Nifedipine对烟草花粉萌发、花粉管生长及生殖核分裂的影响

用细胞学和统计学方法研究了Ｃａ２＋ 通道专一性阻滞剂ｎｉｆｅｄｉｐｉｎｅ（Ｎｉｆ）对烟草（Ｎｉｃｏｔｉａｎａ ｔａｂａｃｕｍＬ．）离体花粉萌发、花粉管生长及生殖核分裂的影响。１０－ ４ ｍ ｏｌ／ＬＮｉｆ可抑制花粉萌发。Ｎｉｆ对花粉管生长的影响与其浓度和处理持续时间有关,１０－ ４ ｍ ｏｌ／Ｌ Ｎｉｆ始终抑制花粉管生长;而１０－ ７～１０－ ５ ｍ ｏｌ／ＬＮｉｆ在较短时间内起不同程度的促进作用,之后逐渐过渡为抑制花粉管生长。较高浓度处理可使花粉管形态趋向异常,细胞质流动趋于停滞。Ｎｉｆ抑制生殖核的有丝分裂,相对推迟分裂高峰。Ｎｉｆ使花粉管中的金霉素（ＣＴＣ）荧光趋于减弱,表明Ｎｉｆ通过抑制Ｃａ２＋ 通道活性产生生理效应。着重讨论了Ｎｉｆ抑制生殖核分裂的可能原因     

外源钙调素和钙调素拮抗剂对烟草离体花粉和生长和生殖核分裂 …

外源花椰菜钙调素,牛脑ＣａＭａｇａｒｏｓｅ以及ＣａＭ拮抗剂ＴＦＰ对花粉管生长与生殖核分裂的作用均具有浓度和时间效应,ＣａＭ在花粉管生长早期,较低浓度能促进花粉管生长和生殖核分裂;但后期,较高浓度则有抑制作用。     

外源钙调蛋白对植物细胞分裂增殖作用的研究

外源钙调蛋白（Ｃａｌｍｏｄｕｌｉｎ,ＣａＭ）对胡萝卜悬浮细胞增殖具明显促进作用,不同浓度ＣａＭ的促进程度不同,７ｕｇ／ｍｌ时促进作用最大。ＣａＭ抑制剂ＴＦＰ（Ｔｒｉｆｌｕｏｐｅｒ－ａｚｉｎｅ）则明显抑制该悬浮细胞的增殖,ＴＦＰ浓度越高则抑制作用越强。另外,外源ＣａＭ可以加快珍珠梅花粉第二次有丝分裂,改变生殖细胞有丝分裂各期花粉管的比例,说明外源ＣａＭ对植物体细胞和性细胞的增殖和分裂均有促进作用。     

钙调素mRNA和蛋白在水稻花药和雌蕊发育过程中的原位定位

利用ＲＮＡ原位杂交和免疫组织化学定位技术分别检测了钙调素ｍＲＮＡ和钙调素蛋白在水稻（ＯｒｙｚａｓａｔｉｖａＬ．）花药和雌蕊发育过程中的时空分布特征。钙调素基因在绒毡层、柱头、花粉管生长途径、退化助细胞以及维管薄壁细胞中大量表达,也可在小孢子母细胞、小孢子、花粉、反足细胞、卵细胞以及中央细胞中检测到。钙调素基因的表达强度随不同的发育阶段而变化：花药发育早期表达强,以后逐渐减弱并向特定部位集中,如绒毡层和花粉萌发孔等。胚胎发育早期,钙调素基因在胚乳细胞中的表达比原胚中强,而后期则在分化胚中比胚乳细胞中强。推测在有性生殖过程中,钙调素可能通过Ｃａ２＋ＣａＭ信号途径调节小孢子发育、花粉萌发、花粉管生长、受精以及物质运输等生理过程     

Nifedipine对烟草粉萌发,花粉管生长及生殖核分裂的影响

用细胞学和统计方法研究了Ｃａ＾２＋通道专一性阻滞剂ｎｉｆｅｄｉｐｉｎｅ对烟草离体花粉萌发,花粉管生长及生殖核分裂的影响。１０＾－４ｍｏｌ／Ｌ Ｎｉｆ可抑制花粉萌发。Ｎｉｆ对花粉管生长的影响与其浓主和和处理持续廛彰关,１０＾－４ｍｏｌ／Ｌ Ｎｉｆ始终抑制花粉管生长;而１０＾－７－１０＾－５ｍｏｌ／Ｌ Ｎｉｆ在较短时间内起不同程度的促进作用,之后逐渐过渡为抑制花粉管生长。     

