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1.
在扫描电镜下对台闽苣苔 (T. oldhamii (Hemsl.) Solereder)进行了花部器官形态发生的观察,为探索该类群的个体发育、类群间的系统发育关系和进化趋势提供依据.研究发现该属植物萼片、花冠和雄蕊发生式样均为五数花类型,它们各自来源于花原基上分化出来的萼片原基、花冠原基和雄蕊原基;花冠与雄蕊的两侧对称性与花冠上唇生长稍快和退化雄蕊原基发育迟滞相关;萼片原基的发生和发育的顺序是不一致的:萼片原基发生的式样为近轴中原基-远轴2原基-2侧原基,发育式样则为近轴中萼片-2侧萼片-远轴2萼片,花蕾时为镊合状排列.花冠裂片原基的发生和发育式样是一致的,即远轴中裂原基(下唇中裂片)-远轴2侧裂原基(下唇2侧裂片)-近轴2裂原基(上唇2裂片).花蕾期卷迭式为覆瓦状排列,从外向内:下唇中裂片-下唇2侧裂片-上唇2裂片或下唇2侧裂片-上唇2裂片-下唇中裂片.雄蕊原基与花冠裂片原基互生,前方雄蕊原基在发生上稍迟于后方雄蕊原基,后者与退化雄蕊原基几乎同时发生,但较小,并与近轴心皮(或柱头上唇)对生.将该属与玄参科(Scrophulariaceae)的地黄属( Rehmannia )、苦苣苔科(Gesneriaceae)的异叶苣苔属( Whytockia)和尖舌苣苔属(Rhynchoglossum )的花部器官比较发现,这四个属在这方面呈现出多样性和交叉.过去一直按子房室数和胎座类型划分玄参科(子房2室、中轴胎座)和苦苣苔科(子房1室、侧膜胎座)这一做法受到了质疑.  相似文献   

2.
三白草科花部发育及其系统学意义   总被引:9,自引:2,他引:7  
本研究从比较三白草科属间小花个体发育及分析花器官数量变异入手,探寻花器官在发生顺序、数目变化及排列方式等方面的演化趋势,揭示系统发育在个体发育中一定程度重现的事实及属间的进化关系。结果简述如下:首先,雄蕊和心皮发生顺序由中部优先演化到两侧优先。其次,由于远中雄蕊和心皮经历了从发育延迟、生长减缓到最终消失的历程,中部雄蕊和心皮由成对演化为单生。此外,两侧生雄蕊对由各自独立的原基发生演化到共同原基发生或减化为1枚,假银莲花属近中1枚雄蕊原基二裂成1对,蕺菜属3枚心皮发生于一环状共同原基等,都是该科花器官演化的重要事实并可归结为融合、减化和复化的结果。文章根据花器官的演化趋势及过渡类型的剖析,论述了三白草科属间的系统进化关系。  相似文献   

3.
花叶芋(天南星科)的花器官发生   总被引:1,自引:0,他引:1  
利用扫描电镜首次观察了天南星科花叶芋(Colocasia bicolor) 的花器官发生过程。花叶芋的肉穗花序由无花被的单性花构成, 雌花发生于花序基部, 雄花发生于花序上部, 中性花位于花序中间部位。雄花: 3 或4 个初生雄蕊原基轮状发生, 随后每个初生原基一分为二, 形成6或8个次生原基; 一部分次生原基在其后的发育过程中融合, 形成5 或7 枚雄蕊; 雄花发育过程中未见雌性结构的分化; 花药的分化先于花丝; 雄蕊合生成雄蕊柱。雌花: 合生心皮, 3或4个心皮原基轮状发生, 未见雄性结构的分化。中性花来源于雌雄花序过渡带上, 属于雄蕊原基的滞后发育以及发育成熟过程中的退化; 与彩叶芋属(Caladium)不同, 此过渡区未见畸形两性花。初生雄蕊原基二裂产生次生原基的次生现象在目前天南星科花器官发生中显得比较特殊, 同时初步探讨了次生原基的融合方式。  相似文献   

