品质,高温胁迫则降低以上品质指标。     

淹水胁迫对不结球白菜渗透调节物质含量的影响

以不结球白菜‘新矮青’品种为材料,研究了不同时间(1、3、5、7d)和不同程度(根淹、半淹、全淹)淹水处理及解除淹水恢复生长后叶片内渗透调节物质含量的变化规律。结果表明:(1)在根淹和半淹胁迫处理下,不结球白菜叶片中可溶性糖、可溶性蛋白和游离脯氨酸含量随处理时间的延长呈先上升后下降的趋势;全淹胁迫下,这3种渗透调节物质的含量随处理时间的延长出现不同程度的下降。(2)解除淹水恢复生长7d后,各处理组的不结球白菜叶片中渗透调节物质的含量在短期(1d)淹水下基本恢复正常,在长期淹水条件下未完全恢复;全淹处理组恢复能力较弱,而根淹处理组恢复能力相对较强;可溶性糖的恢复幅度高于可溶性蛋白和游离脯氨酸。     

不结球白菜幼苗对中、碱性钠盐胁迫响应差异性研究

不结球白菜(Brassica campestris ssp. chinensis)是重要的蔬菜作物, 近年来由于不合理的灌溉及栽培方式导致设施土壤次生盐渍化越来越严重, 对蔬菜生产造成不良影响, 盐碱胁迫也会抑制不结球白菜正常生长。以往有关不结球白菜耐盐碱研究更多的是关注中性盐对不结球白菜生长与生理的影响, 而有关碱性盐对不结球白菜生长与生理的研究则较少。本研究通过水培实验, 设置不同的盐碱胁迫处理, 研究不结球白菜对中、碱性钠盐胁迫响应差异机制。研究发现: 同等胁迫浓度下, 相比于中性盐胁迫, 碱性碳酸盐胁迫下不结球白菜幼苗的鲜重、生物量、各个叶绿素a、叶绿素b、类胡萝卜素和总叶绿素含量降低更多。相比也中性盐, 碱性盐对不结球白菜抗氧化系统影响更大, 过氧化物酶(POD)和超氧化物歧化酶(SOD)活性更高MDA含量和质膜透性(MI)值更高, 而过氧化酶(CAT)活性则在碱胁迫下较低。相比于中性盐胁迫, 碱性碳酸盐胁迫下不结球白菜体内脯氨酸和可溶性糖的积累量更高, 对不结球白菜渗透调节系统影响更大。根据实验结果得出, 相比于中性盐胁迫, 碱性碳酸盐胁迫对不结球白菜生长抑制作用更强, 对其生理影响更大。     

不同老化程度的不结球白菜种子活力指标变化及其相关分析

以不结球白菜品种‘高梗白’种子为材料,采用高温(42℃)高湿(相对湿度100%)人工加速老化处理,研究不同老化程度下种子活力指标的变化及其相关性。结果显示:(1)发芽指标(除不正常苗率)和出苗指标均随种子老化程度的加深而显著下降,不正常苗率显著上升。(2)随老化程度的加深,种子中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性显著下降;种子的超氧阴离子(O2.-)产生速率先增高后降低,过氧化氢(H2O2)含量逐渐增加,丙二醛(MDA)含量下降,种子浸出液相对电导率升高;种子的可溶性糖含量、可溶性蛋白含量和脱氢酶活性下降,α-淀粉酶活性先升高后降低。(3)老化种子的发芽势、发芽率、SOD活性、H2O2含量、相对电导率和可溶性糖含量与出苗指标间均存在极显著相关性。研究表明,不结球白菜种子的发芽势、发芽率、SOD活性、H2O2含量和可溶性糖含量随老化程度加深的变化规律一致,且指标间以及与出苗指标均有极显著相关性,可以作为检验不结球白菜种子活力的候选指标。     

低温胁迫对不同倍性不结球白菜生长及生理生化特征的影响

在田间自然低温条件下对二、四倍体不结球白菜的生长特性进行了比较研究,并在光照培养箱中于-5~5℃条件下,分析低温胁迫对它们生理生化特征的影响。结果表明:(1)四倍体不结球白菜的10叶厚、叶柄宽和厚、单株重、单株叶重、叶重/叶柄重及小区产量等农艺性状均显著高于其同源二倍体;(2)随温度的降低,二、四倍体不结球白菜的叶片可溶性蛋白质、可溶性糖及游离脯氨酸等渗透调节物质含量明显上升,电解质外渗率增大,丙二醛(MDA)含量升高,保护酶SOD、POD和CAT活性则先升高后降,而且四倍体材料的渗透调节物质含量和保护酶活性在低温胁迫过程中始终明显高于二倍体,但电解质外渗率和丙二醛含量低于二倍体。研究发现,低温胁迫下渗透调节物质含量升高和保持较高的保护酶活性是四倍体不结球白菜抗寒性强的主要原因。     

