离体黄瓜子叶节花芽分化与内源激素及多胺的关系

用高效液相色谱法(HPLC)测定了黄瓜子叶节花芽分化期(0-6天)内源激素及多胺的变化。结果显示,子叶培养0-2天生长素(IAA)、赤霉素(GA_3)、玉米素(ZT)、脱落酸(ABA)等4种内源激素均明显下降,4-5天略有上升,表明0-2天IAA、GA_3和ABA的剧降有利于花原基形成,3-5天较高的ZT含量有利于花器官原基的形成。除腐胺(Put)外,精胺(Spm)、亚精胺(Spd)、尸胺(Cad)在0-1天均下降,1-4天上升,4-5天再下降,Put在0-1天急剧上升,而后持续下降,表明高水平的内源多胺总量和Put可能有利于花原基分化,2天后Spm含量上升有利于花器官原基分化,而Cad含量变化可能是区别花芽和营养芽分化的特征之一。     

离体黄瓜子叶节花芽分化与内源激素及多胺的关系

用高效液相色谱法(HPLC)测定了黄瓜子叶节花芽分化期(0—6天)内源激素及多胺的变化。结果显示,子叶培养0—2天生长素(IAA)、赤霉素(GA3)、玉米素(ZT)、脱落酸(ABA)等4种内源激素均明显下降,4—5天略有上升,表明0-2天IAA、GA3和ABA的剧降有利于花原基形成,3—5天较高的ZT含量有利于花器官原基的形成。除腐胺(Put)外,精胺(Spm)、亚精胺(Spd)、尸胺(Cad)在0—1天均下降,1—4天上升,4—5天再下降,Put在0—1天急剧上升,而后持续下降,表明高水平的内源多胺总量和Put可能有利于花原基分化,2天后Spm含量上升有利于花器官原基分化,而Cad含量变化可能是区别花芽和营养芽分化的特征之一。     

植物组织培养中器官建成的生理生化基础

组织培养中器官发生可通过外植体诱导愈伤组织形成,随后出现根、芽分化,也可通过外植体直接分化根、芽。无论哪条途径,愈伤组织诱导和原基的形成是十分重要的,这一过程被称为脱分化过程。脱分化过程从细胞分裂的启动开始,经过分裂形成拟分生组织或分生组织中心,随后形成器官原基。器官原基的形成受外界因素和体内生理生化因素的调节,本文结合我们课题组工作对国内外这方面的新进展作一简单介绍。     

黄瓜子叶培养物花芽形成过程的观察

黄瓜（Ｃｕｃｕｍｉｓｓａｔｉｖｕｓ）子叶培养物在离体培养２～５ｄ时,在子叶柄上可见花原基,再过２～３ｄ,可见花原基上产生一轮二次突起,标志着花原基分化已经开始。培养基中添加ｋｉｎｅｔｉｎ（ＫＴ）,可以明显增加花原基的形成数,可以显著促进花原基的分化和花芽的形成     

红花玉兰MwAG基因在花发育不同时期的表达

MwAG基因是调控红花玉兰(Magnolia wufengensis)雌雄蕊发育的关键转录因子。采用半定量RT-PCR、Northern blot杂交和实时荧光定量PCR技术检测了MwAG基因在红花玉兰花芽形态分化几个关键时期表达的组织特异性和表达水平的变化。研究结果表明, MwAG基因仅在红花玉兰雌雄蕊中表达, 而在幼叶、外轮花被和内轮花被中不表达。在花器官形态分化过程中, MwAG基因在雌雄蕊原基分化期和雌雄蕊成熟期均维持在一个较高的水平, 且在雄蕊中的表达波峰早于雌蕊, 这与雌雄蕊形态分化的时间基本吻合; 在花芽分化早期, 相同大小的花芽, 瓣数越多, MwAG基因在雌雄蕊中的表达量越低, 其结果与不同瓣数雌雄蕊分化的时间一致, 即瓣数越多, 雌雄蕊分化越晚。     

烟草花发育基因Nfbp6在花粉和胚珠形成过程中的特异表达

Nfbp6是从烟草中克隆的一种调节花发育的基因 ,与已知的C类基因有很高的同源性 .应用RNA原位杂交技术 ,对其在烟草花发育的各个阶段的表达进行了研究 .结果表明Nfbp6在花器官原基的早期分化、形成过程中有一定表达 .在后期花芽发育过程中 ,Nfbp6的转录加强 ,尤其在花粉和胚珠发育过程中表达强烈 .同时 ,Nfbp6在花柱引导组织和花药裂缝细胞、早期环式细胞簇中也有一定表达     

