大戟科现代植物花粉形态

对大戟科21属33种植物的现代花粉形态进行了系统的形态学研究。选取的33种大戟科植物基本涵盖了该科绝大部分花粉形态类型。根据花粉的大小、形状、外壁表面纹饰, 结合大戟科亚科分类, 对该科花粉形态特征进行详细对比和分析。结果表明, 每个亚科都有其独特的花粉形态, 各亚科可以根据花粉形态来鉴别。此外, 大戟科多个属(如野桐属、山麻杆属、叶下珠属等)的植物花粉形态特征较明显, 可以鉴定到属甚至种一级水平。研究结果不仅为大戟科花粉形态分类学提供了依据, 同时为地层孢粉分析中花粉的鉴定提供参考。     

The pollen morphology of Phyllanthus (Euphorbiaceae) section Choretropsis

The pollen grain morphology of the eight South American species of the genus Phyllanthus , subgenus Phyllanthus , section Choretropsis , endemic to Brazil, was investigated using light and scanning electron microscopy. The high homogeneity in pollen shape, as well as aperture number and configuration, allowed the definition of a basic pollen type for this section, viz. prolate spheroidal or subprolate, zonocolporate with 4–5 invaginated colpi, sexine reticulate. Two subtypes have been observed, based on pollen grain apertures and exine sculpture. The first subtype is characterized by straight and narrow colpi provided with costae, lalongate endoapertures and a reticulum of rectilineous muri as in P. choretroides and P. spartioides . The second subtype has wider colpi without costae, circular endoapertures and a reticulum with curvilineous muri as in P. flagelliformis , P. goianensis and P. scoparius , or curvilineous-rectilineous muri as in P. angustissimus , P. gladiatus and P. klotzschianus . It was demonstrated that the pollen shape and the number of colpi varied within and between some of the species. The results suggest that pollen grain morphology, in association with plant architecture and the presence of phylloclades, constitute additional evidence to delimit the species of the section Choretropsis and to further understand their evolutionary origin within the genus Phyllanthus.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 243–250.     

Pollen morphology and phylogenetic relationships in neotropical Phyllanthus (Euphorbiaceae)

In order to provide new insights into phylogenetic relationships among the neotropical taxa of Phyllanthus , 28 illustrations are provided of the pollen grains of 22 selected species studied from 11 sections of the subgenera represented in the neotropics. Special attention has been given to subgenus Conami because of its variability in pollen morphology: of eight species illustrated, the apertures are diploporate colpi in three species and pores in five species; exine ornamentation is vermiculate in two species and pilate in the other six species. The six species in the neotropical sections Pityrocladus and Microglochidion (subgenus Emblica ) are characterized by prolate grains with an increased number of colpi (4–8). Of particular interest are species in which the pollen exine is clypeate (with exine shields); clypeate pollen grains are illustrated in two species of subgenus Xylophylla and in one species of section Cyclanthera that has unique exine shields with single central pila. The pollen of the one Brazilian phylloclade-bearing species illustrated (in section Choretropsis ) has 3-colporate grains with reticulate exine, typical for subgenus Phyllanthus , and very different from the clypeate grains of the West Indian phylloclade-bearing species in section Xylophylla . This pollen evidence clearly demonstrates homoplasy in the origin of phylloclades in Phyllanthus . Pollen morphological data suggest that the neotropical taxa of Phyllanthus have arisen following colonization from Africa (subgenus Kirganelia ) and Asia (subgenus Emblica ). © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 325–338.     

Comparative fruit development in some Euphorbiaceae and Phyllanthaceae

Euphorbiaceae s. str. and Phyllanthaceae were earlier components of Euphorbiaceae. This separation was mainly based on molecular data and also on morphological characteristics. Nevertheless, the structure and development of fruits are poorly investigated in these families and considering this, fruits (pericarp and seed) of Euphorbia hyssopifolia L., Croton glandulosus L. (Euphorbiaceae), Phyllanthus niruri L. and Phyllanthus tenellus Roxb. (Phyllanthaceae) were structurally studied to see in what respects they are similar or different. The Euphorbiaceae schizocarps present two meristems (adaxial and subadaxial) in the ovary wall, but the adaxial meristem is entirely lacking in Phyllanthus fruits. The seeds have an exotegmen with Malpighian palisade cells in Euphorbiaceae species and a short palisade in Phyllanthus. Some special structural features, such as nucellar beak, anatropous ovules and schizocarp fruits were found in all the species and constitute a unique combination. From the present results, it appears that there is no significant difference in fruit and seed development between the studied Euphorbiaceae and Phyllanthaceae.     

