Floral morphology and evolution in Anisophylleaceae

TOBE, H. & RAVEN, P. H., 1988. Floral morphology and evolution in Anisophylleaceae. The four genera of Anisophylleaceae ( Anisophyllea, Combretocarpus, Poga , and Polygonanthus ) are very uniform in their floral structures. Characteristic floral features of the family are: flowers small (except for the female flowers of Polygonanthus ), merism nearly fixed (i.e. 3- or 4-mery), petals deeply incised (except in Polygonanthus ), ovary inferior and multi-loculed, ovules few (one or two) per carpel, styles separate, intra- and interstaminal nectariferous tissues present, and floral vasculature simple. Comparisons with related groups support the distinctiveness of Anisophylleaceae, and suggest a close affinity with both Rhizophoraceae and the Myrtales. The presence of incised petals in both groups suggests an especially close relationship between Anisophylleaceae and Rhizophoraceae, while new evidence from comparative floral morphology suggests that Anisophylleaceae occupy an intermediate position between Rhizophoraceae and Myrtales. Within the Anisophylleaceae, Poga and Polygonanthus share several synapomorphies in floral structure, while Combretocarpus is the most divergent genus in the family and is more distantly related to Poga and Polygonanthus . It is uncertain whether Anisophyllea is more closely related to Poga and Polygonanthus or Combretocarpus , because the evidence from comparative floral morphology conflicts with that from embryology; more data from other kinds of characters are needed to resolve this issue.     

On the Systematic Position of Daphniphyllaceae

The present paper deals with the systematic position of Daphniphyllaceae. The genus Daphniphyllum was first described by Blume in 1826 as a member of Rhamnaceae. In 1858 Baillon removed it to the tribe Phyllantheae of Euphorbiaceae, while Müller (1869) raised this genus to the rank of family, Daphniphyllaceae. Although Müller’s treatment has been accepted by most botanists, including the present authors, its systematic position has been debated. The first aim in our studies on the cladistics of Hamamelidae is to answer the question which families should be included in this monophyletic group. By observing their pollen grains and stoma types of some representative species of Daphniphyllaceae, Hamamelidaceae and Buxaceae under light microscope (LM) and scanning electron microscope (SEM,) and analysing morphological, anatomical, palynological, embryological characters and chemical components in the three taxa and Euphorbiaceae, we find that Daphniphyllaceae is very similar to Hamamelidaceae, but greatly different from Euphorbiaceae, in inflorescence racemose or spicate, calyx nearly reduced, stamens numerous and sometimes synandry, connective usually exserted, disc absent, carpels 2; vessel with scalariform perforation plates and often not spiral-thickened, fiber bordered-pitted; stomata mostly paracytic; pollen 3-colpate; tapetum glandular, endosperm development cellular, obturator and caruncle absent; iridoid compounds present; sieve-element plastids S-type. The present authors have noticed the fact that Daphniphyllaceae is also similar to Magnoliaceae in the stamens numerous, anthers larger and filaments very short, connectives obviously exserted and with several bundles; anther wall thicker, endosperm development cellular, embryo small. It is considered that not only are Daphniphyllaceae and Hamamelidaceae phenetically close to each other but also much possibly derived from a common ancestor, the extinct group of Magnoliales. However, Daphniphyllaceae appears to be remote from Euphorbiaceae and Buxaceae in relationship and should be separated from Euphorbiales and Buxales. Meanwhile, since Daphniphyllaceae differs from the members of Hamamelidales in the incompletely septate ovary, drupaceous fruit, indistinct sexine sculpture of pollen grains, small embryo, and an unique alkaloid, daphniphylline, but lacking proanthacyanins, the establishment of an order, Daphniphyllales, for the family, is considered reasonable. According to our opinion, the order is related to Hamamelidales rather than to Euphorbiales as originally suggested by Huru-sawa (1954).     

A Study on the Pollen Morphology of Actinidiaceae and Its Systematic Position

1. The pollen morphology (Table 2) of 23 species and 3 genera (Actinidia, Clematoclethra and Saurauia) were examined under microscope. Among them 10 species were also observed under SEM and 3 species also under TEM. Comparative studies on the Actinidiaceae and its relative families, Theaceae (9 species and 7 genera) and Clethraceae (1 species and 1 genus), were also made. 2. The observation (Table 3) shows that Saurauia differs from Actinidia and Clematoclethra in a number of important features. Hutchinson's and Takhtajan's systems suggest that Saurauiaceae is an independent family, and the observation by the present author is in accord with this view. Pollen morphology also shows the close relationship between Actinidia and Clematoclethra, and therefore they belong to the same family, Actinidiaceae. 3. The comparative analysis of morphological, palynological, embryological and chemical data (Table 4) may shed light on systematic position of Actinidiaceae. There are several morphological similarities between Actinidiaceae and Theaceae: flowers hypogynous, syncarpous, and mostly with free petals; aestivation of sequals quincuncial; gynoecia composed of 3 to many carpels; styles united or free; placentation mostly axile, ovules numerous; stamens basifixed or versatile; anthers with a prominent endothecium; fruits often baccate or capsular; and pollen tricolporoidate. In Actinidiaceae, however, the ovule is unitegmic, endosperm-development cellular, weak terminal haustoria developing at both ends of the embryo sac. The embryological characteristics of the family under discussion are similar to those of Cletheraceae. With systematic position of the family Actinidiaceae, we tend to support Cronquist's view (1981). The embryological similarity shows that they are closely related to each other. 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On the Systematic Position of Paradombeya Stapf

