木通科、大血藤科花粉壁的超微结构研究

应用透射电子显微镜(TEM)观察了木通科Decaisnea,Sinofr-anchetia,Holboellia,Stauntonia属以及大血藤科Sargentodoxa属共18种植物花粉壁的超微结构。所观察的木通科和大血藤科植物具较发达的覆盖层和柱状层;外壁内层以及内壁均在萌发沟处明显增厚;基层通常不甚发达。与扫描特征相对应的覆盖层结构特征,显示出类群的特异性。在Stauntonia属,覆盖层富于形态变化,反映出该属在木通科中较进化的地位;大血藤(Sarg-entodoxa cuneata)花粉壁结构隶属木通型花粉结构,表明大血藤科与木通科的密切关系。     

大血藤科植物的分类学研究

作者对大血藤科植物的花性、叶片内部结构形态、花粉形态、染色体核型及过氧化物酶和脂酶同工酶进行了比较研究,结果表明：１）大血藤科植物外形上的两性花,其雄蕊的形态退化、花药始终不开裂,为功能上的雌花,因此其花为单性,同株,同序或异序;１２）首次指出大血藤属植物的染色体数为２ｎ＝２ｘ＝２２,属小型染色体,与木通科植物２ｎ＝２ｘ＝３２、３０、２８的染色体数明显不同,支持Ｓｔａｐｆ（１９２６）将其从木通科分出另立为科的观点;３）单叶和复叶可出现于同一植株上,而且在叶片内部结构、花粉形态、染色体核型、过氧化物酶及脂酶同工酶等性状上,大血藤与单叶血滕间均无实质性的差异,因此将单叶血藤归并于大血藤中。     

国产含羞草科一些属花粉形态的研究

利用光镜及电镜观察了中国含羞草科金合欢属、合欢属、棋子豆属、围诞树属、朱缨花属、心叶合欢属等６属３７种（含变种）植物的花粉形态,对其花粉大小,外壁纹饰进行了比较分析。结果表明它们均为１６合花粉（除薄叶围诞树Ａｂｅｒａｍａ ｕｔｉｌｅ为８合花粉外）,在分类上无多大价值;而花粉大小及外壁纹饰却有一定分类意义。表现为：金合金欢属花粉较小,直径为２５－３０μｍ,很容易区别;其余属花粉直径均在５０μｍ以上。     

大血藤生殖生物学研究

通过野外观测、实验室分析以及人工套袋授粉等方法,研究了大血藤的繁育系统、开花习性、传粉方式以及花粉-胚珠比等生殖生物学特征.结果表明,大血藤的花为单性花,雌雄同株.雄花单花花期为7~10 d,雌花单花花期为2~3 d,种群开花历时14~17 d,散粉高峰期为4月11~17日,属风媒传粉植物.大血藤花粉-胚珠比为600±20,属兼性异交类型,人工套袋实验进一步证明,大血藤的交配系统为兼性异交类型,但以异交为主.     

中国石蒜属植物花粉形态的研究

利用光学显微镜和扫描电镜对我国石蒜属Lycoris Herb.11种植物花粉形态进行系统地研究,并对其中6种具有代表性植物花粉进行了透射电镜观察。该属植物花粉舟形或肾形;萌发孔为远极单槽;在光学显微镜和扫描电镜下观察,外壁具网状纹饰;在透射电镜下观察,外壁包括外壁-1和外壁-2两层,外壁-1由半覆盖层、柱状层和基层组成,外壁-2很薄。根据花粉形态及其他器官特征,对本属植物分类地位也进行了一些讨论。     

