Genotype-dependent efficiency of endosperm development in culture of selected cereals: histological and ultrastructural studies

The paper reports studies, including histological and ultrastructural analyses, of in vitro cell proliferation and development of immature endosperm tissue isolated from caryopses of Triticum aestivum, Triticum durum, and Triticosecale plants. Endosperm isolated at 7–10 days post-anthesis developed well on MS medium supplemented with auxins and/or cytokinins. The efficiency of endosperm response was highly genotype-dependent and best in two winter cultivars of hexaploid species. The pathways of development and proliferation were very similar among the selected species and cultivars. Histological and scanning electron microscope (SEM) analysis revealed that only the part of the endosperm not touching the medium surface continued growth and development, resulting in swelling. The central part of swollen regions was composed mainly of cells containing many large starch grains. The peripheric parts of developed endosperm consisted of highly vacuolated cells and small cells with dense cytoplasm. SEM showed that cells from the swollen region were covered partially with a membraneous structure. Transmission electron microscope studies of cells from the outer part of the developing region showed features typical for cell activity connected with lipid metabolism.     

Comparative ultrastructural topography of the gut epithelia of the lung fluke Paragonimus (Trematoda: Troglotrematidae)

The gut epithelia in the species of Paragonimus known in Japan, P. westermani, P. ohirai, P. iloktsuenemis, P. miyazakii, and P. sadoensis, were observed with the scanning electron microscope. Transmission electron microscopy was employed to substantiate and clarify the results of these topographic studies. Morphological differences in the cytoplasmic projections of the gut epithelial surface were found to be present among some species of Paragonimus. The cytoplasmic projections in this group are of a sheet-like or broad lamellar type, although fine digitiform type projections have never been described in other trematodes.     

Discopersicus n. gen., a New Member of the Family Tylenchidae ?rley, 1880 with Detailed SEM Study on Two Known Species of the Genus Discotylenchus Siddiqi, 1980 (Nematoda; Tylenchidae) from Iran

Discopersicus iranicus n. gen., n. comb., previously described from Iran as a new species under the genus Discotylenchus, is illustrated using light microscope and scanning electron microscope (SEM) observations and further studied using molecular characters. SEM studies revealed the newly proposed genus has oblique amphidial apertures on the lateral sides of the lip region. SEM images are also provided for two species of Discotylenchus, namely D. discretus and D. brevicaudatus, as the first SEM study of the genus. These results confirmed longitudinal amphidial aperture type on lateral sides of the lip region in genus Discotylenchus, as noted by Siddiqi while erecting the genus with D. discretus as the type species. Molecular phylogenetic analyses using partial small subunit (SSU) and large subunit (LSU) rDNA sequences revealed the affinity of the genus Discopersicus n. gen. with members of the subfamily Boleodorinae, as supported by morphological characters (mainly, the oblique amphidial opening).     

Developmental characteristics of floral organs and pollen of Chinese cabbage (Brassica campestris L. ssp. chinensis)

Morphological and cytological studies are complementary approaches to understand the molecular mechanisms that regulate floral developmental pathways. To better understand abnormal mutant phenotypes in floral development, we conducted detailed observations and investigations of the morphology, cytology, and cell ultrastructure of wild-type Chinese cabbage (Brassica campestris L. ssp. chinensis Makino and syn. B. rapa ssp. chinensis) flowers when they developed from primordia to anthesis. First, we measured bud and organ length with a stereo microscope and observed the developmental status and characteristics of the floral organs using a scanning electron microscope; then we made thin slices of anthers to observe the developmental stage and characteristics of pollen using an optical microscope; and finally, we made super-thin slices of anthers to observe the ultrastructure of pollen during its development with the aid of a transmission electron microscope. In this study, the floral developmental continuum was divided into 17 stages based on significant changes in the shape of floral primordia, and the pollen developmental continuum was divided into 14 stages based on the developmental characteristics. The results could provide the morphological basis for further research on the molecular mechanisms that regulate development of the floral organs and/or pollen of Chinese cabbage and their allied species.     

