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“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。     

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。     

中国水仙NtAP1基因的克隆与表达分析

采用RT-PCR和RACE技术,从中国水仙(Narcissus tazetta var.chinensis)幼嫩花芽中分离得到1个与花发育相关的MADS-box基因,将其命名为NtAP1(GenBank登录号为JN704304)。该基因全长1 155bp,含有1个762bp的开放阅读框,编码253个氨基酸。系统进化分析表明,该基因属于AP1-like基因。半定量RT-PCR分析表明,该基因在水仙品种‘金盏银台’和‘玉玲珑’的花瓣、副冠、雄蕊和雌蕊中均有表达,且在雌蕊中的表达量最高。研究认为,该实验分离出的NtAP1基因在‘玉玲珑’重瓣的形成过程中没有发挥重要的作用。     

基于HS-SPME/GC-MS分析山茶品种‘克瑞墨大牡丹’花器官香气成分

采用顶空固相微萃取法(HS-SPME)提取了山茶品种‘克瑞墨大牡丹’不同花器官自然挥发的花香挥发油,并用气相色谱—质谱联用仪(GC-MS)分析了花香成分。分别从整花、花瓣、雄蕊中检测到了89、80、21种化合物。花香成分主要由萜类、芳香族化合物、脂肪族化合物等组成,其中以单萜中的芳樟醇相对含量最高,以下依次为顺式氧化芳樟醇、水杨酸甲酯、十四烷等。花瓣和雄蕊中花香成分有较大差别,芳樟醇在花瓣和雄蕊中均占首位,相对含量分别为15.12%和63.97%,雄蕊缺乏烷烃和芳香烃。同一朵花所有花瓣的花香绝对挥发量是所有雄蕊的3倍以上,但质量相同时雄蕊的挥发量却明显高于花瓣,表明花瓣和雄蕊对‘克瑞墨大牡丹’的花香具有同样重要的贡献。     

月季品种‘绿萼’Rc AG基因启动子克隆及分析

月季品种‘绿萼’(Rosa chinensis‘Viridiflora’)是中国古老月季最宝贵资源之一,其花瓣、雄蕊及雌蕊均萼片化。本研究以花器官正常发育的月季品种‘月月粉’(R. chinensis‘Old Blush’)为对照,利用实时荧光定量PCR技术对RcAG基因在‘绿萼’花器官中的表达情况进行分析,阐明RcAG基因在‘绿萼’花器官发育中的作用。结果显示,RcAG基因在‘绿萼’中的表达明显下调。进一步克隆‘绿萼’和‘月月粉’的RcAG基因启动子,序列分析结果表明两个启动子均含有TATA、TATC-box和MBS等顺式作用元件,但在‘绿萼’RcAG基因启动子中发现了光响应元件MRE和昼夜节律调控元件Circadian,而光响应元件TCT-motif只在‘月月粉’RcAG基因启动子中被发现。同时,本研究采用重亚硫酸盐测序技术分析了‘绿萼’和‘月月粉’RcAG基因启动子甲基化的情况,发现‘绿萼’RcAG基因启动子区域中有4个CpG位点均发生甲基化,其甲基化程度远高于‘月月粉’。研究结果表明RcAG基因在‘绿萼’花器官中的下调表达可能与其启动子的顺式作用元件及甲基化修饰相关。     

圆瓣姜花花部维管束解剖及其系统学意义

用石蜡切片技术研究了圆瓣姜花(Hedychium forrestii Diels)的花部维管束系统解剖结构,探讨了同源异形的各轮花器官维管束来源和属性.结果表明,圆瓣姜花的2枚花瓣状结构为外轮雄蕊成员;唇瓣是三重结构,其中脉源十1枚外轮雄蕊维管束系统,两侧脉源于2枚内轮雄蕊维管束系统;上位腺体为隔膜蜜腺.本研究支持Thompson和Gregory关于姜科唇瓣是三重结构的观点;与其他姜科植物一样,圆瓣姜花子房延长部形成的上位腺体属于隔膜蜜腺而不是雄蕊成员.与已研究过的姜花属植物比较,姜花属花器官维管束系统的来源与走向是一致的,同源异形现象在姜花属植物花的进化中扮演极为重要的角色,可为解释花器官属性提供重要线索.     

