荷花“重瓣化”的花器官形态发育比较观察

荷花（Nelumbo nucifera）的花型可分5种,最原始为单瓣型,然后由单瓣演化出半重瓣、重瓣、重台和千瓣型。为了揭示荷花重瓣化的分子机理,有必要从花器官的形态发育特征探究荷花花型成因及“重瓣化”的形态发育特征。实验分别选取5种荷花花型的代表品种：‘单洒锦’（单瓣型）、‘大洒锦’（重瓣型）、‘中山红台’（重台型）、‘至尊千瓣’（全重瓣型）、‘千瓣莲’（千瓣型）为材料,进行花芽分化过程形态的石蜡切片比较观察。结果发现：花芽分化过程中5个品种的萼片原基分化期和花瓣原基分化期相似,而雄蕊和雌蕊原基发育存在明显差异：单瓣、重瓣和重台品种均有正常的雄蕊和雌蕊原基分化;全重瓣品种发育初期有雄蕊及雌蕊原基分化,但后期全部瓣化;‘千瓣莲’品种不形成雄蕊和雌蕊原基,而是直接形成2至多个“花瓣增殖中心”,并由此不断分化出细小花瓣。研究认为重瓣型荷花品种的“重瓣化”花瓣主要来源于雄蕊的向心式瓣化,其次是雌蕊瓣化,属于雌雄蕊起源。而对于‘千瓣莲’型品种,花瓣的具体来源方式、花托是否直接参与瓣化及其在重瓣化过程中的作用有待于结合分子生物学手段开展进一步研究。     

单瓣与重瓣垂丝海棠花器官形态发育比较观察

为探究垂丝海棠重瓣花成花原因,该研究以单瓣垂丝海棠和重瓣垂丝海棠为实验材料,应用体式显微镜和扫描电镜观察垂丝海棠单瓣、重瓣品种花器官分化过程;解剖观察重瓣垂丝海棠大蕾期的花与盛开的花,统计其花器官的形态与数目;应用R语言对重瓣垂丝海棠的花瓣数目与其余各轮花器官数目进行相关性分析。结果显示：(1)单瓣和重瓣垂丝海棠的花器官分化均分为萼片原基分化期、花瓣原基分化期、雄蕊原基分化期、雌蕊原基分化期,且各轮花器官按照向心顺序依次分化发育。(2)在花瓣原基分化期,单瓣垂丝海棠仅分化出一轮(5枚)均匀分布于两枚萼片交汇处的花瓣原基,而重瓣垂丝海棠分化出两轮分布散列的花瓣原基,第一轮为5~7枚,第二轮为7~10枚。(3)在重瓣垂丝海棠各轮花器官中存在较多萼片瓣化、雄蕊瓣化、雌雄蕊异常发育的情况。(4)重瓣垂丝海棠各轮花器官数目间相关性分析结果显示,其花瓣数目与雄蕊数目以及瓣化中的雄蕊数目间存在明显的正相关关系,该现象与常规雄蕊瓣化植物表现的雄蕊数目减少、花瓣数目增多的现象不同。研究表明,重瓣垂丝海棠花瓣数目的增多并不完全依赖于雄蕊变瓣,暗示垂丝海棠重瓣花成花原因的多元性与复杂性。     

同株紫斑牡丹中单瓣与重瓣花芽分化及内源激素含量比较北大核心CSCD

该研究以紫斑牡丹‘关公红’为试验材料,通过调查‘关公红’的开花情况,采用光学显微镜、扫描电镜技术考察花芽分化和花瓣发育过程的结构特征,并测定同株‘关公红’单、重瓣花朵的花芽在不同分化阶段内源激素含量,分析单、重瓣花朵的花芽分化及内源激素含量的变化特征,为紫斑牡丹不同花型的培育奠定理论基础。结果表明:(1)‘关公红’单瓣花朵比重瓣花朵花期长,单瓣花朵花瓣表皮细胞光滑平整无明显褶皱,而重瓣花朵花瓣的表皮有明显的褶皱;重瓣花的花芽分化时间明显早于单瓣,花瓣原基的体积也明显增大,这可能与重瓣花中雄蕊瓣化有关系。(2)低浓度GA_(3)有利于‘关公红’单瓣花朵和重瓣花朵的花芽分化;高浓度的ABA促进重瓣花原基的形成;ZR含量增加有助于紫斑牡丹的花芽分化。(3)较高ZR/IAA、ZR/GA_(3)、ABA/GA_(3)、ABA/IAA比值有利于‘关公红’重瓣花朵的花芽分化;ABA/IAA、ZR/IAA比值的增加有利于‘关公红’单瓣花朵花芽分化;(GA_(3)+IAA+ZR)/ABA与(IAA+ZR)/GA_(3)比值减小分别促进重瓣花朵花瓣原基和雄蕊原基的形成。     

