ABA和乙烯在草莓采后成熟衰老中的作用

随着草莓果实采后成熟衰老,ABA和乙烯生成迅速增长,乙烯累积与果实的变质腐烂程度呈正相关。ABA处理能增高纤维素酶活性和呼吸,而GA有抑制作用。ABA能促进乙烯、ACC生成,对MACC则无影响。GA_3抑制乙烯、ACC生成,促进MACC积累。CO_2对草莓有良好保鲜效果,并有效地抑制ABA和乙烯生成,低温下效果更为显著。     

钙对香蕉采后乙烯释放的抑制

本实验用CaCl_2溶液对香蕉(Musa acuminata cf. 'Dwarf Davendish')组织进行真空浸透处理,研究Ca~(2 )对香蕉采后乙烯释放、EFE活性、ACC水平以及ACC/MACC比值的影响。结果表明,Ca~(2 )处理可抑制香蕉果皮和果肉组织乙烯生成,对抑制果皮的乙烯生成尤为明显。Ca~(2 )处理还可降低内源ACC水平,抑制EFE活性。结果还显示,Ca~(2 )处理对组织中ACC/MACC比值有一定影响。     

氧和二氧化碳对莱阳梨果肉切片乙烯生物合成的调节作用

跃变期的莱阳梨果肉切片保温12h期间,降低空气中O_2浓度使乙烯生成减少,ACC含量相应增加,解除处理后,除0％O_2处理外都能恢复相应的乙烯生成速率。CO_2对乙烯生成有促进和抑制双重作用,处理初期表现出促进,O_2浓度低时更显著,随保温时间延长CO_2表现出抑制作用并继续增强。CO_2浓度增高,乙烯生成的抑制增强,ACC含量变化与乙烯减少之间没有很好的相应关系,解除CO_2处理后乙烯生成速率不能恢复。     

苹果双变气调贮藏

苹果双变气调贮藏(TDCA)是在产地简易气调贮藏基础上,总结发展形成的一项新的理论与技术。与传统气调不同,TDCA贮藏初期采用较高温度(10℃或更高),高CO_2(10％以上),并在贮藏期间变动,由高到低。对比试验证明,TDCA贮藏效果优于冷藏,与气调相近。其生理机制在于显著抑制呼吸作用;抑制乙烯的生成和催熟作用,减弱叶绿素和原果胶分解;保持果实色泽和硬度,抑制虎皮病的发生。初步确定的双变模式在生产上应用获得良好效益。同时还讨论了贮藏期间温度和气体成分变动之间相互依赖的辨证关系以及环境因子变动的合理性。     

接触二氧化硫后小麦叶片中逆境乙烯的生物合成

AVG和AOA强烈抑制二氧化硫处理小麦叶片中乙烯产生和ACC合成,对MACC的形成也有一定的抑制作用。CoGl_2明显抑制乙烯产生,而ACC大量积累,MACC含量则未因ACC增加而相应增加。DNP和CCCP也抑制乙烯产生,但前者引起ACC大量积累,后者引起ACC含量下降。CHI对乙烯产生和ACC形成均显示强烈的抑制作用,同时也明显抑制MACC形成。这表明小麦叶片接触SO_2引起的逆境乙烯也是循蛋氨酸→SAM→ACC→乙烯途径。     

高O2或高CO2浓度气调贮藏对“那翁”甜樱桃采后生理和贮藏性的影响

研究了甜樱桃品种“那翁”（Prunus avium L.cv.Napoleon)在1℃的高O2浓度气调（CA－1：70％ O2＋0％,CO2）,高CO2浓度气调（CA－II：5％ O2＋10％ CO2）,自发气调（modified atmosphere package,MAP)和普通冷藏条件下果实生理,品质,耐藏性的变化,结果表明：与其他处理相比,高O2浓度的气调可以抑制果实腐烂,减少果肉中乙醇含量,但果实的丙二醛（MDA）含量迅速上升,褐变严重,高CO2浓度的气调能有效抑制MDA含量上升的速率和多酚氧化酶（PPO）活性,保持果实硬度和维生素C含量,减少果实腐烂和褐变,延长贮藏寿命,不同处理对果实可溶性固形物含量的影响不大。“那翁”甜樱桃在5％ O2＋10％ CO2气调中贮藏80d能保持果实固有的风味品质。在MAP下,70％O2＋0％CO2和普通冷藏中的适宜贮藏期分别为40d,20d和30d。     

