五列木科和肋果茶科花粉外壁超微结构及其与山茶科的系统学关系

借助光学显微镜、扫描电镜和透射电镜对五列木科Ｐｅｎｔａｐｈｙｌａｃａｃｅａｅ和肋果茶科Ｓｌａｄｅｎｉａｃｅａｅ花粉进行了观察,并与山茶科Ｔｈｅａｃｅａｅ若干属的花粉进行了详细的比较,同时参考了猕猴桃科Ａｃｔｉｎｉｄｉａｃｅａｅ的花粉特征。研究表明,肋果茶科的花粉与山茶科的花粉具有较多的相似性,如其形状和大小与山茶科中厚皮香亚科的几乎一致;而花粉的表面纹饰（粗糙至模糊的皱波状纹饰）则与山茶属,Ｆｒｅｚｉｅｒａ属和厚皮香亚科部分属的花粉纹饰相类似。从花粉外壁的结构看,肋果茶的花粉与石笔木属和山茶属的更接近,表现为：花粉外壁层次分化明显,复盖层和柱状层均较厚,外壁内层薄。而五列木科花粉除了形状和萌发孔类型与山茶科的相似外,其纹饰特征和外壁结构均与山茶科的差异较大,如五列木科花粉表面近光滑,外壁覆盖层较簿,柱状层很不发达,外壁内层相对较厚等。孢粉学上认为,肋果茶科与山茶科具有更为密切的关系,五列木科则与山茶科较疏远。支持把肋果茶科作为一个属置于山茶科内或作为山茶科的一个亚科     

穗花杉属花粉外壁的超微结构及其分类意义

本文用光学显微镜、扫描电镜和透射电镜观察了穗花杉属Amentotaxus Pilger花粉外 壁表面和内部的超微结构,并叙述了本属与红豆杉科Taxaceae和三尖杉科Cephalotaxaceae花粉形态的区别。根据花粉外壁超微结构资料,论述了该属的分类位置。     

前胡族花粉外壁超微结构及其系统学意义

报道了前胡族(Peucedaneae Drude)当归亚族(Angelicinae Drude)、阿魏亚族(Ferulinae Drude)和环翅芹亚族(TordyliinaeDrude)等3亚族18属18种植物的花粉外壁表面和内部的超微结构.根据花粉外壁超微结构资料,论述了18种及其所在属的系统位置.对现时尚存疑的问题,诸如当归亚族中的山芹属(Ostericum Hoffm.)等7属(种),经分析认为统归于当归属(Angelica L.)不恰当;阿魏亚族中的球根阿魏(Schumannia turcomanica Kuntze)、伊犁芹(Talassiatransiliensis(Herd.)Korov.)、胀果芹(Phlojodicarpus villosus(Turcz.ex Fisch.et Mey.)Turcz.ex Ledeb.)等属的代表种显示其外壁演化程度相差甚大,应以与阿魏属(Ferula L.)分别独立为宜;环翅芹亚族(Tordyliinae Drude)中大瓣芹属(Semenovia Regel et Herd.)与独活属(Heracleum L.)的代表种其外壁演化程度相距甚远,也以分立为宜.     

中国蓼族(蓼科)植物区系的研究

根据蓼族植物的生境及分布状况,在全国范围内进行多年的野外考察和标本采集,同时参考前人的研究成果对中国蓼族植物区系进行深入研究。结果表明,中国蓼族植物有12属、170余种及变种,包括发现的多个新种(其中3新种已正式发表,1新种已被植物分类学报接受);同时揭示了其区系特点:(1)分布广泛,在全国各省区从低海拔到高海拔的区域内均有分布;(2)区系具温带性质,以北温带成分为主;(3)全国范围内,四川拥有该族在中国分布的全部12属,种及变种数占全国的51.7%,特有种数占全国的44.4%;云南分布11属占全国的91·7%,种及变种数占全国的62.2%,特有种数占全国的55.6%。这表明西南地区的云南、四川是中国蓼族植物的现代分布中心和多样化中心;(4)中国有该族植物12属,170余种及变种,分别占世界属种数的85.7%和48.0%～58.2%。可见中国(尤其是四川、云南)是世界蓼族植物的现代分布中心和多样化中心。     

