不同保鲜剂对香石竹切花的保鲜效果

3种保鲜剂均能不同程度地增加切花鲜重,增大花径,改善切花体内的水分状况,降低过氧化物酶(POD)活性,延长瓶插寿命,其中以保鲜剂3(40mg·L~(-1)苯甲酸+50mg·L~(-1)AgNO_3+3％蔗糖+200mg·L~(-1)8-HQ)的保鲜效果最好。     

保鲜剂及冷藏对鹤望兰切花瓶插品质的影响

本文探讨不同保鲜剂、预处理液及冷藏时间对鹤望兰切花瓶插寿命和观赏品质的影响。结果表明,供试的8组瓶插保鲜液中,以配方5% S+300 mg/L 8-HQC+100 mg/L CA+150 mg/L STS+100 mg/L CoCl₂+25 mg/L EDTA-Na保鲜效果最佳,切花瓶插寿命(23.5 d)比CK延长15.2 d,小花开放率(56.1%)比CK提高1.19倍。供试的5组冷藏预处理液中,以10% S+300 mg/L 8-HQC+75 mg/L KH₂PO₄·3H₂O效果最佳,切花经过2~3周8~10℃冷藏后,瓶插寿命(13.7 d)比CK延长7.9 d,小花开放率(43.6%)比CK提高98.2%;该处理组鹤望兰切花的适宜冷藏时间可延长为3周。     

不同保鲜剂对月季切花的保鲜效应

本试验研究不同保鲜剂对月季切花瓶插寿命、观赏品质的影响。正交试验表明,在供试保鲜剂的9个组合中,配方7(P₇)[0.2% Ca(NO₃)₂+0 Suc+400mg/L B₉+1mmol/L STS]保鲜效果最好,可明显延长月季切花瓶插寿命;以P₇保鲜剂喷洒花瓣可促进花朵生长发育;月季切花在瓶插过程中,其花瓣组织的pH值随切花的衰老而上升。     

氯化钙对非洲菊切花的保鲜作用

以 1 0mg ml的CaCl2 溶液作为保鲜液 ,对非洲菊切花进行瓶插试验 ,通过外部形态观察和生理指标测定 ,结果表明 :用CaCl2 溶液瓶插非洲菊切花可以增强花枝的吸水能力 ,增加花枝的鲜重 ,保持切花的水分平衡 ,减少溶质外渗 ,维持膜结构的相对稳定性 ,从而使切花的瓶插寿命比对照延长 3 3d。     

贮藏方式对切花菊贮后品质的影响

研究了干、湿贮藏方式及其贮藏期对三种不同发育程度切花菊贮后品质的影响。两种湿藏能促进切花发育,贮藏6周后切花花径分别增大了2.54cm(清水)和3.29cm(S+AgNO_3),但不能延长贮藏期;干藏能延长贮藏期,可贮期达4～6周,提高切花催开后品质。     

玫瑰切花保鲜剂配方研究

以蔗糖(S)、8-羟基喹啉(8-HQ)、柠檬酸(CA)为保鲜液的基本配方,分别加入CaCl2 、NaCl、Al2(SO4)3、CaCl2+KAl(SO4)2 组成四种保鲜液,进行玫瑰切花保鲜实验。对切花瓶插寿命、花径、水分平衡值、可溶性蛋白含量和还原糖含量进行分析。结果表明,各种配方保鲜液均能延长玫瑰切花的瓶插寿命、增大花径、改善切花水分代谢状况、降低切花蛋白质和还原糖的分解速度。其中,保鲜液2% S + 280 mg/L CA + 200 mg/L 8-HQ + 1% CaCl2的保鲜效果最好。     

切花保鲜原理和简便方法

切花是指可供插入瓶中进行水养或制成花篮、花环等花卉植物的花朵、花枝、枝叶、果实等器官的统称。切花保鲜主要是研究花枝、花朵的保鲜,延长切花的寿命,增加观赏价值。1切花的衰老与保鲜切花采取后生理代谢发生很大变化,衰老进程比留在母体快。常温下,一般只能保持3～5天的寿命。保鲜就是设法减缓衰老进程。1．且导致切花衰老的主要原因1．1．1体内水分平衡失调,导致切花凋萎维持细胞紧张度是切花保鲜的必要条件之一。细胞含有充足的水分,才能维持本身的紧张度和正常代谢,才能保持花的正常姿态和新鲜度,这就要求保鲜过程中,切花…     

溴代十六烷基吡啶对香石竹切花的保鲜效应

研究切花瓶插液中加入0．3g．L^-1季铵盐化合物溴代十六烷基吡啶（CPB）后,瓶插液中微生物密度和切花茎杆基部病原菌分离频率下降,切花后期的水分平衡和鲜重能较好地维持,花冠直径增大,观赏寿命延长。     

微生物有机肥及杀菌剂对切花菊连作障碍的影响

由切花菊‘优香’长期连作导致的枯萎病不仅严重降低了切花菊的品质及产量,而且致使土壤酶活性降低,土壤微生物种群失调.本文采用大田试验,比较研究了切花菊‘优香’连作土壤中分别施用杀菌剂多菌灵(MBC)、添加有拮抗微生物的有机肥(BOF)及二者的联合施用(MBC+BOF)对切花菊‘优香’品质及土壤酶活性的影响.结果表明： 单独施用微生物有机肥(BOF)或多菌灵(MBC)均能有效防控切花菊连作枯萎病的发生;微生物有机肥(BOF)在增强切花菊‘优香’的根系活力、提高切花菊的主要品质(株高、茎粗、叶绿素含量、舌状花数、植株鲜质量)及切花菊土壤酶活性方面效果显著高于多菌灵(MBC);多菌灵对土壤酶活性有一定抑制作用;二者联合处理(MBC+BOF) 对提高切花菊主要品质及土壤酶活性的综合效果最佳.     

化学药剂预处理对小苍兰蕾期切花的保鲜效果

本文探明了8HQC(8—羟基喹啉柠檬酸盐)、STS(硫代硫酸银)、BA(6—苄基腺嘌呤)等化学药剂和蔗糖预处理对蕾期采收的小苍兰切花的保鲜效果。(1)各种药剂处理均可提高开花率及观赏品质,其中8HQC+STS+BA+蔗糖的组合效果最佳,开花率比对照提高37.6％,花径增大5.6毫米,瓶插寿命延长6.9天。(2)药剂预处理明显提高切花耐藏性,经处理的切花经3～5天冷藏后瓶插,其观赏品质和瓶插寿命仍显著高于未经处理和冷藏的对照组。品种间的耐藏性有差异。作者认为,药剂处理的显著作用之一是改善了切花体内的水份状况。     

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.