GA3浸种对大白杜鹃种子萌发的影响

用不同浓度的GA3浸种大白杜鹃种子并测定其萌发结果表明,不同浓度GA3处理均能增强大白杜鹃种子活力,极显著提高种子发芽率和发芽势,其中500mg·L～GA3浸种处理的效果最明显。GA3处理使种子的可溶性蛋白质含量降低,MDA含量下降,而SOD、POD和CAT活性增强。这表明GA3浸种后能增强抗氧化酶的活性,降低膜脂过氧化程度,从而促进种子提前萌发。     

GA3浸种处理对五种晚花杜鹃种子萌发的影响

晚花杜鹃(late flower Rhododendron)是一类花期较晚的杜鹃品种,具有较高的观赏价值,被广泛应用于庭院种植和园林绿化。随着旅游以及经济发展的需要,开发和利用晚花杜鹃资源显得非常迫切。自然条件下晚花杜鹃萌发率相对较低,因此为提高晚花杜鹃萌发率,探究不同浓度赤霉素(GA_3)处理对五种杜鹃种子萌发的影响,该文以五种晚花杜鹃(小白杜鹃、大白杜鹃、桃叶杜鹃、长蕊杜鹃和九龙山杜鹃)为实验材料,通过不同浓度(0、300、400、500、600、700 mg·L~(-1))的GA_3对五种晚花杜鹃种子进行24 h浸种处理,测定其发芽指数、发芽势、发芽率以及成苗率等指标,分别确定五种杜鹃种子萌发的最适GA_3浓度,并对相同处理下五种杜鹃种子的萌发率和成苗率进行比较。结果表明:(1) GA_3浸种对五种晚花杜鹃种子萌发具有促进作用,在适当GA_3浓度下五种杜鹃种子的发芽指数、发芽势和发芽率均显著高于对照组,萌发时滞、萌发高峰期和持续萌发时间均较对照组浓度相对缩短。(2)大白杜鹃、桃叶杜鹃和九龙山杜鹃种子在GA_3浓度为600 mg·L~(-1)处理时各项萌发指标相对较好;长蕊杜鹃以GA_3浓度为700 mg·L~(-1)浸种处理萌发效果相对较好;小白杜鹃以GA_3浓度为400和700 mg·L~(-1)处理最好。因此,在杜鹃的栽培中,可以采用赤霉素GA_3处理法提高种子发芽率,缩短萌发时间。     

赤霉素浸种时长和施用浓度对重度干旱和盐胁迫下黄芪种子萌发的影响

为研究赤霉素(GA3)浸种时长和施用浓度对重度干旱和盐胁迫下膜荚黄芪种子萌发的影响,使用5个浓度(0、50、100、200、400 mg·L-1)的GA3将种子分别浸泡5个时长(6、12、24、36、48 h)后置入渗透势为-0.6 MPa的PEG和-0.9 MPa的Na Cl溶液中进行发芽试验,测定最终发芽率和平均发芽时间。结果表明:膜荚黄芪种子在两种胁迫下的发芽率均随GA3浸种时间的延长和浓度的上升呈逐渐增高的趋势,处理间差异显著(P0.05);Na Cl胁迫下,100 mg·L-1GA3浸种36 h处理发芽率最高,达到83.33%;而PEG胁迫下,100mg·L-1GA3浸种48 h处理发芽率最高,达到80.00%;使用200 mg·L-1以上浓度的GA3浸种超过24 h开始对萌发产生抑制;GA3浸种能促进种子萌发可能与改变种皮透性和促进胚的活化均相关。采用Design Expert软件通过响应面模拟得出,100 mg·L-1GA3浸种36 h为整合重度渗透胁迫下较为适用的处理组合。     

不同前处理条件对薄荷种子萌发的影响

研究了不同质量浓度(10～250 mg·L~(-1))赤霉素(GA_3)以及清水浸种不同时间(6～36 h)、层积不同时间(5～20 d)和超声波处理不同时间(5～25 min)对薄荷(Mentha haplocalyx Briq. )种子萌发的影响. 结果表明, 用100～200 mg·L~(-1) GA_3处理6 h, 薄荷种子的发芽启动时间缩短且发芽率和发芽势均显著高于对照, 其中, 用150 mg·L~(-1)GA_3浸种,薄荷种子的发芽率最高(57.3%).用清水浸种6～36 h后,薄荷种子的发芽启动时间和发芽持续时间与对照无显著差异,但浸种12 h的薄荷种子发芽率极显著高于对照.于10 ℃层积5～15 d后,薄荷种子的发芽率和发芽势极显著高于对照,发芽启动时间也与对照差异显著,其中层积5～10 d的种子发芽率较高,达47.8%～52.4%.用功率50 W、频率40 kHz超声波处理5～20 min后,薄荷种子发芽率较对照有极显著提高,其中用超声波处理10 min的薄荷种子发芽率最高,达到68.3%.研究结果显示,使用功率50 W、频率40 kHz的超声波处理10 min是打破薄荷种子休眠的最佳方法,可显著提高薄荷种子的发芽率.     