大蒜花序轴离体培养器官发生途径的解剖学研究

以大蒜品种‘三月黄’(Allium sativum L.cv. Sanyuehuang)花序轴为外植体进行离体培养,对其器官发生过程进行了形态学和解剖学观察。结果显示:大蒜花序轴离体培养不经过愈伤组织,通过器官直接发生途径形成不定芽,其不定芽起源于大蒜花序轴维管组织韧皮部一侧周围的皮层薄壁细胞,属于外起源;皮层薄壁细胞经脱分化后,由最先形成的拟分生组织发育为茎尖分生组织,然后环绕其形成叶原基,茎尖和叶共同构成一个完整的不定芽;大蒜花序轴离体培养发生的不定芽与花苞中自然形成的营养芽发生部位一致。不定芽通过壮苗、生根培养可正常生根形成植株,如果继代培养周期超过21 d,鳞茎形成率可达90.56%。     

无外源激素条件下液体和固体培养基对黄瓜子叶培养器官分化的不同影响

在固体ＭＳ基本培养基上,黄瓜子叶能形成约０．８％的直接花芽,其分化高峰约为４５天左右,而在液体ＭＳ基本培养基上,黄瓜子叶花芽分化率为８％,其分化高峰期约在３０天左右．实验结果表明：液体培养基对黄瓜子叶花芽及根的分化效果明显好于固体培养基,而对于营养芽的分化固体培养基好于液培养基,花芽分化与子叶衰老存在着较密切的关系。     

巨峰葡萄花芽分化的研究

以巨峰葡萄(Vitis vinifera L.×V.Labrusca L.cv.Kyoho)为材料,用摘叶、去穗法判定花芽的生理分化期,并用GMA半薄切片法观察花芽分化进程。结果表明:从新梢顶端到第9个展开叶之间的芽处于生理分化期,花芽生理分化期分为成花诱导期和花芽孕育期。葡萄的花序分化阶段可分为未分化期、花序原基分化期和花序第二穗轴分化期3个时期。第1年只进行花序分化,次年进行花器官分化。原分生组织衍生的组织中淀粉粒分布较多,蛋白质则在分裂旺盛的原基组织中含量高。     

穗花牡荆花芽分化过程中形态和生理指标变化

以穗花牡荆为研究材料,通过探究其花芽分化进程和生理特性,为花期调控技术提供成花机理。采用物候期观察和石蜡切片相结合的方法并测定花芽分化过程中相关生理指标,研究花发育过程中的形态和生理变化。结果表明,穗花牡荆花芽分化为一年多次分化型,其进程可划分为七个时期：未分化期、总轴花序原基分化期、初级分轴花序原基分化期、次级分轴花序原基分化期、小花原基分化期、花器官分化前期和花器官分化后期。同一植株不同位置花芽及同一花序中不同单花分化的进程不同,第一季花期后各阶段的花芽分化形态常存在重叠。花芽分化过程中不同时期叶片和花芽的可溶性糖和可溶性蛋白质含量均有上升下降的变化,总体上叶片中营养物质含量高于花芽保证营养供应。花芽分化过程中,IAA、ABA、CTK和GA3整体水平上先升后降有利于花芽分化进行。研究认为,花芽中大量的可溶性糖和蛋白质积累及较高的碳氮比,有利于穗花牡荆花芽形态分化顺利完成。低水平的GA3/ABA和IAA/CTK有利于花序的形成,ABA/CTK和ABA/IAA比值升高促进小花原基和小花萼片原基的分化, GA3/CTK、GA3/ABA和GA3/IAA比值升高促进花瓣原基、雄雌蕊原基发育。     

Overexpression of the cucumber LEAFY homolog CFL and hormone treatments alter flower development in gloxinia (Sinningia speciosa)

Leafy (LFY) and LFY-like genes control the initiation of floral meristems and regulate MADS-box genes in higher plants. The Cucumber-FLO-LFY (CFL) gene, a LFY homolog in Cucumis sativus L. is expressed in the primordia, floral primordia, and each whirl of floral organs during the early stage of flower development. In this study, functions of CFL in flower development were investigated by overexpressing the CFL gene in gloxinia (Sinningia speciosa). Our results show that constitutive CFL overexpression significantly promote early flowering without gibberellin (GA(3)) supplement, suggesting that CFL can serve functionally as a LFY homolog in gloxinia. Moreover, GA(3) and abscisic acid (ABA) treatments could modulate the expression of MADS-box genes in opposite directions. GA(3) resembles the overexpression of CFL in the expression of MADS-box genes and the regeneration of floral buds, but ABA inhibits the expression of MADS-box genes and flower development. These results suggest that CFL and downstream MADS-box genes involved in flower development are regulated by GA(3) and ABA.     

