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  • Angiosperms  (306)
  • Ultrastructure  (190)
  • Springer  (494)
  • American Chemical Society
  • Essen : Verl. Glückauf
  • Krefeld : Geologischer Dienst Nordhein-Westfalen
  • Oxford University Press
  • 2015-2019
  • 2005-2009
  • 1985-1989  (494)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 198 (1989), S. 92-102 
    ISSN: 1432-041X
    Keywords: Vitellogenesis ; Xenopus oocyte ; Yolk-platelet membrane ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The yolk platelets ofXenopus laevis have been studied by thin-section and freeze-fracture electron microscopy to characterize the boundary membrane during yolk formation. Throughout vitellogenesis, large yolk platelets are in close contact with smaller nascent yolk organelles. Two types of primordial yolk platelets (I and II) have been discriminated. After membrane fusion these precursors can be completely incorporated into the main body of existing platelets, numerous yolk crystals then merge and form one uniformly stratified core. Lipid droplets are tightly attached to the membrane at all developmental stages of yolk platelets. A direct connection of endoplasmic reticulum to the membranes of yolk platelets was not observed. On freezeetching replicas, yolk-platelet membranes present fracture faces with intramembranous particles (IMP) of various sizes and a heterogeneous distribution of approximately 200–600 IMP/μm2 at the E face, and 1200–2100 IMP/μm2 at the P face. Again, this presentation of the membrane exhibits neither anastomoses to the endoplasmic reticulum, nor caveolae that exclude the uptake of yolk-containing vesicles into these yolk organelles. Proteinaceous yolk platelets tend to fracture along their periphery through the superficial layers.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 2 (1989), S. 154-166 
    ISSN: 1432-2145
    Keywords: Helianthus annuus ; Unfertilized ovule culture ; Parthenogenesis ; Ultrastructure ; Proembryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Electron microscope studies have been conducted on the parthenogenesis induced by in vitro culture of unfertilized ovules of sunflower (Helianthus annuus). In comparison with the state of the egg prior to inoculation, some eggs 5 days after culture show striking ultrastructural changes, which include, among others, nuclear migration, an increase in the number and activity of the organelles, a loss of polarity and wall formation at the chalazal end of the cell. Most of these changes are similar to those that occur normally in the zygote, indicating that parthenogenic development has been triggered in these eggs. Such eggs have been termed activated and are presumed to be capable of undergoing parthenogenesis. The parthenogenic proembryos which result share some features in common with zygotic proembryos. In addition, some parthenogenic proembryos exhibit unique properties not found in zygotic proembryos. These include embryos that consist of two parts differing markedly in density, an inversion of polarity, the frequent occurrence of autophagic vacuoles, the thickening of cell walls, a centripetal growth mode of wall formation, the appearance of an incomplete cell wall, free nuclear division, amitosis and degeneration. We believe that these ultrastructural peculiarities are the effects of in vitro culture.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 2 (1989), S. 193-198 
    ISSN: 1432-2145
    Keywords: Polymorphism ; Ultrastructure ; Pollen grains ; Canna indica L ; Tannin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Our investigations on Canna indica L. indicate that the pollen of this species is polymorphic: there are two types of pollen — a larger type and a comparatively smaller type. Transmission electron microscopy (TEM) revealed the presence of small vacuoles containing tannic substances in the generative cell (GC) of the larger grains: the GC of the mature grain contained a higher quantity of tannins than the GC of the immature grain. Mitochondria, lipid bodies, rough endoplasmic reticulum (RER) and microtubular bundles were present in the cytoplasm of the GC. Numerous mitochondria, lipid bodies and plastids were also present in the vegetative cell (VC), with the mitochondria clustered around the vegetative nucleus. The plastids were observed to be associated with the RER cisterns. During the maturation process, the number of starch grains contained in the plastids decreased.
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  • 4
    ISSN: 1432-072X
    Keywords: Methanobacterium formicicum ; Formate dehydrogenase ; F420-hydrogenase ; Immunogold ; Ultrastructure ; Methanogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ultrastructural locations of the coenzyme F420-reducing formate dehydrogenase and coenzyme F420-reducing hydrogenase of Methanobacterium formicicum were determined using immunogold labeling of thin-sectioned, Lowicryl-embedded cells. Both enzymes were located predominantly at the cell membrane. Whole cells displayed minimal F420-dependent formate dehydrogenase activity or F420-dependent hydrogenase activity, and little activity was released upon osmotic shock treatment, suggesting that these enzymes are not soluble periplasmic proteins. Analysis of the deduced amino acid sequences of the formate dehydrogenase subunits revealed no hydrophobic regions that could qualify as putative membrane-spanning domains.
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  • 5
    ISSN: 1432-072X
    Keywords: Gallionella ferruginea ; Thiobacillus ferrooxidans ; Iron bacteria ; Chemolithoautotrophy ; Ultrastructure ; Freeze-etching ; Cell wall organization ; Intracytoplasmic membranes ; Carboxysomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By using sodium thioglycolate to dissolve the high amount of excreted stalk material in axenic cultures of the chemolithoautotrophic iron bacterium Gallionella ferruginea, the ultrastructure of Gallionella cells from pure cell suspensions could be studied without any loss of viability or disturbance by dense ferric stalk fibers, and compared with Thiobacillus ferrooxidans, also grown chemolithoautotrophically with ferrous iron as energy source. Both organisms were chemically fixed or freeze-etched. Particular structural differences between these iron-bacteria could be ascertained. G. ferruginea possesses intracytoplasmic membranes and soluble d-ribulose-1,5-bisphosphate-carboxylase, whereas T. ferrooxidans contains carboxysomes but no intracytoplasmic membranes; Gallionella forms poly-β-hydroxybutyrate and glycogen as storage material; T. ferrooxidans produces only glycogen. Both organisms also differ from each other with respect to the freeze fracture behaviour of the cell envelope layers. Whereas the cells of T. ferrooxidans exhibit a characteristic double cleavage, exposing the plasmic fracture face and exoplasmic fracture face of the outer membrane and cytoplasmic membrane, the exceptionally thin multilayered cell envelope of G. ferruginea revealed a particularly intimate association between the layers, resulting in a visualisation of the supramolecular organisation of only the inner fracture face of the cytoplasmic membrane. The results are discussed predominantly in relation to the extremely distinct environments of both organisms.
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  • 6
    ISSN: 1432-072X
    Keywords: Thiothrix sp. ; Beggiatoa sp. ; Sulfideoxidizing ; Polyunsaturated ; Fatty acids ; Inclusions ; Sheath ; Southern California ; Ultrastructure ; Sulfur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Microscopic examination of the whitish mat that covered the substrata around subtidal hydrothermal vents at White Point in southern California revealed a “Thiothrix-like” bacterium containing sulfur inclusions as the dominant filamentous form in this microbial community. The matlike appearance developed as a result of the closely-packed manner inwhich the basal ends of the filaments were anchored to the substrate. The dominant phospholipid fatty acids of these filaments (16:0, 16:1w7c, 18:0, 18:1w7c) were similar to those recovered from a sample of Beggiatoa isolated from a spring in Florida. Filaments from both sources contained small quantities of C18 and C20 polyunsaturated fatty acids, as well. A larger but less abundant sheathless, filamentous form, which also contained sulfur inclusions and displayed a cell wall structure similar to a previously described Thioploca strain, also colonized the substrata around the subtidal mat. The preservation methods used in the preparation of thin-sections of the subtidal mat material were found to be inadequate for defining some key cellular structures of the large filaments. Nevertheless, the results demonstrate that the filamentous bacteria comprising the microbial mat in the vicinity of the subtidal vents exhibit some of the features of the free-living filamentous microorganisms found in deep-water hydrothermal areas.
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  • 7
    ISSN: 1432-0878
    Keywords: Corpora allata ; Ultrastructure ; Precocenes ; Juvenile hormone ; Blattella germanica (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural studies on corpora allata (CA) from different stages during the first gonadotropic cycle of the cockroach Blattella germanica have shown well defined changes which have a correspondence with oocyte length, CA volume and juvenile hormone (JH) biosynthesis. The most significant variations concern the mitochondria and the endoplasmic reticulum. Topically applied precocene II (P II) at a dose of 200 ⧎g induced a transient arrest of CA function, although cytotoxic effects were occasionally observed. When CA were maintained in vitro with 10-3 M of P II, a relationship between the time of treatment (3, 6 or 9 h) and the intensity of the effects was apparent. The 9-h treatment led to an irreversible inhibition of JH production which parallels the severe damages observed in the CA (membrane lysis, nuclear pyknosis, vacuolization). Equivalent studies performed with the chroman derivative 3,4-dihydroprecocene II (DHP II) showed that it is less active than P II. Only treatments as severe as 12 h of incubation with a 10-3 M concentration elicited cytotoxic effects which could be due to radical species involved in the in situ oxidative bioactivation of DHP II. Thus, this compound could be regarded as a new type of pro-allatocidin.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 258 (1989), S. 203-210 
    ISSN: 1432-0878
    Keywords: Epididymis ; Histology ; Ultrastructure ; Antechinus stuartii (Marsupialia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ductus epididymidis of the marsupial mouse Antechinus stuartii was divided into caput, corpus, and caudal regions using several constant morphological landmarks. Tubule diameter and epithelial height increased gradually from caput to cauda. In contrast, the surface area of the lumen of the ductus epididymidis increased to a maximum in the distal caput region, but decreased markedly in the distal cauda in association with characteristic changes in lumen shape (from circular to slit-shaped) and epithelial height. Epithelial cells of the ductus epididymidis were generally similar in structure to those described in other mammalian species. Principal and basal cells were common throughout the epithelium. Clear and mitochondria-rich cells were also identified, but occurred less frequently. Regional variations in cell ultrastructure were observed only in principal cells. Numerous vesicular inclusions occurred in the apical cytoplasm of cells in caput segments, membrane-bounded, electron-dense bodies were common in distal corpus regions, and a brush border of microvilli characterized the luminal surface of principal cells in caudal segments. Sperm index increased in the proximal caput, declined to basal levels in the distal caput and proximal corpus, and then increased to a maximum in segment 9 of the distal corpus and remained at about this level throughout the cauda epididymidis. Nuclear rotation, loss of cytoplasmic droplets, and other sperm maturational changes were observed along the epididymis. Discarded cytoplasmic droplets collected in large masses interspersed between aggregates of spermatozoa throughout the distal regions of the duct. There was no evidence of phagocytosis by principal cells of cytoplasmic droplets. The epididymis of A. stuartii differs from that of other mammals. The unusual caudal region, which has little storage capacity for sperm, is an unusual adaptation in a species in which the male is known to be polygamous.
