模拟硫酸型、硝酸型及其混合型酸雨对油菜生理特性、生长和产量的影响

为了了解我国酸雨污染由硫酸型向硫-硝酸复合型转变所引起的环境效应,以油菜(Brassicanapus)为供试材料,在大田试验条件下,系统研究了模拟硫酸型(SAR)、硝酸型(NAR)及其混合型(MAR)酸雨对农作物生理特性、生长和产量的影响。结果表明,3种酸雨胁迫均能抑制油菜生理、生长和产量形成,但不同类型的酸雨间的抑制效应存在差异。当pH≤4.1时,SAR、NAR、MAR能破坏油菜叶质膜系统、降低光合色素含量及光合速率,从而抑制作物的光合作用;当pH≤3.1时,油菜叶面积减小,叶受害百分率明显增加。pH=4.1可作为酸雨对油菜产量的影响阈值。在pH=7.0–1.5的酸度范围内,油菜叶片膜透性、丙二醛含量、叶受害百分率表现为NARMARSAR,光合速率、光合色素含量、叶面积及产量则表现出SARMARNAR的变化特征。当pH4.1时,3种酸雨处理间差异均不明显,pH≤3.1时,3种酸雨间的胁迫效应差异显著增加(p0.05),且酸度越强,差异越大,其变化趋势为NARMARSAR。说明NAR和MAR胁迫对油菜生理、生长及产量的抑制较大。     

模拟酸雨对油菜花期生理特性和产量的影响

以甘蓝型油菜品种秦优九号为材料,通过盆栽试验研究了不同pH值模拟酸雨处理对油菜花期生理特性和产量的影响.结果表明:当模拟酸雨pH=4.0～5.0时,在一定程度上刺激了油菜的生长,植株的生物量、叶绿素含量、光合生理特性和产量构成因素等指标均略高于对照(pH 6.0)或与对照相当,但差异不显著.随着模拟酸雨酸度的增强,植株的生物量、叶绿素含量、光合生理特性、抗氧化酶活性和非酶抗氧化剂含量等生理指标逐渐下降,且随酸度增强下降幅度增大,丙二醛含量和相对电导率显著增加,膜脂过氧化加剧,最终导致单株角果数、每角粒数、粒重和实际产量等指标逐渐下降.但不同产量构成因素对酸雨敏感性不同,单株角果数、每角粒数随酸雨酸度的增强而显著下降,而粒重受酸雨影响不显著.     

不同pH模拟酸雨对冬小麦籽粒营养品质的影响

在大田试验条件下研究了不同pH模拟酸雨对冬小麦籽粒氨基酸、蛋白质、可溶性糖、还原糖、淀粉以及总酸度的胁迫效应,以期为防治我国农作物的酸雨灾害提供基础理论依据。结果表明,pH≤4.5酸雨处理会抑制总游离氨基酸的合成,且酸度越强,抑制越明显。蛋白质(可溶性蛋白质、总蛋白)含量随着酸雨酸度的增强逐步下降,且在极酸性条件下降低较明显。pH≤4.5酸雨处理对可溶性糖的合成会有较强的抑制作用。pH≤2.5时还原糖的合成明显受抑。随着酸雨酸度的增强,总酸度和酸糖比均表现出先增加后下降的变化趋势,且在pH=3.5处达到最大值。pH≤3.5酸雨处理显著抑制淀粉的合成,且对支链淀粉的影响较明显,致使淀粉支/直比下降。     