低温对梨(Pyrus communis L.)果实后熟过程中乙烯合成和反应的影响(英文)

Passe Crassane梨果实采后需经过 6 0～ 80d的低温处理才能正常后熟。为了明确低温促进果实成熟的机理 ,对果实进行了低温和低温结合 1 MCP(1 甲基环丙烯 ,乙烯作用抑制剂 )和丙烯 (乙烯类似物 )处理。研究发现 :果实经低温处理后 ,乙烯合成前体———ACC含量大幅度升高 ,而未经低温处理的果实 ,无论贮藏在空气中或用丙烯 1 0 0 0μl/L处理 ,果实中ACC、M ACC含量均保持较低水平。但冷藏前用 1 MCP处理可抑制冷藏果实或冷藏后升温的果实ACC含量的增高。这说明果实的后熟过程与低温和依赖乙烯的ACC合成酶的活性和基因的表达密切相关。未经冷藏的果实于 2 0℃下用丙烯处理 ,果实不能自发合成乙烯 ,但当果实经过冷藏后再用丙烯处理 ,则果实对丙烯的反应能力随冷藏时间延长而增强。为了进一步了解低温诱导的乙烯反应过程。我们对乙烯受体基因进行了研究。定量PCR分析结果表明 ,与拟南芥ETR1同源的基因的表达不受低温的调节。但冷藏后升温 ,或在升温后用丙烯处理时 ,mRNA含量降低。这些结果说明 ,低温可能是通过影响乙烯信号转导途径下游的其它因子而调节依赖乙烯的ETR1基因和ACC合成酶基因的表达 ,从而影响果实的成熟过程     

紫罗兰离体叶冷处理后转暖期乙烯和ACC的产生及CO_2的作用

火焰紫罗兰离体叶片在0℃下产生的伤害乙烯,只有当叶片从0℃移到20℃时才释放出来,释放高峰在转暖后四小时。低温直接刺激叶片ACC的合成。这两者的变化与叶片受冷伤害的程度相关。CO_2匮乏抑制冷伤害乙烯释放和ACC形成,这种抑制解除后,此过程又可恢复,照光不影响这种抑制。     

高O2或高CO2浓度气调贮藏对"那翁"甜樱桃采后生理和贮藏性的影响

研究了甜樱桃品种"那翁" ( Prunus avium L. cv. Napoleon)在1 ℃的高O2 浓度气调(CA-I: 70% O2+0% CO2)、高CO2 浓度气调 (CA-II: 5% O2+10% CO2)、自发气调 (modified atmosphere package, MAP) 和普通冷藏条件下果实生理、品质、耐藏性的变化.结果表明:与其他处理相比,高O2 浓度的气调可以抑制果实腐烂、减少果肉中乙醇含量,但果实的丙二醛(MDA)含量迅速上升、褐变严重.高CO2浓度的气调能有效抑制MDA含量上升的速率和多酚氧化酶(PPO)活性,保持果实硬度和维生素C含量,减少果实腐烂和褐变,延长贮藏寿命.不同处理对果实可溶性固形物含量的影响不大."那翁" 甜樱桃在5% O2+10% CO2气调中贮藏80 d能保持果实固有的风味品质.在MAP下, 70% O2+0% CO2和普通冷藏中的适宜贮藏期分别为40 d、20 d和30 d.     

乙酰水杨酸处理对猕猴桃果实成熟衰老的影响及其作用机理

以不同后熟软化阶段猕猴桃果肉组织圆片为材料 ,在 2 0℃下用 1.0mmol L(pH 3.5 )的乙酰水杨酸(ASP)分别处理 4、12和 2 4h后 ,分析其对果实成熟衰老相关因子的影响。结果表明 ,随着果实成熟衰老 ,内源游离SA下降 ,LOX活性增加 ,超氧自由基 (O- ·2 )生成速率增加 ,乙烯释放量加大 ;ASP处理促使组织内源SA水平的增加 ,降低了O- ·2 生成速率 ,抑制了LOX、ACC合成酶和ACC氧化酶的活性以及乙烯的生成。推测ASP可能作为O- ·2 等自由基清除剂 ,通过负反馈调控LOX途径 ,延缓果实的成熟衰老     

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.     

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.     

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.     

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。     

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.     

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.     

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.