Phyllanthus section Choretropsis (Euphorbiaceae) in Brazil

Section Choretropsis genus Phyllanthus (Euphorbiaceae) is formed by plants whose branches are modified into phylloclades. Despite the suitable characteristics of phylloclades within the Phyllanthus genus, the systematics of these species are poorly understood. Morphological data are presented here to allow future revision of this taxonomic group. The section is represented by nine species distributed in South America, eight of them endemic to Brazil. Our taxonomic studies distinguish the species and propose the synonymization of nine varieties of P. klotzschianus and two varieties of P. flagelliformis based on vegetative and reproductive characters. The diversity of branching and the morphology of phylloclades are discussed.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 131–164.     

A Revision of Chinese Phyllanthus (Euphorbiaceae)

The present paper is the outcome of a taxonomic study of Chinese Phyllanthus plants in our flora. Phyllanthus is one of the largest genera in Euphorbiaceae, and is distributed in whole China except for the northwest, extending from 92° to 124° E and 18° to 41°N. It includes 6 subgenera, 7 sections, 33 species and 4 varieties, of which 1 subgenus and 5 species are described as new, and 1 new name and 9 synonyms are proposed.     

POLLEN MORPHOLOGY AND THE RELATIONSHIPS OF SIMMONDSIA CHINENSIS TO THE ORDER EUPHORBIALES

Pollen from Simmondsia chinensis (Simmondsiaceae) was examined in LM, SEM, and TEM. The pollen is shed as monads, triangular in shape in polar view, with a 3-porate aperture type in which the pores are large and poorly defined. The tectum is irregularly scabrate, sometimes forming minute “islands” topped with spinules. In thin section, the endexine is thickened and lamellate in the aperture regions, and narrow in the mesoporus; the foot layer is well-defined but noticeably thicker in the mesoporus; and thin columellae support an essentially complete tectum. The pollen of four genera, Buxus, Pachysandra, Sarcococca, and Styloceras, from the Buxaceae to which Simmondsia has been assigned by some authors, was also examined and illustrated. The pollen morphology of two families frequently aligned with Simmondsiaceae, Euphorbiaceae and Pandaceae, is briefly discussed. For the most part pollen morphology supports the treatment of Simmondsia as a monotypic family, Simmondsiaceae.     

Antihepatotoxic activity of Phyllanthus atropurpureus cultivated in Egypt

The genus Phyllanthus (family Euphorbiaceae) is considered one of the important medicinal and ornamental plants. A phytochemical analysis of the extracts was performed to search for the active ingredient. Results of the investigation of the hepatoprotective activity of Phyllanthus atropurpureus Boj. Hort. Maurit. revealed that the activities of alcoholic extracts of its aerial parts and roots were quite similar to those of silymarin. Both of them improve the parameters of CCl4-induced liver injury including serum aspartate aminotransferase and alanine aminotransferase. Among the extracts tested, the root extract showed maximum activity compared to the aerial parts extract and to silymarin.     

Pollen morphology of the Acalyphoideae and Euphorbioideae (Euphorbiaceae) of the Caatinga ecoregion in Brazil

This study dealt with six species of Acalyphoideae and 18 species of Euphorbioideae occurring in the Caatinga ecoregion, with emphasis on endemic species. Pollen samples were obtained from herbarium specimens and were acetolysed and analysed via light and scanning electron microscopy. The pollen of three genera of Acalyphoideae was medium to large, 3-colporate or 3-colpate, with an echinate-perforate exine that was reticulate, bireticulate, and microreticulate. The six genera of Euphorbioideae studied exhibited pollen grains that were small, medium and large; 3-colporate with margines; and an exine with microreticulate, microreticulate-rugulate, microreticulate-caveate, and reticulate ornamentation. The pollen characteristics were more variable in the Acalyphoideae compared to the relatively homogeneous Euphorbioideae. This study provides new data and interpretations of the pollen morphology of two subfamilies of the Euphorbiaceae of the Caatinga ecoregion in Brazil.     

