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    Ultrastructural features of Mimulus aurantiacus (Scrophulariaceae) pollen tubes in vivo
    (Acad Brasileira De Ciencias, 2009) Ekici, Nuran; Dane, Feruzan; Olgun, Goeksel
    The aim of this study is to give information on ultrastructure of in vivo pollen tubes of Mimulus aurantiacus which werecollected from the Botanical Garden of the University of California at Berkeley. Materials were prepared according to electron microscopy methods and examined under Zeiss electron microscope. Four zones were examined in the pollen tubes of Mimulus aurantiacus. Apical zone: Mitochondria, smooth endoplasmic reticulum, rough endoplasmic reticulum, dictyosomes and secretory vesicles were observed. Subapical zone: This area contained abundant rough endoplasmic reticulum and occasionally some smooth endoplasmic reticulum. The polysomes, mitochondria, proplastids that contain starch, small vacuoles and a few lipid bodies were detected. Nuclear zone: Both generative and vegetative cell nuclei lie in this zone. The vegetative cell nucleus was large and long. Rough endoplasmic reticulum, mitochondria, ribosomes, dictyosomes, and amyloplasts that are rich of starch were observed. Vacuolation and plug formation zone: Cytoplasm of the tubes was full of large vacuoles. Few organelles such as mitochondria, dictyosome and rough endoplasmic reticulum were detected along their periphery.
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    Ultrastructure of endothelium in ovules of Penstemon gentianoides poir. (scrophulariaceae) at mature embryo sac phase
    (Akademiai Kiado, 2007) Dane, Feruzan; Olgun, Goeksel; Ekici, Nuran
    In this study ultrastructural differences between endothelial cells of different location in Penstemon gentianoides have been examined with electron microscope at mature embryo sac phase. Embryo sac is of the Polygonum type and surrounded by endothelium except the micropylar region. The cuticle is located primarily around the chalazal three-fourths of the embryo sac. Endothelium cells around the chalaza and toward the micropylar region are rich in cytoplasmic organelles. The cytoplasm of endothelial cells near the central cell has large vacuoles and few organelles. There are also plasmodesmas on the anticlinal walls of endothelial cells. The endothelium and the micropylar integumentary cells play a role in transport of metabolites into the embryo sac.
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    Vegetative anatomy of some Ophrys, Orchis and Dactylorhiza (Orchidaceae) taxa in Trakya region of Turkey
    (Elsevier Gmbh, Urban & Fischer Verlag, 2010) Aybeke, Mehmet; Sezik, Ekrem; Olgun, Goeksel
    The anatomical properties of leaves, stems, roots and root tubers of 27 taxa belonging to three orchid genera (Ophrys, Orchis and Dactylorhiza) were investigated to determine their diagnostic characteristics and assess interspecific and intergeneric relationships by means of cladistic analyses. Anatomical sections were done using different staining methods, such as Sartur, Phloroglucin-HCl, Delafield's Hematoxylin-Safranin, and Alcian Blue-Periodic Acid-Schiff. Additionally, lengths of raphides (in all the organs), cuticle thickness, cell size and stomata dimensions (in the leaf epidermes), as well as dimensions of starch granules (only in root tubers) were measured and statistically compared. During root tuber investigations, for every taxon the types of meristele were outlined and diagrammed. All morphometric data except starch grain dimensions, are generally not significantly different between the investigated taxa. The anatomical sections showed the following basic anatomical characteristics: Leaf surface was glabrous, stomata were abaxially located and mostly anomocytic. Cuticle was mostly striate. The chlorenchyma was homogeneous. The stem had a uniseriate epidermis with several rows of thick- or thin-walled, sclerenchymatous (or collenchymatous) cortical parenchyms, a pericycle, collateral vascular bundles within a central ground tissue. Orchis purpurea lacks a pericycle. The roots generally had a uniseriate epidermis, an exodermis, a parenchymatous cortex with occasional inclusions of fungal pelotons and hyphae, an endodermis bearing casparian strips, pericycle, and vascular cylinders. Root tubers, from the outside to the centre, had orderly velamen, exodermis, and ground tissue, which were scattered with meristeles, mucilage cells and assimilatory cells bearing cruciate starch grains. Based on the anatomical results, tables were created based on the important primary (species-specific) and secondary (common-specific, used only in some taxa) descriptive characteristics. Some of the primary descriptive characters include the following: Leaf-epidermal wall properties (thin/thick), chlorenchyma cell shape, chloroplast distribution, presence or absence of large lacunae; stem-presence/absence of pericycle, cortical thickness; root-cell shape of exodermis, presence/absence of tilosome passage cells, shapes of endodermal and/or pericycle cells, structures and distributions of archs; root tuber forms of starch grains and mucilage cells and meristele types. In general, leaf chlorenchyma and stem pericycle were found to be thicker and mucilage-water storage cells were more frequent in the Orchis and Dactylorhiza taxa. Cladistically analysed anatomical data support the hypothesis that Ophrys and Dactylorhiza are monophyletic, but contrast the triphyletic states of Orchis, which is very likely to be the reason for uncovering the other Orchis taxa. Finally, we strongly emphasize the importance of this kind of detailed anatomical study to solve identification problems of orchid taxonomy, which have wrongly been disregarded in recent works. (C) 2009 Elsevier GmbH. All rights reserved.