一种新型无花瓣油菜突变不育系花器官的形态解剖研究

在自育的甘蓝型油菜(Brassica napus)无花瓣品系AP197中, 发现并育成由4对隐性核基因控制的无花瓣油菜突变不育系AMS971。AMS是一种雄蕊心皮化为不结实的假性雌蕊而引起的新的雄性不育类型, 不育性非常彻底, 其植株形态特征与AP197相同。比较花器官发现, AMS971除一个正常的雌蕊外,还有6个梭形的心皮化假性雌蕊。假心皮化雌蕊上部变成近似倒U形的柱头结构区, 下部是完全突变的半开裂心皮, 其上着生4~14个不等的裸露的幼小胚珠; 蜜腺比正常油菜小, 数目为0~4个, 这与AP197没有差异。AMS971的四轮花器官由于突变造成了大小和重量的重新分配。推断AMS为类似拟南芥属B功能缺失的突变体。     

一种新型无花瓣油菜突变不育系花器官的形态解剖研究

在自育的甘蓝型油菜(Brassica napus)无花瓣品系AP197中,发现并育成由4对隐性核基因控制的无花瓣油菜突变不育系AMS971.AMS是一种雄蕊心皮化为不结实的假性雌蕊而引起的新的雄性不育类型,不育性非常彻底,其植株形态特征与AP197相同.比较花器官发现,AMS971除一个正常的雌蕊外,还有6个梭形的心皮化假性雌蕊.假心皮化雌蕊上部变成近似倒U形的柱头结构区,下部是完全突变的半开裂心皮,其上着生4～14个不等的裸露的幼小胚珠;蜜腺比正常油菜小,数目为0～4个,这与AP197没有差异.AMS971的四轮花器官由于突变造成了大小和重量的重新分配.推断AMS为类似拟南芥属B功能缺失的突变体.     

臭椿花器官分化的初步研究

利用扫描电镜(SEM)和光镜(LM)对臭椿花序及花器官的分化和发育进行了初步研究,表明:1)臭椿花器官分化于当年的4月初,为圆锥花序;2)分化顺序为花萼原基、花冠原基、雄蕊原基和雌蕊原基。5个萼片原基的发生不同步,并且呈螺旋状发生;5个花瓣原基几乎同步发生且其生长要比雄蕊原基缓慢;雄蕊10枚,两轮排列,每轮5个原基的分化基本是同步的;雌蕊5,其分化速度较快;3)在两性花植株中,5个心皮顶端粘合形成柱头和花柱,而在雄株中,5个心皮退化,只有雄蕊原基分化出花药和花丝。本研究着重观察了臭椿中雄花及两性花发育的过程中两性花向单性花的转变。结果表明,臭椿两性花及单性花的形成在花器官的各原基上是一致的(尽管时间上有差异),雌雄蕊原基同时出现在每一个花器官分化过程中,但是,可育性结构部分的形成取决于其原基是否分化成所应有的结构:雄蕊原基分化形成花药与花丝,雌蕊原基分化形成花柱、柱头和子房。臭椿单性花的形成是由于两性花中雌蕊原基的退化所造成,其机理有待于进一步研究。     

不结球白菜雄蕊心皮化雄性不育系HGMSⅡ特性研究

对不结球白菜雄蕊心皮化雄性不育系HGMS和HGMSⅡ进行花器形态比较、同功酶分析及结实性研究.结果表明:HGMSⅡ较好地保留了HGMS花瓣萼片化、雄蕊心皮化鲜明特征,而且花瓣EST和POD同功酶酶带与萼片酶带基本相同,心皮化器官EST和POD同功酶酶带与雌蕊酶带相同.与完全雄蕊心皮化的HGMS相比,HGMSⅡ雄蕊心皮化突变主要发生在花药部位,导致花药丧失了产生花粉的能力,从而保留了HGMS不育性稳定、彻底的优良特性.与HGMS相比,HGMSⅡ开花习性明显改善,柱头表面花粉明显增多,雌蕊发育基本正常,单株平均籽粒产量达到8.96 g,较HGMS增加了7.17 g,增幅达401%,结实性得到了显著提高.     

