Taxonomic significance of trichomes micromorphology in cucurbits

Studies on trichomes micromorphology using Scanning Electron Microscope (SEM) were undertaken in 23 species with one variety under 13 genera of the family Cucurbitaceae (viz., Benincasa hispida (Thunb.) Cogn., Citrullus lanatus (Thunb.) Matsum. & Nakai, Cucumis melo var. agrestis Naudin, Cucumis sativus L., Diplocyclos palmatus (L.) C. Jeffrey, Edgaria dargeelingensis C.B. Clarke, Gynostemma burmanicum King ex Chakr., Gynostemma pentaphyllum (Thunb.) Makino, Gynostemma pubescens (Gagnep.) C.Y. Wu, Hemsleya dipterygia Kuang & A.M. Lu, Lagenaria siceraria (Molina) Standl., Luffa acutangula (L.) Roxb., Luffa cylindrica M. Roem., Luffa echinata Roxb., Melothria heterophylla (Lour.) Cogn., Melothria leucocarpa (Blume) Cogn., Melothria maderspatana (L.) Cogn., Sechium edule (Jacq.) Sw., Thladiantha cordifolia (Blume) Cogn., Trichosanthes cucumerina L., T. cucumerina var. anguina (L.) Haines, Trichosanthes dioica Roxb., Trichosanthes lepiniana (Naudin) Cogn. and T. tricuspidata Lour.). The trichomes in the family Cucurbitaceae vary from unicellular to multicellular, conical to elongated, smooth to ridges, with or without flattened disk at base and cyctolithic appendages, thin to thick walled, curved at apices to blunt. Trichomes micromorphology in the family Cucurbitaceae was found significant taxonomically.     

Taxonomic significance of leaf anatomy of Aniselytron (Poaceae) as an evidence to support its generic validity against Calamagrostis s. l.

A comparative study of leaf anatomy on Aniselytron Merr. and Calamagrostis Adans. s. l. was conducted to review the systematic status of Aniselytron Merr. Calamagrostis s. l. exhibits wide variation in many features, but basic leaf structures of the genus remain constant: absence of a midrib-keel; median and large vascular bundles are central, with double sheaths, accompanied by girders both adaxially and abaxially; prickles have a bulbous base and are not sunken; the abaxial epidermal cells are short and wide and relatively thick-walled. Aniselytron differs from Calamagrostis s. l. in: midrib-keel is present, consisting of a large central bundle with small ones on either side; all vascular bundles are abaxially situated, with abaxial girders only, parenchyma takes the place of the adaxial sclerenchyma; the bases of the prickles are sunken and are not bulbous; the abaxial epidermal cells are tall and thin-walled. These distinct anatomical features, in combination with the differences in spikelet structure and habitat, suggest that Aniselytron should be generically separated from and not merged with Calamagrostis s. l. Due to the adaxial parenchyma in the midrib which has never been found in Pooideae, Aniselytron might have a relationship with some other subfamily.     

Gemmae in Octoblepharum albidum Hedw.

Abstract

The nine Tortula species and two varieties known from the islands of the subantarctic botanical zone are distinguished in a key. New synonymy, taxonomic notes and illustrations are provided and the presently known distribution of the species is reported and discussed.     

Taxonomic significance of flavonoid variation in temperate species of Nothofagus

Forty-two flavonoids and a stilbene (pinosylvin) were identified in the leaf exudates of 11 temperate species of Nothofagus from South America, Australia and New Zealand. The flavonoid profiles demonstrate significant taxonomic value at the subgeneric level. Most species of subgenus Fuscospora are characterized by the presence of pinosylvin, galangin and galangin methyl ethers. Kaempferol-type flavonols are abundant in subgenus Lophozonia while these flavonols are largely absent from species of subgenus Fuscospora. The flavonoid patterns are largely in agreement with a recent subgeneric classification of Nothofagus.     

Taxonomic significance and ecological role of triterpene glycosides from holothurians

The results of chemotaxonomic research on triterpene glycosides of holothurians (Holothurioidea, Echinodermata) and studies on the ecological role of these glycosides as protective substances and trophic markers are reviewed with a focus on research performed in 2011–2015.     

Taxonomic significance of floral pigments in linum (Linageae)

Floral pigments of 30 taxa, representing five informally ranked subgeneric complexes(Linum schiedeanum, L. virginianum,L. neomexicanum, L. sulcatum, andL. rigidum) of yellow-flowered North American flaxes, were examined by paper chromatography. Earlier studies, based on comparative gross morphology, chromosomal complements, and pollen structure, led to the conclusion that members of theL. schiedeanum complex may be the most primitive and that theL. virginianum, L. neomexicanum, andL. rigidum complexes may have been derived independently, the latter via a taxon similar toL. sulcatum. Data from both carotenoids and flavonoids support this scheme. Spectral analysis reveals the exclusive presence of the Β-carotenoid, violaxanthin, in the X.schiedeanum, L. virginianum, L. neomexicanum, andL. sulcatum com-Taxa of theL. rigidum complex, with the exception ofL. subteres, possesplexes. exclusively the α-carotenoids, lutein and its 5, 6-monoepoxide.L. subteres, in its production of violaxanthin, provides a chemical link to the other complexes, though possession of several species-specific flavonoids suggests an early divergence from other members of theL. rigidum complex. Distinctions in the Chromatographic patterns of quercetin, luteolin, and other flavonoid compounds were found among the five groups. In general the loss of flavonoid pigments may be correlated with increased morphological specialization. Identical patterns in certain species of theL. schiedeanum andL. virginianum complexes support the presumed relationship between these two groups.     