荷花花蕾cDNA文库构建及质量评价

为理解荷花Nelumbo nucifera花器官转录组表达情况,分别选取不同花型的代表品种‘洪湖红莲’Nelumbo nucifera ‘Honghu Honglian’(单瓣)、‘唐招提寺莲’N. nucifera ‘Tangzhaotisi Lian’(重瓣)和‘千瓣莲’N. nucifera ‘Qianban Lian’(千瓣及全重瓣)的花蕾为材料分离mRNA,利用SMART技术合成双链cDNA,经限制性内切酶SfiI酶切后回收去掉接头和500 bp以下片段的cDNA。将cDNA与pUC19载体连接,构建荷花花蕾cDNA文库。经检测,该文库容量为1.12 × 106 pfu·mL-1,插入片段大小集中在500～2000 bp,重组率为95%。该文库的成功构建为荷花花蕾期转录组数据的开发及其花器官发育相关基因的功能研究奠定了分子基础。     

RcAGL61基因调控雄蕊和花瓣之间转变影响月季花瓣数量

【目的】为了探究月季重瓣性状的调控机制,课题组前期筛选到一个与花发育相关的AG同源基因RcAGL61,本研究对该基因的功能进行了分析。【方法】利用荧光定量PCR（qRT-PCR）对该基因在‘窄叶藤本月季花’ב月月粉’杂交群体中重瓣株系和单瓣株系花芽5个发育时期的表达模式进行了分析,以重瓣株系和单瓣株系为材料,克隆RcAGL61,并进行生物信息学分析、亚细胞定位及VIGS实验。【结果】（1）该基因表达水平在单瓣株系的五个发育时期均显著高于重瓣株系,在单瓣株系花发育的S4-S5期比S1-S3期表达量明显升高。（2）RcAGL61编码区序列在单瓣株系和重瓣株系中一致,长度为495 bp,与RcAG基因序列相似度为30.75%,编码164个氨基酸,含有一个MADS-Box保守结构域,属于MADS-Box基因家族。（3）亚细胞定位发现RcAGL61蛋白定位于烟草表皮细胞的细胞核。（4）沉默该基因后,瓣化雄蕊数量增加,雄蕊数量减少,花瓣数量增加,萼片数量和雌蕊数量无显著变化。【结论】RcAGL61参与调控了雄蕊原基和花瓣原基间的转变,影响了月季的花瓣数量。     

千娇万态牡丹花

正牡丹各品种之间,在外部形态存在一定的差异。在观赏新品种的选育过程中,常常把牡丹花色、花型等作为牡丹品种分类的标准。牡丹的花型反映着品种的瓣化水平,是品种开花时整体形态特征的综合体现,从单瓣、半重瓣到重瓣反映了花瓣不断增多和随之发生的外观形态变化。所以,花瓣数目的多少及排列方式构成了不同的花型。常见的有:单瓣型、荷花型、菊花型、蔷薇型、托桂型、皇冠型、绣球型和台阁型。下面我们就把各花型的特点及代表品种介绍一下。     

莲的分子身份证

<正>中国是莲的分布和栽培中心,拥有世界上最多莲的品种资源,目前已经有近千个莲品种。长期以来,人们对莲品种的分类主要依据形态性状,如株形大小(大、中和小),花瓣多少(单瓣、重瓣、重台和千瓣),花色(白色系、粉色系、红色系和复色系)和雄蕊瓣化程度等。这种方法形象直观,操作简单,便于普及和推广。然而,形态鉴定存在一定局限性:(1)表型可塑性。品种的形态性状是由遗传物质与环境共同作用的结果,受环境条件变化等因素影响,会表现出一定变异。例如,将同一只藕栽培到不同规格的盆中,株形高度会     

