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     

澜沧尧花（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.     

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.     

吉祥草的花部器官发生及其系统学意义

利用扫描电镜（SEM）观察了吉祥草（Reineckia carnea）（铃兰科）的花部器官发生发育过程。吉祥草花被片、雄蕊的发生方式是由近轴端向远轴端发生的逆单向型（reversed unidirection）,花发育后期花被片合生形成花被筒,花丝与之贴生。伴随花被片、雄蕊发生,三枚心皮也由近轴向远轴方向相继发生,随后彼此合生发育。花序顶部的花易发生花器官数目变异。结合早期花原基形态以及花器官数目变异情况分析,吉祥草的花被片与雄蕊可能是由共同原基分化而成。从花部器官发生式样和花被筒形成时间两方面比较吉祥草属、白穗花属和铃兰属的特征发现,三属中,铃兰属处于相对进化的位置,而白穗花属比吉祥草属更为原始。     

商陆属植物的花器官发

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。     

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。     

马桑绣球(绣球科)的花器官发生和发育

在扫描电镜下观察了马桑绣球Hydrangea aspera孕性花的发生及发育过程。马桑绣球的花器官向心轮状发生：花萼原基以2/5螺旋式相继发生,花瓣原基几乎同步发生。花瓣开始发育时,与花萼相对的雄蕊发生。与花瓣相对的雄蕊原基与心皮原基几乎同时出现。初始心皮向上扩展,分化出花柱和柱头,向下延伸,嵌入花托,发育为下位子房。花发育成熟时,隔膜于子房的下部连续,而中部和上部不连续,即子房为不完全2室。经过与绣球属已观察过的另外5种1亚种花器官发生和发育比较,发现马桑绣球与藤绣球H. ano mala subs     

泽苔草的花器官发生

本文用扫描电镜观察了泽苔草的花器官发生过程,观察结果表明：花萼以螺旋状方式向心发生,花瓣以接近轮状方式近同时发生,不存在花瓣雄蕊复合原基。雄蕊和心皮均以轮状向心方式发生,6枚雄蕊分两轮分别在对萼和对瓣的位置先后发生,至发育的后期排成一轮,但仍分别处于对萼和对瓣的位置;随后发生的第一轮3个心皮原基与3枚萼片相对,第二、三轮心皮原基分别为1~3个,与前一轮心皮相间排列向心发生。本文首次揭示了泽苔草花被的外轮3个萼片螺旋状发生方式,这种螺旋状方式很可能是泽泻科植物的花部结构在进化过程中适应环境而保留下来的一种较原始的叶性特征。     

眼子菜的花器官发生

运用扫描电镜观察了眼子菜的花器官发生过程。结果表明：花原基从花序轴的基部开始以三数 交互轮状的方式发生,在花原基发生的早期具有明显的苞片原基形成。花器官是以向心的方式发生的, 二枚侧方花被片原基首先形成,紧接着产生二枚中间花被片。四枚雄蕊分两轮分别在与侧方花被和中 间花被相对的位置发生,四枚雄蕊原基在发生时均呈长条形。上述四轮花被和雄蕊虽然在时间上以二 数轮状的方式发生,但在空间上花被片和雄蕊各自分别排成一轮。最后,二个心皮原基在花原基顶端略 偏于一侧并与雄蕊相间的位置同时发生。有些花的二枚心皮原基发生后其中一枚很早即停止生长或仅 有一枚心皮原基形成。本文结果支持了眼子菜属心皮数目逐渐向简化的方向演化的观点。在花原基早期发育的过程中苞片原基的存在表明眼子菜属植物成熟花中缺乏苞片是简化的结果。     

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。     

Floral morphogenesis of Wikstroemia delavayi (Thymelaeaceae) and its phylogenetic implication

Floral morphogenesis of Wikstroemia delavayi Lecomte was investigated by scanning electron microscope (SEM) and compared with its allied groups. Initiation and early development of floral parts in W. delavayi followed unidirectional sequences from the abaxial side to the adaxial side. Because the floral parts grew faster at the adaxial side than at the abaxial one in following development, the zygomorphic pattern in the early development changed and finally became an almost actinomorphic form at anthesis. The disc was initiated from the abaxial base of the floral tube and itslobes were alternate with lower whorl stamens. According to this initiatial and developmental pattern, it is reasonable to interpret the disc as a part of the androecium rather than a modification of the receptacle. The located position and development of the disc was correlative with the development of other floral organs, which might provide insight to delimit Wikstroemia and Daphne based on different floral developmental pattern that might exist between the two genera. The developmental process of W. delavayi indicated that the syncarpous and uniloculate gynoecium was in fact bicarpellate, which consisted of a fertile carpel and a sterile one. It was pseudomonomerous. Even though the ovary in both Wikstroemia and Daphne was uniloculate, the location of the ventral bundles in the ovary was obviously different from each other according to data to date. In this respect, further investigation is undertaken between the two genera.     