Abscisic-acid-induced drought tolerance in Funaria hygrometrica Hedw.

Three-week-old protonemata of Funaria hygrometrica Hedw. cultivated in Petri dishes tolerate slow drying (24 h to complete dryness) but not rapid drying (1h to complete dryness). Slowly dried mosses show, on a dry-weight basis, a sixfold increase in abscisic-acid (ABA) contents during the drying process. Rehydrated, slowly dried protonemata have the ability to tolerate subsequent rapid drying. When ABA is added to three-week-old protonemata at a concentration of 10 M for 16 h, tolerance to rapid drying is induced. These data indicate that the induction of drought tolerance in Funaria hygrometrica is mediated by ABA. Mosses treated with ABA loose their water as fast as controls do; therefore, ABA does not act via reduced water loss. However, induction of synthesis of new proteins by ABA may form an important part of the drought tolerance because 10 M cycloheximide inhibits the ABA-mediated tolerance to rapid drying.Abbreviations ABA abscisic acid - CHI cycloheximide - DW dry weight - FW fresh weight - RWL relative water loss This work was supported by grants from the Deutsche Forschungs-gemeinschaft and by a NATO fellowship awarded to R.M. Ros Espin.     

Comparative stem anatomy in the subfamily Cactoideae

Basic anatomical features of Cactaceae have been studied since the sixteenth century. This anatomical research has focused on selected features related to different external forms or on stem photosynthetic metabolism. Anatomical stem features, however, have rarely been taken into consideration in systematic studies. Recent work has focused on the subfamily Cactoideae because it is the largest and most diverse subfamily of Cactaceae. Molecular analyses support the monophyly of Cactoideae, but tribal and generic relationships are mostly unresolved. A major goal of this study was to synthesize the available information about anatomical stem features of Cactoideae and to evaluate their usefulness in phylogenetic analysis. Although dermal and vascular tissues have been studied for nearly 350 species of Cactoideae, comprehensive investigations are needed for most members of specific genera or tribes. Phylogenetic analysis based on structural data (morphology and anatomy) showed that the subfamily Cactoideae is monophyletic. This result supports molecular evidence and corroborates that highly reduced leaves are the synapomorphy of this clade. With the exception of Cacteae and Rhipsalideae, the tribes are not monophyletic. The morphological characters that have been used to define the tribes are not synapomorphies and have evolved independently in different lineages. Some anatomical features are unique characters that distinguish terminal taxa; for example, silica grains in dermal and hypodermal cells inStenocereus, prismatic crystals in dermal and hypodermal cells ofNeobuxbaumia, and lack of medullary bundles in members of Cacteae. Most anatomical features, however, behave in a highly homoplasious manner in the analysis of the subfamily. Other studies at the tribal or generic level show that anatomical features are informative and contribute to support different clades. Further studies of Cactoideae, at different taxonomic levels, that include anatomical features, are needed in order to understand their evolution.

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Resumen  Desde el siglo dieciseis se inició el estudio los caracteres anatómicos en Cactaceae. La investigación se ha enfocado a caracteres relacionados con las diferentes formas y el metabolismo fotosintético de los tallos. Sin embargo, en pocos estudios las estructuras anatómicas se han empleado en la sistemática de la familia. La investigación se ha centrado en la subfamilia Cactoideae porque es la más grande y diversa dentro de Cactaceae. Estudios moleculares apoyan la monofilia de Cactoideae; sin embargo, las relaciones tribales y genéricas son inciertas. Uno de los objetivos de este trabajo fue sintetizar la información sobre los caracteres anatómicos del tallo en Cactoideae y evaluarla desde una perspectiva filogenética. Aunque se ha estudiado el tejido dérmico o vascular de alrededor de 350 especies de Cactoideae, se requieren estudios que incluyan a la mayoría de las especies de géneros y tribus específicos. El análisis filogenético basado en datos estructurales (morfología y anatomia) mostró que la subfamilia Cactoideae es monofilética. Este resultado apoya las evidencias moleculares y corrobora que las hojas altamente reducidas son la sinapomorfia de este clado. Excepta por las tribus Cacteae y Rhipsalideae, las otras tribus no se recuperaron como monofiléticas. Los caracteres morfológicos que se han empleado para circunscribir las tribus no son sinapomorfias y se han adquirido en forma independiente en varios linajes. Varios caracteres anatómicos son únicos y distinguen a algunos taxa terminales como son la presencia de cuerpos de sílice en la epidermis e hipodermis deStenocereus, los cristales prismáticos en la epidermis e hipodermis deNeobuxbaumia y la ausencia de haces medulares en especies de Cacteae. Sin embargo, la mayoría de los caracteres anatómicos son homoplásicos en el análisis de la subfamilia, pero otros estudios a nivel tribal o genérico han mostrado que son informativos y contribuyen a diferenciar clados. Existe la necesidad de un mayor número de estudios a diferentes niveles taxonómicos que incluyan características anatómicas con la finalidad entender su evolución.