4.
台闽苣苔(苦苣苔科)花部器官的形态发生   总被引:1,自引:0,他引:1  
在扫描电镜下对台闽苣苔 (T .oldhamii (Hemsl.)Solereder)进行了花部器官形态发生的观察 ,为探索该类群的个体发育、类群间的系统发育关系和进化趋势提供依据。研究发现该属植物萼片、花冠和雄蕊发生式样均为五数花类型 ,它们各自来源于花原基上分化出来的萼片原基、花冠原基和雄蕊原基 ;花冠与雄蕊的两侧对称性与花冠上唇生长稍快和退化雄蕊原基发育迟滞相关 ;萼片原基的发生和发育的顺序是不一致的 :萼片原基发生的式样为近轴中原基—远轴 2原基— 2侧原基 ,发育式样则为近轴中萼片— 2侧萼片—远轴 2萼片 ,花蕾时为镊合状排列。花冠裂片原基的发生和发育式样是一致的 ,即远轴中裂原基 (下唇中裂片 )—远轴 2侧裂原基 (下唇 2侧裂片 )—近轴 2裂原基 (上唇 2裂片 )。花蕾期卷迭式为覆瓦状排列 ,从外向内 :下唇中裂片—下唇 2侧裂片—上唇 2裂片或下唇 2侧裂片—上唇 2裂片—下唇中裂片。雄蕊原基与花冠裂片原基互生 ,前方雄蕊原基在发生上稍迟于后方雄蕊原基 ,后者与退化雄蕊原基几乎同时发生 ,但较小 ,并与近轴心皮 (或柱头上唇 )对生。将该属与玄参科 (Scrophulari aceae)的地黄属 (Rehmannia)、苦苣苔科 (Gesneriaceae)的异叶苣苔属 (Whytockia)和尖舌苣苔属 (Rhynchoglossum)的花部器官比较发现  相似文献   

5.
对广义马鞭草科(Verbenaceae)的3个主要亚科的花器官早期发生进行了比较研究,发现花器官发生的两种不同类型:在马鞭草亚科中,存在从远轴至近轴单向发生的顺序,首先远轴位置的萼片、花瓣、雄蕊相继发生,此时近轴位置的萼片、花瓣和雄蕊尚未出现或处于更幼小的时期;在牡荆亚科和莸亚科中表现为向心轮状发生的顺序,萼片同时或依次出现,萼片发生完成后,有一段转向花瓣形成原时间间隔,5枚花瓣几乎在同一时间出现,随后是4枚雄蕊同时发生,花器官发生的研究结果与形态学和rbcL序列分析所得出的系统学推断一致,支持马鞭草亚科和其余亚科不能形成一个单系群的观点。  相似文献   

6.
三白草科花粉形态研究   总被引:2,自引:3,他引:2  
  相似文献   

7.
利用扫描电镜首次对水筛[Blxa japonica(Miq.)Maxim.ex Asch.et Guerk.]花器官的发生进行了观察。结果显示:萼片原基以轮关方式向心发生;花瓣原基轮状近同时发生,与萼片基基交替排列;雄蕊原基以对萼的形式轮关发生,与花瓣原基轮状近同时发生,与萼片原基交替排列;雄蕊原基以对萼的形式轮状发生,与花瓣原基交替排列;花柱原基在整个花的发育过程中发生较晚,以对瓣的形式轮状发生,与雄蕊原基交替排列。与同科其它属的花比较,水筛的花为两性,辐射对称,胚珠多数,体现了较原始的特征。花各部数目均为3,进化程度居于中间水平。该属花各部轮状发生,子房下位,心皮合生,体现了本科在泽泻亚纲中花部结构进化的特征。  相似文献   

