TIBA,LaCl3,Verapamil和TFP对菜豆下胚轴生长素诱导的导管分化…

通过ＴＩＢＡ、ＬａＣｌ３、Ｖｅｒａｐａｍｉｌ和ＴＦＰ对菜豆下胚轴导管分化和形成的调控作用,证明生长素、Ｃａ＾２＋和ＣａＭ是木质部导管分化和形成所必需的。ＮＡＡ能诱导菜豆下胚轴导管的分化;ＴＩＢＡ能抑制生长素类诱导的导管分化和形成;ＬａＣｌ３和ＴＦＰ在导管分化诱导期（最初２４ｈ）具抑制作用;Ｖｅｒａｐａｍｉｌ与ＴＩＢＡ相似,在导管分化诱导期和导管形成期（伤口形成后７２ｈ之内）都有抑制作用。     

光,Ca^2＋和CaM对菜豆叶枕外植体脱落的影响

红光抑制而远红光促进菜豆叶枕外植体的脱落过程。红光抑制脱落必须有Ca~(2 )参与,红光效应与A_(23187)类似。La~(3 )、CPZ和TFP都具有阻止红光抑制脱落的作用。外施Ca~(2 )在红光下对脱落过程稍有促进。     

植物导管分子分化和形成的生理生化机制

从木质素代谢、细胞凋亡、生长素在导管分子分化和形成过程中的作用等方面对近年来植物导管分子分化和形成的生理生化机制研究进展作了介绍.     

脑缺血诱导Ca~（2＋）／CaM依赖性蛋白激酶Ⅱ自身磷酸化的抑制作用

脑缺血诱导Ｃａ~（２＋）／ＣａＭ依赖性蛋白激酶Ⅱ自身磷酸化的抑制作用张光毅,唐放鸣,赵昇皓（徐州医学院生化教研室,２２１００２）关键词脑缺血;Ｃａ~（２＋）／ＣａＭ依赖性蛋白激酶Ⅱ;自身磷酸化兴奋住氨基酸通过其突触后膜受体导致ｏｄｅ内流,不仅具有诱导和...     

生长素、乙烯和一氧化氮对拟南芥下胚轴插条形成不定根的调节

研究生长素、乙烯和一氧化氮（NO）对拟南芥下胚轴插条形成不定根的调节,以及生长素和乙烯信号转导成员在IAA促进不定根形成中的作用的结果表明：拟南芥切条以IAA和硝普钠（N0供体）单独处理7d后的不定根形成均受到促进,其中以50μmol·L^-1 IAAμmol·L^-1 SNP的促进作用为最强,乙烯的促进作用不明显;生长素运输和信号转导以及乙烯信号转导相关突变体对IAA促进生根作用的敏感性比野生型有所下降,特别是IAA14功能获得型的突变体。IAA和NO在促进不定根形成中有协同效应。     

RU486对兔输卵管平滑肌的收缩效应

应用肌肉机械－电换能器和Ｇｉｌｓｏｎ生理记录仪,观察ＲＵ４８６对假孕４ｄ兔离体输卵管平滑肌的收缩效应。结果显示：（１）ＲＵ４８６可直接作用输卵管平滑肌,使其收缩频率增加,而未明显改变收缩张力及振幅,与在体肌内注射ＲＵ４８６观察到的结果相似;（２）ＲＵ４８６部分抑制ｃａ~（２＋）诱发的平滑肌收缩活动,它还与Ｖｅｒａｐａｍｉｌ诱发的抑制效应有协同作用,与ＮＥ诱发的收缩张力有拮抗作用,而对Ｆｏｒｓｋｏｌｉｎ诱发的效应未产生任何影响。以上结果表明,ＲＵ４８６对输卵管平滑肌的作用似乎是改变细胞内游离Ｃａ（２＋）的结果,可能干扰Ｃａ（２＋）的流入、或／和内质网Ｃａ（２＋）释放以及Ｃａ（２＋）－Ｉｐ３信息传递机制。     