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  • 9
    Electronic Resource
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    Cell & tissue research 258 (1989), S. 247-257 
    ISSN: 1432-0878
    Keywords: Zinc ; Timm method ; Ultrastructure ; Synapses ; Avian brain ; Domestic fowl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The brain of young domestic chicks was investigated using a Timm sulfide silver method. Serial Vibratome sections were analyzed under the light microscope, and the localization of zinc-positive structures in selected areas was determined at the ultrastructural level. Both strong and differential staining was visible in the avian telencephalon whereas most subtelencephalic structures showed a pale reaction. The highest staining intensity was found in the nonprimary sensory regions of the telencephalon such as the hyperstriatum dorsale, hyperstriatum ventrale, hippocampus, palaeostriatum augmentatum, lobus parolfactorius and caudal parts of neostriatum. There was an overall gradient of staining intensity in neostriatal areas from rostral to caudal with the heaviest zinc deposits in the caudal neostriatum. Primary sensory projection areas, such as the ectostriatum (visual), hyperstriatum intercalatum superius (visual), nucleus basalis (beak representation), the input layer L2 of the auditory field L and the somatosensory area rostral to field L were selectively left unstained. Fiber tracts throughout the brain were free of zinc deposits except for glial cells. In electron micrographs of stained regions, silver grains were localized in some presynaptic boutons of asymmetric synapses (Gray type I), within the cytoplasm of neuronal somata and sporadically in the nucleus. The possible involvement of zinc in synaptic transmission and other processes is discussed.
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  • 10
    ISSN: 1432-0878
    Keywords: Enterochromaffin-like cells ; Ultrastructure ; Hypertrophy ; Hypergastrinaemia ; Gastrin infusion ; Omeprazole ; Rat (Sprague Dawley) ; Syrian hamster ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present report describes the ultrastructure of the enterochromaffin-like (ECL) cells in the stomach of the rat, hamster and guinea pig, and the ultrastructural consequences of long-term hypergastrinaemia evoked either by continuous infusion of synthetic human (Leu15)-gastrin-17 for 4 weeks (rats) or by daily treatment with large doses of the antisecretory agent omeprazole for 2–10 weeks (rats, hamsters and guinea pigs). As a result, the ECL cells increased greatly in size (maximal effect after 2 weeks of omeprazole treatment, no further gain in size after 4 or 10 weeks). Also the endoplasmic reticulum and Golgi area were enlarged. The most conspicuous feature of the ECL cells is the cytoplasmic vesicles, which are of varying size and either devoid of a dense core or with a small, often eccentrically located dense core. The vesicles probably represent the main storage site of the secretory products of the ECL cell. In addition, the cytoplasm contains granules, which differ from the vesicles in that they possess a more or less electron-dense core, surrounded by a narrow halo. The size of the vesicles ranged from small to very large, while the granules were uniformly small. Many vesicles were seen to lie very close together, some displaying an irregular outline (vacuole-like vesicles), at times giving the impression that they were undergoing fusion. The profile size (median value) of the vesicles was unaffected by gastrin infusion for 4 weeks. However, there was a tendency to a relative increase in the number of very small vesicles. In contrast, the vesicles became larger during the omeprazole treatment. Also, the number of vesicles that seemed to be engaged in fusion increased after omeprazole treatment but not after gastrin infusion. The observations support the view that ECL cells are influenced by gastrin. The effects of gastrin infusion and of omeprazole treatment on ECL cell ultrastructure were not completely identical. It cannot be excluded that the omeprazole-evoked achlorhydria evokes effects unrelated to those of hypergastrinaemia on the ECL cells, or that endogenous gastrins may evoke effects that are in some ways distinct from those of synthetic human (Leu15)-gastrin-17. Alternatively, the additional effects seen after long-term omeprazole treatment may reflect simply the duration of the hypergastrinaemic stimulus.
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  • 11
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    Cell & tissue research 256 (1989), S. 303-307 
    ISSN: 1432-0878
    Keywords: Arachnoid cells ; Tight and gap junctions ; Cold injury ; Ultrastructure ; Freeze-fracture technique ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The junctional complexes of cells in the outer arachnoid layer overlying the cerebral cortex of 2-week-old rats were examined with freeze-fracture electron microscopy up to 60 min after transcranial cold injury to the dorsal surface of the brain. Within 30 min after injury, areas of gap and tight junctions with morphological features characteristic of junction formation and/or junction disruption were found scattered among normal junctional complexes in some arachnoid cells. Within 60 min after injury, tight junctions with features typical of less leaky zonulae occludentes were present in all arachnoid cells examined. These morphological features include increases in the number of tight junctional strands and the number of strand-to-strand anatomoses. Gap junctions were interspersed among the tight junctional strands, and many were completely encircled by the strands. The increase in the number and complexity of the tight junctional strands in response to brain injury may be the morphological basis for the maintenance of the cerebrospinal fluid-blood dural barrier.
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  • 12
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Differentiation ; Tissue culture ; Steroids ; Ultrastructure ; Lipoproteins ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We studied the effects of lipoprotein-derived cholesterol on the ACTH-induced differentiation of cultured fetal rat adrenocortical cells. For this purpose human plasma high-density lipoprotein3 (HDL3) or low-density lipoprotein (LDL) was added to culture media devoid of cholesterol, and thereafter the morphological changes in cells were monitored and the amounts of steroids synthesized were measured. It could be demonstrated that, ultrastructurally, upon ACTH-stimulation the adrenocortical cells differentiated into fasciculata-like cells even in the absence of lipoproteins in the culture medium. The addition of either HDL3 or LDL caused an increase in the number and size of cytoplasmic lipid droplets suggesting uptake and deposition of lipoprotein-derived cholesterol into the differentiating cells. The amount of steroids secreted from cells differentiating in media devoid of cholesterol was only half that observed in cells differentiating in serum-supplemented medium. Addition of either HDL3 or LDL increased the ACTH-stimulated steroid synthesis to the levels observed in serum-supplemented medium. This study demonstrates that both HDL3 and LDL are able to provide cholesterol for steroid synthesis accompanying the ACTH-induced differentiation of fetal rat adrenocortical cells.
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  • 13
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    Cell & tissue research 255 (1989), S. 405-410 
    ISSN: 1432-0878
    Keywords: Pituitary gland, pars intermedia ; Bromocriptine ; Secretory granules ; Golgi apparatus ; Ultrastructure ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphological effect of chronic synthetic and secretory inhibition of the intermediate lobe of the rat pituitary induced by bromocriptine treatment was studied using morphometric techniques in combination with electron microscopy. On the basis of granule diameters, a heterogeneous cell population was shown in the normal intermediate lobe. Bromocriptine treatment did not induce any change in the volume fraction, number or location of electron-dense secretory granules. Instead, there was a shift toward a more homogeneous cell population containing smaller granules, the mean granule volume being reduced by ∼30%. The volume fraction of electron-lucent granules or vacuoles was markedly reduced, indicating a functional significance of these organelles. The volume of the Golgi apparatus was not significantly altered, but the number of condensing granules within the Golgi area was reduced. The volume of the intermediate lobe was decreased, apparently due to a decrease in the mean cell volume.
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  • 14
    ISSN: 1432-0878
    Keywords: Endostyle ; Peroxidase cytochemistry ; Autora diography ; Ultrastructure ; Oikopleura albicans, Oikopleura longicauda (Appendicularia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Oikopleura albicans and O. longicauda belong to the two subgenera Vexillaria and Coecaria, respectively. The morphology and ultrastructure of their endostyles were investigated with conventional microscopic procedures as well as with DAB cytochemistry and 125I autoradiography at both light- and electron-microscopic levels. As expected, the general morphology of these endostyles is similar to all hitherto examined endostyles. They possess a ventral portion consisting of alternating glandular and ciliated cell zones, probably serving food capture, and a dorsal region, the corridor. Autoradiographic grains were found mainly in the corridor lumen associated with the apical surface of the two central rows of corridor cells. The same cells also gave strong positive reactions for peroxidase, the iodinating enzyme. Peroxidase activity was found in the apical plasma membrane as well as in the nuclear envelope, rough endoplasmic reticulum, Golgi area and cytoplasmic vesicles. Definitive conclusions concerning an apical uptake and subsequent release into the body fluid of iodinated material could not be made from the present experiments. Our investigations indicate that the two central rows of corridor cells in both subgenera of oikopleurids constitute the protothyroid region, possibly homologous to the vertebrate thyroid gland.
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  • 15
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    Cell & tissue research 257 (1989), S. 207-216 
    ISSN: 1432-0878
    Keywords: Morphogenesis ; Meninges ; Mesenchyme ; Ultrastructure ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The meninges of albino Wistar rat embryos, aged between the 11th embryonic day (ED) and birth, were sectioned using a specially constructed device. This technique permits optimal microanatomical preservation of all tissues covering the convexity of the brain: skin, muscle, cartilage or bone, and the meninges. At ED11, the zone situated between the epidermis and the brain is occupied by a mesenchymal network. At ED12, part of this delicate network develops as a dense outer cellular layer, while the remainder retains its reticular appearance, thus forming an inner layer (the future meningeal tissue). At ED13, the dura mater starts to differentiate. At ED14, the bony anlage of the skull can be identified, and along with the proceeding maturation of dura mater some fibrillar structures resembling skeletal muscle fibers appear in the developing arachnoid space. At ED15–17, a primitive interface zone — dura mater/ arachnoid — is formed, comprised by an outer electronlucent and an inner electron-dense layer marking the outer aspect of the arachnoidal space. At ED18–19, the innermost cellular row of the inner durai layer transforms into neurothelium, which is separated from the darker arachnoidal cells by an electron-dense band. The arachnoidal trabecular zone with the leptomeningeal cells is formed at ED19. By the end of the prenatal period (ED20–21), its innermost part organizes into an inner arachnoidal layer and an outer and inner pial layer. The results from this study indicate (i) that dura mater and leptomeninges develop from an embryonic network of connective tissue-forming cells, and (ii) that the formation of cerebrospinal fluid (CSF)-containing spaces accompanies the differentiation of the meningeal cellular layers.
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  • 16
    ISSN: 1432-0878
    Keywords: Serotonin-containing cells ; Urophysis ; Spinal Cord ; Ultrastructure ; Leptomeninges ; Poecilia latipinna (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The caudal neurosecretory complex of poeciliids has previously been shown to be innervated by extranuclear and intrinsic serotonergic projections. In the present study, immunohistochemical techniques were used to characterize fibers originating from serotonin neurons intrinsic to the caudal spinal cord. Bipolar and multipolar neurons were oriented ventromedially, and contained numerous large granular vesicles. Three types of serotonergic fibers were distinguished based on their distribution and morphology. Intrinsic Type-A fibers branched into varicose segments near the ventrolateral surface of the spinal cord and contacted the basal lamina beneath the leptomeninges. Type-B fibers coursed longitudinally to enter the urophysis, where they diverged and terminated around fenestrated capillaries. Labelled vesicles in Type-A and Type-B terminals were the same size as those in labelled cells and in unlabelled neurosecretory terminals in the urophysis. Type-C small varicose fibers branched within the neuropil of the caudal neurosecretory complex. Serotonin may be secreted into the submeningeal cerebrospinal fluid, the urophysis, and the caudal vein by Type-A and Type-B fibers, whereas, Type-C fibers may be processes of serotonergic interneurons in the neuroendocrine nucleus. The possibility that urotensins I and II or arginine vasotocin were colocalized in the processes of the intrinsic serotonin neurons was investigated immunohistochemically. The negative results of these experiments suggest that serotonin-containing neurons may represent a neurochemically distinct subpopulation in the caudal neurosecretory complex.