The systematic position of Paradombeya Stapf has been debated until now. The studies on gross morphology, anatomy, palynology and cytology were undertaken to confirm the systematic position and affinities of this genus. The combination of features, e. g., umbel-like cyme, 2-celled anther, presence of staminodes, staminal tube, 15 stamens, bifid cotyledons, wood anatomy, chromosome number of 2n=20, triporate, spiny and spheroidal pollen grains, suggests that the genus be better placed in the tribe Dombeyeaeof the Sterculiaceae.     

The Anatomical Structures and Floral Development of Euryale ferox Salisb

The pedicel of E. ferox possesses closed, scattered vascular bundles and contains no cambium. Four main air canals are well developed. Mesophyll of sepal is differentiated into palisade and spongy parenchyma. Petal is simpler in structure than that of sepal with no palisade tissue differentiated. Stamens show a wide varity of shapes; those in the outer whorls are usually petaloid while the inner whorls are of the conventional type bearing four-loculate anthers. Ovary is inferior, multicarpellarv and syncarpous with laminar plancentae in each locule. The flower primordium grows out from the mixed bud. It is enveloped by an axillary scale. The preliminary indication of floral initiation is the periclinal divisions of the second layer of the shoot apex which is closer to the leaf base. By the time a flower primordium becomes 465μm high, the floral parts begin to arise in a continuous acropetal sequences, namely sepals, petals, stamens and carpels successively with initiation of their primordia by periclinal divisions of the second or third layer on the flank of the floral apex respectively. By the fact that the growth of the outer layered cells of the receptacle is faster than those of the inner ones, an epigynous flower and an inferior ovary is thus to be formed. The ventral margin of the carpel has become conduplicately appressed and fused in the lower portion, while the upper part has not been fused, an ovarian canal is appeared from top of the ovary. There is no differentiation of a style. A central receptacular core is found among the carpels. On the basis of anatomical and developmental studies of the floral organs, we suggest that Euryale ferox exhibits a number of most primitive features, such as petaloid stamens, carpel with ovarian canal, elongated receptacle, prominent residual floral apex and laminar placentation. The development of floral parts and characteristics of ovary indicate that genus Euryale is much more similar to Victoria, Nymphae and Nuphar than to Nelumbo and Brasenia.     

A Systematic Comparison of Supervised Classifiers

Pattern recognition has been employed in a myriad of industrial, commercial and academic applications. Many techniques have been devised to tackle such a diversity of applications. Despite the long tradition of pattern recognition research, there is no technique that yields the best classification in all scenarios. Therefore, as many techniques as possible should be considered in high accuracy applications. Typical related works either focus on the performance of a given algorithm or compare various classification methods. In many occasions, however, researchers who are not experts in the field of machine learning have to deal with practical classification tasks without an in-depth knowledge about the underlying parameters. Actually, the adequate choice of classifiers and parameters in such practical circumstances constitutes a long-standing problem and is one of the subjects of the current paper. We carried out a performance study of nine well-known classifiers implemented in the Weka framework and compared the influence of the parameter configurations on the accuracy. The default configuration of parameters in Weka was found to provide near optimal performance for most cases, not including methods such as the support vector machine (SVM). In addition, the k-nearest neighbor method frequently allowed the best accuracy. In certain conditions, it was possible to improve the quality of SVM by more than 20% with respect to their default parameter configuration.     

Floral Organogenesis and Its Systematic Significance of the Genus Nandina(Berberidaceae)

The initiation of the floral organs of Nandina domestica Thunb. (Berberidaceae) is of the trimemus-whorled pattern. Stamens and petals grew out from the lateral bifurcation of the common stamen-petal primordia; but petals underwent retarded periods of growth in their early development. Carpel initiation belongs to the ascidiate type. Some aspects concerning the trimerous floral organs, the origin of petals, stamen insertion pattem and monocarpellary pistil were discussed. In addition the floral ontogenetic characters among three genera of the Berberidaceae, i.e., Caulophyllum, Podophyllum and Nanclina were compared. It is inferred that the trimerous-whoded arrangement and the diversity of carpel initiation were the two unique characters of Nandina.     