8.
三白草科的比较胚胎学研究   总被引:5,自引:1,他引:4  
研究了裸蒴(GymnothecachinensisDecne)胚胎的发育,同时对三白草(Saururuschinensis(Lour).Baill)和蕺菜(HouttuyniacordataThunb.)的胚胎也进行了观察,并对三白草科(Saururaceae)各属间的胚胎学特征进行比较,以探讨三白草科的内的系统关系。裸蒴具腺质绒毡层。小孢子同时型,极少数小孢子弱细胞的减数分裂II不进行,形成有壁  相似文献   

9.
广义马鞭草科花器官发生的研究   总被引:2,自引:0,他引:2  
  相似文献   

10.
论三白草科的系统演化和地理分布   总被引:10,自引:2,他引:8  
根据细胞学、孢粉学、花器官发生和发育、花部维管结构、胚胎学、比较形态及解剖学等方面的证据,对三白草科4属6种的系统演化关系进行了详细论证。并联系古地理、古气候和古植物的有关史料对三白草科分布区的起源作了据理推论。三白草科大约起源于早白垩纪古北大陆东南部。它的原始类型可能与现代三白草属的形态大体相似,为一种多年生具根状茎的草本,花小、无被、具苞片。白垩纪末期三白草的原始类群已完成它在古北大陆的迁移和  相似文献   

11.
The development of the inflorescence and flowers are described for Gymnotheca chinensis Decaisne (Saururaceae), which is native only to southeast China. The inflorescence is a short terminal spike of about 50–70 flowers, each subtended by a small bract. There are no showy involucral bracts. The bracts are initiated before the flowers, in acropetal order. Flowers tend to be initiated in whorls of three which alternate with the previous whorl members. No perianth is present. The flower contains six stamens, and four carpels fused in an inferior ovary containing 40–60 ovules on four parietal placentae. Floral symmetry is dorsiventral from inception and throughout organ initiation. Floral organs are initiated in the following order: 1) median adaxial stamen, 2) a pair of lateral common primordia which bifurcate radially to produce two stamen primordia each, 3) median abaxial stamen, 4) a pair of lateral carpel primordia, 5) median adaxial carpel, 6) median abaxial carpel. This order of initiation differs from that of any other Saururaceae previously investigated. The inferior ovary results from intercalary growth below the level of stamen attachment; the style elongates by intercalary growth, and the four stigmas remain free. The floral structure of Gymnotheca is relatively advanced compared to Saururus, but its assemblage of specializations differs from that of either Anemopsis or Houttuynia, the other derived genera in the Saururaceae.  相似文献   

12.
泽苔草的花器官发生   总被引:7,自引:2,他引:7  
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。  相似文献   

13.
The inflorescence of Saururus cernuus L. produces lateral “common” primordia in acropetal succession on the flanks of the inflorescence meristem; curiously, the “subtending” bract is initiated upon the lateral primordium rather than subtending it. On the basis of mature floral structure, flowers of S. cernuus have previously been described as having spiral initiation of parts. The current ontogenetic investigation contradicts this interpretation. Stamens arise in three successive pairs; the carpels also are initiated in pairs. Floral symmetry is shown to be bilateral from the onset of organ initiation, a rare feature among primitive angiosperms. On the basis of symmetry and paired initiation of organs, the possibility of close relationships between Saururaceae and Magnolialian or Ranalian lines appears remote.  相似文献   

14.
南天竹属的花部器官发生及其系统学意义   总被引:1,自引:1,他引:1  
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。  相似文献   

15.
16.
荆条花蜜腺发育解剖学研究   总被引:2,自引:0,他引:2  
荆条(Vitex chinensis Mill.)花蜜腺属于淀粉型子房蜜腺,呈圆筒状环绕于子房的基部。蜜腺外观上无特殊结构,表面有。由分泌表皮和泌蜜组织组成,包括分泌表皮、气孔器、泌蜜薄壁组织和维管束。密腺和子房壁起源相同。花蕾膨大期,泌蜜组织细胞中产生大液泡;露冠期,泌蜜组织中形成维管束;花蕾初放期,分泌表皮细胞分化形成气孔器,无气孔下室,淀粉粒的积累在此期达到高峰;盛花期,蜜腺中已无淀粉粒,密  相似文献   