长角凤仙花（凤仙花科）的花器官发生和发育

以不同发育时期的长角凤仙花Impatiens longicornuta Y.L.Chen（凤仙花科Balsaminaceae）为材料,利用扫描电镜技术观察了其花器官的分化及其发育过程。长角凤仙花为两侧对称花,具2枚侧生萼片,唇瓣囊状,旗瓣具鸡冠状突起,雄蕊5枚,子房上位,5心皮5室。其花器官分化顺序为向心式,萼片—花瓣—雄蕊—雌蕊原基。2枚侧生萼片先发生,然后近轴萼片（即唇瓣）原基和2枚前外侧萼片原基近同时发生;但是这3枚萼片原基的发育不同步,远轴的2枚前外侧萼片原基的发育渐渐滞后,然后停止发育,最后渐渐为周围组织所吸收,直至消失不见。花瓣原基中,旗瓣原基最先发生,4个侧生花瓣原基相继成对发生,且之后在基部成对愈合形成翼瓣;5枚雄蕊原基几乎同时发生,5个心皮原基轮状同时发生。本文结果支持凤仙花属植物为5基数的花,并进一步证实了唇瓣的萼片来源;此外,研究结果表明花器官早期发育资料对植物系统与进化研究具有重要参考价值。     

圆明园部分荷花品种评价

<正>大株型白芍药莲Bai Shaoyao Lian育种单位:中国科学院武汉植物园分类地位:中国莲种系·大株型群·重瓣类·白莲型花色:白色,外瓣具淡绿晕。花态:飞舞状。花型:重瓣型。花瓣数:130枚左右。雌蕊:多数正常结实。花径:17厘米。立叶高:54厘米。花期:较早,群体花期短。着花密度:稀少。普者黑白荷Puzhehei Baihe育种单位:云南地方传统品种分类地位:中国莲种系·大株型群·重瓣类·白莲型花色:白色,基部淡黄色。花态:碟状。花型:重瓣     

罗汉果花芽分化过程中形态及其激素水平变化特征

采用石蜡切片和酶联免疫法(ELISA)对罗汉果雄性、雌性、两性花芽分化过程的形态和激素水平变化进行观测,为罗汉果开花调控和品种选育提供科学依据。结果表明:(1)罗汉果雄性、雌性、两性花的花芽分化过程均可分为花芽未分化期、花芽分化初期、花序分化期、萼片原基分化期、花瓣原基分化期、雄蕊原基分化期和雌蕊原基分化期7个阶段。雄蕊原基分化期前,3种花芽分化过程无明显差异,各时期形态特征均依次为:茎端呈圆锥状(花芽未分化期)→茎端经半球形变成扁平状(花芽分化初期)→距茎端5~7节位处分化出穗状花序(花序分化期)→小花原基周围形成5个萼片原基(萼片原基分化期)→萼片原基内侧形成5个花瓣原基(花瓣原基分化期)。雄蕊和雌蕊原基分化期,3种花芽分化过程存在明显差异,雄蕊原基内侧出现雌蕊原基后,雄花芽雄蕊原基继续发育成雄蕊,雌蕊原基停滞生长,退为一个小突起;雌花芽雌蕊原基继续发育成雌蕊,雄蕊原基生长缓慢,退化为小花丝;两性花芽雌蕊和雄蕊原基均继续发育,形成外观正常的雌蕊和雄蕊。(2)内源激素脱落酸(ABA)、赤霉素(GAs)和玉米素核苷(ZR)含量在3种花芽分化过程中变化规律相似,即ABA含量在花芽生理分化期降低,花芽形态分化期升高,而GAs和ZR含量则基本保持不变;吲哚乙酸(IAA)含量在3种花芽分化过程中变化存在明显差异,雌花芽IAA含量在花芽生理分化期升高,花芽形态分化期逐渐降低,而雄性和两性花芽的IAA含量则基本保持不变。ABA/GAs、ABA/IAA、ZR/IAA和ZR/GAs激素含量比值在3种花芽分化过程中变化规律相似,ABA/GAs在花芽生理分化期降低,花芽形态分化期升高,而BA/IAA、ZR/IAA和ZR/GAs则基本保持不变。研究认为,罗汉果花芽分化过程经历一个"两性期",高ABA含量和ABA/GAs比值有利于罗汉果花芽分化,IAA可能对罗汉果花性分化具有重要作用。     

OVERLAPPING ORGAN INITIATION AND COMMON PRIMORDIA IN FLOWERS OF PISUM SATIVUM (LEGUMINOSAE: PAPILIONOIDEAE)

The floral ontogeny of Pisum sativum shows a vertical order of succession of sepals, petals plus carpel, antesepalous stamens, and antepetalous stamens. Within each whorl, unidirectional order is followed among the organs, beginning on the abaxial side of the flower, as in most papilionoids. Unusual features include the four common primordia which precede initiation of discrete petal and antesepalous stamen primordia, and the marked overlap of organ initiations between whorls which are usually separately initiated. The stamens arise in free condition, then become diadelphous by intercalary growth at the base of nine stamens, and finally become pseudomonadelphous by surface fusion between the vexillary stamen filament and the adjacent edges of the filament tube. The early initiation of the carpel is not unique among papilionoids, but is somewhat unusual.     