蓼属-未知花粉类型外壁超微结构的研究

花粉壁的构造提供了若干在系统发育上有用的特征,其中外壁的层次、结构以及纹饰是基本的。为此,本文以花粉壁的外部纹饰和内部结构为重点,用扫描电镜（ＳＥＭ）和透射电镜（ＴＥＭ）的薄切片技术,对蓼属一新的花粉类型－－长花蓼型的花粉外壁构造的特点进行了观察和研究。结果表明：外壁结构分化成两个明显的层次,即外面的外壁外层以及内面的外壁内层,其外壁外层无覆盖层,仅由柱状层和底层组成的。     

中国安徽蓼科蓼属一新变种——圆基愉悦蓼

报道了安徽蓼属Polygonum一新变种——圆基愉悦蓼P.jucundumvar.rotundum Z.Z.Zhou＆Q.Y.Sun。新变种与原变种的区别在于：叶条状披针形,长4.5–9.0cm,宽0.5–0.9cm,基部圆形,近无柄;茎粗1.5–2.0mm。新变种在叶形上还与圆基长鬃蓼P.longisetum var.rotundatum A.J.Li相近,但其植株明显高,可达160cm,茎基部20–26节上生多数不定根,不定根长达10–16cm;花序的花梗长4–5mm,远伸出苞片外,易于区别。对新变种及其近缘种的花粉形态、花被片和瘦果微形态特征进行了扫描电镜比较观察。     

蓼科植物中的大哥大——树蓼

众所周知,全世界拥有800多种的蓼科植物,大多数为草本,少量为亚灌木,多纤细柔弱,高不过2—3米,而高大的乔木种类更是稀少,原产于热带巴拿马至南美北部的树蓼(Triplaris americana)就是其中的一种,它在南、北美洲     

安徽蓼科植物花粉形态的研究

用光学显微镜对安徽省蓼属３８种３变种,酸模属３种,荞麦属１种,金线草属２种,大黄属１种,竹节蓼属１种的花粉形态进行了观察。除了前人报道的３７种外,其中１２种为首次报道。６属的花粉形态多类型,有球型,近球形,近长球形、扁球形、长球形;从萌发孔来看,有３－沟,３（－４）－孔沟,１２－散沟、３０－散沟、９－散孔沟、２０－３０－散孔;外壁纹饰有细网状,粗网状,皱块状,颗粒－穿孔、穿孔、微刺－穿孔－光滑、颗     

前胡族花粉外壁超微结构及其系统学意义(英文)

Transmission electron microscopy (TEM) observation of pollen grains of 18 species belongingto 18 respective genera of the tribe Peucedaneae Drude revealed distinct ultrastructural difference in thepollen exine, including the thickness and features of rectum, columnar layer, foot layer and endexine. Thesystematic position of those 18 species are re-evaluated based on their ultrastructural characteristics ofpollen exine observed in this study. Seven genera related to Angelica L. in Angelicinae Drude have beendeduced to genus Angelica L. For example, Osterfcum grosseserratum (Maxim.) Kitagawa was changed toAngelica L. by some authors, but it differs from Angelica sinensis (Oliv.) Diels in having well developedtectum which is thicker than the columnar layer and foot layer. Its columnar layer is quite well-developedwith long and branched columellae. Besides its surface is tuberculated. Evidently, its development exceedsthat of Angelica sinensis. However, it is only a moderate evolutional species in its genus, and the Angelicasinensis accounts as the most advanced species in Angelica Diels, thus, placing genus Ostencum Hoffm.in Angelica L is not suitable, it may be more appropriate to keep its original position. In addition, Ferulaakitschkensis B. Fedtsch. ex K.-Pol. differs greatly from those of Talassia transiliensis (Herd.) Korov. andSchumannia turcomnnia Kuntze, because of its very well-developed columnar layer, being about four tofive times thicker than the total of tectum and foot layer, tuberculated tectum surface and complicatedstructure of columnellae. As another species Heracleum forrestJ‘iWolff also differs from Semenovia rubtzovii(Schischk.) Monden. in having an even thickness of exine and well-developed columnar layer, it seemssuitable that they should also be treated as two independent genera.     