Capturing the surface texture and shape of pollen: a comparison of microscopy techniques

Research on the comparative morphology of pollen grains depends crucially on the application of appropriate microscopy techniques. Information on the performance of microscopy techniques can be used to inform that choice. We compared the ability of several microscopy techniques to provide information on the shape and surface texture of three pollen types with differing morphologies. These techniques are: widefield, apotome, confocal and two-photon microscopy (reflected light techniques), and brightfield and differential interference contrast microscopy (DIC) (transmitted light techniques). We also provide a first view of pollen using super-resolution microscopy. The three pollen types used to contrast the performance of each technique are: Croton hirtus (Euphorbiaceae), Mabea occidentalis (Euphorbiaceae) and Agropyron repens (Poaceae). No single microscopy technique provided an adequate picture of both the shape and surface texture of any of the three pollen types investigated here. The wavelength of incident light, photon-collection ability of the optical technique, signal-to-noise ratio, and the thickness and light absorption characteristics of the exine profoundly affect the recovery of morphological information by a given optical microscopy technique. Reflected light techniques, particularly confocal and two-photon microscopy, best capture pollen shape but provide limited information on very fine surface texture. In contrast, transmitted light techniques, particularly differential interference contrast microscopy, can resolve very fine surface texture but provide limited information on shape. Texture comprising sculptural elements that are spaced near the diffraction limit of light (~250 nm; NDL) presents an acute challenge to optical microscopy. Super-resolution structured illumination microscopy provides data on the NDL texture of A. repens that is more comparable to textural data from scanning electron microscopy than any other optical microscopy technique investigated here. Maximizing the recovery of morphological information from pollen grains should lead to more robust classifications, and an increase in the taxonomic precision with which ancient vegetation can be reconstructed.     

Nickel localization on tissues of hyperaccumulator species of Phyllanthus L. (euphorbiaceae) from Ultramafic Areas of Cuba

Two species of perennial Phyllanthus (Euphorbiaceae) (Phyllanthus orbicularis and Phyllanthus discolor, both endemic to ultramafic areas of Cuba, and their natural hybrid, Phyllanthus xpallidus) were selected for metal localization microanalysis. Different plant tissues were analyzed by X-ray fluorescence, inductively coupled plasma—atomic emission spectroscopy, and scanning electron microscopy coupled with an energy-dispersive X-ray probe. All of the studied taxa are nickel (Ni) hyperaccumulators and significant concentrations of this element were found in different leaf and stem tissues. The highest Ni content was found in the laticifer tubes, whereas leaf epidermis Ni content resulted to be much more relevant in terms of total metal storage. Calcium and magnesium were found more evenly distributed in leaf and stem tissues.     

Evolution of obligate pollination mutualism in New Caledonian Phyllanthus (Euphorbiaceae)

About half a dozen obligate pollination mutualisms between plants and their seed-consuming pollinators are currently recognized, including fig-fig wasp, yucca-yucca moth, and the recently discovered Glochidion tree-Epicephala moth mutualisms. A common principle among these interactions is that the pollinators consume only a limited amount of the seed crop within a developing fruit (or fig in the case of fig-fig wasp mutualism), thereby ensuring a net benefit to plant reproduction. A novel obligate, seed-parasitic pollination mutualism between two species of New Caledonian Phyllanthus (Euphorbiaceae), a close relative of Glochidion, and Epicephala moths (Gracillariidae) is an exception to this principle. The highly specialized flowers of Phyllanthus are actively and exclusively pollinated by species-specific Epicephala moths, whose larvae consume all six ovules of the developing fruit. Some flowers pollinated by the moths remain untouched, and thus a fraction of the fruits is left intact. Additional evidence for a similar association of Epicephala moths in other Phyllanthus species suggests that this interaction is a coevolved, species-specific pollination mutualism. Implications for the evolutionary stability of the system, as well as differences in mode of interaction with respect to the Glochidion-Epicephala mutualism, are discussed.     

中国头细蛾属昆虫(鳞翅目,细蛾科)与大戟科植物互利共生关系研究进展

细蛾科头细蛾属昆虫与大戟科算盘子属、叶下珠属和黑面神属植物互利共生关系的发现为研究昆虫与植物协同演化过程提供了一个全新的模式。目前,国内对头细蛾与大戟科植物的互利共生关系了解和研究都很少。本文介绍了头细蛾的分类、生物学和形态适应;大戟科相关5属植物(算盘子属、叶下珠属、黑面神属、白饭树属和守宫木属)的生物地理学,开花生物学,花的结构与传粉系统的关系;寄主植物与传粉者的对应关系;互利共生关系的维持机制等。研究表明中国有丰富的头细蛾与大戟科植物资源,开展其互利共生关系的研究有重要科学意义。很多新的、复杂的头细蛾与大戟科植物的生态关系和大量的头细蛾种类有待我们去发现和研究。     

Pollen morphology of Chinese Glochidion (Phyllanthaceae) and its taxonomic implications

The pollen morphology of twenty‐five Chinese species belonging to two sections of Glochidion and one species from Phyllanthus subgen. Phyllanthodendron was examined using scanning electron microscopy (SEM). The results showed that pollen grains of Glochidion are isopolar, spheroidal to rarely subprolate in shape, (3)4–5(6)‐colporate in aperture pattern, and tectate‐reticulate to tectate‐rugulate in exine ornamentation. Fusion of colpus ends was observed in some pollen grains of G. pseudo‐obscurum and G. wrightii. The pollen grains of Phyllanthus dunnianus are similar to those of Glochidion species in their spheroidal shape and four‐colporate aperture pattern, but are slightly larger in size, and show tectate‐perforate exine ornamentation. In Glochidion, pollen morphology appears to be useful for distinguishing several macromorphologically similar. Additionally, palynological characters provide evidence for the taxonomy of the supergenus Phyllanthus s.l.     