外源钙调蛋白对植物细胞分裂增殖作用的研究

外源钙调蛋白（ＣａＭ）对胡萝卜悬浮细胞增殖具明显促进作用,不同浓度ＣａＭ的促进程度不同,７μｇ／ｍｌ时促进作用最大。ＣａＭ抑制剂ＴＦＰ则明显抑制该悬浮细胞的增殖,ＴＦＰ浓度越高则抑制作用越强。另外,外源ＣａＭ可以加快珍珠梅花粉第二次有丝分裂,改变生殖细胞有丝分裂各期花粉管的比例,说明外源ＣａＭ对植物体细胞和性细胞的增殖和分裂均有促进作用。     

蛋白酶体抑制剂MG132对青扦花粉萌发和花粉管生长的影响

泛素／蛋白酶体系统（UPP）是真核细胞内蛋白质选择性降解的主要途径,而蛋白酶体是UPP中蛋白质降解的场所。本文应用细胞学、统计学方法以及FTIR技术研究了蛋白酶体抑制剂MG132对青扦（Pecea wilsonii）花粉萌发、花粉管生长的影响。结果表明：MG132显著抑制青扦花粉萌发和花粉管生长,并导致花粉管形态异常,主要表现为花粉管亚顶端出现液泡化,并且液泡随着培养时间的延长而扩大到整个花粉管,花粉管濒临死亡;而DMSO以及非蛋白酶体抑制剂E-64不产生类似结果;半薄切片结果表明,MG132处理后不仅花粉管细胞质发生液泡化,生殖细胞也发生液泡化;FTIR分析进一步表明,MG132处理后,花粉管顶端的细胞壁蛋白和果胶质含量大幅度下降。上述结果表明：MG132通过抑制蛋白酶体活性显著影响青扦花粉萌发及花粉管生长;UPP在青扦花粉萌发、花粉管极性生长模式的建立和维持过程中起重要作用;抑制蛋白酶体活性将导致青扦花粉管的程序性死亡。     

急性低氧对大鼠脑组织钙调素含量及其依赖性蛋白激酶Ⅱ活性的影响

本实验观察了活性钙调素（ＣａＭ）含量和ＣａＭ依赖性蛋白激酶Ⅱ（ＣａＭｋｉｎａｓｅⅡ）活性在急性低氧（模拟海拔７０００ｍ,５ｈ）和常氧对照大鼠脑子组织中的变化。用流式产胞仪（ＦＡＣＳ）所测两组动物脑皮层细胞的ＣａＭ,平均荧光强度分别为４０．０±４．９和４６．１±５．８,急性低氧组明显低于常氧对照组（Ｐ＜０．０５）;用同位素液闪计数法所测两组动物皮层脑匀浆提取液中ＣａＭｋｉｎａｓｅⅡ活性,分别为１８４．３±８．１和１９８．８±９．４ｐｍｏｌＰｉ·ｍｉｎ－１·ｍｇ－１ｐｒｏ,急性低氧组明显低于常氧对照组（Ｐ＜０．０１）。结果提示ＣａＭ和ＣａＭｋｉｎａｓｅⅡ对低氧较为敏感,急性低氧时中枢神经细胞结构或功能的紊乱可能与活性ＣａＭ的含量减少和ＣａＭｋｉｎａｓｅⅡ活性能下降有关。     

用免疫亲和层析和ELISA测定百合花粉萌发过程中细胞分裂素含量的变化

兰州百合（Ｌｉｌｉｕｍ ｄａｖｉｄｉｉＤａｃｈ．）花粉在ＰＥＧ－４００ 中萌发,用高度灵敏和特异的ｔ－ＺＲ－ＩｇＧ和ｉＰＡ－ＩｇＧ 免疫亲和层析分离纯化萌发花粉和萌发液中细胞分裂素,并用酶检疫连锁鉴定法（ＥＬＩＳＡ）测定Ｎ６－异戊烯腺嘌呤核苷（ｔ－ＺＲ）和异戊烯基腺苷（ｉＰＡ）含量。结果表明每克鲜重花粉含有３９ ｎｇ ｔ－ＺＲ和４８ ｎｇ ｉＰＡ。花粉水合后ｔ－ＺＲ 含量略有下降,而ｉＰＡ 含量明显增高,细胞分裂素总量几乎不变。水合过程中有细胞分裂素的消长,这种变化与花粉管的启动有关。在萌发的前３ 小时,花粉管生长速度最快,ｔ－ＺＲ和ｉＰＡ 在花粉管和萌发液中的含量也随着增加,其增长趋势和花粉管生长速度同步     