澜沧荛花(瑞香科)的花部形态发生yh及其系统学意义(英文)

通过扫描电镜对澜沧荛花Wikstroemiadelavayi花部的形态发生过程进行了观察和分析 ,旨在为该属的系统学研究提供花部发育形态学资料。澜沧荛花花部的发生和早期发育呈远轴面向近轴面的顺序 ,但这一式样由于近轴面的器官在早期发育之后生长加速发生了转变。因此 ,花开放时所表现的所谓辐射对称 ,显然是由同一轮器官的异率生长所导致的次生现象。花盘发生于花萼筒基部的远轴面上 ,与花萼、雄蕊的发生间隔时间较长。花盘原基在下轮雄蕊着生处凹陷或间断 ,与之相对应 ,花盘裂片与下轮雄蕊呈互生。由此 ,花盘显然不是花托的一部分 ,也不是象花萼、雄蕊和心皮一样的独立结构 ,将其解释为雄蕊群的一部分更合理。花盘的发生和早期发育及其着生位置同其他花部器官的发生和发育式样具有明显的相关性 ,这种相关性对进一步阐明瑞香属Daphne和荛花属Wikstroemia的系统发育关系具有一定意义。根据对雌蕊群的发生和发育过程观察 ,该种的子房是由一个近轴面的可育心皮和一个远轴面的不育心皮融合而成的单室子房 ,为假单心皮雌蕊。尽管荛花属和瑞香属均属于单室子房 ,但澜沧荛花的子房维管束中的腹束排列于中轴位置 ,而目前资料显示瑞香属植物的腹束接近于侧膜位置 ,这方面仍需进一步研究     

一种新型矮牵牛花发育突变体的研究

报道了新发现的一种矮牵牛(Petunia hybrida L.)花发育突变体,命名为efficient(eff),并对这一突变体进行了形态学和遗传学分析。eff突变体主要表现为雌蕊心皮数目的增加和雄蕊上长出花瓣状结构,同时,雄蕊、花瓣和萼片数亦有增多,但营养器官无变化。心皮数目的增加导致雌蕊柱头和子房体积的显著增大,并形成较大的果实。雄蕊上花瓣的形成对花粉的产生无明显影响。扫描电镜观察发现,eff突变体在花器官原基形成时发生了相应数目的增加及特征的变化。遗传学分析表明,突变的表现型符合孟德尔单基因遗传规律。     

一种花色突变雄性不育油菜的发现

在甘蓝型油菜杂交种C022(其母本为由3对基因控制育性的隐性细胞核雄性不育系9012A)不育株开放受粉的后代中,发现一种稀有的黄白双色嵌合花瓣的甘蓝型油菜突变体991S。其具有3个形态特征:(1)4片花瓣每片中央均为条带状黄色色斑,而两侧为白色,为嵌合双色花瓣;(2)4片花萼也可发生中间条带状白化;(3)目前只在不同群体的雄性不育株中出现,与同源的黄色花不育株形态相似,植株纤细矮小,花器也较小,花瓣较为平整,雌蕊弯曲,雄蕊退化,花药干缩。通过对其材料来源及后代花色表型分析,初步认为黄白双色性状由可局部表达的隐性白化基因控制。     

澜沧荛花(瑞香科)的花部形态发生 及其系统学意义

通过扫描电镜对澜沧荛花Wikstroemia delavayi花部的形态发生过程进行了观察和分析,旨在为该属的系统学研究提供花部发育形态学资料。澜沧尧花花部的发生和早期发育呈远轴面向近轴面的顺序,但这一式样由于近轴面的器官在早期发育之后生长加速发生了转变。因此,花开放时所表现的所谓辐射对称,显然是由同一轮器官的异率生长所导致的次生现象。花盘发生于花萼筒基部的远轴面上,与花萼、雄蕊的发生间隔时间较长。花盘原基在下轮雄蕊着生处凹陷或间断,与之相对应,花盘裂片与下轮雄蕊呈互生。由此,花盘显然不是花托的一部分,也不是象花萼、雄蕊和心皮一样的独立结构,将其解释为雄蕊群的一部分更合理。花盘的发生和早期发育及其着生位置同其他花部器官的发生和发育式样具有明显的相关性,这种相关性对进一步阐明瑞香属Daphne和荛花属Wikstroemia的系统发育关系具有—定意义。根据对雌蕊群的发生和发育过程观察,该种的子房是由一个近轴面的可育心皮和一个远轴面的不育心皮融合而成的单室子房,为假单心皮雌蕊。尽管荛花属和瑞香属均属于单室产房,但澜沧荛花的子房维管束中的腹束排列于中轴位置,而目前资料显示瑞香属植物的腹束接近于侧膜位置,这方面仍需进一步研究。     