蓼科植物抗肿瘤研究进展

蓼科植物中的多种化学成分都有抗肿瘤作用,抗肿瘤机制比较多样,有广阔的研究及开发前景。本文从蓼科植物抑制癌细胞生长和分裂、抑制癌细胞的侵袭和转移、诱导癌细胞凋亡、抑制癌细胞信号的转导、降低癌细胞的抗药性、直接杀伤癌细胞、预防肿瘤作用等七个方面对蓼科植物抗肿瘤方面的研究进行了综述,以期待为更深入研究本科植物抗肿瘤机制及开发抗肿瘤药物提供参考。     

A Comparative study on pollen exine ultrastructure of Nothofagus and the other genera of Fagaceae

The genus Nothofagus is mainly distributed in South America and New Zealand. The present paper describes its pollen exine ultrastructure and compares the exine ultrastructure with that of the other genera of Fagaceae. The pollen grains were examined using ultrathin sectioning technique under transmission electron microscope. The study shows that the pollen exine ultrastructure of Nothofagus differs from that of the other genera of Fagaceae by its exine structure and thickness, type of aperture, and ornamentation. The pollen exine of Nothofagus is thin and possesses granular bacules, regular foot layer and tectum, spinulate ornamentation, and the endexine is usually visible at poral area, and 5～8 colpate. The pollen exine of the other genera of Fagaceae possesses entire bacules, irregular foot layer and tectum, granulate and tuberculate ornamentation, thicker endexine, and is 3-colporate ( 3-colpate or 3-colporoidate). The pollen exine ultrastructure of Nothofagus may belong to primitive type. The pollen exine ultrastructure data support Kuprianova’s opinion that Nothofagus should be separated from Fagaceae and established as a monogenetic family, i.e. Nothofa-gaceae.     

南水青冈属及壳斗科其他属花粉壁超微结构比较研究

对主要分布于南美和新西兰的南水青冈属Nothofagus 花粉外壁的超微结构进行了观察和研究, 同时与壳斗科其他属花粉外壁的结构进行比较,结果表明,南水青冈属花粉外壁的厚度、结构、萌发孔类 型以及花粉外壁表面的纹饰与壳斗科其他属花粉外壁的超微结构存在明显差别。主要表现为：南水青 冈属花粉外壁的柱状层和内层发育差,为颗粒状;基层和覆盖层无分化结构;覆盖层上为刺状纹饰;萌发 孔为5～8沟。壳斗科其他属花粉外壁的小柱发育好,形成明显的柱状层;覆盖层和基层常具一定的结 构;花粉表面较光滑,或为波状、颗粒或瘤状纹饰;内层发育较好;多数花粉具3孔沟,少数为3沟或3拟 孔沟。本研究认为南水青冈属花粉外壁的结构属于较原始类型,支持kuprianova等将南水青冈属独立为南壳斗科。     

Ultrastructure of pollen exine in centrospermous families

Transmission electron microscopy was utilized to examine pollen walls of selected taxa in theAizoaceae, Amaranthaceae, Basellaceae, Cactaceae, Chenopodiaceae, Didiereaceae, Halophytaceae, Nyctaginaceae, Phytolaccaceae, Portulacaceae, andCaryophyllaceae. This conspectus is an adjunct to scanning electron microscope observations of pollen surfaces and is directed towards elucidating the basic wall structure for these families. Although differences in internal morphology were observed at the inter- and intra-familial levels, they were interpreted as reflecting variations rather than major differences. The data indicate close morphological similarities of the first ten families enumerated above, i.e., those containing betalains. TheCaryophyllaceae, an anthocyanin family, indicated a slightly greater heterogeneity of pollen ultrastructure but not to the extent of disassociating it from the betalain families. In fact, this heterogeneity was rivaled by comparable heterogeneity among and within some of the betalain families. The conclusion is that all families have close pollen morphological relationships.Presented in the Symposium Evolution of Centrospermous Families, during the XIIth International Botanical Congress, Leningrad, July 8, 1975.     

A contribution to the ultrastructural knowledge of the pollen exine in subtribe Inulinae (Inuleae, Asteraceae)

To better understand the relationships within the Asteroideae and Inuleae, the structure of the pollen exine was investigated in seven genera and nine species of the subtribe Inulinae using LM, TEM and SEM. All taxa have a senecioid pattern of exine. The tectal complex consists of three main layers that differ in thickness and morphology: a tectum, a columellar layer, and a layer consisting of the basal region of the columellae. The absence or the vestigial condition of the foramina is considered as a plesiomorphy within the Asteroideae. All taxa have a complex apertural system that consists of an ecto-, a meso-, and an endoaperture. These apertures intersect respectively the tectal complex, the foot layer and the upper part of the endexine, and the inner layer of the endexine. A continuous transition among the different species of Inulinae was found for all the quantitative characters examined. This relative homogeneity of the pollen morphological characters enhances the naturality of the subtribe Inulinae.     

New views of tapetum ultrastructure and pollen exine development in Arabidopsis thaliana

Background and Aims

The Arabidopsis thaliana pollen cell wall is a complex structure consisting of an outer sporopollenin framework and lipid-rich coat, as well as an inner cellulosic wall. Although mutant analysis has been a useful tool to study pollen cell walls, the ultrastructure of the arabidopsis anther has proved to be challenging to preserve for electron microscopy.