根肿病对不结球白菜的生长及生理生化物质和活性氧代谢的影响

以不结球白菜主栽品种‘新夏青2号’和‘新矮青’为试验材料,采用人工气候箱内接种鉴定的方法,研究了感染根肿病对不结球白菜植株幼苗生长、生理生化物质及活性氧代谢的影响。结果显示:(1)与未感病植株(0级)相比,感染根肿病(3级)植株株高、柄长、叶面积及地上部鲜重和叶片中的叶绿素含量均显著降低,根冠比随着感病等级的增大而提高,使幼苗植株生长受到显著抑制,且‘新夏青2号’比‘新矮青’所受抑制程度更强。(2)感病后植株叶片的可溶性蛋白、可溶性糖、游离氨基酸以及叶片、根系中的脯氨酸等渗调物质的含量均比未感病植株显著降低,而叶片和根系中丙二醛(MDA)的含量显著升高,且除游离氨基酸以外‘新夏青2号’感病植株其他渗调物质的升降幅度均大于‘新矮青’。(3)感病植株叶片中硝酸根离子(NO3-)含量、硝酸还原酶(NR)活性和谷氨酰胺合成酶(GS)活性均比未感病(0级)植株降低,直接影响植株的氮素吸收利用能力。(4)植株感病后,叶片和根系中4种抗氧化酶(SOD、POD、CAT和APX)的活性均不同程度降低,且SOD、POD和CAT活性在根系中的降幅大于叶片,而‘新矮青’的感病3级植株根系和叶片中各酶活性的降幅均低于‘新夏青2号’(除叶片中CAT酶活性外)。研究表明,不结球白菜受到根肿病侵染后,各类生理生化物质含量和活性氧代谢均受到影响,膜脂过氧化程度加大,使不结球白菜的光合利用能力、吸收能力、渗透调节能力及抗氧化能力均受到抑制,最终影响植株的整个生长过程;品种‘新矮青’对根肿病的抗性高于‘新夏青2号’;可溶性蛋白、抗氧化酶活性和MDA可以作为不结球白菜早期筛选抗根肿病的生理指标。     

根肿病胁迫下外源SA对不结球白菜抗性诱导和生理生化的影响

以不结球白菜‘新矮青’为试验材料,采用菌土接种法接种根肿病菌,研究不同浓度(0.2~0.8mmol·L~(-1))的外源水杨酸(SA)对根肿病胁迫下不结球白菜植株抗性诱导和感病植株生长的影响,以及植株叶片和根系中防御酶系统的变化规律,探讨外源SA对防治不结球白菜根肿病的可行性。结果显示:(1)根肿病显著影响不结球白菜的生长,加剧植物的膜脂过氧化程度;适宜浓度的外源SA能不同程度地缓解不结球白菜所受根肿病的侵害,并以0.6mmol·L~(-1) SA处理效果最好。(2)外源SA显著降低了根肿病的发病率和病情指数,提高了抗根肿病的诱抗效果,并缓解感病对不结球白菜的生长抑制,显著促进感病植株的生长。(3)外源SA提高了不结球白菜叶片和根系中的超氧化物歧化酶(SOD)、过氧化物酶(POD)和抗坏血酸-过氧化物酶(APX)的抗氧化酶活性,以及多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)、谷胱甘肽还原酶(GR)的防御酶活性;显著降低了植株叶片和根系中的MDA、H2O2含量及O-·2产生速率。研究表明,外源SA诱导不结球白菜对根肿病的抗性,缓解根肿病的伤害,且具有剂量效应,以根部灌施0.6mmol·L~(-1)SA的效果最好;在根肿病的胁迫下,SA可提高不结球白菜植株抗氧化酶和防御酶的活性,增强渗透调节能力和细胞活性氧清除能力,降低根肿病对植株的伤害,从而促进生长。     