南天竹属的花部器官发生及其系统学意义

报道了南天竹（ＮａｎｄｉｎａｄｏｍｅｓｔｉｃａＴｈｕｎｂ．）（小檗科）的花部器官发生。发现该属植物萼片、花瓣和雄蕊的发生式样为三数轮生;雄蕊与花瓣是经它们所具有的共同原基进行侧向分裂而形成的;花瓣发育早期存在迟滞发育的阶段;心皮发生属于瓶状发生类型。讨论了花器官的三基数性质,小檗科花瓣的来源,雄蕊对瓣着生及单心皮雌蕊的形成等问题。对本属的花部个体发育性状同小檗科中已有报道的红毛七属（Ｃａｕｌｏｐｈｙｌｕｍ）、足叶草属（Ｐｏｄｏｐｈｙｌｕｍ）进行了比较,萼片多数轮列与心皮发生的多态现象是南天竹属的独特性状。     

商陆属植物的花器官发生

为进一步研究商陆科的系统位置提供花器官发生和发育的证据,在扫描电子显微镜下观察了商陆Phytolacca acinosa、多雄蕊商陆P. polyandra和垂序商陆P. americana的花器官发生.结果表明: 商陆属植物花被的发生均为2/5型螺旋发生.在同一个种不同的花蕾中,花被的发生有两种顺序:逆时针方向和顺时针方向.远轴侧非正中位的1枚先发生.雄蕊发生于环状分生组织.在单轮雄蕊的种中8-10枚雄蕊为近同时发生;两轮雄蕊的种8枚内轮雄蕊先发生,6-8枚外轮雄蕊随后发生,内轮雄蕊为同时发生,外轮雄蕊发生次序不规则.心皮原基也发生于环状分生组织,8-10枚心皮原基为同时发生.在后来的发育过程中,商陆的心皮发育成近离生心皮雌蕊;其他2种心皮侧壁联合发育成合生心皮雌蕊.对商陆属植物花器官发生的类型及发育形态学做了分析,结果支持商陆科在石竹目系统发育中处于原始地位的观点.     

Microarray analysis reveals altered expression of a large number of nuclear genes in developing cytoplasmic male sterile Brassica napus flowers

To gain new insights into the mechanism underlying cytoplasmic male sterility (CMS), we compared the nuclear gene expression profiles of flowers of a Brassica napus CMS line with that of the fertile B. napus maintainer line using Arabidopsis thaliana flower-specific cDNA microarrays. The CMS line used has a B. napus nuclear genome, but has a rearranged mitochondrial (mt) genome consisting of both B. napus and A. thaliana DNA. Gene expression profiling revealed that a large number of genes differed in expression between the two lines. For example, nuclear genes coding for proteins that are involved in protein import into organelles, genes expressed in stamens and pollen, as well as genes implicated in either cell-wall remodeling or architecture, were repressed in the CMS line compared with B. napus. These results show that the mt genome of the CMS line strongly influences nuclear gene expression, and thus reveal the importance of retrograde signalling between the mitochondria and the nucleus. Furthermore, flowers of the CMS line are characterized by a replacement of stamens with carpelloid organs, and thus partially resemble the APETALA3 (AP3) and PISTILLATA (PI) mutants. In accordance with this phenotype, AP3 expression was downregulated in the stamens, shortly before these organs developed carpelloid characteristics, even though it was initiated correctly. Repression of PI succeeded that of AP3 and might be a consequence of a loss of AP3 activity. These results suggest that AP3 expression in stamens depends on proper mt function and a correct nuclear-mt interaction, and that mt alterations cause the male sterility phenotype of the CMS line.     