Methods

In this work, high-pressure freezing/freeze substitution and transmission electron microscopy were used to examine the sequence of developmental events in the anther that lead to sporopollenin deposition to form the exine and the dramatic differentiation and death of the tapetum, which produces the pollen coat.

Key Results

Cryo-fixation revealed a new view of the interplay between sporophytic anther tissues and gametophytic microspores over the course of pollen development, especially with respect to the intact microspore/pollen wall and the continuous tapetum epithelium. These data reveal the ultrastructure of tapetosomes and elaioplasts, highly specialized tapetum organelles that accumulate pollen coat components. The tapetum and middle layer of the anther also remain intact into the tricellular pollen and late uninucleate microspore stages, respectively.

Conclusions

This high-quality structural information, interpreted in the context of recent functional studies, provides the groundwork for future mutant studies where tapetum and microspore ultrastructure is assessed.     

Significance of exine shedding in Cupressaceae-type pollen

In conifers, which have non-saccate Cupressaceae-type pollen, the pollen must land on a pollination drop or be picked up by the pollination drop from the surface of the cone near the ovule before it can be taken into the ovule. After contact with the drop, the pollen intine absorbs moisture from the drop, expands and the exine is shed. In this study the significance of the shedding of the exine is interpreted from experiments in which simulated pollination drops and micropyles were used to determine the movement of pollen and other particles in suspension. The non-expanded pollen, which can be observed upon contact with the pollination drop, sheds the exine, which then functions as a non-elastic particle, while the pollen from which the exine was shed swells and functions as an elastic particle because it is enclosed by the flexible intine. Non-elastic particles are not easily transferred through narrow passages (the micropyle and micropylar canal) and tend to plug these passages. However, elastic particles, such as the swollen pollen, are easily transferred along narrow passages even when non-elastic particles are present. The simulated experiments demonstrate that exine shedding is an important feature in getting pollen through the narrow micropyle and micropylar canal to the nucellus of the ovule.     

Ultrastructural study of Saffron pollen

Abstract

Pollen of Saffron (Crocus sativus L.), a sterile autotriploid plant was studied using scanning and transmission electron microscopy. The pollen of mature anthers had grains not containing pores or furrows, a discontinuous thin exine and a very thick intine crossed by tubules containing granular electron-dense material. Electron transparent material and lipid bodies were abundant in the cytoplasm which also contained a large number of vesicles. A high percentage of pollen grains showed anomalies.     

The ultrastructure of polymorphic pollen grains of Canna indica L.

Summary Our investigations on Canna indica L. indicate that the pollen of this species is polymorphic: there are two types of pollen — a larger type and a comparatively smaller type. Transmission electron microscopy (TEM) revealed the presence of small vacuoles containing tannic substances in the generative cell (GC) of the larger grains: the GC of the mature grain contained a higher quantity of tannins than the GC of the immature grain. Mitochondria, lipid bodies, rough endoplasmic reticulum (RER) and microtubular bundles were present in the cytoplasm of the GC. Numerous mitochondria, lipid bodies and plastids were also present in the vegetative cell (VC), with the mitochondria clustered around the vegetative nucleus. The plastids were observed to be associated with the RER cisterns. During the maturation process, the number of starch grains contained in the plastids decreased.     

中国蓼科萹蓄属植物花粉形态及其分类意义

利用扫描电镜研究了中国萹蓄属(Polygonum) 13种、1变种、1变型植物的花粉形态.结果表明,中国萹蓄属植物的花粉粒为长球形或超长球形,具三孔沟,外壁纹饰可分为4种类型(1)花粉粒表面具细网状纹饰;(2)花粉粒表面具颗粒纹饰;(3)花粉粒表面仅两端具颗粒纹饰,其余部分光滑;(4)花粉粒表面仅沟间区两端肩部光滑,其余部分具颗粒纹饰.根据花粉形态类型,结合该属植物的习性、叶柄基部及花柄上关节的有无、花柱和柱头的数目以及瘦果形态等特征,参照前人的研究处理意见,将中国萹蓄属植物划分为4个组,即小灌木组section Fruticulosae (Boiss.) F.Z.Li et Y.T.Hou,stat.& comb.nov.、萹蓄组section Polygonum、丝茎萹蓄组section Pseudomollia Boiss.和铁马鞭组section Plebeia Tzvel..