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。     

脯氨酸对不结球白菜（Brassica chinensis）镉积累的影响

采用溶液培养的方法,研究了过量Cd对不结球白菜（Brassica chinensis）幼苗内源脯氨酸含量的影响及外源脯氨酸在不结球白菜Cd积累中的作用。100μmol？L-1 Cd处理明显增加不结球白菜叶片脯氨酸（Pro）的含量,并且随着Cd胁迫时间的延长,其含量也显著上升。100μmol？L-1 Cd处理明显降低脯氨酸脱氢酶（PDH）活性,而增加δ1-吡咯啉-5-羧酸合成酶（P5CS）的活性。1~5 mmol？L-1外源Pro处理显著降低不结球白菜幼苗地上部Cd含量,对根系Cd含量无显著影响,但外源Pro处理并不能缓解过量Cd对不结球白菜幼苗生物量的抑制作用。外源Pro处理下,不结球白菜叶片中Pro含量与其地上部干重呈显著的负相关关系。     

秸秆浸提液漂浮栽培对不结球白菜产量及相关品质特性的影响

以1/4园试营养液为对照,以腐熟发酵的农业秸秆(苋菜和番茄植株残体)浸提液模拟富含N、P的水体进行不结球白菜(Brassica campestris ssp.chinensis Makino)的漂浮栽培,对茎叶的单株鲜质量和干质量及叶片的VC、可溶性蛋白质、蔗糖、果糖、葡萄糖含量及可溶性糖总含量进行了比较分析。结果表明:在24 d的栽培周期内,随生长时间的延长,处理组和对照组茎叶的单株鲜质量和干质量均呈增加趋势,但从第10天开始,处理组茎叶的单株鲜质量和干质量均显著低于对照组。栽培初期叶片VC含量均最高且处理组叶片VC含量显著低于对照组;从第10天开始,叶片VC含量降低,但处理组叶片VC含量与对照组无显著差异。处理组与对照组叶片可溶性蛋白质含量均呈波动的变化趋势,但总体差异不显著。处理组叶片蔗糖含量总体上与对照组差异不显著,仅在第24天显著低于对照组。处理组叶片的果糖含量均高于对照组,特别是在第24天为对照组的1.81倍,差异显著。叶片葡萄糖含量均呈先升高后降低的趋势,可溶性糖总含量则呈波动的变化趋势,对照组叶片葡萄糖含量和可溶性糖总含量总体上高于处理组,但差异不显著。研究结果显示:用秸秆浸提液漂浮栽培,虽然不结球白菜的生长量(即产量)有所减少,但相关的品质指标变化不大,对果糖合成和积累还有一定的促进作用,因而,此种秸秆浸提液可用于栽培商品不结球白菜。     

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.     

The effects of glutamine of the maintenance of embryogenic cultures of Cryptomeria japonica

Summary Embryogenic tissues of sugi (Cryptomeria japonica) were induced on a modified Campbell and Durzan (CD) medium containing 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 600 mg l⁻¹ glutamine, and subcultured in the medium of the same composition for over 1 yr. This resulted in a mixed culture of embryogenic and non-embryogenic cells. When embryogenic cells were isolated and cultured independently, their capacity to form embryogenic aggregates was lost. Thus, the non-embryogenic cells present within a mixed culture system were essential to the formation of embryogenic aggregates. When embryogenic tissues were isolated and cultured independently on a high glutamine-containing (2400 mg l⁻¹) medium, dry weights and endogenous levels of glutamine increased, and the tissue could generate a large number of embryogenic aggregates. Amino acid analysis of embryogenic and non-embryogenic cells from the maintenance culture indicated a higher level of glutamine was present in the latter. The high endogenous level of glutamine in the non-embryogenic portion of mixed cell masses may be the supplier of glutamine for maintaining the embryogenic property of the tissues.     

Specificity of action of piperidylcholine derivatives as substrates of cholinesterases of various origin

The review deals with study of enzymologic properties of a novel highly specific acetylcholinesterase substrate, N-(β-acetoxyethyl) piperidinium iodomethylate (“piperidylcholine”), and its 30 derivatives that were tested as effectors of cholinesterases of mammals and various species of Pacific squids. It was proven for the first time that responsible for specificity of action was structure of cyclic ammonium grouping of the alcohol part of molecule of the ester substrate. Analysis of specificity is performed based on enzymatic hydrolysis parameters—activity of catalytic center of cholinesterases and bimolecular constant of the reaction rate that are determined at optimal and low substrate concentrations. Among the specially synthesized group of thioester compounds there is revealed one more highly specific acetylcholinesterase substrate—N-(β-acetoxyethyl) piperidinium.     

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.