Ectopic expression of pMADS3 in transgenic petunia phenocopies the petunia blind mutant.

We cloned a MADS-box gene, pMADS3, from Petunia hybrida, which shows high sequence homology to the Arabidopsis AGAMOUS and Antirrhinum PLENA. pMADS3 is expressed exclusively in stamens and carpels of wild-type petunia plants. In the petunia mutant blind, which shows homeotic conversions of corolla limbs into antheroid structures with pollen grains and small parts of sepals into carpelloid tissue, pMADS3 is expressed in all floral organs as well as in leaves. Ectopic expression of pMADS3 in transgenic petunia leads to phenocopies of the blind mutant, i.e., the formation of antheroid structures on limbs and carpelloid tissue on sepals. Transgenic tobacco plants that overexpress pMADS3 exhibit an even more severe phenotype, with the sepals forming a carpel-like structure encasing the interior floral organs. Our results identify BLIND as a negative regulator of pMADS3, which specifies stamens and carpels during petunia flower development.     

APETALA1启动子驱动AtIPT4在转基因拟南芥中表达导致花和花器官发育异常

细胞分裂素对拟南芥（Arabidopsis thaliana）花分生组织细胞的分裂和分化具有重要作用。本研究利用APETALA1（AP1）特异启动子在花分生组织和第1、2轮花器官中表达细胞分裂素合成酶（isopentyl transferase,IPT）基因IPT4,研究细胞分裂素对花和花器官发育的影响。在pAP1∷IPT4转基因植株中出现了花密集和花器官数目增多等现象。原位杂交和GUS组织染色结果发现,在pAP1∷IPT4转基因植株中,花分生组织特征决定基因LEAFY（LFY）与花器官特征决定基因AP1、PISTILLATA（PI）和AGAMOUS（AG）的表达量均有不同程度的提高。研究结果表明在拟南芥中表达pAP1∷IPT4影响其花和花器官的正常发育。     

Organelle Simple Sequence Repeat Markers Help to Distinguish Carpelloid Stamen and Normal Cytoplasmic Male Sterile Sources in Broccoli

We previously discovered carpelloid stamens when breeding cytoplasmic male sterile lines in broccoli (Brassica oleracea var. italica). In this study, hybrids and multiple backcrosses were produced from different cytoplasmic male sterile carpelloid stamen sources and maintainer lines. Carpelloid stamens caused dysplasia of the flower structure and led to hooked or coiled siliques with poor seed setting, which were inherited in a maternal fashion. Using four distinct carpelloid stamens and twelve distinct normal stamens from cytoplasmic male sterile sources and one maintainer, we used 21 mitochondrial simple sequence repeat (mtSSR) primers and 32 chloroplast SSR primers to identify a mitochondrial marker, mtSSR2, that can differentiate between the cytoplasm of carpelloid and normal stamens. Thereafter, mtSSR2 was used to identify another 34 broccoli accessions, with an accuracy rate of 100%. Analysis of the polymorphic sequences revealed that the mtSSR2 open reading frame of carpelloid stamen sterile sources had a deletion of 51 bases (encoding 18 amino acids) compared with normal stamen materials. The open reading frame is located in the coding region of orf125 and orf108 of the mitochondrial genomes in Brassica crops and had the highest similarity with Raphanus sativus and Brassica carinata. The current study has not only identified a useful molecular marker to detect the cytoplasm of carpelloid stamens during broccoli breeding, but it also provides evidence that the mitochondrial genome is maternally inherited and provides a basis for studying the effect of the cytoplasm on flower organ development in plants.     

