Seed testa sculpture of species of Allium L. (Amaryllidaceae) and its taxonomic implications

We investigated the seed testa sculpture of twenty-four species belonging to thirteen sections and five subgenera of Allium from the herbarium materials or collected from plants in living collections. Seed testa sculpture of 21 species were described for the first time in this study. According to our results, the straight anticlinal wall and one large verruca or dense granules periclinal wall were found among the species in subgenus Amerallium, Cepa, Polyprason and Reticulatobulbosa. Only A. ochroleucum (sect. Daghestanica, subg. Polyprason) has U-type undulation anticlinal wall, which is similar to species of subg. Allium. The U- to Omega-type undulation anticlinal walls and several big verrucae with marginal verrucae periclinal wall were found in subg. Allium. Our results suggest that seed testa sculpture is important character of species and sections level of the genus Allium.

Morpho-anatomy of the cypselae of native species of Mutisieae (Asteraceae) from Mexico

The aims of this study were to describe and illustrate cypselae of 15 Mexican species of Mutisieae from observations using optical and scanning electron microscopy. The cypselae are heteromorphic with pilose, sericeous or glandular indumentum. The primary sculpture of the surface has two microstructural patterns: reticulate and plicate. The secondary sculpture is striate in 13 taxa, but in two species, Chaptalia estribensis and C. mexicana, differences were found in the secondary sculpture of the external and internal cypselae. The most distinctive anatomical trait is in the epicarp, which has rectangular or square-shaped cells that have a convex periclinal wall in most species of Chaptalia. The mesocarp has vascular bundles with fibers in all species of Chaptalia, but fibers are absent in Adenocaulon, Gerbera and Leibnitzia. In addition, the cells of the mesocarp inner layer have either thick walls or only an anticlinal wall in nine species of Chaptalia. The micromorphological characteristics of the primary or secondary sculpture of the surface, the type of trichomes and the variation they present have taxonomical value for recognizing closely-related taxa, whereas anatomical traits of the mesocarp distinguish Adenocaulon, Gerbera and Leibnitzia from most Chaptalia species.

Seed micromorphology of representatives of holoparasitic Orobanchaceae genera from the Caucasus region and its taxonomic significance

Obligate parasitic plant species from the Orobanchaceae family belong to the most critical genera of world flora. Due to their strongly reduced vegetative organ architecture, there arise many difficulties and mistakes in species identification, and extra characteristics of systematic importance are required. Seed micromorphology is a highly informative taxonomic criterion that helps to resolve ambiguities in plant taxonomy and evolution, and has proved to be a valuable complementary tool for Orobanchaceae species identification. In this study, seeds of 43 holoparasitic species from the Cistanche, Diphelypaea, Orobanche and Phelipanche genera collected in the Caucasus were subjected to micromorphological analysis. The Caucasus is one of the most important centres of world biodiversity, with many endangered and endemic parasitic plants. Twenty two quantitative/qualitative micromorphological seed parameters were analysed using stereo ZOOM, confocal scanning laser (CLSM) and scanning electron (SEM) microscopy. Three types of seed were established based on periclinal wall ornamentation: 1) clearly pitted sculpturing in all Cistanche, Diphelypaea, and most Orobanche seeds; 2) fibrillar and veined sculpturing in Phelipanche seeds; and 3) smooth, granular or rugged (very rarely visibly pitted) outer periclinal wall in O. coerulescens and O. colorata seeds. However, CLSM, used in present studies for Orobanchaceae seeds for the first time, revealed more details of wall lignification and ornamentation invisible in SEM images. The best micromorphological characteristics for species identification are the type of ornamentation of the periclinal wall, the width of anticlinal wall, the character of perforation, perforation length and width, the fibrillar character, and fibrillar and vein width. A comparison of the main characteristics distinguishing the seeds of Orobanchaceae is also presented and discussed.

Description of Dermea persica (Dermateaceae, Helotiales), a new asexual Ascomycete from Iran, and an updated key to Dermea species

We found one specimen of Dermea on dead branches of an unknown tree in Arasbaran forests of Iran in 2015. Based on phylogenetic analysis of combined ITS, LSU, SSU sequence data, as well as morphological observations, a new species of Dermea, D. persica, is described and illustrated here. This species, the only species of Dermea lacking a sexual morph, is mainly characterized by beaked pycnidia, hyaline to pale brown at the base and dark brown at the apex, opening by a circular ostiole, discrete or integrated conidiogenous cells with a minute periclinal wall thickening and falcate, aseptate conidia, 20–25(–30) × 2.5–3.5 µm, and lacking microconidia. The relatedness between D. persica and its close relatives is discussed. An updated key to Dermea species is also provided.