FLORAL ORGANOGENESIS IN NICOTIANA TABACUM: A COMPARISON OF TWO CYTOPLASMIC MALE-STERILE CULTIVARS WITH A MALE-FERTILE CULTIVAR

Flower buds of two cytoplasmically male-sterile cultivars and one male-fertile cultivar of Nicotiana tabacum (L.) were studied by light and scanning electron microscopy to compare their floral ontogenies. In [gla]tbc, a cultivar with N. tabacum nuclear genes and N. glauca cytoplasm, the five small stamen primordia cease growth soon after they are initiated. They remain unchanged at the flanks of the ovary throughout flower maturation, so the mature flower appears stamenless. In `[pbg]tbc,‘ a N. tabacum cultivar with cytoplasm that was thought to have been derived from N. plumbaginifolia, the divergence from normal stamen development occurs before carpel emergence at which point the primordia are already notably smaller and less cylindrical than primordia of the male-fertile cultivar. After carpel emergence the primordia continue to develop, forming pink structures called petalodes, which are more similar to petals than stamens. Histological sections show that formation of procambial vascular traces is similar in the abortive stamen primordia of [gla]tbc, the petalode primordia of `[pbg]tbc‘ and stamen primordia of male-fertile N. tabacum. The two cytoplasmic male-sterile cultivars studied here and one reported elsewhere show a common developmental stage at which the normal ontogenic pattern is altered. We suggest that this stage is the first visible point in N. tabacum androgenesis which requires genetic input from the mitochondrial genome.     

月季花瓣数量遗传分析

以‘窄叶藤本月季花’( Rosa chinensis ‘Zhaiye Tengben Yuejihua’)ב月月粉’( R. chinensis ‘Old Blush’)杂交群体为材料, 分析其花瓣数量的分离特点, 对单瓣花与重瓣花的花芽分化过程进行观察, 并对花瓣、雄蕊及瓣化雄蕊进行表皮细胞超微结构的观察.结果显示...     

Developmental study on the inflorescence and flower of Caldesia grandis Samuel (Alismataceae)

The inflorescence and floral development of Caldesia grandis Samuel is reported for the first time in this paper. The basic units of the large cymo‐thyrsus inflorescence are short panicles that are arranged in a pseudowhorl. Each panicle gives rise spirally to three bract primordia also arranged in a pseudowhorl. The branch primordia arise at the axils of the bracts. Each panicle produces spirally three bract primordia with triradiate symmetry (or in a pseudowhorl) and three floral primordia in the axils of the bract primordia. The apex of the panicle becomes a terminal floral primordium after the initiations of lateral bract primordia and floral primordia. Three sepal primordia are initiated approximately in a single whorl from the floral primordium. Three petal primordia are initiated alternate to the sepal primordia, but their subsequent development is much delayed. The first six stamen primordia are initiated as three pairs in a single whorl and each pair appears to be antipetalous as in other genera of the Alismataceae. The stamen primordia of the second whorl are initiated trimerously and opposite to the petals. Usually, 9–12 stamens are initiated in a flower. There is successive transition between the initiation of stamen and carpel primordia. The six first‐initiated carpel primordia rise simultaneously in a whorl and alternate with the trimerous stamens, but the succeeding ones are initiated in irregular spirals, and there are 15–21 carpels developed in a flower. Petals begin to enlarge and expand when anthers of stamens have differentiated microsporangia. Such features do not occur in C. parnassifolia. In the latter, six stamen primordia are initiated in two whorls of three, carpel primordia are initiated in 1–3 whorls, and there is no delay in the development of petals. C. grandis is thus considered more primitive and C. parnassifolia more derived. C. grandis shares more similarities in features of floral development with Alsma, Echinodorus, Luronium and Sagittaria. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 140 , 39–47.     

