共查询到20条相似文献，搜索用时 328 毫秒
1.
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。 相似文献
2.
通过扫描电镜观察了宽叶泽苔草Caldesia grandisSamuel.的花器官发生。宽叶泽苔草 的萼片3枚，逆时针螺旋向心发生 ；花瓣3枚，呈一轮近同时发生，未观察到花瓣_雄蕊复合原基；雄蕊、心皮原基皆轮状向心 发生，最先近同时发生的6枚原基全部发育成雄蕊，随后发生的6枚原基早期并无差别，在发 育过程中逐渐出现形态差异，直至其中1－4枚发育成心皮，其余的发育成雄蕊；而后的几轮 心皮原基，6枚一轮，陆续向心相间发生。本文揭示了3枚萼片螺旋状的发生方式，并推测这种螺旋方式是泽泻科植物进化过程中保留下来 相似文献
3.
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。 相似文献
4.
福建柏是我国特有裸子植物之一。它的原胚经过三次有丝分裂，产生8个游离核，然后形成细胞壁。原胚属标准型。开放层细胞与初生胚细胞的比率多数为4:4；少数为5:3或6:2。福建柏具裂生多胚，由于初生胚柄的生长速度不同，引起胚细胞的独立发育，从而产生多胚。 从早期胚胎发育的资料看，福建柏属与柏木属、扁柏属比较类似，它们应属于柏木亚科。福建柏属的系统位置，可能介于扁柏属和圆柏属之间。 相似文献
5.
秤锤树(Sinojakia rylocarpa Hu)为我国特产的稀有观赏树木。迄今，国内外对其胚
胎发育缺乏系统报道，本文报告这方面的研究结果。 其花药为4个花粉囊组成，小孢子四
分体呈四面体形排列，小孢子母细胞减数分裂时，胞质分裂属于同时型。2胞花粉，具 3 孔沟，
有不规则穴状纹饰。 花药壁的分化过程为双子叶植物型，在其成熟时，药室内壁和部分表皮细
胞的细胞壁上出现微弱的条状纤维加厚。腺质绒毡层。雌蕊为3心皮构成，开放型花柱，子房
内含多枚倒生胚珠。单珠被，薄珠心，未发现珠孔塞结构。大孢子四分体多呈线形，个别的为
T形。蓼型胚囊。受精前，2个极核相互靠拢，但未见融合。反足细胞较小，寿命似较长。成熟
胚囊中充满淀粉粒。从有关胚胎发生的资料分析，野茉莉科与柿树科、山榄科、山矾科关系密 切，这支持了将它们共同列入柿树目的植物分类系统的观点。 相似文献
6.
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。 相似文献
7.
白豆杉属(Pseudotaxus Cheng)是我国裸子植物特有属之一,它的胚胎发育十分类似于红豆
杉属。白豆杉受精卵经4次有丝分裂,形成16个游离核的原胚,紧接着形成细胞壁。简单多
胚普遍存在,但没有裂生多胚。在后期胚胎发育中,根原始细胞主要向上分化形成原形成层和
胚皮层,向下提供根冠较少。因此,根冠组织弱小,而次生胚柄系统则十分发达。成熟胚具2
枚子叶,下胚轴中没有髓部,也没有任何分泌分子。
通过白豆杉胚胎发育的研究,作者认为白豆杉属在红豆杉科中的排列位置是：红豆杉属、
白豆杉属、澳洲红豆杉属、穗花杉属和榧树属。其中红豆杉属和白豆杉属比较原始,而榧树属
则比较进化。同时作者认为：从胚胎学资料看,将红豆杉科从松柏目中分离出来,单独成立红 豆杉目,这种观点得不到支持。 相似文献
8.
利用解剖镜和扫描电子显微镜详细观察了泽泻科星果泻属全部5种植物的果实形态和微形态特征，发现该属植物的果实：常为蓇葖果具2～6枚种子；稀瘦果具1枚种子，扁压，不规则长方形，顶端一侧延伸成尾状长喙；或果实三角形，喙不明显。果皮上有角质层覆盖，角质层的纹饰为条状或细条状，上面密被碎屑状、颗粒状或稀疏的颗粒状蜡质附属物。这些特征可作为属下分类的依据。本文在前人研究的基础上对该属的分类进行了讨论并写出新的分种检索表。笔者认为将星果泻和星状星果泻各自作为独立的种可能更为合理；加州星果泻仍应放在星果泻属内，而星果泻则可能是加州星果泻与该属其它种联系的一个中间过渡类型；多籽星果泻不宜与星果泻全并，仍应保留为一独立的种。笔者还首次发现该属植物的果皮上分布有气孔。 相似文献
9.