月季‘绿萼’花器官发育相关microRNA的鉴定及分析

利用高通量测序技术,构建了中国古老月季‘绿萼’(Rosa chinensis ‘Viridiflora’)和‘月月粉’(R.chinensis‘Old Blush’)花蕾期的microRNA(miRNA)文库,并对其进行了测序和序列分析。结果显示,在‘绿萼’文库中,鉴定到已知的miRNA成熟体39个,miRNA前体42个;预测到新的miRNA成熟体56个,前体57个。在‘月月粉’文库中,鉴定到已知RNA成熟体39个,已知miRNA前体40个;预测到新的miRNA成熟体53个,前体57个。与‘月月粉’相比,‘绿萼’中差异表达的miRNA有31个,其中17个上调、14个下调。荧光定量PCR实验结果表明,miR156、miR398和miR535在2种月季的花蕾期表达上调,而miR167、miR172和miR396表达下调。进一步检测miR172和miR156在2种月季不同花器官中的表达差异,发现miR172在‘绿萼’的花瓣、雌、雄蕊中表达显著下调,提示miR172可能通过负调控其靶基因RcAP2的表达,在‘绿萼’花器官发育过程中起重要作用。     

基于 HS-SPME/GC-MS 分析山茶品种‘克瑞墨大牡丹’花器官香气成分简

采用顶空固相微萃取法（HS-SPME）提取了山茶品种‘克瑞墨大牡丹’不同花器官自然挥发的花香挥发油,并用气相色谱—质谱联用仪（GC-MS）分析了花香成分。分别从整花、花瓣、雄蕊中检测到了89、80、21种化合物。花香成分主要由萜类、芳香族化合物、脂肪族化合物等组成,其中以单萜中的芳樟醇相对含量最高,以下依次为顺式氧化芳樟醇、水杨酸甲酯、十四烷等。花瓣和雄蕊中花香成分有较大差别,芳樟醇在花瓣和雄蕊中均占首位,相对含量分别为15.12%和63.97%,雄蕊缺乏烷烃和芳香烃。同一朵花所有花瓣的花香绝对挥发量是所有雄蕊的3倍以上,但质量相同时雄蕊的挥发量却明显高于花瓣,表明花瓣和雄蕊对‘克瑞墨大牡丹’的花香具有同样重要的贡献。     

Floral development of petaloid Alismatales as an insight into the origin of the trimerous Bauplan in monocot flowers

Monocots are remarkably homogeneous in sharing a common trimerous pentacyclic floral Bauplan. A major factor affecting monocot evolution is the unique origin of the clade from basal angiosperms. The origin of the floral Bauplan of monocots remains controversial, as no immediate sister groups with similar structure can be identified among basal angiosperms, and there are several possibilities for an ancestral floral structure, including more complex flowers with higher stamen and carpel numbers, or strongly reduced flowers. Additionally, a stable Bauplan is only established beyond the divergence of Alismatales. Here, we observed the floral development of five members of the three ‘petaloid’ Alismatales families Butomaceae, Hydrocharitaceae, and Alismataceae. Outer stamen pairs can be recognized in mature flowers of Alismataceae and Butomaceae. Paired stamens always arise independently, and are either shifted opposite the sepals or close to the petals. The position of stamen pairs is related to the early development of the petals. In Butomaceae, the perianth is not differentiated and the development of the inner tepals is not delayed; the larger inner tepals (petals) only permit the initiation of stamens in antesepalous pairs. Alismataceae has delayed petals and the stamens are shifted close to the petals, leading to an association of stamen pairs with petals in so-called stamen–petal complexes. In the studied Hydrocharitaceae species, which have the monocot floral Bauplan, paired stamens are replaced by larger single stamens and the petals are not delayed. These results indicate that the origin of the floral Bauplan, at least in petaloid Alismatales, is closely linked to the position of stamen pairs and the rate of petal development. Although the petaloid Alismatales are not immediately at the base of monocot divergence, the floral evolution inferred from the results should be a key to elucidate the origin of the floral Bauplan of monocots.     