FON1, an Arabidopsis gene that terminates floral meristem activity and controls flower organ number.

A novel gene that regulates floral meristem activity and controls floral organ number was identified in Arabidopsis and is designated FON1 (for FLORAL ORGAN NUMBER1). The fon1 mutants exhibit normal vegetative development and produce normal inflorescence meristems and immature flowers before stage 6. fon1 flowers become visibly different from wild-type flowers at stage 6, when the third-whorl stamen primordia have formed. The fon1 floral meristem functions longer than does that of the wild type: after the outer three-whorl organ primordia have initiated, the remaining central floral meristem continues to produce additional stamen primordia interior to the third whorl. Prolonged fon1 floral meristem activity also results in an increased number of carpels. The clavata (clv) mutations are known to affect floral meristem activity. We have analyzed the clv1 fon1, clv2 fon1, and clv3 fon1 double mutants. These double mutants all have similar phenotypes, with more stamens and carpels than either fon1 or clv single mutants. This indicates that FON1 and CLV genes function in different pathways to control the number of third- and fourth-whorl floral organs. In addition, to test for possible interactions between FON1 and other floral regulatory genes, we have constructed and analyzed the relevant double mutants. Our results suggest that FON1 does not interact with TERMINAL FLOWER1, APETALA1, APETALA2, or UNUSUAL FLORAL ORGAN. In contrast, normal LEAFY function is required for the expression of fon1 phenotypes. In addition, FON1 and AGAMOUS both seem to affect the domain of APETALA3 function, which also affects the formation of stamen-carpel chimera due to fon1 mutations. Finally, genetic analysis suggests that FON1 interacts with SUPERMAN, which also regulates floral meristem activity.     

Arabidopsis thaliana (L.) Heynh. as a model object for studying genetic control of morphogenesis

A vast amount of information on the genetic control of plant development has been obtained in Arabidopsis thaliana with classical genetic and molecular biological methods. The genes involved in multistep regulation of floral morphogenesis have been identified. The formation of floral meristem is controlled by the LEAFY (LFY), UNUSUAL FLORAL ORGANS (UFO), APETALA1 (AP1), and APETALA2 (AP2) genes. Studies of the abruptus and bractea recessive monogenic mutants from the collection of the Department of Genetics and Selection, Moscow State University, showed that the ABRUPTUS (ABR) and BRACTEA (BRA) genes also play an important role in inflorescence differentiation. The ABR gene controls the early formation of organ primordia on the inflorescence and the formation of floral organ primordia after floral initiation. Further differentiation of inflorescence organ primordia in vegetative or generative organs depends on the activity of the LFY gene, and floral organ identity is determined by the homeotic genes. Presumably, the major function of the ABR gene is to determine the auxin polar transport. The BRA gene suppresses the development of bracts on the inflorescence and constrains cell division at the base of primordia of rosette and cauline leaves.     

Expression patterns of several floral genes during flower initiation in the apical buds of apple (Malus × domestica Borkh.) revealed by in situ hybridization

The apple (Malus?×?domestica Borkh.) is one of the commercially important fruit crops in the worldwide. The apple has a relatively long juvenile period (up to 4?years) and a long reproductive period between the flower initiation and the mature fruit (14?C16?months), which prevent the fruit breeding. Therefore, the understanding of the flowering system is important to improve breeding efficiency in the apple. In this study, to examine the temporal and spatial expression patterns of the floral genes, MdTFL1, MdAP1 (MdMASD5), AFL2, and MdFT, we conducted in situ hybridization analysis in the apple shoot apex. In vegetative phase, MdTFL1 was expressed on the rib meristem zone. When vegetative meristem began converting into inflorescence meristem, the expression level of MdTFL1 was drastically decreased. At the early stage of inflorescence meristem, the expression levels of AFL2, MdFT, and MdAP1 were up-regulated in the leaf primordia and the upper region of cell layers on the shoot apex. In late stage, the expression levels of AFL2 and MdAP1 were up-regulated in the young floral primordia. At a more advanced stage, high expression of MdAP1 was observed in the inflorescence primordium through the inner layer of sepal primordia and the outer layer of receptacle primordia and floral axis. Our results suggest that AFL2, MdFT, and MdAP1 affect to convert from the vegetative meristem into the inflorescence meristem after the decline of MdTFL1 expression. After that, AFL2 and MdAP1 promote the formation of the floral primordia and floral organs.     