     

Taxonomic significance of yeast sphaeroplast release after enzymatic treatment of intact cells.

Treatment of whole yeast cells with a mixture of a reducing agent and 1,3-beta-glucanase isolated from Basidiomycete QM806 led to the production of sphaeroplasts from ascomycetes, from some fungi imperfecti, but not from basidiomycetes. Association of 1,3-beta-glucanase with a second enzyme, 1,4-alpha-glucanase, from Trichoderma viride, was required for sphaeroplast release from some, but not all, basidiomycetes and fungi imperfecti. The ability of yeast cells to liberate sphaeroplasts following appropriate enzymic treatment is proposed as a taxonomic criterion for differentiating basidiomycetous from ascomycetous yeasts and for classifying fungi imperfecti yeasts.     

Chlorophyll Fluorescence during Drying and Rehydration in the Mosses Rhytidiadelphus loreus (Hedw.) Warnst.,Anomodon viticulosus (Hedw.) Hook. & Tayl. and Grimmia pulvinata (Hedw.) Sm.

Chlorophyll-fluorescence parameters of three mosses, Rhytidiadelphusloreus (Hedw.) Warnst.,Anomodon viticulosus (Hedw.) Hook &Tayl. and Grimmia pulvinata (Hedw.) Sm. were measured duringdrying, and following remoistening after a period of desiccation.Most changed little with drying until the full-turgor pointwas approached, when rapid changes accompanied loss of cellwater. In R. loreus all parameters decreased together down toa water content of about 30% d.wt (RWC approx. 0.15). At lowwater contents (5–16% d.wt; RWC approx. 0.02–0.08)saturating pulses tended to suppress rather than stimulate fluorescence.In A. viticulosus F_v/F_m, q_Pand     

Taxonomic significance of variation in sexual condition in Pelekium Mitt. and related genera (Thuidiaceae)

Sexual condition has been employed as a key character within the moss family Thuidiaceae to discriminate the dioicous genera Aequatoriella and Thuidiopsis from the monoicous Pelekium. Here, we implemented phylogenetic analyses of the chloroplast trnL-F region and two unicopy nuclear regions to test the monophyly of Pelekium, and hence, the taxonomic significance of the variation in sexual systems. Aequatoriella was deeply nested within Pelekium, suggesting that the sexual condition is not a fixed character state that can be used to circumscribe genera in the Thuidiaceae and, therefore, that Aequatoriella should be sunk. Incongruence among loci rendered the interpretation of the position of Thuidiopsis challenging, and we suggest maintaining it as a separate genus pending further evidence.     

Taxonomic, evolutionary and ecological implications of the leaf anatomy of rhizomatous Iris species

The leaf anatomy of the rhizomatous Iris species with ensiform leaves and the related genera Pardanthopsis and Belamcanda is described. Their isobilateral leaves may or may not have a pseudo-dorsiventral structure. Variable characters of their leaf blades include: outline in transverse section, height and shape of papillae, form and structure of stomata, transverse section outline of marginal fibre strands and sclerenchy matous inner bundle sheath at phloem and xylem poles, forms of mesophyll arrangement, mesophyll structure and air canals, vascular bundle arrangement and the detailed structure of the larger vascular bundles, distribution of tannin, size and distribution of crystals. The taxonomic and ecological significance of these characters has been evaluated.
The anatomical characteristics of 25 supraspecific taxa in three genera are presented and compared in tables. The relationships and evolutionary position of these taxa are discussed. Each of the three subgroups within Iris appears to be correlated with a syndrome of anatomical characters. Some species currently of uncertain taxonomic position are discussed, and their classification based on anatomical data is suggested.
Some characters related to xeromorphy or helomorphy are mentioned.     

Polytrichum commune Hedw. and Polytrichadelphus magellanicus (Hedw.) Mitt. used as decorative material on New Zealand Maori cloaks

Abstract

Confirmation of the occurrence of the moss Ptychomnion densifolium on the main islands of New Zealand is provided and the features which separate it from the more common P. aciculare are outlined. A brief account of the history of P. densifolium in New Zealand is given and its morphology there is discussed. A key to the two species in New Zealand is provided and habitat differences between them outlined. New Zealand material differs from type locality (Tristan d' Acunha) material in having longer and more twisted acumens, and in this respect is similar to New Zealand material of P. aciculare. New Zealand populations of P. densifolium are recognisable in having stem leaves reflexed from an oblong sheathing base, and well developed basal leaf plications. It is a relatively widespread species in New Zealand, occurring in mostly upper elevation, open sites.