脂氧合酶、茉莉酸和水杨酸对猕猴桃果实后熟软化进程中乙烯生物合成的调控

20℃下后熟果实的LOX活性增加先于自由基产生和乙烯生成;JA处理对果实后熟软化启动期(采后1d)和果实快速软化期(采后5d)果实切片中的LOX活性、自由基产生和乙烯生物合成有促进作用,至果实软化后期(采后7d)这种效应消失;亚油酸只在采后1d果实切片中促使LOX活性和乙烯生成;SA处理抑制了果实后熟进程中组织切片的LOX活性、自由基产生和乙烯的生物合成;SA和JA对LOX活性和乙烯生物合成具有明显的拮抗作用。     

香蕉一个Ⅲ类酸性几丁质酶基因与果实成熟关系的研究

为了解Ⅲ类酸性几丁质酶基因(MaCHⅢ)与香蕉果实采后成熟过程的相互关系,对经乙烯和1-甲基环丙烯(1-MCP)处理的巴西香蕉果实采后乙烯释放量、Ⅲ类酸性几丁质酶基因(MaCHⅢ)表达以及几丁质酶活性进行了测定.结果显示:(1)乙烯催熟处理的香蕉果实,乙烯释放量比对照处理的果实提前15 d达到高峰;1-MCP处理的香蕉果实,乙烯生物合成和果实成熟明显受到了抑制.(2)外源乙烯加速了MaCHⅢ基因的下调表达和Ⅲ类酸性几丁质酶活性的下降,MaCHⅢ表达量和Ⅲ类酸性几丁质酶活性分别在采后第3天和第4天下降到最小值.(3)1-MCP处理使MaCHⅢ基因呈现上调表达,Ⅲ类酸性几丁质酶活性上升,MaCHⅢ基因表达量和Ⅲ类酸性几丁质酶活性分别在采后18 d和25 d达到高峰.研究表明,MaCHⅢ基因可能与香蕉果实采后成熟呈负相关.     

PRO—LONG涂膜处理对后熟香蕉果实乙烯形成以及其它有关生…

香蕉果实采后以商业上推荐使用的１．５％Ｐｒｏ－ｌｏｎｇ溶液处理,贮藏于２０℃和７５％相对湿度下,分别测定果实的ＡＣＣ含量、ＭＡＣＣ含量、ＥＦＥ酶活性、乙烯释放、叶绿素含量的变化和果实的硬度变化。结果表明,ＰＲＯ－ＬＯＮＧ处理延缓了香蕉果实果皮的叶绿素降解、硬度的下降以及乙烯释放的增加。在后熟过程中,处理果实的ＡＣＣ含量发生积累。ＡＣＣ含量的高峰在乙烯释放高峰和ＥＦＥ酶活性高峰之前出现。与对照比较,     

低温对梨（Pyrus communis L.）果实后熟过程中乙烯合成和反？…

Ｐａｓｓｅ－Ｃｒａｓｓａｎｅ梨果实采后需经过６０－８０ｄ的低温处理才能正常后熟。为了明确促进果实成熟的机理,对果实进行了低温结合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１０００μｌ／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     

采后果蔬对乙烯受体抑制剂的响应及贮运保鲜技术的研究

近几年来 ,随着重氮环戊二烯和环丙烯类等乙烯受体抑制剂的发现 ,为控制乙烯敏感型的果蔬采后成熟、衰老提供新的技术手段。从乙烯受体抑制剂的特性、作用特点以及可能作用机理等方面概述了采后果蔬对乙烯受体抑制剂的响应和应用乙烯受体抑制剂延长采后果蔬贮运保鲜的技术。     

黄瓜果实圆片诱导呼吸和乙烯产生的研究

黄瓜在采后成熟过程中发生呼吸上升现象。采后1天果实的圆片陈化后,伤诱呼吸增加近3倍,乙烯产生也大量增加;陈化初期,呼吸率升高与乙烯产生增加平行发展。诱导呼吸发生及伤害诱导乙烯产生受到氯霉素、环己亚胺、放线菌素D和5-氟尿嘧啶的明显抑制。GA和IAA抑制乙烯的产生,而ABA则促进乙烯的产生。     

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.     

钙对中华猕猴桃果实采后乙烯释放和呼吸的影响

不同浓度ＣａＣｌ２溶液真这渗透处理中华猕猴桃果实采后乙烯释放明显的抑制作用,其中０．５ｍｏｌ／ＬＣａ＾２＋处理尤为显著,采用５天果实人有保持极低水平的内源乙烯,乙烯峰也延迟２－４天出现。     

成串采收对番茄果实采后乙烯合成及贮藏品质的影响

为研究成串采收对番茄果实采后乙烯合成及贮藏品质的影响,对广西田阳县两个栽培区两种嫁接砧木的串收番茄的采后生理指标进行测定,探讨了该采收方式对番茄果实采后保鲜的作用机制。结果表明:整个贮藏期,不同栽培区不同嫁接砧木的番茄成串采收的果实,乙烯生成量明显低于对照的常规单果采收。其中,砧木1号Ⅰ区的串收番茄的乙烯生成量,采后5 d即下降至最低点(0.35 nL·g~(-1)·h~(-1)),显著低于其对照(1.36 nL·g~(-1)·h~(-1)),其他栽培区和砧木组合的串收番茄,在采后15 d乙烯生成量达到最低值。串收番茄的类胡萝卜素、番茄红素和抗坏血酸等果实内天然抗氧化物质的含量,在贮藏前期快速升高,且峰值显著高于对照。此外,成串采收处理还一定程度抑制了果实后熟阶段可溶性糖的积累和可滴定酸的分解。因此,番茄成串采收处理,可能通过抑制果实采后乙烯的合成,同时提高类胡萝卜素、番茄红素和抗坏血酸的水平,并且推迟糖和酸等营养物质的后熟变化进程,实现其延长果实货架期,提高商品品质的作用。     

脂氧合酶,茉莉酸和水杨酸对猕猴桃果实后熟软化进程中乙烯？…

２０℃下后熟果实的ＬＯＸ活性增加先于自由基产生和乙烯生成;ＪＡ处理对果实后熟软化启动期（采后１ｄ）和果实快速软化期（采后５ｄ）果实切片中的ＬＯＸ活性、自由基产生和乙烯生物合成有促进作用,至果实软化后期（采后７ｄ）这种效应消失;亚油酸只在采后１ｄ果实切片中促使ＬＯＸ活性和乙烯生成;ＳＡ处理抑制了果实后熟进程中组织切片的ＬＯＸ活性、自由基产生和乙烯的生物合成;ＳＡ和ＪＡ对ＬＯＸ活性和乙烯生物合成具有明     

Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

Principles of organization and evolution of systems of regulation of functions

Evolution of living organisms is closely connected with evolution of structure of the system of regulations and its mechanisms. The functional ground of regulations is chemical signalization. As early as in unicellular organisms there is a set of signal mechanisms providing their life activity and orientation in space and time. Subsequent evolution of ways of chemical signalization followed the way of development of delivery pathways of chemical signal and development of mechanisms of its regulation. The mechanism of chemical regulation of the signal interaction is discussed by the example of the specialized system of transduction of signal from neuron to neuron, of effect of hormone on the epithelial cell and modulation of this effect. These mechanisms are considered as the most important ways of the fine and precise adaptation of chemical signalization underlying functioning of physiological systems and organs of the living organism