亚精胺对苹果花粉萌发与花粉管伸长的抑制效应及其与Ca^2 …

２０～１００μｍｏｌ．ｌ＾－１外源亚精胺（Ｓｐｄ）抑制苹果（品种：国光、富士、金冠）花粉萌发与花粉管伸长,其效应随浓度增加而增强;Ｃａ＾２＋（１ｍｍｏｌ．Ｌ＾－１）在一定程度上削弱这种抑制效应,而Ｃａ＾２＋的良好作用则又为Ｃａ＾２＋通道竞争性抑制剂Ｌａ＾２＋所消除,Ｃａ＾２＋载体Ａ２３１８７仅削弱Ｃａ＾２＋对花粉管 工的良好作用。     

花柱和花粉胞外钙调素对花粉萌发和花粉管伸长的影响

以烟草为材料,通过半体内实验,就花柱和花粉胞外钙调素对花粉萌发和花粉管伸长的影响进行了观察。发现用EGTA及钙调素抗血清处理柱头或花粉均可抑制花粉在柱头上的萌发;向花柱引导组织中显微注射纯化钙调素可促进花粉管束伸长,而注射钙调素抗血清可抑制花粉管束伸长;同时证实玉米花柱和花粉细胞壁中均存在钙调素及钙调素结合蛋白,而且花粉和花柱细胞壁中钙调素结合蛋白的种类有差异。结果表明存在于花粉和花柱细胞外的钙调素对花粉萌发和花粉管伸长均有促进作用。     

The effects of extracellular calmodulin on initiation of Hippeastrum rutilum pollen germination and tube growth

The effects of anti-calmodulin (CaM) serum, the CaM antagonist W7-agarose, the Ca²⁺ chelator ethyleneglycol-bis-(β-aminoethyl)-N,N,N′,N′-tetraacetic acid (EGTA) and exogenous pure CaM on pollen germination and tube growth of Hippeastrum rutilum Herb were studied. Pollen germination and tube growth were inhibited or completely stopped by anti-CaM serum in a dose-dependent manner, while the same amount of preimmune serum had no effect on either process. Pollen germination and tube growth were also inhibited or completely stopped by the CaM antagonist W7-agarose and the Ca²⁺ chelator EGTA. The addition of exogenous pure CaM enhanced pollen germination and tube growth, whereas the same amount of bovine serum albumin had no effect. The inhibitory effects caused by anti-CaM serum, W7-agarose and EGTA-washing could be reversed completely by the addition of exogenous pure CaM. These results indicate that extracellular CaM initiates pollen germination and tube growth, whereas exogenous CaM enhances the above processes, and may provide a novel view for understanding the control of pollen germination and tube growth. Received: 12 December 1996 / Accepted: 15 January 1997     

Computer-assisted Video Image Analysis of Spatial Variations in Membrane-associated Ca2+ and Calmodulin during Pollen Hydration, Germination and Tip Growth in Nicotiana tabacum L.

Video images of the distributional pattern of membrane-associatedcalcium (Ca²⁺) and calmodulin (CaM) have been documented andanalysed during pollen hydration, germination and tip growthin Nicotiana tabacum. Digitization of fluorescence microscopeimages of chlorotetracycline (CTC) and fluphenazine (FPZ)-fluorescenceemissions reveal that there is a maximum concentration of membrane-associatedCa²⁺ and also CaM in the vicinity of germination apertures ofhydrated pollen. With the onset of germination relatively higheramounts of Ca²⁺ and CaM were found to regionalize towards theaperture through which the pollen tube would emerge Both shortand long growing pollen tubes manifest tip-to-base Ca²⁺ andCaM gradients which are disturbed in non-growing tubes. Tubegrowth and the Ca²⁺-gradient were significantly affected byvanadate and verapamil suggesting that both a vanadate-sensitiveCa²⁺-transport system and verapamil-sensitive Ca²⁺ channelsare involved in maintaining Ca²⁺ homeostasis during pollen germinationand tube growth. The possible interactions of Ca²⁺ and CaM withdifferent cytoskeletal proteins modulating organelle movementare also briefly discussed. Image analysis, calcium, calmodulin, Nicotiana tabacum L., pollen germination, pollen tube, tip growth, Ca²⁺-channels, Ca²⁺ transport ATPase     