Seed morphology of Epilobium and Chamaenerion (Onagraceae) in Turkey

Macro- and micro-morphological features of seeds belonging to 26 taxa from Turkey were observed under the light and scanning electron microscopy. Present findings partly agree with segregation of Epilobium and Chamerion at generic level. The members of the genus Epilobium were distinguished by seeds with conical, semispherical, cylindrical or crest-like papillae or without papillae, granulate periclinal surfaces, papillae with parallel, radial, irregular or spirally furrow and the members of Chamerion were distinguished by seeds crest-like papillae or without papillae and without granulate periclinal surfaces and without furrow. The results also showed that seed shape, presence/absence of papillae and beak, papillae shape and ornamentation, and periclinal wall features are valuable for delimiting the examined taxa specific level within both genera. A key to Turkish Epilobium and Chamerion taxa based on seed morphology is presented for the first time

Seed micromorphology of central European Orobanche and Phelipanche (Orobanchaceae) in relation to preferred hosts and systematic implications

Holoparasitic genera within family Orobanchaceae are characterised by greatly reduced vegetative organs; therefore, seed micromorphology has proved to be a useful complementary taxonomic criterion. Seeds of 160 samples from 54 localities of 26 taxa of the Orobanche and Phelipanche genera occurring in central Europe, specifically from Poland, the Czech Republic, Austria and Slovakia, supplemented by samples from Spain, France and Ukraine, were investigated using scanning electron microscopy. Thirteen quantitative or qualitative morphological characters of seeds were analysed. The following three types of periclinal wall sculpture of seeds were identified: veined and fibrillar in Phelipanche; with oval or elliptic perforations (pitted) in almost all species of Orobanche; with outer periclinal wall smooth, granular or rugged (very rarely visibly pitted), impeding vision of the inner one, occurring only in O. gracilis Sm. and O. coerulescens Stephan in Willd. The influence of different hosts on the features of seeds of eight species is also presented, as well as relationships between seed morphology and taxonomic classification, including problematic taxa. The best diagnostic features include type of ornamentation of the periclinal wall, perforation diameter (in pitted sculpture), fibrillar diameter (in fibrillar sculpture) and width of anticlinal walls. Size and shape of the seeds and cells and the presence of median troughs are variable; however, these features can be helpful when using larger samples. The usefulness of micromorphological studies on seeds of Orobanche and Phelipanche is demonstrated.

Taxonomic Evaluation of Fifteen Species of Ipomoea L. (Convolvulaceae) from South-Western Nigeria using Foliar Micromorphological Characters

Foliar micromorphological study was carried out on I. triloba, I. eriocarpa, I. alba, I. hederifolia, I. muricata, I. intrapilosa, I. asarifolia, I. batatas, I. aquatica, I. mauritiana, I. carnea, I.involucrata, I. nil, I. heterotricha and I. obscura to determine the patterns of variation in their epidermal characteristics and search for useful and stable anatomical characters for the identification of the species. Leaf epidermal features that provided useful specific distinctions are cell shape, anticlinal wall pattern, stomata shape, stomata type, trichome, cuticular striations, crystal, granular periclinal wall, stomata size, stomata index, scale and tannin. The characters revealed interrelationships among the Ipomoea species and also suggest their monophyly.

Investigating the Dynamics of Organelle-Actin Assembly with Dielectrophoresis

Dielectrophoresis is a technique of using high-frequency electric fields to manipulate dielectric particles. This work applies this technique to study the changes of intracellular properties in response to environmental changes. In a number of plant cells, chloroplasts change their positions for optimizing photosynthetic light absorption. Only between 2 and 20% of the light energy absorbed by algae and higher plants is actually used in CO2 fixation. Comparing with other micro-manipulative methods, dielectrophoresis is a relative simple method for investigating the microscopic mechanisms involved in chloroplast repositioning. Leaves of Egeria densa were subjected to different lighting conditions before conducting dielectrophoresis. Under dim light, chloroplasts situate on the periclinal wall. Under high-intensity light, chloroplasts move from the periclinal wall to the anticlinal walls. Under electric fields, chloroplasts treated with different lighting condition exhibit different motions. It is expected that actin configuration as well as chloroplast-actin binding strength contributes to the repositioning of chloroplasts.

Bulliform cells in Loudetiopsis chrysothrix (Nees) Conert and Tristachya leiostachya Nees (Poaceae): structure in relation to function

This work reports anatomic and ultrastructural characteristics of bulliform cells in Loudetiopsis chrysothrix (Nees) Conert and Tristachya leiostachya Nees. Both the species presented leaf rolling under water stress. The main characteristics observed in these cells were: periclinal wall thinner than the adjacent epidermal wall; abundance of pectic substances in cuticular layer; sinuous anticlinal walls with ramified plasmodesmata; vacuome formed by a developed vacuole or innumerous small vacuoles; abundance of phenolic substances and oil drops. These characteristics suggested the involvement of bulliform cells in the mechanism of foliar involution in the studied species.