单穗升麻的雌蕊群由1～5枚离生心皮组成。子房单室,4～9枚倒生胚珠,双珠被,厚珠心;大孢子四分体呈线形或T形排列,合点端一个具功能。胚囊发育为蓼型。成熟胚囊中3个单核反足细胞,胞质浓密,在球形胚时期尚能观察到其退化痕迹。极核融合早,次生核位于合点端。胚胎发生为柳叶菜型;核型胚乳。雄蕊凋谢后1～2天花柱顶端腹缝线周围出现乳突细胞,雄蕊凋谢后3～5天延长成柱头毛。讨论了单穗升麻与南川升麻柱头可授期与花粉生活力的差异对传粉效果和结籽率的显著影响。 相似文献
10.
穗花杉 Amentotaxus argotaenia 胚胎发育的主要特点是： 原胚在16核时形成细胞壁， 幼胚发育缓慢，并要经过一个冬季低温阶段，一直到第二年种子脱落时，它们还处于简单多胚 的选择时期, 后期胚的发育是在种子脱离母树后进行的。根据胚胎发育特点，穗花杉属在红豆杉科中的系统位置(由原始到进化的顺序)是：穗花杉属，澳洲红豆杉属，红豆杉属，白豆杉属，榧树属。 相似文献
11.
马金双 《中国科学院研究生院学报》1989,27(5):321-364
本文通过对东亚和南亚马兜铃属的研究，修改了马兜铃属的分类系统，补充论证了演化趋势；并
在分析该属地理分布的基础上提出马兜铃属分布与分化的第二个中心——中国的横断山区。 本文确
认2亚属、7组、4系、68种和1变种，其中有3新组、2新种及13个新异名。 相似文献
12.
This paper reports the bisexual structure of the flowers of Pterocarya
stenoptera. The bisexual flowers are borne at the end of a leafy shoot of the current year
in many-flowered terminal pendulous catkins. They have the same structure as the general
female ones. Each flower grows in the axil of a bract, with a pair of bracteoles and four
small perianths. Each flower has two or three carpels in the centre of the flower, and upon
them there are two or three styles with stigmas on the inner face. They differ from the ge-
neral female ones in that each of them contains 4-6 stamens, forming a single whorl. The
stamens alternates with, or is opposite to, the perianth elements. Sometimes they contain
8 (-10) stamens, forming two whorls, with 6 in the outer whorl and 2 (-4) in the in-
ner whorl, and in this case the pistil in the bisexual flower of terminal catkins often becomes
a rudiment.
It is interesting that we have also found bisexual flowers in another tree, which are
borne in lateral male catkins. They have the same structure as general male ones, and the
pistils are often represented by a rudiment.
Manning (1940) points out that some female flowers of Pterocarya stenoptera and P.
fraxinifolia occasionally have stamens ( ? ) opposite the sepals. In P. stenoptera we have found
that both the stamens and the stigmas of bisexual flowers are functional. They are capable
of producing functional fruits. This is the same case as in Myrica Gale described by Davey
and Gibson (1917). Rendle (1952) points out that in the male flowers of Platycarya the
pistils often appeared as a rudiment. He considers, however, the male flowers derived from
the bisexual flowers with an indefinite number of stamens. The rudimentary pistils of later-
al male catkins in P. stenoptera we found are just the same as the ones found in Platycarya
by Rendle.
The discovery of the bisexual flowers in P. stenoptera may prove that the unisexual
flowers of the present-day Juglandaceae are derived from ancestors with bisexual flowers.This tends to support the hypothesis that Cycadicae is the possible ancestor of the angiosperms. 相似文献
13.
