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,     

采后梨果实皮层和髓中EFE活性、ACC和多胺含量变化及其与乙烯生成的关系

菊水梨皮层和髓的乙烯合成酶（ＥＦＥ）活性和氨基环丙烷羧酸（ＡＣＣ）含量及其果实乙烯释放量均分别高于二十世纪梨。在同一品种果实的皮层和髓中,ＡＣＣ含量无明显差异,但髓的ＥＦＥ活性明显高于皮层。梨果实内含有丁二胺、亚精胶和精胺３种内源多胺,而以丁二胺和亚精胺含量为最高,精胺含量虽低但较稳定。果实在乙烯释放高峰出现前,其皮层和髓中的丁二胺和亚精胺含量变化有明显差异。采后梨果实的乙烯生成与果实内ＥＦＥ活性,ＡＣＣ含量、多胺含量的变化有密切关系,而乙烯生成的差异不仅表现在品种间,而且在果实的皮层和髓之间也存在差异,梨果实的髓似乎对整个果实的乙烯生成有更重要的影响。     

多胺对香蕉果实乙烯发生的影响

多胺对香蕉果实乙烯发生的影响蒋跃明,张东林,李月标,陈芳,刘淑娴（中国科学院华南植物研究所,广州５１０６５０）ＥＦＦＥＣＴＳＯＦＰＯＬＹＡＭＩＮＥＳＯＮＴＨＥＥＴＨＹＬＥＮＥＥＶＯＬＵＴＩＯＮＯＦＢＡＮＡＮＡＦＲＵＩＴＳＪｉａｎｇＹｕｅ－ｍｉｎｇ;Ｚ...     

成熟香蕉果实活性氧与乙烯形成酶活性的关系

香蕉果实成熟过程,随着活性氧产生速率从低水平→迅速跃升→高峰→下降的变化,其乙烯形成酶活性及乙烯产生也经厅了基本同步的过程。显示了三者之间具有某种内在联系。外源超氧阴离子自由基能使乙烯形成酶活性及乙烯产生出现跃升和高峰的时间明显提前;超氧歧化酶则使ＥＦＥ活性及乙烯产率明显下降。进一步说明了在香蕉果实成熟过程中,Ｏ２可能是引起ＥＦＥ活性及乙烯产生迅速上升的原因之一,而过氧化氢则被证明与ＥＦＥ活性及乙     

麝香石竹花衰老过程中钙调蛋白含量变化与乙烯生物合成的关系

麝香石竹（Ｄｉａｎｔｈｕｓ ｃａｒｙｏｐｈｙｌｌｕｓｓｕｕ ｂｅａｍ ’）切花在第４ 天开始释放乙烯,１－氨基－环丙烷－１－羧酸（ＡＣＣ）含量、ＡＣＣ合酶活性相应增加,乙烯释放第６ 天达到高峰,随后逐渐下降。钙调蛋白含量的变化和ＡＣＣ合酶活性的变化趋势一致。ＧＡ、硫代硫酸银（ＳＴＳ）和氨基氧乙酸（ＡＯＡ）处理的切花中钙调蛋白含量比同期对照的低,乙烯生物合成被抑制,切花衰老被推迟。钙离子促进花瓣乙烯的释放。钙调蛋白抑制剂氯丙嗪（ＣＰＺ）对乙烯释放具有抑制作用     

记忆增强肽促进大鼠海马内CREB磷酸化

五肽ＺＮＣ（ＣＰＲ（ｐＢＧｌｕ－Ａｓｎ－Ｃｙｔ－Ｐｒｏ－Ａｒｇ－ＯＨ）是精氨酸加压素（ＡＶＰ）在脑内的天然酶解产物,具有促进学习记忆的中枢效应。为了进一步阐明其作用的分子机制,以整体大鼠海马及离体大鼠海马切片为对象,研究了ＺＮＣ（Ｃ）ＰＲ对ｃＡＭＰ反应元件结合蛋白（ＣＲＥＢ）磷酸化的作用。发现ＺＮＣ（Ｃ）ＰＲ及其类似物ＮＬＰＲ能诱导大鼠海马内ＣＲＥＢ磷酸２化,该作用能被其拮抗剂ＺＤＣ（Ｃ）ＰＲ、Ｇ     