省藤族十六种植物的花粉形态

对棕榈科（Palmae）省藤亚科（Calamoideae）省藤族（Calameae）省藤属（Calamus）8种4变种、钩叶藤属（Plectocomia）1种、黄藤属（Daemonorops）1种、蛇皮果属（Salacca）2种共4个属16种植物的花粉进行了光镜和扫描电镜观察。省藤属植物的花粉均为两沟型花粉,外壁纹饰为网状、穿孔或小凹穴等类型;黄藤属的黄藤（Daemonorops matgaritae）花粉为近环沟型,外壁纹饰为颗粒状,其萌发孔特征与以前报道不一致。钩叶藤属的钩叶藤（Plectocomia kerrana）花粉为两沟型,外壁纹饰为网状。蛇皮果属的滇西蛇皮果（Salacca secunda）花粉的萌发孔为2沟,外壁纹饰为稀疏的穿孔或者小孔穴,而蛇皮果（S.zal-acca）花粉萌发孔为近环沟型,外壁纹饰为刺状突起,刺之间为密集的小穿孔。研究表明,花粉特征可以反映省藤属内的种间差异,支持褐鳞省藤（Calamus balansaeanus var.castaneolepis）、滇缅省藤（C.erectus var.birmanicus）及长穗省藤（C.palustrisvar.longistachys）作为变种,支持勐腊鞭藤（C.karinensis）作为种的等级地位;另外花粉特征对于探索省藤属和其他属的亲缘关系具有重要的参考价值。     

中国荞麦属花粉形态及花被片和果实微形态特征的研究

研究了中国荞麦属Fagopyrum　Mill.的花粉形态、花被片和果实微形态特征。根据沟膜的有无,花粉可以明显地区分为具沟膜者和不具沟膜者2类。透射电镜下显示,荞麦F. esculentum Moench的花粉外壁分化成两个明显的层次,即外壁外层和外壁内层。其外壁外层由覆盖层及柱状层组成,无基层。对花被片腹面的扫描电镜观察表明,根据细胞形状和表面纹饰,这些种类的花被片可分为3类。对果实表面的扫描电镜观察表明,这些种类的果实纹饰也可分为3类。根据上述结果,讨论了荞麦属的种间关系及花粉形态、花被片和果实一些微观性状的演化趋势。荞麦属的花粉形态极为一致,其外壁纹饰均为细网状,萌发孔为三孔沟,这支持将荞麦属从蓼属中分出独立成属的观点。本文还根据花粉形态特征及花被片和果实微形态特征讨论了国产荞麦属的种间关系,探讨了一些特征的演化趋势。     

中国石蒜属植物花粉形态的研究

利用光学显微镜和扫描电镜对我国石蒜属ＬｙｃｏｒｉｓＨｅｒｂ．１１种植物花粉形态进行系统地研究,并对其中６种具有代表性植物花粉进行了透射电镜观察。该属植物花粉舟形或肾形;萌发孔为远极单槽;在光学显微镜和扫描电镜下观察,外壁具网状纹饰;在透射电镜下观察,外壁包括外壁－１和外壁－２两层,外壁－１是由半覆盖层、柱状层和基层组成,外壁－２很薄。根据花粉形态及其他器官特征,对本属植物分类地位也进行了一些讨论。     

中国木犀科花粉形态研究

本文利用扫描电子显微镜和光学显微镜研究国产的木犀科花粉共11属、26种。根据花粉粒大小和外壁纹饰本科花粉可分为两个主要类型:第一类型为花粉粒较大,外壁网状纹饰粗;第二类型为花粉粒较小,外壁网状纹饰细。从花粉形态特征看本科花粉第一类型类似于金缕梅科的蜡瓣花属 Corylopsis;第一类型类似于金缕梅科的金缕梅属 Hamamclis 和木属Loropetalum。     

国产省藤属植物的花粉形态学

对国产棕榈科省藤属(Calamius L.)15种植物的花粉进行了光学和扫描电镜观察,其中12种为首次报道。省藤属的花粉均为两沟型花粉,外壁覆盖层多为网状纹饰(大喙省藤C．macrorrhynchus)或具穿孔(华南省藤C.rhabdocladus)。首次发现省藤属花粉的外壁纹饰存在穿孔和外壁疣状突起的类型(阔叶鸡藤C.pulchellus)以及皱波状突起的类型(长鞭省藤C.flagellum)。花粉的大小、形状、外壁纹饰、外壁是否有突起,外壁厚度和网状纹饰网眼的大小,对于省藤属的种级分类有较大的意义。     