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。     

Patterns of flower morphology and structural changes during interconversion between chasmogamous and cleistogamous flowers in Viola philippica北大核心CSCD

Aims: Viola philippica is a species with a typical chasmogamous-cleistogamous (CH-CL) mixed breeding system. It provides a flower model system to investigate floral organs development under different photoperiods. Morphological changes of intermediate cleistogamous (inCL) flowers have been observed, the trends in variation of changes from CH flowers to CL flowers or from CL flowers to CH flowers have been analyzed, the localized effects of poorly developed stamens and petals in CL and inCL flowers have been identified. This research provided morphology and structural changes with implication for the evolutionary significance of the dimorphic flower formation for further study in dimorphic flower development. Methods: We used methods of anatomy and structural analysis to observe the morphological structures of flowers under different photoperiods. Important findings: Photoperiod played an important role in the development of CH and CL flowers in V. philippica. Under short-day light and intermediate-day light, both CH and inCL flowers developed simultaneously. Most of the floral buds were CH flowers under a photoperiod of short-day light, but most of the floral buds were inCL flowers under mid-day light. Complete CL flowers formed under long-day lights. However, there were a series of transitional types in the number and morphology of stamens and petals among inCL flowers, including five stamens with three petals related to CH flowers and two stamens with one petal related to CL flowers. The former type was dominant under short-day light conditions, and the latter type was dominant under mid-day light. Further more, there were localized effects in stamen and petal development for CL and inCL flowers. The development of ventral lower petal (corresponding to the lower petal with spur of CH flower) and the adjacent two stamens in inCL flowers were best, and the back petal was similar to that of CL flowers, an organ primordium structure. The adjacent stamens with the back petals tended to be poorly developed. In extreme cases, these stamens in inCL flowers had no pollen sac, only a membranous appendage or even a primordium structure. When the plants with CL or CH flowers were placed under short-day light or long-day light, the newly induced flowers all showed a series of inCL flower types, finally the CL flowers transformed into CH flowers, and the CH flowers transformed into CL flowers. This result indicates the gradual effects of different photoperiods on dimorphic flowers development of V. philippica. A long photoperiod could inhibit the development of partial stamens and petals, and a short photoperiod could prevent the suppression of long-day light and promote the development of stamens and petals.     

Patterns of flower morphology and structural changes during interconversion between chasmogamous and cleistogamous flowers in Viola philippica

Aims Viola philippica is a species with a typical chasmogamous-cleistogamous (CH-CL) mixed breeding system. It provides a flower model system to investigate floral organs development under different photoperiods. Morphological changes of intermediate cleistogamous (inCL) flowers have been observed, the trends in variation of changes from CH flowers to CL flowers or from CL flowers to CH flowers have been analyzed, the localized effects of poorly developed stamens and petals in CL and inCL flowers have been identified. This research provided morphology and structural changes with implication for the evolutionary significance of the dimorphic flower formation for further study in dimorphic flower development.Methods We used methods of anatomy and structural analysis to observe the morphological structures of flowers under different photoperiods.Important findings Photoperiod played an important role in the development of CH and CL flowers in V. philippica. Under short-day light and intermediate-day light, both CH and inCL flowers developed simultaneously. Most of the floral buds were CH flowers under a photoperiod of short-day light, but most of the floral buds were inCL flowers under mid-day light. Complete CL flowers formed under long-day lights. However, there were a series of transitional types in the number and morphology of stamens and petals among inCL flowers, including five stamens with three petals related to CH flowers and two stamens with one petal related to CL flowers. The former type was dominant under short-day light conditions, and the latter type was dominant under mid-day light. Further more, there were localized effects in stamen and petal development for CL and inCL flowers. The development of ventral lower petal (corresponding to the lower petal with spur of CH flower) and the adjacent two stamens in inCL flowers were best, and the back petal was similar to that of CL flowers, an organ primordium structure. The adjacent stamens with the back petals tended to be poorly developed. In extreme cases, these stamens in inCL flowers had no pollen sac, only a membranous appendage or even a primordium structure. When the plants with CL or CH flowers were placed under short-day light or long-day light, the newly induced flowers all showed a series of inCL flower types, finally the CL flowers transformed into CH flowers, and the CH flowers transformed into CL flowers. This result indicates the gradual effects of different photoperiods on dimorphic flowers development of V. philippica. A long photoperiod could inhibit the development of partial stamens and petals, and a short photoperiod could prevent the suppression of long-day light and promote the development of stamens and petals.     

Tinkering with the C-Function: A Molecular Frame for the Selection of Double Flowers in Cultivated Roses

Background

Roses have been cultivated for centuries and a number of varieties have been selected based on flower traits such as petal form, color, and number. Wild-type roses have five petals (simple flowers), whereas high numbers of petals (double flowers) are typical attributes of most of the cultivated roses. Here, we investigated the molecular mechanisms that could have been selected to control petal number in roses.