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  • 17
    ISSN: 1432-0878
    Keywords: Insect muscle ; Denervation ; Ultrastructure ; Development, ontogenetic ; Neoconocephalus robustus (Insecto)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The singing muscles of the katydid Neoconocephalus robustus develop adult ultrastructure late in the last nymphal instar and during the first few days of adult life. The ultrastructural changes during early adulthood were not affected by unilateral axotomy shortly after the adult molt. Both denervated and innervated muscles developed adult proportions of mitochondria, myofibril, and sarcoplasmic reticulum and transverse tubules.
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  • 18
    ISSN: 1432-0878
    Keywords: Zona pellucida ; Ovarian follicles ; Atresia ; Ultrastructure ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present study provides further details on the fine-structural three-dimensional architecture of the zona pellucida (ZP) in growing and atretic follicles of mice by use of ruthenium red in combination with the detergents Triton X100 and saponin. These detergents were used for extraction of the “soluble” fraction of the zonal proteins in an attempt to expose the “structural” zonal glycoproteins, which in turn can be viewed as minute three-dimensional networks upon transmission- and scanning electron-microscopic examination. By use of these methods, the ZP of growing follicles appeared to be formed by interconnected filaments which also bind to globular structures building up a three-dimensional lattice. In contrast, the ZP of stage I as well as other (II and III) stages of atretic follicles showed a structure characterized by the presence of closely packed granules connected with short filaments to form a close-mesh reticulum. This structural change of the ZP, which in the present study is also associated with the disappearance of “gap junctions” within the granulosa and cumulus cell population, might represent one of the early events involved in the onset of atresia. These changes, most probably depending on an altered secretory activity of both oocytes and follicle cells, might lead to a degradation of the ZP network structure and to its subsequent increased density (condensation). All these morphodynamic events eventually contribute to a sequestration of the oocyte in the early stage of atresia.
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  • 19
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    Cell & tissue research 257 (1989), S. 405-414 
    ISSN: 1432-0878
    Keywords: Mollusc ; Ultrastructure ; Musculature ; Hydroskeleton ; Retraction reflex ; Clione limacina (Mollusca)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Wing (parapodial) retraction in the pteropod mollusc Clione limacina is a reflex triggered by tactile stimulation. Light and transmission electron microscopy revealed three groups of smooth muscles in the wing hemocoel that participate in retraction movements: transverse, longitudinal, and dorsoventral. Among these, two subtypes of muscle cells were identified. The first (type A) appears in all three groups and forms a well-organized lattice-like structure. The second (type B) is the major component of transverse muscles and runs in one direction only. Quantitative ultrastructural comparisons of dimensions, abundance, and organization of dense bodies, thick and thin filaments, membrane invaginations, sarcoplasmic reticulum, and mitochondria suggest that type A cells are able to contract and relax more quickly with less endurance whereas type B cells are capable of generating stronger contractions with more endurance and slower relaxation speed. Furthermore, type A cells have a unique pattern of thick filament organization, here referred to as pseudosarcomeres. The roles played by the different cell types in wing retraction are discussed.
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  • 20
    ISSN: 1432-0878
    Keywords: Hippocampus ; Mossy fibers ; Picrotoxin ; Ultrastructure ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural changes in hippocampal granule cells, mossy fibers and mossy fiber boutons were examined following the administration of picrotoxin in adult rats. Generalized seizures occurred within 5–10 min after the intraperitoneal injection of picrotoxin. The electron-microscopic examination of hippocampal tissues from rats that had been perfused with fixative during the seizure revealed that the large dense-core vesicles increased in number and accumulated on the presynaptic membranes of mossy fiber boutons; some of these vesicles appeared to be fused with the membranes, and omega-shaped exocytotic profiles were frequently seen. Furthermore, greatly increased numbers of coated vesicles (60–90 nm in diameter) were observed on the maturing faces of Golgi fields of granule cells. Thus, our study not only indicates an increased incidence of exocytosis of large dense-core vesicles during picrotoxin-induced seizures, but also suggests that these vesicles are replaced in excess from the perikaryon of the granule cell.
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  • 21
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    Plant systematics and evolution 162 (1989), S. 213-229 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Fagaceae ; Cuticles ; Recent ; Tertiary ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A systematic reassessment of megafossil records ofFagaceae in Central Europe has been undertaken on the basis of leaf cuticular characters. The oldest representatives date back to the Eocene:Quercus subhercynica spec. nova,Dryophyllum furcinerve (Rossm.)Schmalh.,Trigonobalanopsis rhamnoides (Rossm.) gen. & comb. nov. In the Oligocene other members of extant genera appear:Quercus rhenana (Weyl. & Kilpp.)Knobloch & Kvaček,Fagus attenuata Goepp.,Lithocarpus saxonicus spec. nova. In the Neogene these ancient taxa (except inFagus lineage), are gradually replaced by deciduous species ofQuercus andCastanea. Trigonobalanus andCastanopsis are recorded by fruits (or wood) only.
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    Plant systematics and evolution 162 (1989), S. 165-191 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Chloranthaceae ; Platanaceae ; Trochodendrales ; Fagaceae ; Cercidiphyllum ; Paleobotany ; phylogeny ; floral structure ; leaf architecture
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    Notes: Abstract Paleobotanical studies indicate that several isolated and systematically depauperate groups of extant woody dicotyledons originated in the Mid Cretaceous. TheChloranthaceae had probably differentiated into insect-pollinated (Chloranthus andSarcandra) and wind-pollinated (Ascarina andHedyosmum) forms by the end of the Albian, and leaves referable to theTrochodendrales are known from the Albian and Cenomanian. In the latest Cretaceous and Early Tertiary, extinct representatives of theTrochodendrales includedNordenskioldia and theJoffrea-Nyssidium complex. ThePlatanaceae also differentiated before the end of the Albian and initially had insect-pollinated, unisexual flowers with five carpels or stamens. Some of these features persisted in the platanoid lineage until the Early Tertiary, and during the Paleocene and Eocene thePlatanaceae included forms with elliptical, palmate and pinnate foliage. The history of thePlatanaceae suggests that several features of the reproductive morphology of extant taxa may have arisen in association with a trend toward wind pollination. In the Mid Cretaceous, platanoid foliage partially intergrades with pinnateSapindopsis and pedateDebeya-Dewalquea leaves suggesting a close relationship betweenPlatanaceae andRosidae andFagaceae respectively. TheChloranthaceae, Trochodendrales, andPlatanaceae all occupy a somewhat intermediate position between theMagnoliidae andHamamelidae and are of considerable interest with respect to their role in the initial radiation of nonmagnoliid (“higher”) dicotyledons.
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    Plant systematics and evolution 162 (1989), S. 193-211 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Hamamelididae ; Trochodendrales ; Hamamelidales ; Hamamelidaceae ; Hamamelideae ; fossilHamamelidaceae ; Floral structure ; fruit ; seed ; valvate anther dehiscence ; Floral evolution
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    Notes: Abstract New investigations on the flower and fruit structure of extantHamamelidaceae and other LowerHamamelididae together with new finds of fossil flowers and seeds from the Upper and Lower Cretaceous provide the outline of an increasingly more differentiated picture of the early evolution of the subclass. Three patterns of valvate anther dehiscence are recognized in the subfamilyHamamelidoideae (and the subclassHamamelididae). The basic (plesiomorphic) type within theHamamelididae has 2 valves per theca. The type with 1 valve but 2 pollen sacs per theca is both consistent and exclusive for the 5 southern genera of theHamamelidaceae. They seem to be the remnants of a homogeneous group that originated before the Upper Cretaceous. This is supported by fossil hamamelidaceous flowers from the Upper Cretaceous that have thecae with 1 valve. Since several-seededHamamelidaceae predate one-seeded forms in the fossil seed record (in Europe) and the systematic structure of the one-seeded group is relatively more homogeneous, several-seeded groups are considered to be more ancient. Several parallel evolutionary trends are recognized within theHamamelidaceae as well as within the LowerHamamelididae: anther dehiscence with 2 valves per theca → 1 slit or 1 valve; pollen sacs per theca 2 → 1; pollen tricolpate → polyforate; exine coarsely reticulate → finely reticulate; loss of perianth (tepals or petals and sepals) and concomitant loss of fixed number of floral organs; differentiation of exposed nectaries.
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    Plant systematics and evolution 162 (1989), S. 231-250 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Juglandaceae ; Paleobotany ; pollen ; fruits ; evolution ; Cretaceous ; Tertiary
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    Notes: Abstract The major radiation of theJuglandaceae occurred during the early Tertiary as recorded by the proliferation of juglandaceous pollen and the appearance of fruits representing extinct and extant genera of the family. Juglandaceous pollen types of the Paleocene were predominantly triporate and exhibited a greater diversity in patterns of exinous thinning than occurs in the family today. Analyses of in situ pollen from early Tertiary juglandaceous inflorescences confirms the taxonomic value of certain patterns of exinous thinning. Data from co-occurring fruits and pollen indicate that relatively unspecialized, isopolar triporate pollen of the type presently confined to the tribeEngelhardieae also occurred in other tribes of the family during the Paleocene. Pollination has been mostly anemophilous throughout the Tertiary. Both wind and animal fruit-dispersal syndromes were established early in the radiation of the family but a greater diversity of wind-dispersed genera has prevailed.
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    Plant systematics and evolution 162 (1989), S. 251-265 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Rutaceae ; Phylogeny ; fructifications ; morphology ; anatomy ; paleogeography ; Cretaceous ; Tertiary
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    Notes: Abstract A comparative analysis of the seed morphology and anatomy of fossil and extantRutaceae (mainlyZanthoxyleae andToddalioideae) is presented. This allows to place the most important fossil taxa in a time-table and on paleogeographical maps. A phylogenetic scheme demonstrates the postulated historical relationships ofEvodia, Zanthoxylum, Fagara, Rutaspermum, Acronychia, Toddalia, Fagaropsis, andPhellodendron.
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    Plant systematics and evolution 162 (1989), S. 267-283 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Buxaceae ; Buxus ; Pollen morphology ; leaf venation ; fossil records ; systematics ; evolution ; chorogenesis
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    Notes: Abstract Trends of pollen grain aperture evolution and exine characters as well as characters of leaf venation, petiole and axial vascularization are briefly described and related to geographical distribution and classification ofBuxus. A review of fossil records is given. Three major taxonomic groups can be delimitated within the genus, and aspects of their relationships and chorogenesis are presented. The level of differentiation, the pattern of distribution and the fossil record speak in favour of an ancient origin of the genus.