基于广义形态学性状对木通科的分支系统学分析

基于43个广义的形态学性状,对木通科进行了分支系统学分析。经过简约性分析,得到了68个同等简约的分支树。50％多数规则一致树的分支结构与以前建立的族划分系统基本一致。外类群大血藤属与木通科的勃奎拉藤属形成姐妹群,与以前的分支分析结果一致,但在分子系统发育树中,大血藤属却是整个木通科的姐妹群;除此之外,形态分支树的结构与分子树的结构差别不大,但一致性指数、保持性指数和各分支内部支持率均较低。单型的猫儿屎族和串果藤族位于分支树的基部,拉氏藤族与木通族是姐妹群,在木通族内,长萼木通属和木通属是姐妹群,作为一个分支;另一分支是PHS（牛藤果属、八月瓜属和野木瓜属）复合群,牛藤果属位于八月瓜属和野木瓜属各类群的基部。但八月瓜属和野木瓜属的属内系统发育关系仍有待进一步研究。     

A unique pollen wall mutation in the family Compositae: ultrastructure and genetics

During a routine screening of pollen fertility in the n = 2 chromosome race of Haplopappus gracilis, a spineless pollen wall mutation was discovered that renders the otherwise functional pollen grains completely unrecognizable as Compositae pollen. Normal Haplopappus pollen is characterized by an outer layer, the ektexine, consisting of large spines supported by a roof (tectum), which in turn is supported by collumellae that are joined basally. A large cavity (cavea) stretches from aperture to aperture and separates columellae bases from the final ektexine unit, the foot layer. The spines, tectum, columellae, and columellae bases are filled with perforations (internal foramina), while the foot layer is without them. Immediately underlying the foot layer is a thickened, lamellate, disrupted, internal foramina-free second exine layer, the endexine. In contrast, the mutant pollen ektexine is a jumble of components with randomly dispersed spines as the only clearly definable unit. The endexine layer is similar to the endexine in normal pollen. The mutation apparently disrupts only the organization of ektexine units, and mutant pollen appears to be without the caveae and foot layer characteristic of normal pollen. In genetic tests, the mutant allele is recessive. There is a simple Mendelian pattern of inheritance of the mutant gene, and its phenotype is under sporophytic control.     

A Study on the Seed of Lardizabalaceae and Sargentodoxaceae, (1) A SEM Examination of Testa

Testa SEM characters of Lardizabalaceae and Sargentodoxaceae have not been used in former studies of taxonomy and phylogeny. In this work examined by scanning electron microscope (SEM). was the testa surface of 5 genera including 15 species of Lardizabalaceae and Sargentodoxaceae. Sargentodoxaceae is found quite different from Lardizabalaceae in its smooth test. The testa sculpture of Akebia, Holboellia and Stauntonia is basically striate, but that of Sinofranchetia, though striate, is verrucous on striations. Decaisnea is very isolated for its mosaic testa sculpture. The tesa examination confirms the rationality of the taxonomic treatment of Sargentodoxaceae by Stapf, the isolated taxonomic position of Decaisnea and Sinofranchetia in Lardizabalaceae, and the close interrelationship among Akebia, Holboellia, and Stauntonia.     

五叶风藤茎尖染色体核型分析

用五叶风藤 (HolboelliafargesiiReaub)茎尖染色体制片 ,研究其染色体组型 ,结果表明 :五叶风藤的染色体组型公式为 2n =2x =16 =12m 4sm ,染色体基数x =8,第 4号染色体上有一对染色体随体 ,核型为 2B类型 ,其中 2n =4x =32 =2 4m 8sm的四倍性细胞相当普遍。     

Wall development and its autofluorescence of sterile and fertileVicia faba L. Pollen

Summary The ultrastructural changes of the pollen wall of three types of fertile and one of sterileVicia pollen were related to the autofluorescence of the pollen wall, measured by a microspectroscopic method. Till the liberation of the microspores from the tetrad, the spectrum of the ectexine shows sometimes two maxima and has a very low intensity. After this period the endexine is formed and its spectrum has one maximum with a high intensity. The differences of the pollen wall between the sterile and fertile pollen exist of the presence of one spectral maximum during the tetrad stage, a thick endexine and the absence of the intine in the sterile pollen. The different types show much differences during the tetrad stage in the callose wall as well as the ectexine. The autofluorescence illustrates the complexity and specificity of the pollen wall development.     