Evolutionary stasis in Euphorbiaceae pollen: selection and constraints

Although much attention has been paid to the role of stabilizing selection, empirical analyses testing the role of developmental constraints in evolutionary stasis remain rare, particularly for plants. This topic is studied here with a focus on the evolution of a pollen ontogenetic feature, the last points of callose deposition (LPCD) pattern, involved in the determination of an adaptive morphological pollen character (aperture pattern). The LPCD pattern exhibits a low level of evolution in eudicots, as compared to the evolution observed in monocots. Stasis in this pattern might be explained by developmental constraints expressed during male meiosis (microsporogenesis) or by selective pressures expressed through the adaptive role of the aperture pattern. Here, we demonstrate that the LPCD pattern is conserved in Euphorbiaceae s.s. and that this conservatism is primarily due to selective pressures. A phylogenetic association was found between the putative removal of selective pressures on pollen morphology after the origin of inaperturate pollen, and the appearance of variation in microsporogenesis and in the resulting LPCD pattern, suggesting that stasis was due to these selective pressures. However, even in a neutral context, variation in microsporogenesis was biased. This should therefore favour the appearance of some developmental and morphological phenotypes rather than others.     

Diuretic activity of an aqueous extract of Phyllanthus sellowianus.

Phyllanthus sellowianus Muell. Arg. (Euphorbiaceae) is used widely as a hypoglycemic and diuretic agent in South American folk medicine. In order to assess the diuretic activity of this plant, test animals were treated with a single oral administration of an aqueous extract (5% w/v) of the stem bark of P. sellowianus (400 mg/kg body weight), which produced after 8 h a significant increase in the urinary excretion. In the studies on acute toxicity in mice neither mortality nor neurobehavioral or autonomic profile changes could be observed.     

Pollen morphology of Trigonostemon and its relatives (Euphorbiaceae)

The pollen of Trigonostemon and the related genera Dimorphocalyx, Ostodes, Tritaxis and Jatropha (outgroup) has been studied with light microscopy, and scanning and transmission electron microscopy. The two major pollen types within Trigonostemon correlate well with macromorphological characters. Species belonging to the Trigonostemon reidioides type have pollen with ‘croton pattern’ ornamentation, a pistil with deeply divided stigmas (to at least half the length of the stigma arm) and stamens with a protruding appendage on the connective, while species of the Trigonostemon verrucosus type have verrucate (to almost gemmate) pollen, stigmas that are shortly cleft and stamens without an appendage on the connective. Dimorphocalyx, Ostodes, Tritaxis and Jatropha (outgroup) have similar pollen morphology, while Trigonostemon deviates from these genera in the absence of the ‘vertically’ striate ornamentation on the subunits. Therefore, when compared with an existing phylogeny of the Euphorbiaceae, the pollen characters of Trigonostemon appear to be derived. Moreover, because the ‘croton pattern’ ornamentation itself is widely shared by the ‘inaperturate crotonoids’, the loss of that structure in the Trigonostemon verrucosus type pollen is considered a further apomorphy.     

CYTOTAXONOMIC STUDIES IN THE EUPHORBIACEAE,SUBTRIBE PHYLLANTHINAE

Webster , Grady L. (Purdue U., Lafayette, Ind.), and J. R. Ellis . Cytotaxonomic studies in the Euphorbiaceae, subtribe Phyllanthinae. Amer. Jour. Bot. 49:(1): 14–18. Illus. 1962.—Chromosome numbers are reported for 18 species of mostly West Indian Euphorbiaceae, subtribe Phyllanthinae, 13 of these for the first time (including the first published count for the genus Margaritaria). For 4 species, a number different from previous determinations has been recorded. The base chromosome number in Breynia, Fluggea, Margaritaria, and most species of Phyllanthus appears to be 13. However, in Phyllanthus subg. Isocladus haploid numbers of 8 and 18 were observed. One species, Phyllanthus pulcher, is a sterile hexaploid (n = 39) of presumably hybrid origin. The cytological data do not support Perry's suggestion that annual taxa are primitive in the Euphorbiaceae.