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    Plant systematics and evolution 165 (1989), S. 227-237 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Eucalyptus ; Eudesmieae ; Floral morphology ; calyx ; corolla ; operculum ; growth ; allometry ; convergence
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    Notes: Abstract In theEudesmieae B eucalypts and inEucalyptus caesia, the perianth of the mature flower consists of a single, anatomically continuous, opercular structure that is crowned by the tips of the original free and separate calycine and corolline whorls. Ontogenetic and comparative evidence supports the hypothesis that this operculum is mostly corolline in composition, and that the calycine parts have been elevated distally onto the dorsal surface. In theEudesmieae B eucalypts this condition appears to be due to precocious initiation of the corolline primordia, followed by expansion and continuity of their growth centres which incorporates the areas at or below the base of the still differentiating calycine whorl. InEucalyptus caesia the corolline primordia are not precocious, but a similar situation is effected by a seemingly retarded increase in receptacle diameter relative to lateral expansion of the corolline growth centre(s). In these two examples the same final perianth form apparently derives from two different sets of growth processes which, nonetheless, result in the same allometric relationships within the developing flower. Although identical at maturity, the operculum form in these two taxa is best described in terms of convergence, rather than homology.
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    Plant systematics and evolution 166 (1989), S. 41-44 
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    Keywords: Angiosperms ; Araceae ; Arum spp. ; Pollen types ; pollination
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    Notes: Abstract In a second paper onArum pollen seven further taxa are investigated. Most of them have spinose pollen, only inA. korolkowii the pollen is scabrose. The possible relation between pollen sculpturing and the actual pollination mode is discussed.
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    Plant systematics and evolution 166 (1989), S. 11-30 
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    Keywords: Angiosperms ; monocotyledons ; Amaryllidaceae ; Eucharis ; Phenetics ; chromosome morphology ; isozyme electrophoresis ; speciation ; sibling species
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    Notes: Abstract Eucharis candida andE. formosa are two often sympatric species of bulbous geophytes restricted to neotropical rain forest understory. The species are most common in eastern Ecuador, and are the only two east Ecuadorean species of the genus found north of the Pastaza valley. Data from phenetic, karyotypic, and preliminary isozyme electrophoretic analyses of both species are represented. The species are distinguishable phenetically and karyologically, but isozyme-based relationships are more complex. Phenetic resolution of the isozyme phenotypes supports recognition of two species in Ecuador. A Peruvian isolate ofE. formosa, though not morphologically distinct, shows both allozyme and chromosomal divergence from Ecuadorean populations. Cladistic relationships based on overall allozyme data do not support species distinction, but a novel electrophoretic phenotype for glutathione reductase is shared only by individuals ofE. candida. An apparent geographic component within the monophyletic groups resolved in the cladogram suggests that some degree of gene flow between these two species has been maintained without the complete loss of morpholgoical species identity. This may have been mediated either by artificial population structures due to a probable long history of cultivation, or via Pleistocene refugia effects. Both species may have originated in eastern Ecuador from a common ancestral population which has since radiated outward, perhaps several times.
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    Plant systematics and evolution 166 (1989), S. 45-67 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Espeletia ; Diallel cross ; pollen donors ; parental effects ; outcrossing distance ; inbreeding ; seed abortion ; incompatibility ; pollen tube growth
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    Notes: Abstract The influence of different pollen donors on seed formation was investigated in three populations ofEspeletia schultzii that differ in environmental conditions and life history characteristics. Self pollen and pollen from different donors (〈 15m apart) within each population was used in a diallel design in order to test the genetic base of seed set variation. Three measures of seed formation were used: (1) achene number; (2) proportion of filled achenes (fruits) that distinguishes between achenes with seeds and empty achenes; (3) proportion of aborted seeds that distinguishes between viable and aborted seeds. Self-pollinations resulted in empty achenes. Achene number did not vary between the different pollen donors. A bimodal pattern of filled achenes was found in two populations in two consecutive years. On the other hand, a unimodal pattern was found in crosses between more distant donors (〉 30m). These patterns seems to be the results of a sporophytic incompatibility system. Seed abortion was highest at the higher elevations and seems to be correlated with elevation rather than with any genetic effect.
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    Plant systematics and evolution 166 (1989), S. 69-78 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Leguminosae ; Medicago lupulina ; M. secundiflora ; Chromosomes ; karyotypes ; chloroplast DNA evolution ; phylogeny
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    Notes: Abstract Studies were made on the chromosome complements and chloroplast genomes ofMedicago lupulina andM. secundiflora, which comprise sectionLupularia ofMedicago. Both types of analyses indicated more substantial differences between these species than suggested by external morphology.Medicago lupulina has a relatively asymmetrical karyotype in terms of centromeric position and relative length. The karyotype ofM. secundiflora is comparatively more asymmetrical in centromeric position and reduced in absolute size but exhibits greater symmetry in relative length. The restriction endonuclease fragmentation patterns of the chloropiast DNA of these two species (with Bam HI, Eco RI, Bgl II, and Xho I) show little similarity, with only 17% of the fragments matching in size. The lack of interspecific congruence among data of morphology, karyology and cpDNA inLupularia is contrary to consistency exhibited among these data inMedicago subsect.Intertextae.
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    Plant systematics and evolution 166 (1989), S. 131-139 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Najadaceae ; Najas marina ; Isozymes ; polyploidy ; Polymorphism
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    Notes: Abstract The genetic variability of five natural populations ofNajas marina L., i.e. one diploid of subsp.marina (Europe), two of subsp.intermedia (Europe) and both a diploid (C. Africa) and a tetraploid (Middle East) of subsp.armata, has been estimated by means of electrophoretic studies. These populations differ in their morphology and karyotype. Emphasis is placed on the characteristics and status of a tetraploid cytotype from Merkaz Sappir (Israel). Almost all the variation observed is expressed in seed alcohol dehydrogenase (ADH). The differences are in a unique allele of theAdh-2 locus and in the formation of novel heteromeric isozymes.Adh genes in seeds can be used as a marker for the autotetraploid character. The other enzyme systems tested failed in this respect. The genetic variability based on 23 loci is rather low. Nevertheless, the autotetraploid population has a higher or equal ratio of polymorphic loci than the related diploids. Cluster analysis illustrated not only thatNajas marina subsp.marina has diverged much from subsp.intermedia and subsp.armata, but also showed the difference between the latter two taxa, as well as the intermediate position of the autotetraploid population.
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    Plant systematics and evolution 166 (1989), S. 183-196 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Myrtaceae ; Eucalyptus ; E. clöeziana ; Monocalyptus ; Floral morphology ; operculum ; androecium ; staminophore ; phyllotaxy
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    Notes: Abstract Flowers ofEucalyptus clöeziana have two clearly distinct perianth whorls. The small free parts of the outer (calycine) whorl cease growth early and are lost from the flower; the parts of the inner (corolline) whorl become continuous laterally by confluence of growth centres and form an operculum in the mature flower. The stamens are inserted on a circumfloral buttress (staminophore) that is homologous to the adaxial corolline component inAngophora and the bloodwood andEudesmia eucalypts. Flowers ofMonocalyptus have only one perianth whorl, which is opercular. The stamens are similarly inserted on a circumfloral buttress. Developmental study does not provide conclusive evidence for either a calycine or corolline determination of theMonocalyptus operculum, but comparison with other eucalypt groups, includingE. clöeziana (the sister taxon), predicts an essentially corolline composition.
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    Plant systematics and evolution 166 (1989), S. 211-223 
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    Keywords: Angiosperms ; Poaceae ; Triticeae ; Hordeum brachyantherum ; H. californicum ; H. capense ; H. secalinum ; Morphometrics ; cluster analysis ; classificatory discriminant analysis ; canonical analysis ; sheared principal component analysis ; bootstrap validation ; identification key
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    Notes: Abstract Field collections and 296 herbarium sheets were examined for 27 morphometric variables. A priori species identifcation was based on geographical distribution except forH. californicum, a diploid species primarily occurring in California and differing from the much more widespread tetraploidH. brachyantherum that thrives in N. America and N.E. Asia;H. capense grows in S. Africa andH. secalinum mainly in Europe. Various cluster analyses were used followed by cluster recovery verification. Classificatory discriminant analysis and validation by the bootstrap yielded 85–90% overall total correct classification of the four species. Canonical analysis revealed thatH. californicum occupies an intermediate phenetic position among the other three distinct species. Factors of shape differences were unravelled and portrayed by shearing. A revised key to species was drawn up.
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    Plant systematics and evolution 166 (1989), S. 225-241 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Geraniaceae ; Geranium caespitosum ; Breeding system ; ecotype ; gynodioecy ; pollen sterility ; self-fertility ; selfing ; inbreeding depression ; stigma receptivity
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    Notes: Abstract Characters that have the potential to alter the breeding system ofGeranium caespitosum were investigated. The characters differ mechanistically, functioning either endogenously and independent of pollen transfer, or exogenously by influencing pollen transfer. Little variation in self-fertility (endogenous mechanism) was measured among populations from different elevations grown in a common garden. Variation in floral morphology (exogenous mechanism) was limited and unlikely to create a change in the breeding system. Macroscopic variation (exogenous mechanism), including gynodioecy, sexual specialization, and pollen sterility, was observed in extreme elevation populations and probably has a sizeable effect on the breeding system.
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    Plant systematics and evolution 166 (1989), S. 249-252 
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    Keywords: Angiosperms ; Primulaceae ; Cyclamen ; C. somalense ; Taxonomy ; phytogeography ; Mediterranean floristic element ; Flora of Somalia
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    Notes: Abstract Cyclamen somalense Thulin & Warfa, spec. nova, the first member of the genus known from tropical Africa, is described from the Al Miskat Mts in NE. Somalia. The new species is closely related to the E. MediterraneanC. persicum Mill. The disjunct Mediterranean element in the mountain flora of northern Somalia, to whichC. somalense belongs, is believed to be largely a relict of Tertiary origin.
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    Keywords: Angiosperms ; Ranunculaceae ; Ranunculus cantoniensis ; R. chinensis ; R. silerifolius ; Amphidiploid ; aneuploid induction ; cytotaxonomy ; fertility ; habitat segregation ; hybrid ; multivalent ; speciation
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    Notes: Abstract Cytogenetical studies were carried out on the successive generations of offsprings from the induced tetraploid hybrid (2n = 32) betweenRanunculus silerifolius (2n = 16) andR. chinensis (2n = 16). Aneuploids, 2n = 30 to 35, frequently occurred. In latter subsequent generations the deviation of aneuploids increased, but the proportion of euploids decreased, accompanied by the reduction of fertility of pollen grains and seed sets. F2 and F4 PMCs constantly exhibited meiotic abnormality, i.e. formation of quadrivalents and univalents. The speciation process ofR. cantoniensis (2n = 32), which was presumed to arise from tetraploid hybrids between the above two species, is discussed on the basis of the above evidences.