草原龙胆MADS-box基因的克隆及表达分析

植物MADS-box基因家族编码高度保守的转录因子,参与了包括花发育在内的多种发育进程。为阐释双子叶植物草原龙胆（Eustoma grandiflorum）花器官发育的分子调控机制,根据MADS-box基因保守序列设计简并引物,用3＇-RACE方法从草原龙胆中克隆了4个花器官特异表达的MADS-box家族基因。序列和系统进化树分析表明,这4个基因分别与金鱼草DEF基因、矮牵牛FBP3基因和FBP6基因以及拟南芥SEP3基因具有很高的同源性,分别属DEF/GLO、AG-like和SEP-like亚家族。从而将这4个基因分别命名为EgDEF1、EgGLO1、EgPLE1和EgSEP3-1。推导的氨基酸序列显示,这些基因编码的蛋白质都包含高度保守的MADS结构域、I结构域和K结构域,每个基因均有其亚家族特异的C-末端功能域。基因特异性RT-PCR检测结果显示：EgDEF1在萼片、花瓣、雄蕊及胚珠中高丰度表达,在心皮中微量表达;而EgGLO1在花瓣和雄蕊中高丰度表达,在萼片中微量表达;在根、茎、叶等营养器官中均未检测到上述2个基因的表达。EgPLE1在雌蕊、心皮和胚珠中特异表达,但表达的丰度存在差异,在雄蕊中的表达有所减弱。SEP-like亚家族基因EgSEP3-1在四轮花器官和胚珠中均特异表达,且表达丰度相对一致。     

Isolation and characterisation of an <Emphasis Type="Italic">HpSHP</Emphasis> gene from <Emphasis Type="Italic">Hosta plantaginea</Emphasis>

Based on genetic and molecular analyses, the ABC model has been proposed to explain the genetic control of floral development. C-class MADS-box genes play crucial roles in Arabidopsis thaliana development by regulating the organ identities of stamens and gynoecium. The present research reports for the first time the cloning of an HpSHP gene from Hosta plantaginea (Lam.) Aschers. Phylogenetic analysis shows that HpSHP is a member of the C-class MADS-box genes that is closely related to C-lineage SHP homologues from monocot species. Semi-quantitative and real-time polymerase chain reaction analyses show that HpSHP expression is stamen and gynoecium specific. HpSHP also has spatial and temporal expression patterns in the reproductive organs of H. plantaginea. A functional analysis is carried out in Arabidopsis by overexpression of HpSHP. Homeotic transformations of sepals into carpelloid organs, bent ovaries, and prematurely shattering fruits are observed in 35S::HpSHP transgenic plants. All these results show that HpSHP plays a crucial role in gynoecium development.     

Expression of the Arabidopsis floral homeotic gene AGAMOUS is restricted to specific cell types late in flower development.

Mutations in the AGAMOUS (AG) gene cause transformations in two adjacent whorls of the Arabidopsis flower. Petals develop in the third floral whorl rather than the normal stamens, and the cells that would normally develop into the fourth whorl gynoecium behave as if they constituted an ag flower primordium. Early in flower development, AG RNA is evenly distributed throughout third and fourth whorl organ primordia but is not present in the organ primordia of whorls one and two. In contrast to the early expression pattern, later in flower development, AG RNA is restricted to specific cell types within the stamens and carpels as cellular differentiation occurs in those organs. Ectopic AG expression patterns in flowers mutant for the floral homeotic gene APETELA2 (AP2), which regulates early AG expression, suggest that the late AG expression is not directly dependent on AP2 activity.     

Type specification and spatial pattern formation of floral organs: A dynamic development model

A mathematical model simulating spatial pattern formation (positioning) of floral organs is proposed. Computer experiment with this model demonstrated the following sequence of spatial pattern formation in a typical cruciferous flower: medial sepals, carpels, lateral sepals, long stamens, petals, and short stamens. The positioning was acropetal for the perianth organs and basipetal for the stamens and carpels. Organ type specification and positioning proceed non-simultaneously in different floral parts and organ type specification goes ahead of organ spatial pattern formation. Computer simulation of flower development in several mutants demonstrated that the AG and AP2 genes determine both organ type specification and formation of the zones for future organ development. The function of the AG gene is to determine the basipetal patterning zones for the development of the reproductive organs, while the AP2 gene maintains proliferative activity of the meristem establishing the acropetal patterning zone for the development of the perianth organs.