1-MCP对‘粉红女士’苹果冷藏期间品质变化和香气形成的影响

以'粉红女士'苹果为试验材料,研究了1 μL/L 1-MCP(1-甲基环丙烯)对苹果冷藏期间乙烯释放速率、呼吸速率、果实硬度以及香气成分和相对含量的影响.结果表明,1-MCP处理可显著抑制'粉红女士'苹果冷藏期间呼吸作用和乙烯释放,有效延缓果实硬度的下降.冷藏期内'粉红女士'苹果香气物质主要有醇类、醛类、酯类、烯类、酸类和烷烃类等,并以酯类香气为主(占46.15%);1-MCP能显著减少果实贮藏期间酯类、醇类和烷烃类香气成分种类和相对含量,处理果中酯类和醇类香气成分种类比同期对照分别减少了50%和78%,主要香气成分丁酸己酯在处理和对照果实的相对含量分别为1.12%～1.73%和1.87%～5.18%.可见,1-MCP处理对'粉红女士'苹果具有良好保鲜效果,也显著地抑制了贮藏期间香气的形成.     

甜柿采后生理特性及对1-MCP处理的反应

以甜柿品种‘阳丰’为材料,在20℃和0℃贮藏条件下研究了1-MCP(1-甲基环丙烯)处理对不同成熟度甜柿果实采后乙烯释放速率、呼吸速率和品质特性的影响。结果表明:1-MCP处理可延缓贮藏和货架期间甜柿果实的软化、抑制呼吸速率和可溶性固形物含量(SSC)的变化,但对乙烯释放速率的作用不一致。1-MCP处理对成熟度I果实的效果优于成熟度Ⅱ。低温贮藏虽然能显著延缓果实硬度的下降,但在0℃贮藏30、60和90 d后7 d货架期结束时,对照果完全软化,而经1-MCP处理后果实果肉硬度仍保持“脆”性。因此,贮前0.50μL.L-11-MCP处理结合低温贮藏是延长‘阳丰’甜柿贮藏期的有效途径,具有广泛的应用前景。     

不同后熟期‘菊水’梨果实对外源乙烯和1-MCP处理的生理响应

用80uL·L-1外源乙烯和1.0 uL·L-11-甲基环丙烯(1-MCP)处理不同后熟期'菊水'梨果实,分析处理后果实品质和生理指标在(25±1)℃贮藏温度下的变化特征.结果显示:在采收当天(采后0 d)和呼吸跃变初期(采后4 d),外源乙烯处理能明显促进果实硬度和可溶性同形物含量(SSC)的下降,降低活性氧清除酶(SOD、CAT和APX)的活性,提高呼吸速率和乙烯释放速率,促进果实后熟,1-MCP处理却表现出与乙烯相反的效应,且采收当天比呼吸跃变初期的作用效果更明显;在呼吸跃变中期(采后12 d),外源乙烯和1-MCP处理效果均不明显.研究发现,外源乙烯能促进果实后熟而1-MCP却抑制果实后熟,其效果因处理果实后熟期的不同而存在显著差异,果实后熟程度越高,其处理的效果越不明显.     

1-MCP对室温贮藏下不同成熟度猕猴桃的生理效应

以适期采收(成熟度Ⅰ)和晚采收(成熟度Ⅱ)的'海沃德'猕猴桃果实为材料,研究0.5 μL·L~(-1) 1-甲基环丙烯(1-MCP)处理对室温贮藏(20℃)条件下两种果实的生理生化指标的影响.结果显示:1-甲基环丙烯(1-MCP)处理能有效延缓贮藏期间两种成熟度果实的硬度、可滴定酸含量、维生素C含量的下降,显著降低二者的乙烯释放速率和呼吸强度及其峰值,提高果实的POD、CAT和SOD活性.与成熟度Ⅰ相比,成熟度Ⅱ果实的硬度下降较快,且丙二醛含量和呼吸速率却明显较高,呼吸速率和乙烯释放量高峰时间相对提前.研究表明,在相同的贮藏条件下,晚采收的'海沃德'猕猴桃果实成熟衰老进程明显快于适期采收果实,贮藏效果较差;1-MCP能够明显延长猕猴桃果实的贮藏时间,表现出显著的保鲜效果.     