17.
The spicate inflorescence of Saururus cernuus L. (Saururaceae) results from the activity of an inflorescence apical meristem which produces 200–300 primordia in acropetal succession. The inflorescence apex arises by conversion of the terminal vegetative apex. During transition the apical meristem increases greatly in height and width and changes its cellular configuration from one of tunica-corpus to one of mantle (with two tunica layers) and core. Primordia are initiated by periclinal divisions in the subsurface layer. These are “common” primordia, each of which subsequently divides to produce a floral apex above and a bract primordium below. The bract later elongates so that the flower appears borne on the bract. All common primordia are formed by the time the inflorescence is about 4.4 mm long; the apical meristem ceases activity at this stage. As cessation approaches, cell divisions become rare in the apical meristem, and height and width of the meristem above the primordia diminish, as primordia continue to be initiated on the flanks. Cell differentiation proceeds acropetally into the apical meristem and reaches the summital tunica layers last of all. Solitary bracts are initiated just before apical cessation, but no imperfect or ebracteate flowers are produced in Saururus. The final event of meristem activity is hair formation by individual cells of the tunica at the summit, a feature not previously reported for apical meristems.  相似文献   

18.
The inflorescence of Houttuynia cordata produces 45–70 sessile bracteate flowers in acropetal succession. The inflorescence apical meristem has a mantle-core configuration and produces “common” or uncommitted primordia, each of which bifurcates to form a floral apex above, a bract primordium below. This pattern of organogenesis is similar to that in another saururaceous plant, Saururus cernuus. Exceptions to this unusual development, however, occur in H. cordata at the beginning of inflorescence activity when four to eight petaloid bract primordia are initiated before the initiation of floral apices in their axils. “Common” primordia also are lacking toward the cessation of inflorescence apical activity in H. cordata when primordia become bracts which may precede the initiation of an axillary floral apex. Many of these last-formed bracts are sterile. The inflorescence terminates with maturation of the meristem as an apical residuum. No terminal flowers or terminal gynoecia were found, although subterminal gynoecia or flowers in subterminal position may overtop the actual apex and obscure it. Individual flowers have a tricarpellate syncarpous gynoecium and three stamens adnate to the carpels; petals and sepals are lacking. The order of succession of organs is: two lateral stamens, median stamen, two lateral carpels, median carpel. The three carpel primordia almost immediately are elevated as part of a gynoecial ring by zonal growth of the receptacle below the attachment of the carpels. The same growth elevates the stamen bases so that they appear adnate to the carpels. The trimerous condition in Houttuynia is the result of paired or solitary initiations rather than trimerous whorls. Symmetry is bilateral and zygomorphic rather than radial. No evidence of spiral arrangement in the flower was found.  相似文献   

19.
兰花蕉花的形态解剖学   总被引:2,自引:1,他引:1  
兰花蕉(Orchidantha chinensis)的子房室顶部闭合后向上延长成延长部,实心,但有花柱沟和隔膜蜜腺管通过,隔膜蜜腺管,可分为中央蜜腺管和三条侧蜜腺管;中央蜜腺管位于三个心皮连接处,自子房室区下部产生,向上于延长部的部顶端终止;三条侧管分别位于两个心皮连接处,于子房室区近中部产生,开口于花柱基部。兰花蕉子房室区与延长部均具6枚雄蕊的维管束系统,即3枚心皮背束的伴束与3枚隔膜束,近轴面1枚事膜向上进入唇瓣的维管束系统,位于唇瓣的中央,致使兰花蕉仅具5枚功能雄蕊,唇瓣具双重结构,本文还讨论了兰花蕉科的系统发育位置。  相似文献   

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