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    Plant systematics and evolution 167 (1989), S. 137-148 
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    Keywords: Angiosperms ; Orchidaceae ; Leporella ; Formicidae ; Myrmecia ; Ant pollination pseudocopulation ; floral morphology
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    Notes: Abstract Leporella fimbriata is a self compatible orchid of southern Australia. It is dependant across its range on unique pollination by sexually attracted male winged antsMyrmecia urens, which pseudocopulate with the flower. Typical pollination sequences began with an initial circling then zig-zag flight to the flower. Vectors usually alighted on the inflorescence stem and quickly crawled to the flower where they adopted a copulatory position sideways along the wide labellum, pseudocopulatory probing immediately followed. In this position pollen carried on the thorax was deposited on the stigma. Departure from the labellum usually resulted in pollinium removal. Pollinator movements were restricted and the distribution leptokurtic with a mean of 3.141 ± 4.59 m. Pollination was widespread but variable from site to site and season to season with a maximum of 70% of all flowers being pollinated. Pollinator limitation is indicated. Traits essential for this pollination interaction include the coincidence of orchid and ant geographic distributions and the coincidence of flowering with the flight period of the ant. The production of pheromonelike substances and the distinctive floral morphology are also essential for attraction and manipulation of male ants. The ant mating system which the orchid can exploit is also important.
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    Plant systematics and evolution 167 (1989), S. 189-194 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Magnoliidae ; Annonaceae ; Annona ; Rollinia ; Beetle pollination ; flower evolution
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    Notes: Abstract Dynastid scarab beetle pollination appears basic within the genusAnnona. Those species ofAnnona which are more morphologically derived, as well as allRollinia spp. possess reduced floral chambers and attract small beetles likeNitidulidae orStaphylinidae. Pollination of the primitive species ofAnnona byDynastinae would imply that the genus had not evolved before the Tertiary. The fossil record is in congruence with this hypothesis. Once again it is stressed that the cantharophilous syndrome, as it is found in theAnnonaceae, Magnoliaceae, Eupomatiaceae andCalycanthaceae, with beetles being exclusive pollinators, is a secondary and derived condition and obviously different from the expected basic entomophily of the original angiosperms.
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    Plant systematics and evolution 168 (1989), S. 49-57 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Hypochoeris ; Karyotype ; karyogram ; idiogram ; basic chromosome number ; symmetry of karyotype ; asymmetrical index
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    Notes: Abstract FiveHypochoeris spp. from Sicily have been investigated:H. glabra L. (2n=10),H. radicata L. (2n=8),H. cretensis L. (2n=6),H. laevigata L. (2n=12),H. robertia Fiori (2n=8). Basic chromosome numbers are very variable, x = 3, 4, 5, 6. The karyotype of each species is presented. Geographical origin (S. America or Mediterranean region) of the genusHypochoeris and the taxonomic position ofH. robertia are discussed.
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    Plant systematics and evolution 168 (1989), S. 143-148 
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    Keywords: Angiosperms ; Caryophyllaceae ; Silene sect.Siphonomorpha ; sect.Auriculatae ; Crossing experiments
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    Notes: Abstract Ten species in the genusSilene sectt.Siphonomorpha andAuriculatae were crossed artificially involving 612 crosses to test inter- and infraspecific, intervarietal and intersectional crossability. In sect.Siphonomorpha all interspecific crosses (between diploids) failed due to cross- or seed-incompatibility; however, intervarietal crosses betweenS. gigantea var.gigantea andS. gigantea var.incana produced hybrids. In sect.Auriculatae hybrids were produced betweenS. vallesia andS. boryi, both tetraploids, but crosses between these and the diploid species were unsuccessful. The delimitation and status of the species in both sections was supported by the crossing results.
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    Plant systematics and evolution 168 (1989), S. 159-165 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Orchidaceae ; Coryanthes ; Fragrance analyses ; 2-N-methylaminobenzaldehyde ; taxonomic studies
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    Notes: Abstract All members of the investigated genusCoryanthes (subtribeStanhopeinae) are pollinated by male euglossine bees. The different fragrance profiles are the primary reproductive isolating mechanisms, because the flowers are interfertile. The fragrance patterns of 17 species ofCoryanthes were analyzed by gas chromatography as a means to improve the classification of this genus. A first amine (2-N-methylaminobenzaldehyde) was found to be the main fragrance compound of an as yet unclassifiedCoryanthes species.
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    Plant systematics and evolution 168 (1989), S. 221-225 
    ISSN: 1615-6110
    Keywords: Angiosperms ; monocotyledons ; Araceae ; Pothos sect.Allopothos ; Pothos crassipedunculatus ; spec. nova ; Taxonomy ; systematics ; Flora of India
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    Notes: Abstract Pothos crassipedunculatus Sivadasan & Mohanan (Araceae), a new species closely related to the SW. Indian endemic and little known speciesP. thomsonianus Schott is described. It is characterized by the the non-ligulate, shortly vaginate petiole, thickly peduncled inflorescence, broadly ovate spathe and a sessile spadix. It is included in ser.Brevivaginati Engler of sect.Allopothos Schott.
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    Plant systematics and evolution 168 (1989), S. 123-141 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Liliiflorae ; Liliales ; Dioscoreales ; Asparagales ; Cladistics ; relationships ; taxonomy
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    Notes: Abstract Comparisons between previous intuitive or phenetic classifications of the netveinedLiliiflorae was used to determine a suitable group of taxa for cladistic analyses. The resultant 48 genera and generic groupings comprising 19 families from within theAsparagales, Liliales andDioscoreales were then analysed. The cladistics largely supported previous treatments, with theLiliales, Dioscoreales andAsparagales all monophyletic.
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    Keywords: Angiosperms ; Leguminosae ; Medicago truncatula ; Medicago littoralis ; Bruchidius bimaculatus ; Bruchid infestation
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    Notes: Abstract The bean weevilBruchidius bimaculatus was found in fruits of 68 of 217 populations of theMedicago truncatula — M. littoralis complex of Israel, Greece, Italy and Spain. Infestation was higher in fruits of somewhat larger than mean size, and in the more pubescent and tightly coiled fruits. Bean weevil size proved to be independent of fruit size, so that the “preference” for larger fruits does not seem due to adaptation to a larger food source or a larger domicile. Fruit size has been used to delimit the host “species”M. truncatula andM. littoralis, but the character proved to be unimodal, and it is apparent that the taxonomy of the plant complex requires further clarification. Of the 11 472 fruits examined, less than 4% were infested. Given that the plants have evolved indehiscent legumes in which typically only one of the approximately six seeds survives to reproduce, and that very few seeds of a fruit are destroyed, the bruchid's infestation appears to be non-harmful, and indeed the association may be mutualistic.
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  • 46
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    Plant systematics and evolution 163 (1989), S. 53-69 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Liliaceae ; Lilium ; C-banding ; heterochromatin ; karyosystematics ; karyotype
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    Topics: Biology
    Notes: Abstract C-band patterns are described for 20Lilium spp. distributed across six sections. All species have a similar basic karyotype (n = 12) but C-bands differ markedly between them. The patterns are characterized by a dispersed scattering of thin intercalary bands as well as centric and NOR bands. Only one species,L. canadense, shows a clear equilocal pattern with intercalary C-bands occurring proximally in all of the longer chromosome arms. Comparing species, similar patterns are revealed forL. regale andL. sulphureum, forL. formosanum andL. longiflorum (all in sect.Leucolirion) and to a lesser extent forL. hansonii, L. martagon, andL. tsingtauense (sect.Martagon). The pattern forL. henryi (previously classed in sect.Sinomartagon) matches those ofL. regale andL. sulphureum quite well and its transfer to sect.Leucolirion is proposed. This is consistent with results from interspecies hybrids betweenL. henryi andL. regale (and related species) which are reportedly fertile. No other clear similarities in C-band patterns were seen across species. It seems that C-band patterns change rapidly inLilium and hence their usefulness in classification will be restricted to identifying closely related species.
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  • 47
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    Plant systematics and evolution 163 (1989), S. 81-85 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Ranunculaceae ; Anemone ; Pulsatilla ; Hepatica ; Chloroplast DNA ; restriction endonuclease analysis
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    Topics: Biology
    Notes: Abstract Chloroplast DNA of seven species belonging toAnemone (sectt.Omalocarpus, Anemonidium, andAnemonanthea),Hepatica, andPulsatilla have been analyzed by restriction enzymes. According to the dendrogram constructed, the sections ofAnemone and the generaHepatica andPulsatilla seem to be evolutionary approximately equidistant to each others. This supports the concept that these groups should be treated on a similar taxonomic level, either as genera or subgenera.
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  • 48
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    Plant systematics and evolution 163 (1989), S. 87-92 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Alliaceae ; Allium ; B-chromosomes ; nucleolar activity
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    Topics: Biology
    Notes: Abstract Nucleolar activity was analyzed in two samples of plants of the wild onion speciesAllium cernuum, one from Canada (2n=14) and one from the United States of America (2n=14+3B), using phase contrast analysis and C- and Ag-NOR-banding. Three chromosome pairs of the standard A-chromosome complement show small telomeric satellites, which corresponds to the maximum number of Ag-NOR-bands at metaphase and to the telomeric C-heterochromatin. However, the maximum number of nucleoli observed at interphase was eight, indicating that another chromosome pair possesses nucleolar activity. Corresponding results were obtained for the A-chromosome complement of plants from the United States of America, however, these plants further possess three small metacentric supernumerary chromosomes, which show telomeric satellites on both arms, corresponding to two telomeric Ag-NOR-bands observed after silver staining. The presented data clearly indicate that the B-chromosomes ofAllium cernuum possess rDNA gene clusters which show strong nucleolar activity.
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  • 49
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    Plant systematics and evolution 163 (1989), S. 93-105 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Leguminosae (Fabaceae) ; Caesalpinioideae (Caesalpiniaceae) ; Cassia ; Chamaecrista ; Senna ; Stigma morphology ; taxonomy ; floral ecology
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    Notes: Abstract Two stigma forms occur inChamaecrista andSenna, but only one inCassia. In the common chambered form, a stigma pore is positioned on the reflexed style tip and is the entrance to a tapering chamber. The pore rim is fringed by hairs which vary in number, size, distribution and shape. In the alternative form the stigma is situated at the apex of the curved style and is crateriform. The crater rim is fringed by hairs of variable number and shape. The stigmatic hairs are predominantly unicellular and cutinized. Stigma and hair differences aid in the taxonomy of the genera. Their functions in pollination biology are discussed.
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  • 50
    ISSN: 1615-6110
    Keywords: Angiosperms ; Orchidaceae ; Orchis ; Dactylorhiza ; Gymnadenia ; Taxonomy ; interspecific relationship ; enzyme electrophoresis ; computer evaluation
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    Notes: Abstract Ten species of orchid plants belonging to the generaOrchis (7),Dactylorhiza (2), andGymnadenia (1) were analyzed by enzyme electrophoresis. Each species can be identified by a combination of enzyme bands different from those of all other species examined. The electrophoretic data were used for the construction of phenetic and phylogenetic trees with the help of computer programs. The trees were almost identical regardless which method was used. Our results differ considerably from a classification based on morphological evidence. The electrophoretic data indicate that the genusOrchis is not a monophyletic group.