丛枝菌根真菌、磷和生长素对枳侧根形成的调控效应

为探讨丛枝菌根真菌(AMF)、磷水平和生长素对植物侧根形成的影响,在两种磷水平下接种AMF(Rhizophagus irregularis BGC JX04B),施用IBA、生长素运输抑制剂(TIBA),观察AMF、磷水平和生长素对枳Poncirus trifoliata幼苗侧根形成的调控效应。结果表明,AMF对植株生物量及各级侧根数量无显著影响,但显著降低一级侧根长度;磷水平对植株生物量、侧根数量及长度无显著影响;TIBA显著降低植株生物量、侧根数量和侧根长度,而IBA对各项指标无显著影响。AMF和生长素对主根长度的影响存在显著互作;AMF、磷水平和生长素对二级和三级侧根数量的影响存在显著互作。因此,AMF对枳侧根形成的调控可能涉及生长素信号途径,而生长素运输是枳侧根形成的关键因素。     

红光对绿豆下胚轴线粒体Ca~(2+)积累、ATPase及NAD激酶活性的影响

绿豆下胚轴切段经红光处理后10min,其线粒体的Ca~(2+)积累下降15％,Ca~(2+)-ATPase 及 Mg~(2+)-ATPase活性也分别下降29％和10％,切段CaM含量增加近1倍。Ca~(2+)存在时,红光能促进线粒体NAD 激酶活性。说明Ca~(2+)-ATPase及一部分Mg~(2+)-ATPase可作为钙泵控制Ca~(2+)进入线粒体。     

GM_3、GD_3作用下SMMC－7721肝癌细胞内磷脂酰肌醇（1，4，5）三

外源性ＧＭ３（１０ｎｍｏｌ／ｍＬ）、ＧＤ３（１ｎｍｏｌ／ｍＬ）可使ＳＭＭＣ－７７２１人肝癌培养细胞内钙浓度呈快速的短暂升高,其到达峰值时间为４５秒,一次作用后,内钙水平于２－３ｍｉｎ内恢复至对照水平。在一定时间间隔中连续几次加入ＧＭ３或ＧＤ３后内钙水平的变化表明,ＧＭ３所引起的［Ｃａ２＋］ｉ的增加依赖于内质网钙贮的释放和细胞外钙的流入;而ＧＤ３增加［Ｃａ２＋］ｉ与此二系统无关。进一步研究表明,在细胞内钙达峰值时,１０ｎｍｏｌ／ｍＬＧＭ３可使ＩＰ３（１,４,５）浓度增加９．３倍,ｃＡＭＰ浓度增加８２％;１ｎｍｏｌ／ｍＬＧＤ３反使Ｉｐ３浓度增加１．２倍,提示ＧＭ３、ＧＤ３升高内钙的不同机制。     

ABA、IAA和CaM对发育菜豆子叶质膜H~＋－ATPase活力的效应

以亲水性两相分配法从发育菜豆子叶制备的质膜制剂经冻融循环操作,部分膜微囊可转变成密闭的翻转型。取冻融４次的质膜微囊用于Ｈ＋－ＡＴＰａｓｅ试验表明,ＡＴＰａｓｅ活力为ＡＢＡ和ＣａＭ显著地激活,但受ＩＡＡ显著抑制;质子泵活力被ＡＢＡ显著促进,但为ＣａＭ显著抑制,ＩＡＡ对质子泵活力无显著效应。可以认为：ＡＢＡ促进发育菜豆子叶吸收光合同化物可能是通过促进质膜Ｈ＋－ＡＴＰａｓｅ活力,从而促进质子／蔗糖同向运输而获得;ＩＡＡ则可能对菜豆子叶的质膜Ｈ＋－ＡＴＰａｓｅ无显著效应。在激素信号传导途径中,ＣａＭ对质膜Ｈ＋－ＡＴＰａｓｅ活力可能无直接影响。     

Regulation of Auxin-induced Ethylene Production in Mung Bean Hypocotyls: Role of 1-Aminocyclopropane-1-Carboxylic Acid

Ethylene production in mung bean hypocotyls was greatly increased by treatment with 1-aminocyclopropane-1-carboxylic acid (ACC), which was utilized as the ethylene precursor. Unlike auxin-stimulated ethylene production, ACC-dependent ethylene production was not inhibited by aminoethoxyvinylglycine, which is known to inhibit the conversion of S-adenosylmethionine to ACC. While the conversion of methionine to ethylene requires induction by auxin, the conversion of methionine to S-adenosylmethionine and the conversion of ACC to ethylene do not. It is proposed that the conversion of S-adenosylmethionine to ACC is the rate-limiting step in the biosynthesis of ethylene, and that auxin stimulates ethylene production by inducing the synthesis of the enzyme involved in this reaction.     