Fine structure of the mouthparts of Diostrombus politus and Proutista moesta (Hemiptera: Derbidae)

Insect mouthparts are important sensory and feeding structures, morphological studies of this organ can provide additional data for phylogenetic studies. The planthopper superfamily Fulgoroidea is among the dominant groups of phytophagous insects, however, the mouthparts ultrastructure of this superfamily remains unsatisfactorily studied. This study investigates the ultrastructure of the mouthparts of two species in the family Derbidae (Hemiptera: Fulgoroidea), Diostrombus politus Uhler and Proutista moesta (Westwood), using a scanning electron microscope. The results show that these two derbids are of a typical piercing-sucking type found in Hemiptera. They consist of a cone-shaped labrum, a three-segmented labium and a stylet fascicle with two interlocked maxillary stylets incompletely wrapped by two mandibular stylets. The arrangement of the sensilla on the labial tip differ slightly between the two derbid species, and the subapical labial sensilla are likely different among genera in the family Derbidae.     

Micromorphological study on leaves of someCordia (Boraginaceae) species used in traditional medicine

The genus Cordia (Boraginaceae) is made up of a great many species widely distributed in tropical and subtropical regions of the world. The leaves ofCordia myxa, as also those of many other species of the same genus, have been utilized in the traditional medicine of many countries for the treatment of a variety of diseases. Observed by light microscope and by scanning electron microscope the histological characteristics of the leaf ofCordia francisci, C. martinicensis, C. serratifolia andC. ulmifolia, species grown in Sicily, compared also with those of the leaves ofC. myxa originating from Africa, are described in detail. It has been possible to reveal some morphological elements that allow leaf identification and the differentiation of the drugs examined.     

Essential mycorrhizal partners of the endemic Chilean orchids Chloraea collicensis and C. gavilu

Orchids are obligate mycoheterotrophic plants, relying on fungal nutrient resources to grow for their entire life or until they develop into photosynthetic seedlings. In Chile, orchids are represented by 7 genera and 63 species, 27 of which are endemic. Some Chilean species are considered endangered or rare, but many are insufficiently known. This study aims to isolate, culture, and identify fungal species found in symbiosis with the endemic Chilean orchids Chloraea collicensis Kraenzl. and Chloraea gavilu Lindl. for their potential to be used in future conservation programs. Roots of both species of orchids were collected in the field and those presenting pelotons were firstly cultured in agar-water and thereafter sub-cultured in potato dextrose agar media. Fungal colony growth was measured under the dissecting microscope. Fungal isolates from C. gavilu showed a higher growth rate than isolates from C. collicensis and could be used as inoculum for seed germination in further studies. Isolated colonies showed morphological characteristics of the form genus Rhizoctonia and presented two nuclei per cell. The ITS-nrDNA sequences confirmed their morphological identification as species of Tulasnella.     

Molecular identification of two Sarcocystis species in fallow deer (Dama dama) from Lithuania

Due to the lack of molecular research conducted, little is known about Sarcocystis species diversity in the fallow deer (Dama dama). Until now, Sarcocystis jorrini and Sarcocystis morae were described to form sarcocysts in the muscles of this host. In the present study diaphragm muscle samples of free-ranging fallow deer from Lithuania were investigated for Sarcocystis species. Sarcocysts were detected in 39 out of 48 (81.3%) fallow deer examined. Under a light microscope two types of sarcocysts having hair-like and finger-like protrusions were observed. Based on DNA sequence analysis of cox1 and 18S rDNA, two species, S. morae and Sarcocystis entzerothi were identified. In prior studies, the latter species was only detected in Lithuanian roe deer (Capreolus capreolus) and in sika deer (Cervus nippon). The haplotype network of S. morae sequences specified close relationships between haplotypes found in the same country. According to current knowledge, the fallow deer is characterised by low Sarcocystis species richness as compared with other cervid species from Europe.     