模拟酸雨条件下Pb2+和Cr6+对蕹菜光合作用及品质的影响

以蕹菜（Ipomoea aquatica Forsk．）为供试对象,通过盆栽试验,研究了不同酸度模拟酸雨（AR）条件下,Pb^2＋和Cr^6＋对其光合作用、营养品质及食用安全性的影响。结果表明：酸雨条件下,重金属对蕹菜叶片光合作用和品质的胁迫表现为Pb〉Pb＋Cr〉Cr;随酸度增加,AR＋Pb和AR＋Pb＋Cr处理的危害性显著增加,pH=3．5时,AR＋Pb＋Cr处理的胁迫性明显大于其他处理水平,对蔬菜造成伤害;3个光合作用参数均随酸雨酸度增加有不同程度的下降,但对胁迫的敏感性存在差异;pH〈5．6时,蕹菜中蛋白质和游离氨基酸含量与pH值呈正相关;随酸度增加,可溶性糖含量增加,而还原性糖含量下降,表现出对环境胁迫的应激反应;除了Cr污染处理外,Pb污染和Pb＋Cr污染都能显著促进蕹菜中硝态氮积累,其含量随酸雨酸度上升而增加;蕹菜中Pb和Cr存在竞争吸附作用,且随着酸雨酸度下降,蕹菜对2种重金属的富集有加快趋势。     

模拟酸雨对朱砂叶螨寄主植物三月早茄生理生化的影响

以朱砂叶螨的寄主植物三月早茄为对象,研究了不同pH值和不同时间模拟酸雨胁迫下,茄子对酸雨的抵抗、适应能力和营养物质含量变化.结果表明,随酸雨酸度增强,茄叶的过氧化氢酶(CAT)活性、磷和可溶性蛋白含量呈单峰变化趋势;而过氧化物酶(POD)活性、可溶性糖含量呈单谷变化趋势;还原糖含量和超氧化物歧化酶(SOD)活性随酸度增加呈上升趋势;茄叶pH值呈下降趋势,含水量不受酸雨影响.POD对酸雨作用反应迟缓,而SOD、CAT较敏感,其他几项生理指标则对酸雨作用时间反应灵敏.高pH(4.0～5.6)的酸雨刺激茄叶的保护能力增强,促进茄叶的生长发育.由于茄叶内糖含量、磷及可溶性蛋白含量的改变,植物的适口性有所变化,可促进叶螨生长,而在强酸性酸雨(pH＜3.0)胁迫下,植物的生长受到抑制,营养物质含量降低,抑制朱砂叶螨的生长.     

模拟酸雨对小麦叶片同化物、生长和产量的影响

以小麦为材料,通过大田试验研究了模拟酸雨对小麦生长和产量的胁迫效应.结果表明：酸雨胁迫对小麦产量有较大影响,当酸雨pH≤3.5时显著低于对照（P＜0.01）;当pH≤ 2.5时,小麦株高明显变矮,叶片外观出现明显的受害症状,当pH≤3.5时,叶面积和比叶 鲜质量显著降低.酸雨胁迫下,小麦叶片叶绿素a、b和类胡萝卜素含量都明显降低,但对叶绿素a的影响更显著.酸雨胁迫导致小麦叶片可溶性糖和还原糖的合成受抑,当pH≤3.5时, 受抑作用较强,且酸度越高,影响越大;酸雨胁迫下,小麦叶片的总游离氨基酸和可溶性蛋白质含量均随着酸雨酸度的增加而降低,并分别在pH≤3.5和pH≤4.5时显著低于对照（P＜0.05）.     

模拟酸雨和铝调控对茶叶主要化学品质与铝积累的影响

为研究模拟酸雨和铝(Al)对茶叶主要化学品质与Al积累的影响及其交互作用,采用3个酸度水平(pH 3.0、4.0、5.0)和4种Al浓度水平(0、10、20、30 mg L-1),用溶液培养法研究茶叶的主要化学指标和Al含量的异同.结果表明,在模拟酸雨下,茶叶的茶多酚和咖啡碱含量随酸度增加先增加后下降,氨基酸、儿茶素和...     