Pollen wall development in Sciadopitys verticillata (Sciadopityaceae)

Pollen wall development of Sciadopitys verticillata was observed by transmission electron microscopy. The pollen of S. verticillata is non-saccate and spherical, and the exine consists of the outer thick, sculptured ectexine and the inner lamellated endexine. At the early tetrad stage, the initial ectexine and lamellae of the initial endexine begin to form on the microspore plasma membrane. The ectexine granules gradually swell. Deposition of sporopollenin materials on the ectexine granules then results it their becoming partially connected to each other. Identification of the original small ectexine granules then becomes difficult, and, finally, the ectexine appears as a homogeneous, partially discontinuous layer. The granules of the early ectexine cannot be identified. At maturity, there are four to five endexine lamellae. Recent molecular data have shown that Sciadopitys first branches off from the Cupressaceae plus Taxaceae clade, which is characterized by granular exine. Although the ectexine of Sciadopitys is similar to that of the Cupressaceae during initial development, the morphology of the ectexine is significantly different in the mature pollen. The initial stage of pollen development clearly shows the structural homology of the granular ectexine. Divergence of the exine structure occurs in the later stages.     

Pollen morphology supports the transfer of Wendlandia (Rubiaceae) out of Rondeletieae

Pollen morphology of 27 species, eight subspecies and one variety of Wendlandia was studied using scanning electron microscopy (SEM). Wendlandia pollen are monads, radiosymmetric, small in size, tricolporate (rarely tetracolporate or bicolporate) and spheroidal (rarely subprolate or suboblate) in equatorial view. The compound aperture consists of ectocolpus, mesoporus and endocolpus. In addition, reticulate sexine and granular nexine were observed. The pollen wall ultrastructure of two Wendlandia spp. was examined by transmission electron microscopy (TEM). The exine consists of the tectum, columellae, foot layer and endexine. The endexine is thickened into a costa around the aperture. The intine forms a protruding oncus at the aperture. The palynological characters show a remarkable uniformity among the Wendlandia spp. Differences with Rondeletia, the main genus of tribe Rondeletieae, exist in the exine pattern, the endoaperture and the pollen wall structure. Our observations indicated that the endoaperture type and the structure of the pollen wall of Wendlandia were similar to those of the Gardenieae–Pavetteae–Coffeeae–Octotropideae clade, which provided palynological evidence for a closer relationship of Wendlandia to subfamily Ixoroideae and the transfer of Wendlandia out of Rondeletieae. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 164 , 128–141.     

Re-evaluation of a neglected layer in pollen wall development with comments on its evolution

This study focuses on one particular layer of the pollen wall, which develops below the endexine in the free microspore stage and prior to the initiation of the intine. This membranous-granular layer (MGL) has been described by different terms in the literature and has often been interpreted either as part of the endexine, or the intine. During ontogeny, however, the granular material shows a development that is clearly distinct, both in timing and mode of formation, from the endexine as well as the intine. Its chemical composition is also characteristic; the MGL resists acetolysis. Our ontogenetic observations from four dicot and one monocot species are used to illustrate the systematically widespread occurrence of this wall layer, its ultrastructure and histochemistry, and its comparable nature throughout angiosperms.     

Pollen wall development in Vigna vexillata I. Characterization of wall layers

Light and electron microscope observations characterized the layers that comprise Vigna vexillata L. pollen walls, and identified the timing of their development. Exine sculpturings form an unusually coarse ektexinous reticulum. The structure of the ektexine is granular; this differs from the columellate/tectate type of structure typical of most angiosperm pollen. The ektexine overlies a homogeneous-to-lamellar, electron-dense endexine, which in turn surrounds a thick, microfibrillar intine. Pollen grains are triporate and operculate, with Zwischenkörper and thickened intine underlying the apertures. The ektexine forms during the tetrad period of microspore development, the endexine and Zwischenkörper during the free microspore stage, and the intine during the bicelled (pollen) stage. Coarsely reticulate exine sculpturings and the granular structure of the patterned exine wall of the pollen grains are features that make this species suitable for detailed studies of pollen wall pattern formation.