Comparative floral development in Lamioideae (Lamiaceae): Marrubium,Phlomis, and Stachys

A comparative study of floral ontogeny and development was carried out on three genera (Marrubium L., Phlomis L., Stachys L.), representing three tribes of Lamioideae (Marrubieae, Phlomideae, Stachydeae) using epi-illumination light microscopy. The sequence of organ whorl appearance in all three genera is sepals, petals plus stamens, and carpels. Sepal appearance is reversed unidirectional starting from the adaxial side in all except Phlomis, which is unidirectional. Order of petal appearance is bidirectional in Marrubium and Stachys, and simultaneous in Phlomis. Stamens appear unidirectionally starting from the adaxial side in all except in Phlomis, which has an abaxial to adaxial unidirectional sequence. Significant developmental features distinguishing the three genera from each other include (1) weakly monosymmetric, elongated calyx tube, five-lobed corolla, divergent anthers with thecae transverse to the filament, unequally bifid stigma and ovary with glandular hairs in Marrubium; (2) actinomorphic hairy calyx, four-lobed corolla and unequally bifid stigma in Phlomis; and (3) glabrous calyx, equally bifid stigma and symmetric disc nectary in Stachys. Our results indicate some potential for floral ontogenetic features in delimiting the different tribes. The hypothetical evolutionary pathway of organogenesis sequences is discussed.     

数珠珊瑚(商陆科)的花器官发生

对数珠珊瑚的花器官发生和子房的发育过程进行了观察。结果表明：(1)数珠珊瑚花被呈2／5螺旋状发生,远轴侧的1枚先发生,其次为近轴侧的1枚发生,最后侧方的2枚花被几乎同时发生,第3枚花被在靠近第1枚的位置发生,第2枚和第3枚之间有1个空隙;(2)4枚雄蕊是同时发生的;(3)心皮发生于分生组织的远轴侧,心皮原基形成后,向上向轴生长,在子房成熟前在近轴侧非正中位形成1个孔,该孔为心皮最终愈合前的残迹,到子房成熟时．因子房的生长孔被挤压缩小,在进一步的生长过程中愈合。子房由1枚心皮构成;(4)从子房发育过程的切片看,该植物的胚珠是在子房发生后不久发生的,子房上的圆孔形成时,从近轴侧的分生组织发生胚珠原基,由胚珠原基分化出珠被与珠心。     

A SCANNING ELECTRON MICROSCOPIC STUDY ON THE INITIATION AND DEVELOPMENT OF FLORAL ORGANS OF BRASSICA NAPUS (CV. WESTAR)

The initiation and development of the floral organs of Brassica napus L. (cv. Westar) were examined using the scanning electron microscope. After transition of the vegetative apex into an inflorescence apex, flower primordia were initiated in a helical phyllotactic pattern. The sequence of initiation of the floral organs in a flower bud was that of sepals, stamens, petals and gynoecium. Of the four sepal primordia, the abaxial was initiated first, followed by the two lateral and finally the adaxial primordium. The four long stamens were initiated simultaneously in positions alternating with the sepals. The two short stamens were initiated basipetal to and outside the long stamens, and opposite the lateral sepals. The petals arose on either side of the two short stamens and the gynoecium was produced from the remainder of the apex. During development, the sepal primordia curved sharply at the tips and tightly enclosed the other organs. Stamen primordia developed tetralobed anthers at an early stage while filament elongation occurred just prior to anthesis. A unique pattern of bulbous cells was present on the abaxial surface of the anther. Growth of petal primordia lagged relative to the other floral organs but expansion was rapid prior to anthesis. The gynoecium primordium was characterized by an invagination early in development. At maturity, there was differentiation of a papillate stigma, an elongated style and a long ovary marked externally by sutures and divided internally by a septum. Distinct patterns of cuticular thickenings were observed on the abaxial and adaxial surfaces of the petals and stamens and on the surface of the style. The patterns were less obvious on the sepals and ovary. Stomata were present on both surfaces of the mature sepals, on the style and restricted areas on the abaxial surface of the anthers and nectaries but were absent from the petals, the adaxial surface of the stamens and the ovary. No hairs were present on any of the floral organs.     

Comparative floral development in the tribe Mentheae (Nepetoideae: Lamiaceae) and its bearing on the evolution of floral patterns in asterids

A comparative developmental study of flowers was carried out using epi-illumination light microscopy on four genera of Lamiaceae (Nepeta, Rosmarinus, Salvia, andZiziphora), representing all three subtribes of Mentheae. All species examined share unidirectional (adaxial to abaxial) sepal initiation, except Rosmarinus, which has the reverse unidirectional sequence, starting abaxially. Initiated but suppressed bracteoles were detected only in Rosmarinus. In Rosmarinus, Salvia, and Ziziphora, initiation of petals and stamens proceeds unidirectionally from the abaxial side. Floral initiation of Nepeta has bidirectional inception of petals and unidirectional stamen initiation from the adaxial side. Temporal overlap in organ initiation between petal and stamen whorls occurs in all taxa, though this feature is more prominent in Rosmarinus. Significant structural and developmental features that distinguish the four genera include: (1) polysymmetric calyx tube, highly tomentose corolla and deeply four-partitioned ovary in Nepeta; (2) monosymmetric two-lipped calyx and shallowly four-partitioned ovary in Ziziphora; and (3) suppression of adaxial stamens in Salvia and Rosmarinus. Adaxial stamens are absent from Rosmarinus, but reduced stamens remain as staminodia in Salvia. In a phylogenetic context, the late monosymmetry of Nepeta and very early monosymmetry of Rosmarinus could both be regarded as derived conditions compared with the early monosymmetry ofSalvia and Ziziphora.     