DIOECY IN BAUHINIA RESULTING FROM ORGAN SUPPRESSION

Bauhinia malabarica and B. divaricata have both been reported to have dimorphic flowers; floral development of these species has been investigated and compared using SEM. B. malabarica is subdioecious, with three types of flowers: perfect, staminate, and carpellate. Individual trees usually have only one type of flower. Perfect and carpellate flowers have similar initiation of floral organs; each has five sepals, five petals, two whorls of five stamen primordia and a carpel primordium. The carpels of carpellate flowers do not differ from those of perfect flowers throughout development. Both have a gynophore or stipe and a cuplike hypanthium. Stamen development diverges markedly after mid-development: the perfect flowers have ten stamens in two whorls, the outer with longer filaments than the inner. All stamens have anthers, which are covered abaxially with abundant inflated trichomes. Carpellate flowers have a circle of short cylindrical staminodia, each bearing a few hairs, about the base of the carpel on the rim of the hypanthium. Heteromorphy in B. malabarica is effected by suppression of stamen development, even though the usual number of stamen primordia is initiated. Suppression of stamens occurs at midstage in development in carpellate flowers of B. malabarica, and is complete. In B. divaricata nine stamen primordia are released from suppression in late stage, undergo intercalary growth and form a staminodial tube around the carpel stipe. The dimorphy in B. divaricata is expressed late in bud enlargement as divergent rates of growth in the carpel in the two morphs.     

Negative regulation of the Arabidopsis homeotic gene AGAMOUS by the APETALA2 product.

We characterized the distribution of AGAMOUS (AG) RNA during early flower development in Arabidopsis. Mutations in this homeotic gene cause the transformation of stamens to petals in floral whorl 3 and of carpels to another ag flower in floral whorl 4. We found that AG RNA is present in the stamen and carpel primordia but is undetectable in sepal and petal primordia throughout early wild-type flower development, consistent with the mutant phenotype. We also analyzed the distribution of AG RNA in apetela2 (ap2) mutant flowers. AP2 is a floral homeotic gene that is necessary for the normal development of sepals and petals in floral whorls 1 and 2. In ap2 mutant flowers, AG RNA is present in the organ primordia of all floral whorls. These observations show that the expression patterns of the Arabidopsis floral homeotic genes are in part established by regulatory interactions between these genes.     

莲花(Nelumbo nucifera)雌性器官变态的初步观察

莲花雄蕊的瓣化致使产生了很多重瓣或半重瓣的品种,而雌蕊的变态则使花朵呈“台阁”状花态。这些性器官的变态,不仅在育种上有实用的价值,可以选育各种特异花型的品种;而且在遗传性变异的基础研究方面也有意义。本文根据在美国加州Modesto市中国文化中心莲园夏播莲花实生苗当年开花植株的观察,初次报道莲花雌性器官的变态现象。雌性器官变态,系指心皮的变态和花托的不同程度退化或消失。作者根据心皮与花托的形态发育状况将其分为六个等级。有关这些性状变异的细胞学基础,尚待进一步研究。     

Pistillate and staminate flower development in dioecious Pistacia vera (Anacardiaceae)

The development of staminate and pistillate flowers in the dioecious tree species Pistacia vera L. (Anacardiaceae) was studied by scanning electron microscopy with the objective of determining organogenetic patterns and phenology of floral differentiation. Flower primordia are initiated similarly in trees of both sexes. Stamen and carpel primordia are initiated in both male and female flowers, and the phenology of organ initiation is essentially identical for flowers of both sexes. Vestigial stamen primordia arise at the flanks of pistillate flower apices at the same time functional stamens are initiated in the staminate flowers. Similarly, a vestigial carpel is initiated in staminate flowers at the same time the primary, functional carpel is initiated in pistillate flower primordia. Differences between the two sexes become apparent early in development as, in both cases, development of organs of the opposite sex becomes arrested at the primordial stage. Male flowers produce between four and six mature functional stamens and female flowers produce a gynoecium with one functional and two sterile carpels.     

Light and scanning electron microscopic studies of flower development inLindenbergia macrostachya Benth. (Scrophulariaceae)

All the floral primordia are homologous to leaves in their development inLindenbergia macrostachya. The sepals follow an anterior to posterior sequence of initiation. The petals and stamens are initiated almost simultaneously but sequentially in order of petals followed by stamens. There is no sign of development of fifth posterior stamen. p ]The calyx tube is formed by interprimordial growth followed by zonal growth. The combined interprimordial growth between the petal primordia and growth on the abaxial side of stamen primordia results in the formation of upper corolla tube whereas lower corolla tube is formed only by zonal growth. The zonal growth extends below the bases of stamen primordia also due to which they become epipetalous. The placentae arise from the carpellary margins, move inwards and get fused in the lower half and remain free in the upper part of the ovary. Thus the ovary appears biloeular with axile plaeentation in the lower haler and unilocular with parietal placentation in the upper half.