超声波和赤霉素对川西獐牙菜种子萌发能力的影响

采用超声波、赤霉素、超声波和赤霉素相结合的方法处理种子,研究3种处理对川西獐牙菜种子萌发能力影响的结果表明：超声波超声20-40min对种子的萌发均有促进作用,其中以超声35min的效果较好,种子发芽提前1-2d;浓度为1000-2000mg·L^-1的赤霉素（GA3）对种子萌发有一定的促进作用,其中以1500mg·L^-1GA3浸种24h的效果较好;超声波和赤霉素共同处理对种子发芽有协同效应,其中以超声35min和赤霉素浓度为1250-1500mg·L^-1浸种22h的效果较为明显。     

藏药多刺绿绒蒿种子萌发特性研究

多刺绿绒蒿(Meconopsis horridula)为罂粟科绿绒蒿属一年生草本植物,是一种极具观赏价值和药用价值的高山植物,目前处于濒危状态,因此研究多刺绿绒蒿种子的萌发特性对其种子育苗及人工栽培具有重要意义。为了提高多刺绿绒蒿的种子发芽率,该研究以多刺绿绒蒿的种子为材料,分析了不同消毒剂、浸种时间、温度和外源植物激素对种子萌发特性的影响。结果表明:(1)最适消毒方法为75%乙醇1 min+3%H2O25 min,最适浸种时间为24 h,最适温度和光照条件为20℃/10℃(光照12 h/黑暗12 h),用无菌水浸种后的种子发芽率为49.67%。(2) GA_3100～600 mg·L~(-1)和NAA 5～30 mg·L~(-1)可以提高种子的发芽率、发芽势和发芽指数,缩短发芽启动时间和发芽持续时间,对种子的萌发有促进作用。(3) 6-BA 5 mg·L~(-1)和10 mg·L~(-1)对种子的萌发有一定的促进作用,但不显著,6-BA浓度≥15 mg·L~(-1)则抑制种子的萌发。(4)用GA3500 mg·L~(-1)浸种后的种子发芽指标最好,发芽率、发芽势和发芽指数分别为69.67%、33.00%、4.51,种子的发芽起始时间和发芽持续时间分别为10.67 d、11.67 d。     

野生药食两用植物青葙种子萌发的初步研究

测定青葙种子吸水和温度、光、暗、不同浓度GA,和0．2％KNO,影响其种子发芽的结果表明：青葙种子于25℃恒温下浸种8h后吸水达到饱和,其适宜发芽温度为30-35℃,萌发受光照抑制。10、50和100mg·L^-1GA3浸种的发芽率分别为61％、66％和72％,0．2％KNO3处理的发芽率达到81％。     

濒危植物毛柄小勾儿茶种子休眠与萌发生理的初步研究

毛柄小勾儿茶（Berchemiella wilsonii （Schneid．）Nakai var．pubipetiolata H．Qian）为中国特有种,国家三级保护植物。TTC染色法测得毛柄小勾儿茶种子的生活力较低,仅为32％,空粒和无生活力的种子分别为28％和40％,说明毛柄小勾儿茶发育完全的种子较少。种子吸水速度试验证明毛柄小勾儿茶种皮透水性较差,不利于种子萌发时对水分的吸收,发芽抑制物的生物鉴定结果表明,毛柄小勾儿茶种子的不同部位都存在发芽抑制物,且种胚中的含量最高,不利于种子的萌发,使毛柄小勾儿茶种子处于休眠状态之中。几种不同浓度GA。溶液浸种24h的预处理可以不同程度地提高毛柄小勾儿茶种子的发芽率和发芽指数,其中300mg／L GA3的效果最显著,并且300mg／L GA3的预处理可以在萌发初期（萌发前3天）显著地提高毛柄小勾儿茶种子中过氧化物酶、过氧化氢酶和脱氢酶的活性。毛柄小勾儿茶种子生活力低,且处于休眠状态,再加上与种子发芽力有关的几种酶的活性较低,致使毛柄小勾儿茶种子的发芽率较低,同时这些也是从种子萌发生理方面导致毛柄小勾儿茶濒危的重要原因。     

NaCl胁迫及Ca2+和GA3对南瓜属3种蔬菜种子发芽的影响

研究了NaCl胁迫对南瓜(Cucurbita moschata Duch.)、笋瓜(C. maxima Duch.)和西葫芦(C.pepo L.)种子萌发的影响及不同浓度外源Ca2+和GA3对NaCl胁迫下南瓜种子发芽的效应.结果表明,用30 mmol·L-1NaCl处理,南瓜种子的发芽率高于对照(蒸馏水),而用100和170 mmol·L-1NaCl处理,西葫芦和笋瓜种子的发芽率下降率为负值,表明较低浓度NaCl胁迫可一定程度提高西葫芦、笋瓜和南瓜种子的发芽率;高浓度NaCl胁迫对种子发芽有明显的抑制作用.种子萌发期耐盐能力从大至小依次为西葫芦、南瓜、笋瓜.在170 mmol·L-1NaCl胁迫下,施加5～30 mmol·L-1外源Ca2+或浸种处理,对南瓜种子发芽有促进作用,但高浓度外源Ca2+(≥50 mmol·L-1CaCl2)则具有抑制作用.在170 mmol·L-1NaCl胁迫下,用不同浓度GA3浸种处理,对南瓜种子发芽有抑制作用.     

GA诱导NaCl胁迫下黄瓜种子萌发和幼苗耐盐性效应

研究外源GA对NaCl胁迫下黄瓜种子萌发和幼苗生长的影响.结果显示:(1)0和75mmol·L-1NaCl处理可促进种子萌发,浓度为100mmol·L-1及以上时,随着浓度的增加,种子萌发受抑程度越严重;(2)150mmol·L-1NaCl胁迫下,添加外源GA可显著提高黄瓜种子发芽率、发芽势、发芽指数、活力指数和a-淀粉酶活性;促进种子萌发,以100和150mg·L-1GA处理效果较好;(3)外源GA显著提高幼苗生物量,提高SOD和POD活性,降低MDA含量,以100mg·L-1GA处理效果较好.研究表明一定范围的外源GA可缓解盐害对黄瓜种子萌发和幼苗生长的抑制作用,诱导其耐盐性的提高.     

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.