An apoplastic mechanism for short-term effects of rare earth elements at lower concentrations

The short-term effects of rare earth elements on pollen germination and tube growth were tested. Concentrations of 2.5 approximately 20 micro m lanthanum(La3+) or cerium (Ce3+)increased pollen germination and pollen tube growth, whereas concentrations higher than 40 micro m La3+ and Ce3+ inhibited this process. The most effective concentration of La3+ needed for promotion shifted from 10 to 40 micro m, depending on the Ca2+ concentration in the medium. Calmodulin (CaM) antagonist W7-agarose and anti-CaM antibody depressed La3+-promoted pollen germination and tube growth in a dose-dependent manner. La3+-CaM complexes (La3+-CaM) increased pollen germination and tube growth more than CaM or La3+ alone. Pertussis toxin (PTX) inhibited La3+-promoted pollen germination and tube growth. Cholera toxin (CTX) partially recovered the inhibition of the above La3+-promoted process by the anti-CaM antibody. Concentrations of 10-7 approximately 10-9 m La3+-CaM increased GTPase activity inside plasma membrane vesicles of the pollen tube, but apo-CaM or La3+ alone had no positive effects. The results suggest that apoplastic CaM may be involved in the promotion effects of lower concentrations of La3+ on pollen germination and tube growth, and the heterotrimeric G-protein on the plasma membrane may transduce La3+-activated CaM signalling. The present studies provide an apoplastic mechanism for short-term effects of rare earth elements at lower concentrations in the pollen system.     

肌醇磷脂信号途径参与胞外钙调素启动花粉萌发和花粉管伸长

高等植物有性生殖是植物发育生物学研究的重要内容之一,而作为雄配子体的花粉在雌蕊柱头上萌发及花粉管在花柱内的持续生长是有性生殖实现的关键。已有许多研究表明Ca2 在花粉萌发和花粉管生长过程中起重要作用。最近,我室在多年细胞外钙调素（calinodulin,CaM）存在。性质及生物学功能研究（孙大业等1995;Sun等1994,1995;Tang等1996）的基础上,通过不过膜的大分子CaM拈抗剂或抗体并结合恢复实验证实细胞外CaM对花粉的萌发和花粉管的伸长具有启动作用（马力耕和孙大业1996）,并发现G蛋白、质膜Caz”通道及胞内依赖Caz”的蛋白…     

The presence of a heterotrimeric G protein and its role in signal transduction of extracellular calmodulin in pollen germination and tube growth

The role of heterotrimeric G proteins in pollen germination, tube growth, and signal transduction of extracellular calmodulin (CaM) was examined in lily pollen. Two kinds of antibodies raised against animal Gzalpha, one against an internal sequence and the other against its N terminus, cross-reacted with the same 41-kD protein from lily pollen plasma membrane. This 41-kD protein was also specifically ADP ribosylated by pertussis toxin. Microinjection of the membrane-impermeable G protein agonist GTP-gamma-S into a pollen tube increased its growth rate, whereas microinjection of the membrane-impermeable G protein antagonist GDP-beta-S and the anti-Galpha antibody decreased pollen tube growth. The membrane-permeable G protein agonist cholera toxin stimulated pollen germination and tube growth. Anti-CaM antiserum inhibited pollen germination and tube growth, and this inhibitory effect was completely reversed by cholera toxin. The membrane-permeable heterotrimeric G protein antagonist pertussis toxin completely stopped pollen germination and tube growth. Purified CaM, when added directly to the medium of plasma membrane vesicles, significantly activated GTPase activity in plasma membrane vesicles, and this increase in GTPase activity was completely inhibited by pertussis toxin and the nonhydrolyzable GTP analogs GTP-gamma-S and guanylyl-5'-imidodiphosphate. The GTPase activity in plasma membrane vesicles was also stimulated by cholera toxin. These data suggest that heterotrimeric G proteins may be present in the pollen system where they may be involved in the signal transduction of extracellular CaM and in pollen germination and tube growth.     