番茄果实ACC合成酶的纯化

以伤诱导的番茄囊果皮为材料,改进了ＡＣＣ合成酶（ＥＣ４．４．１．１４）纯化方法,经改进的５步纯化后,ＡＣＣ合成酶被纯化７３００倍,比活性达到１１６８７０Ｕ／ｍｇ蛋白,回收率为７％,以较少的步骤得到了较高的纯化倍数,纯化的ＡＣＣ合成酶经ＳＤＳ－ＰＡＧＥ和银染检验为一条带,分子量为５０ｋＤ,等电点为ｐＨ６．５。     

渗透胁迫下水稻幼苗中叶绿素降解的活性氧损伤作用

水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）幼苗在渗透胁迫下,随着胁迫强度的增加及时间的延长,Ｃｈｌ降解加剧,活性氧Ｏ－·２ 、Ｈ２Ｏ２ 及脂质过氧化产物丙二醛（ＭＤＡ）含量明显增加,抗氧化剂抗坏血酸（ＡｓＡ）还原型谷胱甘肽（ＧＳＨ）及胡萝卜素（ＣＡＲ）含量显著降低,叶绿素蛋白复合体（Ｃｈｌ－Ｐｒｏ）结合度松弛． Ｃｈｌ含量的降低和Ｏ－·２ 、Ｈ２Ｏ２ 及ＭＤＡ 含量呈显著的负相关,与ＡｓＡ、ＧＳＨ及ＣＡＲ含量的下降呈良好的正相关性．ＡｓＡ、α－生育酚（ＶｉｔＥ）及甘露醇预处理可使胁迫诱导的ＭＤＡ 增多及Ｃｈｌ降解延缓,而Ｆｅ２＋ 、Ｈ２Ｏ２ 及Ｆｅｎｔｏｎ 反应则刺激ＭＤＡ 增加． Ｆｅｎｔｏｎ 反应可加速Ｃｈｌ降解． 渗透胁迫下水稻幼苗Ｃｈｌ的降解可能主要是由Ｏ－·２ 和Ｈ２Ｏ２ 的代谢产物·ＯＨ氧化损伤之故     

种子萌发和幼苗生长的抗逆能力与乙烯产生及组织对乙烯敏感性的变化

种子萌发和幼苗生长的抗逆能力与乙烯产生及组织对乙烯敏感性的变化黄学林（中山大学生物学系,广州５１０２７５）ＳＥＥＤＧＥＲＭＩＮＡＴＩＯＮ,ＳＥＥＤＬＩＮＧＧＮＯＷＴＨＡＮＤＥＴＨＹＬＥＮＥＰＲＯＤＵＥＴＩＯＮＯＦＰＬＡＮＴＳＡＮＤＴＨＥＩＲＳＥＮＳＩ...     

授粉诱导蝴蝶兰雌蕊中乙烯合成和ACC氧化酶基因表达

对蝴蝶兰（Ｐｈａｌａｅｎｏｐｓｉｓ “Ｇｅｎｅｒａｌｋｕ”ｈｏｒ．）在授粉后乙烯的合成和１－氨基环丙烷－１－羧酸（ＡＣＣ）氧化酶基因的表达进行了研究。实验结果显示在授粉后１２、２４ 和４８ ｈ,柱头和花柱中乙烯的产生和ＡＣＣ氧化酶ｍ ＲＮＡ 的积累显著下降,而子房中则明显上升,表明授粉后雌蕊中乙烯的产生与ＡＣＣ氧化酶基因的表达密切相关。此外,授粉后雌蕊的柱头中合成的乙烯相对量最多,花柱次之,子房中则较少     

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。     

The effect of plant-hormone pretreatments on ethylene production and synthesis of 1-aminocyclopropane-1-carboxylic acid in water-stressed wheat leaves