1-甲基环丙烯对猕猴桃乙烯产生和贮藏品质的影响

室温和0℃两种贮藏条件下,100 nL*L-1的1-MCP显著抑制“秦美“猕猴桃果实乙烯的释放,延缓乙烯高峰的出现,延缓果实硬度和可滴定酸含量的下降以及可溶性固形物含量的增加.     

1-MCP对梨采后某些生理生化指标的影响

1.0μL·L-1 1-MCP抑制梨品种"京白"、"五九香"、"锦香"果实采后呼吸速率.随着冷藏期的延长,货架期间经1-MCP处理的果实呼吸速率逐渐上升;冷藏后货架期间1-MCP延缓果实硬度下降,梨果实的酸度、淀粉、果皮叶绿素含量得以保持,但作用大小因品种而异;1-MCP还可以抑制"锦香"梨冷藏和货架期间黑皮病的发生,防止果实腐烂.     

1-MCP和CO2对‘南果梨’冷藏后货架期能量代谢特性的影响

分别对‘南果梨’果实采用0.75μL/L 1-甲基环丙烯(1-MCP)在20℃熏蒸20h后装入保鲜袋(0.02mm)、用2%CO2充气果实包装袋(0.04mm)、以保鲜袋果实为对照,各处理组果实均置于(0±1)℃贮藏5个月后移至室温下(18℃±3℃),测定各处理果实在货架期间的褐变度以及果实线粒体蛋白含量、MDA含量、ATP含量,以明确1-MCP和CO2对南果梨冷藏后果实货架期的能量代谢特性。结果显示:(1)1-MCP和CO2处理可不同程度延缓南果梨冷藏后货架期果实果心褐变指数和褐变度,且1-MCP处理效果更好,但CO2处理在货架后期反而使果实褐变度较对照提高。(2)1-MCP和CO2处理可有效抑制果实MDA含量增加,延缓细胞膜透性的升高,保持细胞完整性。(3)1-MCP处理有利于提高货架前期果实中线粒体蛋白质含量,能够在货架后期保持较高的ATP含量和能荷水平,而CO2处理在货架前期果实内含有较高水平的ATP,促进了果实内的能荷水平。研究发现,1-MCP和CO2处理均可以通过影响南果梨果实的能量代谢特性从而影响果实的成熟衰老进程,且1-MCP处理可以抑制货架前期的ATP含量和能量供应,有利于保持细胞膜完整性,抑制果心褐变的发生,延缓果实成熟衰老进程;而2%CO2处理与对照相比对果实能量代谢特性的影响不大。     

1-甲基环丙烯(1-MCP)对''''嘎拉''''苹果贮藏期间果肉细胞结构的影响

在室温[(25±1)℃]条件下观察1-甲基环丙烯(1-MCP)影响下‘嘎拉’苹果采后果肉细胞结构变化的结果表明,随着贮藏时间的延长,未作1-MCP处理的果实果肉细胞逐渐失去张力,细胞壁皱褶,中胶层逐渐降解,继而出现胞间裂痕,细胞间隙逐渐增大,细胞壁纤维松散,细胞器逐渐空泡化等现象;1-MCP显著抑制果肉细胞的结构损伤,最终减缓果实的软化。     

1-MCP对香蕉果实货架期的影响

香蕉果实经乙烯利处理后当天和1d分别用1-甲基环丙烯(1-MCP)处理,果实色泽转变、软化及淀粉降解均受到明显抑制,货架期延长5d以上;而乙烯利处理后贮放2d或3d再用1-MCP处理已失去对果实后熟的抑制作用。香蕉果实经1-MCP处理后在常温下贮藏11d完全恢复对乙烯敏感。     

1-甲基环丙烯对台湾青枣采后生理效应的影响

研究了台湾青枣(Ziziphus mauritiana Lam．cv．Liuxiang)在25℃下贮藏期间1-甲基环丙稀(1-MCP)处理对果实品质和一些生理指标的影响。结果表明：250μgL^-1的1-MCP有效抑制了果实腐烂和褐变。在25℃下贮藏12d,对照和处理的好果率分别为12．5％和92．5％。果实经1-MCP处理后,乙烯合成受到显著抑制,乙烯高峰出现延迟,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性提高,从而减缓了丙二醛(MDA)的积累和细胞膜透性的升高。     

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.     

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.     

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.