Pollen brush of Astragalus L. subgenus Pogonophace Bunge (Leguminosae) and its systematic significance

The style morphologies of Astragalus subgenus Pogonophace (Leguminosae) were examined using the scanning electron microscope. The results showed that in most species, there are erect and upwardly pointed trichomes on the style. This kind of structure is exactly a pollen brush. The style of A. craibianus Simps. is glabrous, and there are finger-like projections formed by the epidermal cells only on the stigma. A. hoantchy Franch. has a penicillate stigma. The three types of styles are not homologous. These supported the exclusion of sect. Sesbanella and A. craibianus from Pogonophace. In molecular studies, some Pogonophace species are nested within the Coluteinae clade. This study found that those species rightly have the structure of pollen brush. Therefore, the pollen brush is likely to be a synapomorphy of Pogonophace and Coluteinae. The close relationship between Pogonophace and subtribe Coluteinae (tribe Galegeae) can be supported by the pollen brush.     

Deposit-feeding mechanisms and resource partitioning in tropical holothurians

Aspidochirote holothurians found on tropical reef flats feed on particulate deposits which form a variety of substrata. The synaptid holothurian Opheodesoma grisea (Semper) feeds in a similar manner by scraping deposits from the surfaces of sea grasses. Distributional and gut content analyses showed that species partitioning is on the basis of substratum and particle size preference. Scanning electron microscopy revealed that the tentacles of aspidochirotes have a nodular surface while those of O. grisea have a tessellated surface structure. The twelve different species examined were shown to have different tentacular surface textures which bore an apparent relationship with the mean particle sizes selected by the different species. Light microscope studies of tentacle sections confirmed earlier observations on the extent of the water vascular system in aspidochirote and pinnate tentacles. From these observations a functional interpretation is proposed for tentacular operation and the means of particle selection in such holothurians.     

Description of a New Species of the Andean Butterfly Genus Forsterinaria Gray (Lepidoptera: Nymphalidae) with Considerations on an Apparently New Structure in Male Genitalia

The butterfly genus Forsterinaria Gray is the only strictly montane representative of the diverse Neotropical subtribe Euptychiina (Nymphalidae, Satyrinae), with 24 described species. Recent research in some of the most isolated and highly diverse Andean regions, such as central Peru, show that its total species richness is still underestimated. An example is the new species described here, Forsterinaria emo n. sp., which is particularly interesting because of an unusual structure discovered in its male genitalia which consists of a bunch of bristle-like processes, composing a fringe-like formation on the dorsum of the tegumen. No similar, homologous structure was found in any congener, nor indeed, in any species of diurnal Lepidoptera. Scanning electron microscope studies revealed that the microstructure of the processes resembles a membrane lining the tegumen. Its function is unknown but two hypotheses are discussed based on a comparative study with other genital structures of butterflies. We argue that it may help stabilizing the partners in the process of mating or it may serve as a ‘mating plug’, preventing the female from multiple copulations.     

Phytoplankton of an eutrophic tropical reservoir: comparison of biomass estimated from counts with chlorophyll-a biomass from HPLC measurements

The seasonal variation of phytoplankton in an eutrophic tropical reservoir was evaluated through photosynthetic pigments analyzed by HPLC. The contributions of algal classes to total chlorophyll a (TChl-a) were estimated by two procedures. The first one used fixed marker pigment/chlorophyll a ratio available from culture studies of the major species of each class. In the second procedure, a matrix factorization program (CHEMTAX) was used to analyze the pigment data. The pigment data were compared with carbon biomass estimated from microscope analysis. A significant correlation between total chlorophyll a (measured by HPLC) and total biomass was obtained, indicating only a slight variation in the content of algal chlorophyll a when compared to its fluctuations in carbon biomass. The interpretation of pigment data with CHEMTAX resulted in a good agreement with biomass. Although displaying some differences, the general pattern of the phytoplankton community dynamics and the major shifts in composition, biomass and the cyanobacterial bloom were evidenced. In contrast, Chl-a biomass estimates from fixed Xan/Chl-a ratios presented poor agreement with microscope data and did not register the principal changes in phytoplankton. Our results also highlighted the needs of better understanding of the relationships between marker pigments, chlorophyll-a and algal biomass.     