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  • 51
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    Plant systematics and evolution 163 (1989), S. 121-125 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Acanthaceae ; Justicia sect.Ansellia ; J. brevipedunculata ; spec. nova ; Flora of Tropical East Africa
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    Topics: Biology
    Notes: Abstract Justicia brevipedunculata, a new species ofJ. sect.Ansellia endemic to Tanzania, is described and illustrated. Detailed palynological information is given, and relationships to other species of the section are discussed.
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  • 52
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    Plant systematics and evolution 163 (1989), S. 127-131 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Portulacaceae ; Grahamia bracteata ; Chromosome number ; karyotype ; base number
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    Notes: Abstract The somatic and gametic chromosomes of the monotypical genusGrahamia (G. bracteata) have been studied for the first time: 2n = 18, n = 9. The karyotype is symmetrical; of the nine m pairs one has microsatellites. The basic chromosome number x = 9 is considered to be primitive within the family.
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  • 53
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    Plant systematics and evolution 163 (1989), S. 147-152 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Beilschmiedia ; Calluna ; Polyalthia ; Strelitzia ; Acetolysis ; palynology ; sporoderm ; exine ; intine ; pollen characters
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    Topics: Biology
    Notes: Abstract The acetolysis method intreduced byGunnar Erdtman is still a very welcome and highly successful technique in palynology. However, acetolysis destroys all pollen material with the exception of sporopollenin that forms the outer pollen wall, the exine. Modern palynology in its application to plant systematics and phylogeny must consider all sporoderm characters, not only those of the exine. The neglect of the intine may distort some principal palynological aspects. This is illustrated by cases of total breakdown or gross modification of thin exine structures (e.g. inBeilschmiedia, Strelitzia) and by the clarification of apertures (e.g.,Polyalthia, Fissistigma, Calluna). In our view the investigation of both acetolysed and non-acetolysed pollen is obligatory for a well balanced view of pollen structure and function.
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  • 54
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    Plant systematics and evolution 163 (1989), S. 133-146 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Cucurbitaceae ; Cucumis ; C. sativus ; C. melo ; C. metuliferus ; C. anguria ; C. zeyheri ; C. myriocarpus subsp.leptodermis ; comb. nov. ; Crossing experiments ; meiosis of hybrids ; polyploidy ; isozymes ; DNA analysis ; evolution
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    Notes: Abstract Meiosis in seven interspecificCucumis hybrids has been analysed i.a. inC. metuliferus ×C. zeyheri, where the parents belong to different sections. In the triploid hybrids a remarkably high number of trivalents has been found. Additional data from literature on geographical distribution, cucurbitacins, flavonoid patterns, isozymes, C-banding, genome size, DNA amount and chloroplast DNA are used to discuss species relationships and evolution. The African cross-compatible group is divided into theMyriocarpus subgroup with the diploid speciesC. africanus, C. myriocarpus subsp.leptodermis and subsp.myriocarpus, and theAnguria subgroup withC. anguria, C. dipsaceus, C. ficifolius, C. prophetarum, C. zeyheri and all polyploids (exceptC. heptadactylus). It is argued that the Asian subg.Melo with x = 7 is derived from the African subg.Cucumis with x = 12; the latter contains all the polyploid species and has the most common basic chromosome number of theCucurbitaceae. This phylogenetic advance is interpreted with concepts of the quantum model of evolution.
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  • 55
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Taraxacum ; Agamospermy ; NOR-chromosome ; chromosomal rearrangement ; transposable genetic elements
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    Notes: Abstract Morphological variation for the NOR chromosome was studied for four half-siblings of a sexual outbreedingTaraxacum, for three siblings of the obligate agamospermT. pseudohamatum, and for two individuals of the agamospermT. brachyglossum. No rearrangement was detected for the 113 chromosomes of sexuals, or for 41 chromosomes of two agamospermous individuals. In the other three agamospermous individuals, 3/16, 5/50, and 5/20 chromosomes showed evidence of chromosomal rearrangement. The majority of rearrangement events (10/13) occurred to the satellite rather than to the body of the NOR-chromosome. It is considered that such high levels of somatic chromosomal rearrangement in agamospermousTaraxacum may be the result of activity by transposable genetic elements. This recombination may be of selective advantage to asexual plants which cannot generate genetic variability through the sexual process.
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  • 56
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    Plant systematics and evolution 163 (1989), S. 211-226 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Loasaceae ; Petalonyx ; Inflorescence ; floral ontogeny ; vascular pattern ; androecium ; gynoecium ; nectary ; symmetry
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    Notes: Abstract Inflorescence and floral structure ofPetalonyx linearis are described to assist in understanding homologies among the diverse flowers ofLoasaceae. The inflorescence consists of racemose axes, along which each individual flower is recaulescent with its subtending leaf. Both floral vascularization and appendage initiations show a set of variations. The pseudomonomerous gynoecium may be derived from a triplacental condition. Nectary position, on a collar on which the perianth and androecium are inserted, appears homologous to the ovarian dome position of the nectary among otherLoasaceae.
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  • 57
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    Plant systematics and evolution 163 (1989), S. 201-209 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Iridaceae ; Moraea inclinata ; M. brevistyla ; Bees ; Anthophoridae ; Halictidae ; Pollination mechanism ; flower morphology
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    Notes: Abstract Individual flowers ofMoraea inclinata are nectariferous and last about six hours. They appear to be pollinated largely by bees in the familyHalictidae (Lasioglossum spp.,Nomia spp.,Zonalictus) and to a lesser extent by bees in the familyAnthophoridae (Amegilla). The mechanism of bee-pollination inM. inclinata is the “Iris type”; i.e., each flower consists of three pollination units (an outer tepal, a partly exserted anther, and the opposed style branch which terminates in a pair of petal-like crests). Bees rarely visit more than one pollination unit per flower. Transferral of pollen to the bee is passive and nototribic although all bees collected on the flowers were female and 55% of the bees carried pollen loads with 2–5 pollen taxa in their scopae.Moraea brevistyla flowers are nectariferous but lack scent and last two days. They are visited infrequently by bees and only one femaleLasioglossum spec. carried the pollen ofM. brevistyla. Unlike flowers ofM. inclinata those ofM. brevistyla deposit pollen only on the head and thorax. Bee-mediated autogamy in both species is avoided due to the erratic foraging patterns of the bees and the flexibility of each stigma lobe as the bee backs out of the flower. Approximately 2–4 flowers in the inflorescences of both species (6–8 flowers/infloresence) develop into capsules.
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    Plant systematics and evolution 163 (1989), S. 187-199 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Marantaceae ; Inflorescence morphology ; monotely and polytely ; homogenization ; racemization ; truncation ; pseudoflorescence
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    Notes: Abstract In contrast toW. Troll's typology of inflorescences which aims at more or less rigid, well defined types, this investigation accentuates the processes that constitute the evolutionary transformations leading from one typical form to another.Troll divided the inflorescences into the two types of monotelic and polytelic synflorescences, the first with a terminal flower on the main axis, the latter with a homogeneous florescence on the indeterminate axis. Both forms are enriched by proximal branches which repeat the structure of the main axis (paracladia). The evolutionary processes leading from the more primitive monotelic type to the advanced polytelic type are truncation (loss of the terminal flower) and homogenization of the distal branches, which thus form a homogeneous florescence. A closer survey of the polytelic groups reveals the fact that, usingTroll's criteria, the same distinction can be found within these groups themselves. Loss of the terminal florescence (truncation of 2nd and higher degree) as well as homogenization of the distal paracladia may lead to florescence-like units of higher complexity. Examples can be found inAsteraceae (Figs. 1 and 2),Fabaceae (Fig. 3 a),Mimosaceae (Fig. 3 b),Acanthaceae, and also in Monocots, as exemplified by theMarantaceae (Figs. 4 and 5). The so-called racemization (inversion of efflorescences from basipetalous to acropetalous) may be mentioned as a third element of transformation, emphasizing the unity of the florescences.—In consequence, there are more organizational levels than reflected in the twoTroll types. The polytelic type comprises several degrees of truncation and homogenization, the basis for a reasonable organizational analysis should therefore be the degree of ramification of flowering branches rather than the mere question of a terminal flower on the main shoot axis (Fig. 6). On the other hand the three processes of truncation, homogenization and racemization are evolutionary transformations that may occur independently from one another, thus giving rise to a large number of variations, which can not be satisfactorily interpreted by exactly defined types. On the basis of these considerations the question of homologous parts in inflorescences is reviewed. The homology of partial florescences and paracladia is accentuated contrary toTroll's interpretation (Fig. 7). Homogenization as an evolutionary trend may transform paracladia of different degree of ramification, leading to one-flowered units on the one side and to highly complex structures as in theMarantaceae on the other.
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    Plant systematics and evolution 163 (1989), S. 227-280 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Papaveraceae ; Hypecoum ; Taxonomy ; morphological variation ; mating system ; autogamy ; UV-reflection ; pollen morphology ; chromosome numbers
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    Notes: Abstract Hypecoum sect.Hypecoum comprises 8 species, one with 2 additional subspecies, in the Mediterranean area and the Middle East. Five of these are recognized for the first time, viz.Hypecoum procumbens L. subsp.fragrantissimum Å. E. Dahl,H. procumbens L. subsp.atropunctatum Å. E. Dahl,H. trullatum Å. E. Dahl,H. angustilobum Å. E. Dahl andH. torulosum Å. E. Dahl. H. dimidiatum Delile andH. pseudograndiflorum Petr., which have generally been included inH. imberbe Sm., are reestablished as distinct species. Morphology and variation patterns are described and discussed with special reference to mating systems. Self-incompatibility is dominating butH. procumbens subsp.procumbens andH. torulosum are self-compatible. The broad variation ranges of the former taxon in traits presumably related to mating system (petal, anther and stigma sizes as well as pollenovule ratios) indicate varying rates of outcrossing. SEM micrographs are given of petal and stigma surfaces and of pollen grains. Chromosome counts are presented for seven taxa. All are diploid with 2n = 16.