Study on the Systematic Position of Tetraena Maxim

Tetraena Maxim. is an endemic genus of Inner Mongolia and the desert region of Central Asia. It is also a rare and endangered plant. Some botanists had made some research on the systematic positions of this genus, but their views are debatable. Through a comprehensive study: research history, morphology (pistil, fruit), pollen grains, chromosomes, the authors suggest that this genus be separated from Zygophylloideae (Zygophyllaceae, Takhtajan. 1987) and a new subfamily-Tetraenoideae be set up for it. A key to subfamilies of Zygophyllaceae (sen. str.) is provided. The systematic position of Tetraena Maxim. is: Rutales-Zygophyllaceae -Tetraenoideae-Tetraena.     

Floral Morphology of Populus lasiocarpa Oliv and Its Phylogenetic Position in Populus

The results of this study, which involved macroscopic, microscopic and SEM investigation of flowers of Populus lasiocarpa Oliv., may be stated as follows: 1. Female, male and bisexual flowers possess well developed perianth greenish in color with obvious veins and glandular teeth. The branched vascular bundles and stomata apparatus are observed in the transection of the perianth. It suggests that the perianth is homologous with the leaf. 2. Each pistil of female and bisexual flowere possesses 3(–5) separate styles. The ovary is I-celled with 16–34 ovules. Each male flower has 41–110 stamens. The connective of stamen is protrusive. Presence of bisexual, polygamous flower and monoecism is not rare. 3. In comparison with several other species of Populus, P. lasiocarpa is supposed to be the most ancient and primitive species of the Populus. The central and south-west China perhaps is one of distributional center of Populus.     

Floral Developmental Evidence for the Systematic Relationships of Tropaeolum(Tropaeolaceae)

The floral ontogeny of three species of Tropaeolum was studiedusing scanning electron microscopy to find morphological evidencefor discussing the systematic position of the family. The initiationof the androecium is highly unusual: there are always eightstamens which arise (1) either in a spiral sequence startingwith the stamen opposite sepal four, running in a directionopposite to the sequence of the sepals, and with reversals inthe direction of the spiral, or (2) as a sequence of pairedand unpaired stamens. The floral symmetry changes twice duringthe development of the flower, from polysymmetrical at sepaland petal initiation, through oblique monosymmetry at stameninitiation, and ending with median monosymmetry in later developmentalstages. The occurrence of median monosymmetry is a late-developmentalevent and is caused by the initiation of a hypanthial spur,and the unequal growth of the petals and styles. The originfor the unusual sequence of stamen initiation reflects a trendaffecting the whole flower which is linked with the changingpatterns of floral symmetry. Octandry is enhanced by multiplecauses, such as the loss of two stamens in an originally diplostemonousandroecium and the regulating pressure of the gynoecium. Thechange in symmetry during ontogeny is significant for discussingthe systematic position of Tropaeolaceae in comparison withthe glucosinolate-producing taxa and the Sapindales. The combinationof an androecium with eight stamens and oblique monosymmetryis either a single event in evolution and links Tropaeolum withthe Sapindales, or it has evolved at least twice, once in theSapindales, and once in a clade comprising Tropaeolaceae, Akaniaceaeand Bretschneideraceae. Morphological data support a sistergroup relationship of the three latter families, which is inline with macromolecular studies. Copyright 2001 Annals of BotanyCompany Tropaeolum, Tropaeolaceae, Glucosinolate clade, Sapindales, oblique monosymmetry, androecium, octandry, floral development, phylogeny     

On the Pollen Morphology and Systematic Position of Trigonobalanus doichangensis

The present paper describes the pollen morphology of Trigonobalanus doichangensis (A. Camus) Forman of Fagaceae. Comparative study on pollen grains was carried out by means of light microscope, scanning and transmission electron microscope. The pollen grains of T. doichangensis are subspheroidal or suboblate but in polar view they are subtriangular, and in equatorial view they are subcircular they are 27.3, 23.1-29.4)×27.3(25.2-29.4) μm in size and 3-colporate goniotreme. The exine is 2-layered, 2.4-4.2μm, thick in apocolpia. The sexine cosists of tectum, bacules and endonexine under TEM. On the basis of pollen shape, type of aperture and exine structure the pollen grains of T. doichangensis are distinguishable, from those of other genera in Fagaceae and it may belong to a new type of Fagaceae.     