Scanning electron microscope observations on the miracidium of Schistosoma

Miracidia of two species of Schistosoma, viz. haematobium and japonicum, were studied with the scanning electron microscope to more clearly visualize what is seen with the light microscope and the transmission electron microscope, and more specifically, to relate the structure of the apical papilla to its function in snail penetration.The apical papilla of schistosome miracidia is composed of corrugated areas which form tiny suckerlike cups, presumably used by the miracidium to facilitate attachment to the snail during penetration. A lateral opening (secretory pore) on the apical papilla and short stubby apical cilia (tactile or sensory) are also demonstrated.     

Ultrastructure of the cyst wall of Sarcocystis spp. from some rodents in Malaysia.

The cyst wall of Sarcocystis cysts from the skeletal muscles and subcutaneous tissues of 4 species of rats and 1 species of bandicoot in Malaysia was examined under the electron microscope. Three types of sarcosysts with morphologically distinct cyst walls were found in these rodents. These morphologically distinct types of sarcocysts occurred as single or mixed infections in their various rodent hosts, suggesting that these rodents are important, though non-specific, intermediate hosts in the life cycle of at least 3 species of Sarcocystis. The final hosts of these Sarcocystis species are unknown.     

Pollen morphology of Carthamus L. species in Anatolian flora

In flora of Turkey, there are six species of Carthamus L: Carthamus dentatus (Forssk.) Vahl., C. glaucus M. Bieb. subsp. glaucus, C. lanatus L., C. tenuis (Boiss. & Blanche) Bornm., C. persicus Desf. ex Willd. and C. tinctorius L. Within these species, C. tinctorius L. is an alien species for the Turkish flora. The pollen grains belonging to six taxa collected from different locations of Anatolia and examined both under light microscope (LM) and under scanning electron microscope (SEM). As a result of these examinations and measurements, pollen grains of taxa are radially symmetrical, isopolar, oblate-spheroid, spheroid, tricolporate rarely tetracolporate, echinate. There are high similarities among taxa but some differences are recorded in size and spin length. According to cluster analyses of Carthamus species’ pollens, C. glaucus and C. tenuis have the most similar pollens. C. dentatus grouped with these two. C. persicus placed as the closest relative of C. tinctorius in the dendrogram.     

Comparative morphological,anatomical and biochemical studies of the urticating apparatus and urticating hairs of some lepidoptera: Thaumetopoea pityocampa Schiff., Th. processionea L. (Lepidoptera,Thaumetopoeidae) and Hylesia metabus Cramer (Lepidoptera,Saturniidae)

• 1.1. Morphological similarities and differences for the urticating apparatus of three Lepidoptera were studied using a scanning electron microscope.
• 2.2. Complementary anatomical studies of the urticant apparatus were undertaken to explain the morphological results.
• 3.3. Biochemical identity of a thaumetopoein-like protein (an urticating protein) was demonstrated for Thaumatopoea urticating hairs but not for Hylesia moth spicules.
• 4.4. Urticating mechanisms appear to be different across species of Lepidoptera.

     

The variability of the morphological and structural elements of the frustule in genetically homogeneous and heterogeneous groups of the diatom Nitzschia rectilonga Takano, 1983 (Bacillariophyta)

The inter- and intraclonal variability of the morphology and ultrastructure of the frustule of Nitzschia rectilonga Takano, 1983 was investigated. This study showed a wider intraclonal variability than in the diagnosis of the species. An emended diagnosis of the species is provided; a twofold reduction in the density of striae that are visible under a light microscope was found compared to electron-microscope images.     

海链藻(Thalassiosira)与圆筛藻(Coscinodiscus)的形态学比较研究

海链藻属（Thalassiosira）和圆筛藻属（Coscinodiscus）的种类繁多,是硅藻门中的大属和代表属。两者的形态学特征具有较多相似之处,易混淆鉴定。通过光学显微镜和电镜观察,比较研究了海链藻和圆筛藻种类的形态学特征。海链藻种类除了具有1~2个唇形突之外,还具有数量较多的支持突,少数种类具有闭合突;筛膜位于壳面内侧;中孔在壳面外侧。而圆筛藻种类只具有数量众多的唇形突,且其中两个较大;筛膜位于壳面外侧;中孔在壳面内侧。由于两属形态学特征的区别只有在电镜下才能清晰观察到,因此尚有较多的分类修订工作需要进行。