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  • 60
    ISSN: 1615-6102
    Keywords: Adhesion ; Carbohydrates ; Exocytosis ; K-bodies ; Lectins ; Saprolegnia ; Ultrastructure
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    Topics: Biology
    Notes: Summary Electron and fluorescence microscopy were used to identify organelles involved in attachment of secondary zoospores ofSaprolegnia ferax as they were transformed into secondary cysts. When secondary zoospores were exposed to 1.0% peptone in the absence or presence of a substrate, they began to encyst. If substrates were present when encystment was induced, the groove surface of the secondary zoospores adhered to them. The first event in attachment was secretion of contents of the kinetosome-associated organelle (K-body), which was typically oriented with the tubule-filled cavity positioned toward the cell surface of the groove region in the zoospore. The tubules which contained carbohydrates became coarsely granular, the matrix became more fibrous, and the shell remained along the membrane concavity that was formed as the K-body fused with the plasma membrane. Five minutes later, a cyst coat appeared, and cysts were not readily dislodged from a substrate. The concavity was no longer found, presumably because it had evaginated; but a layered pad of adhesion material was between the cyst coat and substrate. The layers of the adhesion pad corresponded to the structure of the matrix of K-bodies. As with the tubules of the K-body, the coarsely granular portion at the edge of the pad stained for carbohydrates. Similarly, the lectins WGA and GS-II labeled with fluorescein stained the rim of the adhesion pad on cysts, indicating the presence of glycoconjugates containing N-acetylglucosamines. Because globular areas near the kinetosomes and groove of zoospores (where K-bodies were located) also bound WGA and GS-II, K-bodies contained the same carbohydrates as the adhesion pad. We conclude that K-bodies function in the attachment of encysting zoospores to substrates as the cell differentiates. The tubular portion of the K-body matrix contains carbohydrates which might assist in the adhesion process.
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    Protoplasma 150 (1989), S. 83-95 
    ISSN: 1615-6102
    Keywords: Drosophila melanogaster embryo ; Cellularization ; Cleavage furrow ; Ultrastructure ; Cytoskeleton ; Mitosis
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    Topics: Biology
    Notes: Summary The distribution and arrangement of cytoskeletal components in the early embryo ofDrosophila melanogaster were examined by thin-section electron microscopy to elucidate their involvement in the formation of the cellular blastoderm, a process called cellularization. During the final nuclear division in the cortex of the syncytial blastoderm bundles of astral microtubules were closely associated with the surface plasma membrane along the midline where a new gutter was initiated. Thus the new gutter together with the pre-formed ones compartmentalized the embryo surface to reflect underlying individual daughter nuclei. Subsequently such gutters became deeper by further invagination of the plasma membrane between adjacent nuclei to form so-called cleavage furrows. Nuclei simultaneously elongated in the direction perpendicular to the embryo surface and numerous microtubules from the centrosomes ran longitudinally between the nucleus and the cleavage furrow. Microtubules often appeared to be in close association with the nuclear envelope and the cleavage furrow membrane. The plasma membrane at the advancing tip of the furrow was always undercoated with an electron-dense layer, which could be shown to be mainly composed of 5–6 nm microfilaments. These microfilaments were decorated with H-meromyosin to be identified as actin filaments. As cleavage proceeded, each nucleus with its perikaryon became demarcated by the furrow membrane, which then extended laterally to constrict the cytoplasmic connection between each newly forming cell and the central yolk region. The cytoplasmic strand thus formed possessed a prominent circular bundle of microfilaments which were also decorated with H-meromyosin and bidirectionally arranged, similar in structure to the contractile ring in cytokinesis. These observations strongly suggest that both microtubules and actin filaments play a crucial role in cellularization ofDrosophila embryos.
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  • 62
    ISSN: 1615-6102
    Keywords: Plectonema boryanum ; Cyanobacteria ; Ultrastructure ; Nitrogen fixation ; Nitrogen starvation ; Immunogold localization
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    Notes: Summary The ultrastructure of fructose-supplemented and unsupplemented nitrogen-fixing (fix +) and nonfixing (fix −)Plectonema boryanum UTEX 581 cells was examined by transmission electron microscopy. The most prominent structural differences included the arrangement and morphology of the thylakoids and alterations in the appearance of the interthylakoidal spaces. These ultrastructural differences, together with other observations such as glycogen content and presence of nitrogenase (using acetylene reduction assay and immunogold localization), readily distinguished nonfixingP. boryanum from nitrogen-fixing cells.
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    Protoplasma 152 (1989), S. 57-64 
    ISSN: 1615-6102
    Keywords: Angiosperms ; Plastid inheritance, uniparental ; Plastid inheritance, biparental ; Plastid distribution ; Plastid transmission
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  • 64
    ISSN: 1615-6102
    Keywords: Apiaceae ; Apium nodiflorum ; Endoplasmic reticulum ; Pollen grain ; Polysaccharide particles ; Ultrastructure
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    Notes: Summary The ultrastructural events in 3-cellular pollen grains ofApium nodiflorum L. are investigated during pollen maturation. Three distinct developmental stages are distinguished from the formation of sperm cells up to anthesis, whereby the rough endoplasmic reticulum (RER) is mainly involved. The most conspicious form is the highly dilated RER in the vegetative cytoplasm of the youngest pollen grains, which changes to vesicular RER in the following stage. In mature pollen grains the RER has a narrow cisternal configuration and often forms stacks. Pollen activation is preceded by the accumulation of polysaccharide particles.
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    Protoplasma 151 (1989), S. 47-56 
    ISSN: 1615-6102
    Keywords: Scenedesmus ; Fuel oil ; Ultrastructure
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    Topics: Biology
    Notes: Summary Characteristic changes in the ultrastructure of the green algaScenedesmus armatus, grown in batch culture in the presence of aqueous fuel-oil extract (AFOE) have been observed. The changes affected mainly chloroplasts and mitochondria. The regular arrangement of the thylakoid stacks became distorted and the whole chloroplast lobed. Plastoglobules were more numerous in the treated cells than in the controls, especially after long-term exposure to AFOE. The mitochondrial matrix cells exposed to AFOE were more electron-translucent. An increase in the number of small mitochondrial profiles was observed after prolonged treatment with AFOE. The number and size of osmophilic bodies increased markedly in the cytoplasm of the treated cells. The cytochemical reaction of these bodies with Sudan black B indicated their lipid composition. Plasmalemma invagination into the cytoplasm and vacuoles, cytoplasmic “layers”, and an increase in size of the vacuolar compartment were observed in cells exposed to AFOE for a long time. The possibility that detoxification, involving microbody activity, may have occurred inScenedesmus is suggested.
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  • 66
    ISSN: 1615-6102
    Keywords: Bryophyte ; Notothylas ; Nuclear metamorphosis ; Phaeoceros ; Posterior mitochondrion ; Spermatogenesis ; Ultrastructure
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    Topics: Biology
    Notes: Summary Ultrastructural observations reveal that the spermatozoids of the hornwortsNotothylas andPhaeoceros contain two mitochondria and not one as described previously. Mitochondrial ontogeny and nuclear metamorphosis during spermiogenesis in these plants differ from all other archegoniates. The discovery that the posterior region of the coiled nucleus (when viewed from the anterior aspect) lies to the left of the anterior, in striking contrast to the dextral coiling of the nucleus of spermatozoids of other embryophytes, underlines the isolated nature of the hornworts among land plants. As the blepharoplast develops, the numerous ovoid mitochondria initially present in the nascent spermatid fuse to form a single elongated organelle which is positioned subjacent to the MLS and extends down between the nucleus and plastid. At the onset of nuclear metamorphosis, the solitary mitochondrion has separated into a larger anterior mitochondrion (AM) associated with the MLS and a much smaller posterior mitochondrion (PM) adjacent to the plastid. The PM retains its association with the plastid and both organelles migrate around the periphery of the cell as the spline MTs elongate. By contrast, in moss spermatids, where mitochondria undergo similar fusion and division, the AM is approximately the same size as the PM and the latter is never associated with the spline. As in other archegoniates, except mosses, spline elongation precedes nuclear metamorphosis in hornworts. Irregular strands of condensed chromatin compact basipetally to produce an elongated cylindrical nucleus which is narrower in its mid-region. During this process excess nucleoplasm moves rearward. It eventually overarches the inner surface of the plastid and entirely covers the PM.
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    Protoplasma 152 (1989), S. 14-21 
    ISSN: 1615-6102
    Keywords: Differentiation ; Heterochronic lysis ; Polarity ; Root protophloem sieve elements ; Triticum aestivum ; Ultrastructure
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    Notes: Summary Developing protophloem sieve elements in roots of wheat are arranged in single vertical files. In the last immature differentiating sieve element bearing ribosomes the proximal end of the cytoplasm displays a diluted appearance in contrast to the distal end where the cytoplasm exhibits a considerably increased electron density. Differences can also be observed in ribosome quantity, organelle ultrastructure and the time of initiation of cell component degradation, those at the proximal end disorganizing first, suggesting a nonsimultaneous disorganization of the cell components in the two areas. This phenomenon, termedheterochronic lysis, is presumably an expression of an existing polarity not detectable in younger stages, but it might also be the result of an asynchronous enzymatic activity.
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    Protoplasma 153 (1989), S. 104-110 
    ISSN: 1615-6102
    Keywords: Nicotiana sylvestris ; Pollen tube growth ; Heat shock ; Ultrastructure ; Endoplasmic reticulum ; Mitochondria ; Golgi apparatus
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    Notes: Summary The effect of elevated temperatures on semivivo growth and ultrastructure of tobacco pollen tubes was investigated. Tube growth was decreased by about 50% at 35 °C, independent of the duration of treatment, and at 40 °C and above there was no growth of tubes. Heat treatment caused ultrastructural changes like accumulation of membranous materials, concentric stacking of rough endoplasmic reticulum, reduction in vesicle production by dictyosomes, increase in the fenestrated regions of the Golgi cisternae, swelling of mitochondrial saccules and increase in the electron density of the mitochondrial matrix. Furthermore, the dictyosomes of the treated tubes showed significant increase in the number of cisternae from 30 to 45 °C. The temperature induced changes were persistant at least for 24 h in 35 °C grown pollen tubes. The possible reasons for the tube growth inhibition are discussed on the basis of the ultrastructural alterations caused by elevated temperatures.
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    Plant systematics and evolution 163 (1989), S. 1-12 
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    Keywords: Angiosperms ; Asteridae ; Verbenaceae ; Oleaceae ; Nyctanthes ; Intranuclear inclusions ; mesophyll cells ; ultrastructure
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    Notes: Abstract TEM observations were carried out on 40 taxa of the familyVerbenaceae and 35 taxa of the familyOleaceae, in order to ascertain distribution, ultrastructure and morphology of the intranuclear proteinic inclusions in the mesophyll parenchymatic cells. The investigated genera amount to some 25% and 60% respectively of the genera of the two families. Inside theVerbenaceae, lamellar inclusions (L-type) occur in 6 out of 23 investigated genera: they are mostly present inside the tribesCitharexyleae andVerbeneae (both belonging toVerbenoideae), while they are absent in other subfamilies. All of the investigatedOleaceae genera show intranuclear crystalline inclusions (C 1-type) of three different shapes. Among theAsteridae this is a character peculiar toOleaceae. They appear to be a well defined natural group, including the controversial genusNyctanthes.