A Fine Structural Analysis of Auxin-induced Elongation of Cucumber Hypocotyls, and the Effects of Calcium Antagonists and Ionophores

The fine structure of epidermal cells, particularly in relationto dictyosomes, has been examined in different regions of dark-growncucumber hypocotyls and in response to auxin treatment, usingboth dot overlay and image analysis techniques. The most noticeablechange in cell structure along the hypocotyls is the increasein vacuolar volume. The volume fraction occupied by dictyosomesand secretory vesicles also increased, whereas that for mitochondriaremained relatively constant. During auxin treatment, the volumefraction for dictyosomes showed an increase after 30 min followedby a fall, whereas that occupied by secretory vesicles fellsteadily over 90 min. The number of cisternae per dictyosomeshowed some increase after 2 h of auxin treatment, althoughthe increase in dictyosomal material with cell expansion waslargely accounted for by an increase in the number of dictyosomes. Auxin-stimulated elongation growth of the hypocotyls was inhibitedby a range of calcium antagonists, chelators and ionophores.The most marked inhibitions were observed with calcium chloride,the chelator chlortetracycline and the ionophores verapamil,nigericin and monensin. Linear transducer experiments showedthat these compounds generally caused an immediate reductionin the rate of growth. Fine structural observations carriedout on epidermal cells showed the most obvious effects withmonensin and nigericin which caused dictyosomes and secretoryvesicles to swell. EGTA and LaCl₃ caused secretory vesiclesto accumulate around dictyosomes, while the ionophore A23187had little effect. The results suggest that the concentration of Ca²⁺ in the cytoplasmmay be critical for cell elongation. Compounds which chelateCa²⁺ appear to be more effective inhibitors of growth in theinitial acid-induced phase, whereas those which affect ionicgradients are more disruptive in the second phase.Copyright1993, 1999 Academic Press Calcium, Cucumis sativus hypocotyle, dictyosomes, elongation growth, indoleacetic acid, stereology     

Inactivity of Oxidation Products of Indole-3-acetic Acid on Ethylene Production in Mung Bean Hypocotyls

The suggestion that indole-3-acetic acid (IAA)-stimulated ethylene production is associated with oxidative degradation of IAA and is mediated by 3-methyleneoxindole (MOI) has been tested in mung bean (Phaseolus aureus Roxb.) hypocotyl segments. While IAA actively stimulated ethylene production, MOI and indole-3-aldehyde, the major products of IAA oxidation, were inactive. Tissues treated with a mixture of intermediates of IAA oxidation, obtained from a 1-hour incubation of IAA with peroxidase, failed to stimulate ethylene production. Furthermore, chlorogenic acid and p-coumaric acid, which are known to interfere with the enzymic oxidation of IAA to MOI, had no effect on IAA-stimulated ethylene production. Other oxidation products of IAA, including oxindole-3-acetic acid, indole-3-carboxylic acid, (2-sulfoindole)-3-acetic acid, and dioxindole-3-acetic acid, were all inactive. 1-Naphthaleneacetic acid was as active as IAA in stimulating ethylene production but was decarboxylated at a much lower rate than IAA, suggesting that oxidative decarboxylation of auxins is not linked to ethylene production. These results demonstrate that IAA-stimulated ethylene production in mung bean hypocotyl tissue is not mediated by MOI or other associated oxidative products of IAA.     

Effect of 2,4-Dinitrophenol on Auxin-induced Ethylene Production and Auxin Conjugation by Mung Bean Tissue

Auxin-induced ethylene production by mung bean (Phaseolus mungo L.) hypocotyl segments was markedly inhibited by 2,4-dinitrophenol regardless of whether or not kinetin was present. Uptake of indoleacetic acid-2-¹⁴C was also inhibited in the presence of 2,4-dinitrophenol. Segments treated only with indoleacetic acid rapidly converted indoleacetic acid into indole-3-acetylaspartic acid with time whereas kinetin suppressed indoleacetic acid conjugation. Formation of indole-3-acetylaspartic acid was significantly reduced when 2,4-dinitrophenol was present. The suppression of indoleacetic acid conjugation by kinetin and 2,4-dinitrophenol appeared to be additive, and the free indoleacetic acid level in segments treated with 2,4-dinitrophenol in the presence of indoleacetic acid or indoleacetic acid plus kinetin was remarkably higher than in corresponding segments which received no 2,4-dinitrophenol.     