Excised wheat (Triticum aestivum L.) leaves, when subjected to drought stress, increased ethylene production as a result of an increased synthesis of 1-aminocyclopropane-1-carboxylic acid (ACC) and an increased activity of the ethyleneforming enzyme (EFE), which catalyzes the conversion of ACC to ethylene. The rise in EFE activity was maximal within 2 h after the stress period, while rehydration to relieve water stress reduced EFE activity within 3 h to levels similar to those in nonstressed tissue. Pretreatment of the leaves with benzyladenine or indole-3-acetic acid prior to water stress caused further increase in ethylene production and in endogenous ACC level. Conversely, pretreatment of wheat leaves with abscisic acid reduced ethylene production to levels produced by nonstressed leaves; this reduction in ethylene production was accompanied by a decrease in ACC content. However, none of these hormone pretreatments significantly affected the EFE level in stressed or nonstressed leaves. These data indicate that the plant hormones participate in regulation of water-stress ethylene production primarily by modulating the level of ACC.Abbreviations ABA abscisic acid - ACC 1-aminocyclopropane-1-carboxylic acid - BA N⁶-benzyladenine - EFE ethylene-forming enzyme - IAA indole-3-acetic acid     

Chilling-Induced Ethylene Production in the Peel and Pulp of Banana

Ethylene production rates and 1-aminocyclopropane-1-carboxylic acid (ACC) synthetase activities were 0. 78,0.91 nl· g-l ·h-land 0.02,0.05 nmol·g-1·h-1 respectively in the peel and pulp of newly harvested banana fruits(Musa acuminata Colla “warf cavendish”),their ethylene-forming enzyme(EFE)activities were yet as high as 10.5 and 5.1 nl·g-1·h-1. When the fruits were chilled at 1.5℃ ,the ethylene production and EFE activities of the peel and pulp kept decreasing with the time course of chilling treatment. However, after these chilled fruits were transferred to 20℃ for 24 h,their ACC synthetase activities increased markedly,and ethylene production had separate peaks(1.75 and 2.45 nl·g-1 ·h-1) in the peel and pulp. In this case,the endogenous low content of S-adenosylmethionine (SAM)in vivo was insufficient for its ACC synthesis, The inhibitory effect of cycloheximide on ACC synthesis showed that chilling-induced ethylene production was mainly the result of activity of the resynthesized ACC synthetase induced by chilling treatment. The production of chilling-induced ethylene could be good indicator of chilling injury, but it is unlikely an indicator of chilling damage during ripening process in banana. In the severly chilling-injured fruits, both the peel and pulp still had the capability of converting ACC to ethylene.     

Regulation of Ethylene Biosynthesis in Avocado Fruit during Ripening

Preclimacteric avocado (Persea americana Mill.) fruits produced very little ethylene and had only a trace amount of l-aminocyclopropane-1-carboxylic acid (ACC) and a very low activity of ACC synthase. In contrast, a significant amount of l-(malonylamino)cyclopropane-1-carboxylic acid (MACC) was detected during the preclimacteric stage. In harvested fruits, both ACC synthase activity and the level of ACC increased markedly during the climacteric rise reaching a peak shortly before the climacteric peak. The level of MACC also increased at the climacteric stage. Cycloheximide and cordycepin inhibited the synthesis of ACC synthase in discs excised from preclimacteric fruits. A low but measurable ethylene forming enzyme (EFE) activity was detected during the preclimacteric stage. During ripening, EFE activity increased only at the beginning of the climacteric rise. ACC synthase and EFE activities and the ACC level declined rapidly after the climacteric peak. Application of ACC to attached or detached fruits resulted in increased ethylene production and ripening of the fruits. Exogenous ethylene stimulated EFE activity in intact fruits prior to the increase in ethylene production. The data suggest that conversion of S-adenosylmethionine to ACC is the major factor limiting ethylene production during the preclimacteric stage. ACC synthase is first synthesized during ripening and this leads to the production of ethylene which in turn induces an additional increase in ACC synthase activity. Only when ethylene reaches a certain level does it induce increased EFE activity.     