Methodology/Principal Findings

We have analyzed the expression of several candidate genes known to be involved in floral organ identity determination in roses from similar genetic backgrounds but exhibiting contrasting petal numbers per flower. We show that the rose ortholog of AGAMOUS (RhAG) is differentially expressed in double flowers as compared to simple flowers. In situ hybridization experiments confirm the differential expression of RhAG and demonstrate that in the double-flower roses, the expression domain of RhAG is restricted toward the center of the flower. Conversely, in simple-flower roses, RhAG expression domain is wider. We further show that the border of RhAG expression domain is labile, which allows the selection of rose flowers with increased petal number. Double-flower roses were selected independently in the two major regions for domestication, China and the peri-Mediterranean areas. Comparison of RhAG expression in the wild-type ancestors of cultivated roses and their descendants both in the European and Chinese lineages corroborates the correlation between the degree of restriction of RhAG expression domain and the number of petals. Our data suggests that a restriction of RhAG expression domain is the basis for selection of double flowers in both the Chinese and peri-Mediterranean centers of domestication.

Conclusions/Significance

We demonstrate that a shift in RhAG expression domain boundary occurred in rose hybrids, causing double-flower phenotype. This molecular event was selected independently during rose domestication in Europe/Middle East and in China.     

NORMAL FLORAL ONTOGENY AND COOL TEMPERATURE-INDUCED ABERRANT FLORAL DEVELOPMENT IN GLYCINE MAX (FABACEAE)

Floral onset in soybean (Glycine max cv. Ransom) is characterized by precocious initiation of axillary meristems in the axils of the most recently initiated leaf primordium. During floral transition, leaf morphology changes from trifoliolate leaf with stipules, to a three-lobed bract, to an unlobed bract. Soybean flowers initiated at 26/22 C day/night temperatures are normal, papilionaceous, and pentamerous. Sepal, petal, and stamen whorls are initiated unidirectionally from the abaxial to adaxial side of the floral apex. The median sepal is located abaxially and the median petal adaxially on the meristem. The organogeny of ‘Ransom’ flowers was found to be: sepals, petals, outer stamens plus carpel, inner stamens; or, sepals, petals, carpel, outer stamens, inner stamens. The outer stamen whorl and the carpel show possible overlap in time of initiation. Equalization of organ size occurs only within the stamen whorls. The sepals retain distinction in size, and the petals exhibit an inverse size to age relationship. The keel petals postgenitally fuse along part of their abaxial margins; their bases, however, remain free. Soybean flowers initiated at cool day/night temperatures of 18/14 C exhibited abnormalities and intermediate organs in all whorls. The gynoecium consisted of one to ten carpels (usually three or four), and carpel connation varied. Fusion of keel petals was often lacking, and stamen filaments fused erratically. Multiple carpellate flowers developed into multiple pods that were separate or variously connate. Intermediate type organs had characteristics only of organs in adjacent whorls. These aberrant flowers demonstrate that the floral meristem of soybean is not fixed or limited in its developmental capabilities and that it has the potential to produce alternate morphological patterns.     

Gene trap lines define domains of gene regulation in Arabidopsis petals and stamens

To identify genes involved in Arabidopsis thaliana petal and stamen organogenesis, we used a gene trap approach to examine the patterns of reporter expression at each stage of flower development of 1765 gene trap lines. In 80 lines, the reporter gene showed petal- and/or stamen-specific expression or lack of expression, or expression in distinct patterns within the petals and/or the stamens, including distinct suborgan domains of expression, such as tissue-specific lines marking epidermis and vasculature, as well as lines demarcating the proximodistal or abaxial/adaxial axes of the organs. Interestingly, reporter gene expression was typically restricted along the proximodistal axis of petals and stamens, indicating the importance of this developmental axis in patterning of gene expression domains in these organs. We identified novel domains of gene expression along the axis marking the midregion of the petals and apical and basal parts of the anthers. Most of the genes tagged in these 80 lines were identified, and their possible functions in petal and/or stamen differentiation are discussed. We also scored the floral phenotypes of the 1765 gene trap lines and recovered two mutants affecting previously uncharacterized genes. In addition to revealing common domains of gene expression, the gene trap lines reported here provide both useful markers and valuable starting points for reverse genetic analyses of the differentiation pathways in petal and stamen development.