本文研究并报道了百合科蜘蛛抱蛋亚族的花粉形态，主要结论如下：1．开口箭属含两种花粉类型即：(1)单槽、椭圆形；(2)无萌发孔、球形。具单槽、椭圆形花粉的种类含单型性核型，花形较小，柱头小而花柱短，雄蕊高于柱头；无萌发孔、球形花粉的种类则为单型性核型，花形较大，柱头常高度膨大，雄蕊常着生在花被筒基部。2．万年青属花粉为椭圆形，具单槽；蜘蛛抱蛋属花粉则为球形，无萌发孔；开口箭属花粉一部分与万年青属相似，另一部分则与蜘蛛抱蛋属雷同。3．蜘蛛抱蛋亚族中最原始的花粉类型为单槽椭圆形，具孔状或网状外壁纹饰。球形，无萌发孔，外壁具皱波状、瘤状或芽孢状纹饰的花粉为派生类型。4．蜘蛛抱蛋亚族种下花粉形状、萌发孔类型和外壁纹饰基本稳定，可作为分种特征。 相似文献
14.
黄淑美 《中国科学院研究生院学报》1987,25(5):384-389
Dichroa Lour., a small genus of Saxifragaceae, contains about 12 species,
ranging from the mainland of S. E. Asia southward to Pacific islands. But most of
the species are more restricted in distribution. Of the 12 recognized species, six are
known from South China and Indochina; three are confined to west and northwest
New Guinea; two are endemic to the Phillipines. Only one species is widely distributed
in S. E. Asia. In the present paper, the genus is divided into two sections and two
series based on the number of stamens and the characteristics of the ovary. One spe-
cies is described as new. 相似文献
15.
本文为独叶草形态学研究的一部分,主要报道其根状茎结构的初步观察结果。根状茎的初
生结构的基本图案类似一般多年生草本植物的根状茎。但其维管束连接成简状,缺乏髓射线,
以后产生的次生维管组织中亦缺乏明显的射线。木质部的导管主要为梯纹加厚。梯纹导管的分
子的穿孔板呈水平的和不同程度的倾斜状的,水平的和一部分倾斜状的穿孔板上只具有单个
大穿孔,而另一些倾斜状的穿孔板上,呈一种复穿孔到单穿孔的过渡形式。参照Bailey(1956)
指出的管状分子的演化是不可逆的观点,联系到毛茛科植物一般具有单穿孔的导管,应属于一种原始的结构特征。独叶草的营养叶,鳞片叶和芽苞叶都具有单叶隙,前者具四个叶迹,后两
者都具有一个双重性的叶迹。参照前人的看法,联系独叶草的叶,花和导管分子中的一些原始性状推测,可能如Foster(1960,1961)曾指出的,在三叶隙和多叶隙占多数的毛莨科中,独叶草的单叶隙可能是一种原始的形态。 相似文献
16.
陈心启 《中国科学院研究生院学报》1965,10(3):193-206
Tangtsinia* S. C. Chen, a monotypic genus, is discovered in southeastern Szechuan
in China. It possesses a rather ordinary monocotyledonous habit, namely with a short
rhizome, non-thickend annual stem with scattered, spiral-arranged leaves and a terminal
inflorescence. Its habit somewhat similar to that of some very primitive genera, viz.
Apostasia, Tropidia, Cephalanthera and Selenipedilum, is of much morphological and
phylogenetic interest.
The primitive and significant floral features consist chiefly in the erect, hardly twisted
flower with nearly regular perianth and a unilocular ovary, in the column composed of
a terminal stigma and five small projections, in an erect anther with four naked pollinia,
and in the absence of the rostellum. Of special interest is the occurrence of five small
projections in the upper part of the column, and this is, however, a unique instance in
the family, including the Apostasieae. Among the five projections three are larger and
opposite to the petals respectively. Of these the two lateral ones bear a strong resem-
blance in texture to the two auricles in the Orchideae and some members of the Limo-
dorinae, which P. Vermeulen considered not as staminodia, but as appendages of the
single fertile stamen as usually seen in Allium. In the case of Tangtsinia, there exists the
third projection which, being situated in the front of the column and thus opposite to the
median petal (lip), shows no difference both in appearance and texture from the other
two. These three projections are at equal distance around the terminal stigma. In
view of these facts they can be no other organ than staminodia, representing the three
stamens of the inner whorl. And the other two smaller projections are also staminodia
which together with the single fertile stamen represent the outer whorl of three stamens.