Two discrete cis elements control the Abaxial side-specific expression of the FILAMENTOUS FLOWER gene in Arabidopsis

Our previous studies showed that a member of the YABBY gene family, FILAMENTOUS FLOWER (FIL), plays a role in specifying the abaxial side tissues in the development of lateral organs such as cotyledons, leaves, young flower buds, and flower organs. We examined the expression pattern of FIL and found a temporal change of expression domains in the developmental process of the floral meristem. We also examined the cis control regions by constructing a series of transgenic plants that carry green fluorescent protein under the control of the FIL promoter with several types of deletions, base changes, and tandem repeats and showed that the unique expression pattern is dependent on at least two cis-acting elements in the 5' regulatory region. One element proximal to the FIL gene would be responsible for the expression of both the abaxial and adaxial sides, and the other element of the 12-bp sequence would work to repress expression on the adaxial side.     

Floral development in Scutellaria pinnatifida (Lamiaceae): the ontogenetic basis for sepal reduction

The Scutellaria is a Labiatae genus (subfamily Scutellarioideae) with a highly specialised floral structure. The genus is characterised by a peculiar two‐lobed calyx with a projecting appendage, named the scutellum. Here, we present a detailed analysis of floral development, using epi‐illumination light microscopy, to clarify open questions about its floral organisation. Floral whorls appeared in an acropetal sequence, with a marked temporal overlap of petal and stamen appearance. Organ appearance in each whorl proceeded unidirectionally from the abaxial to the adaxial side. Significant developmental features included the formation of the scutellum, reduction of sepal lobes and formation of a three‐lobed nectary disc. Our study revealed that both loss of organ initiation and fusion of primordia are responsible for the reduction in sepal members in Scutellaria. The nectary structure was markedly different from most other studied Lamiaceae.     

FLORAL DEVELOPMENT IN CAESALPINIA (LEGUMINOSAE)

Utilizing scanning electron microscopy, we studied the early floral ontogeny of three species of Caesalpinia (Leguminosae: Caesalpinioideae): C. cassioides, C. pulcherrima, and C. vesicaria. Interspecific differences among the three are minor at early and middle stages of floral development. Members of the calyx, corolla, first stamen whorl, and second stamen whorl appear in acropetal order, except that the carpel is present before appearance of the last three inner stamens. Sepals are formed in generally unidirectional succession, beginning with one on the abaxial side next to the subtending bracts, followed by the two lateral sepals and adaxial sepal, then lastly the other adaxial sepal. In one flower of C. vesicaria, sepals were helically initiated. In the calyx, the first-initiated sepal maintains a size advantage over the other four sepals and eventually becomes cucullate, enveloping the remaining parts of the flower. The cucullate abaxial sepal is found in the majority of species of the genus Caesalpinia. Petals, outer stamens, and inner stamens are formed unidirectionally in each whorl from the abaxial to the adaxial sides of the flower. Abaxial stamens are present before the last petals are visible as mounds on the adaxial side, so that the floral apex is engaged in initiation of different categories of floral organs at the same time.     

The development of pistillate and perfect florets in Xeranthemum squarrosum (Asteraceae)

The formation of capitulum inflorescence with two different types of floret is an interesting issue in floral biology and evolution. Here we studied the inflorescence, floral ontogeny and development of the everlasting herb, Xeranthemum squarrosum, using epi‐illumination microscopy. The small vegetative apex enlarged and produced involucral bracts with helical phyllotaxy, which subtended floret primordia in the innermost whorl. Initiation of floret primordia was followed by an acropetal sequence, except for pistillate peripheral florets. The origin of receptacular bracts was unusual, as they derived from the floral primordia rather than the receptacular surface. The order of whorl initiation in both disc and pistillate flowers included corolla, androecium and finally calyx, together with the gynoecium. The inception of sepals and stamens occurred in unidirectional order starting from the abaxial side, whereas petals incepted unidirectionally from the adaxial or abaxial side. Substantial differences were observed in flower structure and the development between pistillate and perfect florets. Pistillate florets presented a zygomorphic floral primordium, tetramerous corolla and androecium and two sepal lobes. In these florets, two sepal lobes and four stamen primordia stopped growing, and the ovary developed neither an ovule nor a typical stigma. The results suggest that peripheral pistillate florets in X. squarrosum, which has a bilabiate corolla, could be considered as an intermediate state between ancestral bilabiate florets and the derived ray florets.