蚕豆下表皮细胞外钙调素的存在及其对气孔运动的调节

细胞外钙调素可能作为多肽第一信使,调节细胞增殖、花粉萌发、特定基因表达等生理过程.气孔能灵敏地对外界刺激作出反应,快速开闭.本文用免疫电镜和免疫荧光显微镜技术证明保卫细胞及其它表皮细胞胞外都存在钙调素.外源纯化钙调素能促进气孔关闭、抑制气孔开放,最适浓度为10-8mol/L;不能透过质膜的大分子钙调素拮抗剂W7-agarose和钙调素抗血清都能抑制气孔关闭、促进开放,说明保卫细胞的内源胞外钙调素确实能促进气孔关闭、抑制开放,而且只能在细胞外起作用.推测在自然情况下,保卫细胞内源胞外钙调素可能作为胞外第一信使和其它信号分子一起调节气孔的开关运动,而且可能在环境刺激与细胞响应之间起重要作用.     

桃花粉离体萌发和花粉管生长特性研究

采用花粉离体萌发法研究不同培养基组分和培养条件对桃花粉萌发和花粉管生长的影响,同时对不同贮藏温度下的桃花粉寿命进行研究.结果表明:固体培养基与液体培养基对桃的花粉萌发率和花粉管长度影响差异不显著;10%蔗糖是大多数桃品种花粉的最适萌发条件;硼能提高桃花粉的萌发率,但对花粉管的生长没有促进作用;桃花粉在20℃～25℃的培养温度下萌发率最高,花粉管最长;桃花粉萌发率和花粉管长度在培养前3 h内上升最快,3～5 h上升趋势减弱,5 h后基本停止;随着贮藏温度的升高和贮藏时间的延长,花粉生活力呈降低的趋势.     

蚕豆下表皮细胞外钙调素的存在及其对气孔运动的调节

细胞外钙调素可能作为多肽第一信使,调节细胞增殖,花粉萌发,特定基因表达等生理过程,气孔能灵敏地对外界刺激作出反应,快速开闭,本文用免疫电镜和免疫荧光显微镜技术证明保卫细胞及其它表皮细胞胞外都存在钙调素;外源纯化钙调素能促进气孔关闭,抑制气孔开放,最适浓度为10^-8mol/L;不能透过质膜的大分子钙调素拮抗剂W—-agarose和钙调素抗血清都能抑制气孔关闭,促进开放,说明保卫细胞的内源胞外钙调素确实能促进气孔关闭,抑制开放。而且只能在细胞外起作用,推测在自然情况下,保卫细胞内源胞外钙调素可能作为胞外第一信使和其它信号分子一起调节气孔的开关运动,而且可能在环境刺激与细胞响应之间起重要作用。     

培养基组分及培养条件对蜡梅花粉萌发及花粉管生长的影响

采用液体培养法研究不同培养基组分和培养条件对蜡梅花粉萌发和花粉管生长的影响。结果表明:(1)PEG-4000是蜡梅花粉离体培养所必需的培养基成分,当培养基中无PEG-4000时,花粉不能正常萌发。(2)培养基内低浓度蔗糖对花粉萌发和花粉管的生长无显著影响,但随着蔗糖浓度的升高,则对花粉萌发和花粉管生长表现出强烈的抑制作用,且浓度越高,抑制效应越强。(3)培养基内其它组分分别在一定浓度范围(0～250g/L PEG-4000、0～50mg/L硼酸、0～30mg/L硝酸钙)内对花粉萌发及花粉管生长有促进作用,但超过上述高限值时则起抑制作用。(4)培养基内镁和钾的浓度对花粉萌发及花粉管生长影响不显著。研究表明,蜡梅最适花粉液体培养基组分为250g/L PEG-4000+50mg/L H3BO3+30mg/L Ca(NO3)2.4H2O,且在pH 5.5、温度15℃和600lx的光照培养条件下蜡梅花粉萌发和花粉管生长最佳。