模拟酸雨对小麦产量及籽粒蛋白质和淀粉含量及组分的影响

以宁麦13和徐麦31两种小麦(Triticum aestivum)品种为材料,通过盆栽试验研究了不同pH值酸雨对小麦产量和籽粒品质的影响。结果表明:模拟酸雨抑制了小麦的生长,减少了生物量的积累。pH值2.0酸雨处理后宁麦13的单穗粒数和单茎产量分别较对照下降了48.6%和56.7%,徐麦31则分别下降了31.2%和39.7%,差异显著。小麦籽粒主要营养成分对酸雨胁迫响应不同,酸雨处理提高了籽粒氨基酸、蛋白质含量,pH值2.0酸雨处理后,宁麦13和徐麦31小麦籽粒中氨基酸含量分别比对照高36.6%和30.9%,总蛋白含量分别比对照高20.6%和15.1%,均与对照差异显著。而小麦可溶性糖、淀粉和脂肪含量较对照降低,且总体表现为酸度增强变化幅度增大。不同蛋白组分也对酸雨胁迫反应不同,酸雨处理提高了籽粒中清蛋白和球蛋白含量,而降低了谷蛋白含量和谷/醇。pH值2.0的酸雨处理后,宁麦13和徐麦31的清蛋白含量较对照分别增加了13.1%和23.9%,但与对照差异不显著。酸雨胁迫降低了总淀粉和支链淀粉含量,宁麦13和徐麦31的pH值2.0酸雨处理总淀粉含量分别较对照下降了11.8%和20.2%,与对照差异显著,但对直链淀粉含量影响不明显。可见酸雨不仅影响小麦的产量,而且对品质也有明显影响。酸雨处理尽管提高了籽粒总蛋白含量,但降低了谷蛋白和谷/醇,降低了其加工品质。     

外源NO对酸雨胁迫下龙眼幼苗生理特性的影响

研究了外源NO供体硝普钠(SNP)对pH3.0酸雨胁迫下龙眼幼苗叶绿素含量、抗氧化酶活性和渗透调节物质含量的影响.结果表明:酸雨胁迫下,龙眼幼苗叶片中的超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性降低,叶绿素、蛋白质和可溶性糖含量下降,丙二醛含量升高,呈现出一定的毒害效应.外源NO对酸雨胁迫下龙眼幼苗的生理代谢的作用具有双重性,0.1 ～0.5.mmol·L-1SNP显著提高叶绿素、可溶性糖和蛋白质含量,增强SOD、POD和CAT活性,降低丙二醛含量;其中0.5 mmol·L-1 SNP处理效果最好,叶绿素、可溶性糖和蛋白质含量分别比单独酸雨胁迫处理增加了76.0％、107.0％和216.1％,SOD、POD和CAT活性分别提高150.0％、350.9％和97.1％,丙二醛含量降低了46.4％.低浓度外源NO能通过刺激抗氧化酶活性来清除活性氧,减轻氧化胁迫,缓解酸雨胁迫对龙眼幼苗的毒害作用;而高浓度外源NO对酸雨胁迫的缓解作用减弱.     

模拟秋季酸雨对三角枫叶片光合生理特性的影响

以三角枫幼苗为材料,采用盆栽方法,研究了pH 5.6、pH 4.0、pH 3.0和pH 2.0酸度模拟酸雨胁迫对三角枫叶片光合生理特性的影响,以探讨酸雨胁迫下三角枫的光合生理响应机制。结果显示:(1)随着酸雨浓度的增加和胁迫时间的延长,三角枫叶片相对叶绿素含量下降幅度逐步增大;叶片丙二醛含量呈逐渐上升的趋势,且各处理均显著高于对照;叶片质膜透性和脯氨酸含量均呈先升高后降低的趋势,且pH 2.0处理的叶片质膜透性在试验20d时迅速增大,升高幅度最大(146.3%)。(2)叶片净光合速率、蒸腾速率、水分利用效率、表观光能利用效率以及表观CO2利用效率在胁迫下也均呈显著下降趋势,且以pH 3.0和pH 2.0处理降幅最大。研究表明,pH 4.0的模拟酸雨对三角枫叶片的光合生理指标无显著影响,而pH≤3.0的强酸雨胁迫使三角枫叶片叶绿素含量显著下降、膜保护系统受损、光合作用效率显著下降;三角枫能适应弱酸雨(pH≥4.0)环境,可作为酸雨地区的园林绿化树种。     

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.