Now it is safe to say that the two auricles existing in Cephalanthera, Epipactis and the
Orchideae are, in fact, also staminodia, representing the two lateral stamens of the in-
ner whorl. In consequence, there is fairly good reason to believe that the column in
Orchidaceae has developed from the union of six stamens and a central style, and this
is in agreement with the conclusion drawn by Swamy from vascular anatomy of orchid
flowers. Furthermore it is also an interesting fact that the pollen grains in this genus,
like those of Cephalanthera, Pogonia (sensu stricto), Aphyllorchis and some species of
the Vanillinae, are single, while in the vast majority of the Orchidoideae they are united
into tetrads. This feature, as well as the texture of pollen grains, is of considerable
significance in the classification and phylogeny of Orchidaceae.
On the basis of its morphological characters mentioned above, the present genus is
evidently one of the most primitive types in the subfamily Orchidoideae. It bears a
strong resemblance both in habit and floral features to Cephalanthera, especially C. falcata
(Thunb.) Bl. The relationship between these two genera is apparently much closer to each
other than to any of other existing primitive orchids. In addition, the similarity in some
of significant floral characters between Tangtsinia and the saprophytic Aphyllorchis, especi-
ally in the nearly regular perianth and a subterminal stigma of A. simplex Tang et
Wang, indicates their close relationship. It is quite possible that Cephalanthera and
Aphyllorchis are derived from Tangtsinia or Tangtsinia-like ancestor. Thus, Tangtsinia
is here placed as the most primitive genus in the Limodorinae. Furthermore this new
genus likewise shows more or less close affinity to Neottia, probably through N. gaudis-
sarti Hand.-Mzt., in which the flowers consist of nearly regular perianth and a very
primitive column with a terminal stigma and without the rostellum. On the other hand,
in comparing Tangtsinia with the Apostasieae, there occurs also some similarity, but a
closer investigation of their ovaries, perianthes, stigmas and some other features indicates
that there is little evidence of close or direct relationship between these two taxa, al-
though both are the ancestral types in this large family. The probable relationships be-
tween Tangtsinia and its allies may be diagrammed as follows:
With regard to the pollination, Tangiorchis is found to be self-pollinated. In the great
majority of cases, its flowers do not open at all, and none of which has been seen to be
visited by any insects. It is interesting to note that in almost all nearly faded flowers
examined by the writer the bases of the pollinia together with the base of the anther have
become attached to the stigma of the same flower, and thus self-pollination has taken
place. This type of pollination might be comparable with that of Cephalanthera dama-
sonia Druce.
Finally the writer should say something about its geographical distribution. This mo-
notypic genus is confined to Gin-fu-shan (Mt. Gin-fu) and its adjacent region in Nan-
chuan District of southeastern Szechuan, where it occurs at scattered points within an area
of no more than 250 square km. at an altitude between 700-2100 m. In view of its mor-
phology, pollination and geographical distribution, Tangtsinia might be an ancestral relic of
the family Orchidaceae and would give a possible clue as to the origin of this complicatedfamily. 相似文献
17.
陈之端 《中国科学院研究生院学报》1991,29(6):494-503
对桦木科植物(包括6属36种)的花粉进行了光学显微镜、扫描电镜和透射电镜观察；系统地描
述了各属的花粉形态，划分了三种花粉类型，即桦木型、榛型、鹅耳枥型，并澄清了前人在带状加厚、孔盖和颗粒层等概念上的模糊认识。根据花粉的形态，作者不支持Hutchinson(1973)和Dahlgren(1983)把桦木科分成两个科，即榛科(包括榛属、虎榛子属、鹅耳枥属和铁木属)和桦科(包括桤木属和桦木属)；而同意Abbe(1974)将桦木科作为三个族来处理，并且认为虎榛子属应该从榛族分出，置于鹅耳枥族；尽管作者不支持Kuprianova(1963)将桦木科划分为三个科，但本文所提出的三个族与Kuprianova的三个科只是分类等级上的差异。 相似文献
18.
梁汉兴 《中国科学院研究生院学报》1994,32(5):425-432
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
19.
20.
现代被子植物的花粉类型绝大部分可以归入两大形态系列——连续式系列和短轴式系列。这两
个系列从原始到进化的诸多花粉类型不仅存在于现代植物中，而且地层中的化石花粉也揭示出类似的演化趋向。 本文着重讨论了与这些形态系列关系较为密切的一些植物类群，以及它们在系统发育方面的意义。 相似文献