突脉金丝桃的花器官发生及其系统学意义

利用扫描电镜（SEM）观察了突脉金丝桃（Hypericum przewalskii）（金丝桃科）的花部器官发生发育过程。结果表明,突脉金丝桃2枚苞片原基首先发生,花原基在苞片原基的包裹中完成发育。在苞片原基发生后,5枚萼片原基沿2/5圆周依次发生。萼片原基发生近完成时,5枚雄蕊—花瓣共同原基在萼片原基之间的角隅处近同时发生,此后,雄蕊—花瓣共同原基下部向外伸展形成花瓣原基,上部向上凸起形成与花瓣原基相对的雄蕊原基,之后雄蕊原基由内向外依次分化发育产生次生雄蕊原基,随着次生雄蕊原基的发育和数目的增多,形成了5束雄蕊。次生雄蕊原基发生的同时,5枚心皮原基近同时发生。突脉金丝桃雄蕊束的发生方式表明,金丝桃属的雄蕊束可能起源于5基数的单轮雄蕊。金丝桃科与藤黄科植物花瓣及雄蕊原基发生方式的显著不同,支持了APG Ⅲ系统将金丝桃亚科从藤黄科中独立为金丝桃科的观点。     

吉祥草的花部器官发生及其系统学意义

利用扫描电镜（SEM）观察了吉祥草（Reineckia carnea）（铃兰科）的花部器官发生发育过程。吉祥草花被片、雄蕊的发生方式是由近轴端向远轴端发生的逆单向型（reversed unidirection）,花发育后期花被片合生形成花被筒,花丝与之贴生。伴随花被片、雄蕊发生,三枚心皮也由近轴向远轴方向相继发生,随后彼此合生发育。花序顶部的花易发生花器官数目变异。结合早期花原基形态以及花器官数目变异情况分析,吉祥草的花被片与雄蕊可能是由共同原基分化而成。从花部器官发生式样和花被筒形成时间两方面比较吉祥草属、白穗花属和铃兰属的特征发现,三属中,铃兰属处于相对进化的位置,而白穗花属比吉祥草属更为原始。     

Peptides and Peptoids - A Systematic Structure Comparison

A systematic analysis of the conformational space of the basic structure unit of peptoids in comparison to the corresponding peptide unit was performed based on ab initio MO theory and complemented by molecular mechanics (MM) and molecular dynamics (MD) calculations both in the gas phase and in aqueous solution.The calculations show three minimum conformations denoted as C_7ß, a_D and a that do not correspond to conformers on the gas phase peptide potential energy hypersurface. The influence of aqueous solvation was estimated by means of continuum models. The MD simulations indicate the a_D form as the preferred conformation in solution both in cis and trans peptide bond orientations.     

Floral sesquiterpenes and their synthesis in dioecious kiwifruit

Kiwifruit species are vigorously growing dioecious vines that rely on bees and other insects for pollen transfer between spatially separated male and female individuals. Floral volatile terpene cues for insect pollinator attraction were characterized from flowers of the most widely grown and economically important kiwifruit cultivar Actinidia deliciosa ‘Hayward’ and its male pollinator ‘Chieftain’. The sesquiterpenes α-farnesene and germacrene D dominated in all floral tissues and the emission of these compounds was detected throughout the day, with lower levels at night. Two terpene synthase (TPS) genes were isolated from A. deliciosa petals that produced (+)-germacrene D and (E,E)-α-farnesene respectively. Both TPS genes were expressed in the same tissues and at the same times as their corresponding floral volatiles. Here we discuss these results with respect to plant and insect ecology and the evolution and structure of sesquiterpene synthases.Key words: terpene, dioecy, kiwifruit, volatile, ecology, evolution, flower     

Floral meristem size and organ number correlation in <Emphasis Type="Italic">Eucryphia</Emphasis> (Cunoniaceae)

We present a comparative flower ontogenetic study in five species of the genus Eucryphia with the aim of testing whether differences in the organ number observed can be explained by changes in the meristematic size of floral meristem and floral organs. Species native to Oceania, viz. E. milliganii, E. lucida and E. moorei, have the smallest gynoecia with ca. 6 carpels, while the Chilean E. glutinosa and E. cordifolia present more than ten carpels. E. milliganii has the smallest flower with the lowest stamen number (ca. 50), while the other species produce around 200 stamens and more. Standardized measurements of meristematic sectors were taken in 49 developing flowers that were classified into three well-defined ontogenetic stages. Sizes of meristems varied significantly among species within each developmental stage as revealed by ANOVA analyses. Significant regressions between organ number and corresponding meristem size were consistent with the premise that a larger meristem size prior to organ initiation could be determining for a higher organ number. Flower organogenesis in Eucryphia also involves relevant meristem expansion while the organs are initiated, which results in a particular androecium patterning with a chaotic stamen arrangement. Meristem expansion also appears to be slower but more extensive in species with larger initial meristematic size, suggesting that flower phenotype can be determined in ontogeny by this heterochronic interplay of space and time.