百脉根类LATERAL ORGAN BOUNDARIES基因的分离及表达方式

植物顶端分生组织可分为中央区,周缘区和肋区。在植物胚后发育中,侧生器官产生于顶端分生组织的周缘区。顶端分生组织和侧生器官之间的边界的建立和维持是一个非常重要的发育过程,许多调节子参与控制这个过程。拟南芥的LATERAL ORGAN BOUNDARIES（LOB）基因具有独特的表达模式,其表达的范围与上述的边界区域重合。LOB基因隶属于一个大的基因家族一,OB结构域基因家族。该家族编码的蛋白在N端具有一个保守的LOB结构域,该家族LOB基因以外的成员也参与拟南芥不同的发育过程。为了探讨在与拟南芥亲缘关系较远的豆科中LOB同源基因的功能,我们在豆科模式植物百脉根中分离了3个LOB同源基因,命名为LjLOB基因,并用RNA原位杂交方法研究了这3个基因的表达模式。研究结果显示,LjLOB1和LjLOB3都强烈地在小叶原基的基部表达,这种表达模式可能与小叶原基和复叶原基之间的边界相关。而LjLOB4则在发育中的花芽不同轮之间的边界上表达。百脉根中这3个基因具有不同的表达模式,强烈地提示它们的功能发生了分歧：LjLOB1和LjLDB3可能在复叶发育中具有重要功能;而LjLOB4则可能参与了花的发育。     

Cloning and Analysis of CFL-A LFY-like Gene from Cucumber

LFY and LFY-like genes have been shown to control the initiation of floral meristems in higher plants. The homologous eDNA of LFY, CFL, were cloned from cucumber ( Cucumis sativus L. ). Southern blot analysis showed it was a single copy gene in the cucumber genome. Northern blot analysis showed that it expressed in the floral buds and young leaves. The possible role of CFL in the floral and vegetative development of cucumber plant was discussed.     

A putative lipase gene EXTRA GLUME1 regulates both empty-glume fate and spikelet development in rice

Recent studies have shown that molecular control of inner floral organ identity appears to be largely conserved between monocots and dicots, but little is known regarding the molecular mechanism underlying development of the monocot outer floral organ, a unique floral structure in grasses. In this study, we report the cloning of the rice EXTRA GLUME1 ( EG1 ) gene, a putative lipase gene that specifies empty-glume fate and floral meristem determinacy. In addition to affecting the identity and number of empty glumes, mutations in EG1 caused ectopic floral organs to be formed at each organ whorl or in extra ectopic whorls. Iterative glume-like structures or new floral organ primordia were formed in the presumptive region of the carpel, resulting in an indeterminate floral meristem. EG1 is expressed strongly in inflorescence primordia and weakly in developing floral primordia. We also found that the floral meristem and organ identity gene OsLHS1 showed altered expression with respect to both pattern and levels in the eg1 mutant, and is probably responsible for the pleiotropic floral defects in eg1 . As a putative class III lipase that functionally differs from any known plant lipase, EG1 reveals a novel pathway that regulates rice empty-glume fate and spikelet development.     

黄瓜中LFY同源基因CFL的克隆和分析

ＬＦＹ同源基因在高等植物花分生组织的发生中发挥着重要的作用。克隆了黄瓜（ Ｃｕｃｕｍｉｓｓａｔｉｖｕｓ Ｌ．） 中的ＬＦＹ同源基因ＣＦＬ,Ｓｏｕｔｈｅｒｎ 杂交的结果显示它在黄瓜基因组中为单拷贝基因,Ｎｏｒｔｈｅｒｎ 杂交结果显示它主要在花芽和幼叶中表达。讨论了ＣＦＬ基因在黄瓜开花和营养生长中可能发挥的作用