Ethylene-promoted conversion of 1-aminocyclopropane-1-carboxylic Acid to ethylene in peel of apple at various stages of fruit development

Internal ethylene concentration, ability to convert 1-amino-cyclopropane-1-carboxylic acid (ACC) to ethylene (ethylene-forming enzyme [EFE] activity) and ACC content in the peel of apples (Malus domestica Borkh., cv Golden Delicious) increased only slightly during fruit maturation on the tree. Treatment of immature apples with 100 microliters ethylene per liter for 24 hours increased EFE activity in the peel tissue, but did not induce an increase in ethylene production. This ability of apple peel tissue to respond to ethylene with elevated EFE activity increased exponentially during maturation on the tree. After harvest of mature preclimacteric apples previously treated with aminoethoxyvinyl-glycine, 0.05 microliter per liter ethylene did not immediately cause a rapid increase of development in EFE activity in peel tissue. However, 0.5 microliter per liter ethylene and higher concentrations did. The ethylene concentration for half-maximal promotion of EFE development was estimated to be approximately 0.9 microliter per liter. CO₂ partially inhibited the rapid increase of ethylene-promoted development of EFE activity. It is suggested that ethylene-promoted CO₂ production is involved in the regulation of autocatalytic ethylene production in apples.     

Ethylene production and β-cyanoalanine synthase activity in carnation flowers

The relationship between ethylene production and the CN^--assimilating enzyme -cyanoalanine synthase (CAS; EC 4.4.1.9) was examined in the carnation (Dianthus caryophyllus L.) flower. In petals from cut flowers aged naturally or treated with ethylene to accelerate senescence the several hundred-fold increase in ethylene production which occurred during irreversible wilting was accompanied by a one- to twofold increase in CAS activity. The basal parts of the petal, which produced the most ethylene, had the highest CAS activity. Studies of flower parts (styles, ovaries, receptacles, petals) showed that the styles had a high level of CAS together with the ethylene-forming enzyme (EFE) system for converting 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene. The close association between CAS and EFE found in styles could also be observed in detached petals after induction by ACC or ethylene. Treatment of the cut flowers with cycloheximide reduced synthesis of CAS and EFE. The data indicate that CAS and ethylene production are associated, and are discussed in relation to the hypothesis that CN^- is formed during the conversion of ACC to ethylene.Abbreviations ACC 1-aminocyclopropane-1-carboxylic acid - AVG aminoethoxyvinylglyoine - CAS -cyanoalanine synthase - CHI cycloheximide - EFE ethylene-forming enzyme     

Wound ethylene and 1-aminocyclopropane-1-carboxylate synthase in ripening tomato fruit

Ethylene production, 1-aminocyclopropane-1-carboxylic acid (ACC) levels and ACC-synthase activity were compared in intact and wounded tomato fruits (Lycopersicon esculentum Mill.) at different ripening stages. Freshly cut and wounded pericarp discs produced relatively little ethylene and had low levels of ACC and of ACC-synthase activity. The rate of ethylene synthesis, the level of ACC and the activity of ACC synthase all increased manyfold within 2 h after wounding. The rate of wound-ethylene formation and the activity of wound-induced ACC synthase were positively correlated with the rate of ethylene production in the intact fruit. When pericarp discs were incubated overnight, wound ethylene synthesis subsided, but the activity of ACC synthase remained high, and ACC accumulated, especially in discs from ripe fruits. In freshly harvested tomato fruits, the level of ACC and the activity of ACC synthase were higher in the inside parts of the fruit than in the pericarp. When wounded pericarp tissue of green tomato fruits was treated with cycloheximide, the activity of ACC synthase declined with an apparent half life of 30–40 in. The activity of ACC synthase in cycloheximide-treated, wounded pericarp of ripening tomatoes declined more slowly.Abbreviation ACC 1-aminocyclopropane-1-carboxylic acid