Effects of AgNO3 and Ethylene Biosynthetic Inhibitors on Auxin-induced Petiole Epinasty of Morus alba

A family-4 α-galactosidase Mel4A of Bacillus halodurans was expressed in Escherichia coli and characterized. Recombinant enzyme rMel4A depended on NAD⁺, some divalent cations such as Mn²⁺, and reducing reagents such as dithiothreitol. rMel4A was active on small saccharides such as raffinose but not on highly polymerized galactomannan. Immunological analysis indicated that raffinose induced the production of Mel4A in B. halodurans.     

乙烯利、ACC、AOA和AgNO3对绿豆下胚轴插条不定根形成的作用

以绿豆下胚轴插条为实验材料,研究了乙烯利、ACC、AOA和AgNO,对其不定根形成的影响。结果表明：乙烯利和ACC能促进绿豆下胚轴插条的生根,最适浓度分别为50μmol／L和10μmol／L;AOA和AgNO3明显抑制不定根形成,随浓度增加,抑制作用增强。插条离体后24h内对ACC的促进作用和AOA的抑制作用敏感。插条在0-6h和18-24h用ACC处理,在0-2h和22-24h用50μmol／L乙烯利处理的生根效果好。乙烯在不定根形成的诱导期和起始晚期起促进作用。     

Somatic Embryogenesis and Bud Formation on Cultured Fagopyrum esculentum Hypocotyls

An indirect somatic embryogenesis via the development of proembryogenic cell complexes (PECC) was observed in the in vitro cultured hypocotyl explants of 4–5-day-old buckwheat (Fagopyrum esculentum Moench.) seedlings. PECC development was shown to depend on culturing conditions, including 2,4-D concentration and the period of explant exposure to 2,4-D, sucrose concentration, and explant density. The culturing protocol was designed to ensure the development of buckwheat somatic embryos in two-month period. The cytogenetic analysis demonstrated that this protocol did not affect the chromosome numbers in the regenerated plants.     

H2O2在黄瓜和绿豆下胚轴不定根形成中的作用

以黄瓜和绿豆下胚轴插条为试验材料,研究了H2O2对不定根形成的诱导作用,以及在此过程中与IAA、NO的关系。结果表明,H2O2能促进不定根的形成,最佳浓度是100μmol/L;H2O2的清除剂———过氧化氢酶(CAT)抑制了IAA诱导的不定根形成,说明H2O2可能介导了IAA诱导不定根形成的过程;NO清除剂———PTIO能抑制H2O2诱导的不定根形成,表明NO在H2O2诱导不定根形成的过程中起介导作用。综合上述结果,推测在不定根形成的过程中可能存在以下关系:IAA首先诱导H2O2合成,H2O2升高后,再诱导NO产生,最终导致不定根生成。     

盐胁迫下氯丙嗪和LaCl_3对稻苗K~ 、Na~ 、Cl~-吸收转运的影响

研究了氯丙嗪 (CPZ)和LaCl3 预处理阻碍Ca2 ·CaM信使系统传导后 ,盐胁迫下稻苗体内Na 、K 和Cl-含量及吸收转运的变化 ,结果表明 :CPZ和LaCl3 预处理后 ,盐胁迫下稻苗对K /Na 的选择性吸收下降 ,致使稻苗K 含量减少、Na 含量增加 ,Na /K 比值显著增加 ;并且稻苗地上部Cl-含量也显著增加。盐胁迫处理稻苗 2d后解除盐胁迫 ,改用蒸馏水培养 ,在蒸馏水中加入CPZ或LaCl3 时 ,稻苗中含有较高的Na ,即CPZ和LaCl3 抑制稻苗将体内Na 排出体外的能力。上述结果表明 ,盐胁迫下 ,Ca2 ·CaM信使系统可能参与稻苗对K 、Na 和Cl-的吸收转运以适应盐胁迫