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    Plant systematics and evolution 163 (1989), S. 13-20 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Aegilops cylindrica var.kastorianum ; New variety ; karyotype analysis ; protein and esterase patterns ; isoelectric focusing
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    Notes: Abstract A native population ofAegilops cylindrica was encountered for the first time in Greece in 1980 (near Kastoria, NW. Greece), completely isolated and at a great distance from its main distribution area. There are morphological and chromosomal, but no protein and esterase pattern differences from otherAe. cylindrica populations. This justifies the recognition of a new variety: var.kastorianum. Our comparative and karyotypic observations support the view thatAe. caudata var.polyathera and not var.caudata (typica) is the possible donor of genome C of the new variety.
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    Plant systematics and evolution 163 (1989), S. 31-34 
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    Keywords: Angiosperms ; Aristolochiaceae ; Aristolochia krisagathra spec. nova ; A. indica ; Ornithoptera ; Taxonomy ; butterflies ; host plants ; Flora of India
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    Notes: Abstract Aristolochia krisagathra, a new species from the Western Ghats of Peninsular India is described, illustrated and included into a key to the four Indian species of the genus. Notes on the host-relationships of these species are also provided, paticularly ofA. indica to papilionid butterflies.
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    Plant systematics and evolution 163 (1989), S. 21-29 
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    Keywords: Angiosperms ; Sarraceniaceae ; Melastomataceae ; Rapateaceae ; Gentianaceae ; Loranthaceae ; Malpighiaceae ; Ericaceae ; Orchidaceae ; Campylopterus duidae ; Diglossa duidae ; Anoura geoffroyi ; africanized honey bee ; Pollination by bees ; buzz pollination ; Flora of Neblina
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    Notes: Abstract During 20 days in 1985, floral biological observations were made at 1 850–2 100m elevation on Cerro de la Neblina in Venezuela.Heliamphora tatei var.neblinae (Sarraceniaceae) is nectarless and has poricidal anthers.Heliamphora tatei, Graffenrieda fruticosa, G. polymera, G. reticulata, Tocca pachystachya, T. tepuiensis (Melastomataceae),Saxofridericia compressa, andStegolepsis neblinensis (Rapateaceae), are buzz-pollinated by ten species ofBombus, Eulaema, Melipona, Centris, Xylocopa, Dialictus, andNeocorynura. Additional observations of floral visits on tepui species ofGentianaceae, Loranthaceae, Malpighiaceae, Ericaceae, Orchidaceae, andAsteraceae are reported. Visitors include the hummingbirdCampylopterus duidae, the flower-piercerDiglossa duidae, the nectarivorous batAnoura geoffroyi, and various species ofCentris andBombus bees. Scent baits for euglossine bees attracted very few bees.Apis mellifera adansonii-scutellata, the africanized honey bee, was caught at 1 850m elevation.
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    Plant systematics and evolution 163 (1989), S. 71-79 
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    Keywords: Angiosperms ; Ericaceae ; Arctostaphylos ; Arctous ; Calluna Erica ; Loiseleuria ; Rhododendron ; Rhodothamnus ; Oxycoccus ; Vaccinium ; Empetraceae ; Empetrum ; n-Alkanes ; epicuticular waxes ; chemotaxonomy ; environmental effects
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    Notes: Abstract Alkane distribution patterns were determined in the epicuticular wax of the leaves of 13 species and a hybrid fromEricaceae and one species ofEmpetrum (Empetraceae). As chemotaxonomic indicators, the results are of limited use only. The most uniform genus wasRhododendron, the most heterogeneousVaccinium. The dominant effect of genetic over environmental factors was apparent in most cases.
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  • 74
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    Plant systematics and evolution 162 (1989), S. 315-329 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Aceraceae ; Betulaceae ; Celastraceae ; Fagaceae ; Juglandaceae ; Oleaceae ; Rosaceae ; Staphyleaceae ; Summer-green woody plants ; submediterranean ; distribution types ; climatic conditions ; post-Pleistocene dispersal
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    Notes: Abstract The deciduous wood flora of southern Europe is characterized as a special “nemoral-Submediterranean element”. The distribution patterns of some representatives (total ranges and local areas in Roumania) are described and explained by recent climatic conditions. The northern limits of Submediterranean and Submediterranean-middle European deciduous forest taxa exhibit a continuous gradation, but only a few species with a wide ecological amplitude extend into the temperate zone.
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    Plant systematics and evolution 164 (1989), S. 65-73 
    ISSN: 1615-6110
    Keywords: Algae ; Glaucocystophyceae ; Cyanoptyche gloeocystis f.dispersa ; Ultrastructure ; endocytobiosis ; cyanelles
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    Notes: Abstract Cyanoptyche gloeocystis f.dispersa (Geitler)Starmach is a palmelloid colonial alga that contains prokaryotic blue-green endocytobionts (cyanelles) instead of chloroplasts. The periphery of the host cell shows a peculiar lacunae system with underlying microtubules. Vegetative cells possess two rudimentary flagella. Zoospores are dorsiventrally shaped with two heterokont and heterodynamic flagella which originate from a subapical depression. This depression can also be seen in vegetative cells. Both flagella possess non-tubular mastigonemes. Main reserve product is starch lying freely in the cytoplasm. Cyanelles, enclosed singly in a host vesicle, are provided with a remnant cell wall. Thylakoids are arranged concentrically. The central part of each cyanelle harbours its DNA and one large polyhedral body, probably a carboxysome.Cyanoptyche gloeocystis f.dispersa shares all taxonomically essential characters with the monadoidCyanophora, the palmelloidGloeochaete, and the coccoidGlaucocystis. All of them are members of the cyanelle-bearing small algal classGlaucocystophyceae. Members of this class serve as model organisms for the evolution of chloroplasts from cyanophycean ancestors.
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    Plant systematics and evolution 164 (1989), S. 197-208 
    ISSN: 1615-6110
    Keywords: Algae ; Chlorophyta ; Desmidiaceae ; Micrasterias ; Ultrastructure ; electron microscopy ; cell multiplication ; salt stress
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    Notes: Abstract Cells ofMicrasterias denticulata Bréb. were kept in nutrient solution of high osmolality (salt stress) for four weeks. In a special cell multiplication test it was established that cell division is gradually inhibited at increasing salt concentrations and totally arrested at the highest concentration (26 mosm/kg). “Recovery studies” proved that even cells from the highest concentration range start dividing immediately after being placed in aqua bidest. thus indicating the full reversibility of the inhibiting effect. — Cells of the highest concentration range show marked ultrastructural changes. Besides an enormous accumulation of starch and oil bodies and a condensed appearance of the ground plasma, a reduction of mitochondria, ER and the Golgi-system is found. The most striking effect occurs on the vacuolar system which appears extremely reduced and condensed. The cell wall is thickened by the formation of an additional cell wall layer with a “spongy” electron microscopical appearance. Through the cell wall many droplets of a probably fat-like substance are excreted. — In summary, salt stress induces growth-inhibited “akinete” cells in the sense ofFritsch; these can be reactivated by decreasing the salt concentration. The salt-induced “akinete state” seems to be an ecological adaption to unfavourable conditions rather than a degeneration of the cells.
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  • 77
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    Keywords: Angiosperms ; Hyacinthaceae ; Scilla cilicica ; S. morrisii ; Karyotype evolution ; C-banding ; genome size ; Endemism ; flora of Cyprus
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    Notes: Abstract S. cilicica Siehe andS. morrisii Meikle are two little known sibling species of theScilla siberica alliance with previously difficult taxonomy, especially with regard to specific delimitation and geographic distribution. Quantitative C-band karyotyping and DNA content determinations were performed in four provenances, including the type localities. Both species (2n = 12) differ strikingly in their banding patterns despite of similar DNA content. Karyotype diversification involved changes in eu- and heterochromatin quantities and resulted in some changes of chromosome form. Despite this, actual phylogenetic relatedness is indicated by a chromosomal marker (NOR-position) of rare occurrence in the alliance. Karyological results and circumstantial evidence from the literature suggest thatS. morrisii is an endemic, exclusive to Cyprus as a member of theS. siberica alliance.S. cilicica seems to be restricted to continental S. Anatolia opposite to Cyprus. Its occurrence on Cyprus is questionable.
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    Plant systematics and evolution 165 (1989), S. 95-100 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Gesneriaceae ; Didymocarpus ; Morphology ; floral ecology ; Flora of Malaysia ; SE. Asia
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    Notes: Abstract Didymocarpus geitleri spec. nov. is described from Sungai Pandan, Kuantan distr., Pahang, Peninsular Malaysia. Distinctive features include: leaden-grey leaves with long, erect hairs on the upper side and whitish, campanulate flowers with a long exserted, bright yellow style. The colouring of the latter is caused by densely arranged glands. Together with two yellow blotches in front of the filament insertion, the style apparently acts as an anther (pollen) dummy.
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    Plant systematics and evolution 165 (1989), S. 189-198 
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    Keywords: Angiosperms ; Iridaceae ; Gladiolus ; G. atroviolaceus ; G. communis ; G. illyricus ; G. imbricatus ; G. italicus ; Geography ; morphology ; multivariate analysis ; chromosome numbers
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    Notes: Abstract Representative specimens of the EuropeanGladiolus species (excl.G. palustris) were used to study variability and relationships. 25 characters were measured for cluster, principal component and Wells hybrid analyses (Figs. 1–3). Three (with PCA) respective five (cluster analysis) main groups are revealed. Bulb characteristics appear to be very useful for indentification. The subspecific status ofG. communis subsp.byzantinus is confirmed. Hybrids of four different parental combinations were detected in our collection. Most species include polyploid series. Partly 3x, 4x, 6x, 8x, 12x and aneuploid cytotypes but no diploids were found. Polyploids as pioneers and hybridization of sympatric species are apparently linked to migrations during the glacial periods.
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    Plant systematics and evolution 165 (1989), S. 239-254 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Myrtaceae ; Eucalyptus ; Eudesmia ; Floral morphology ; corolla ; operculum ; androecium ; staminophore ; growth centres ; continuity ; heterotopy ; epipetaly
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    Notes: Abstract In the early stages of ontogeny, the corolline parts of theEudesmia eucalypts develop as compound structures directly comparable to the early stages of the petals ofAngophora and the bloodwood eucalypts, but with the onset of androecial formation a marked difference takes place. Rather than forming on the floral apex, the stamen primordia arise on the basal adaxial components of the young corolline parts; this basal component develops into the staminophore of the mature flower. The operculum consists only of the dorsal components of the corolline parts, the homologues of the “dorsal keels” of theAngophora petals. If the corolline parts remain more or less free in their early developmental stages, corresponding groups of stamens are produced. Early corolline continuity leads to a continuous ring of stamens. The staminophore is not an organ sui generis, but a derivative of the corolla. The bundles of stamens in some species are best referred to as epipetalous groups, not antepetalous fascicles.
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    Plant systematics and evolution 166 (1989), S. 91-104 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Agropyron ; Elymus ; Biometrics ; Wells' distance diagram ; morphological variation ; Flora of S. America ; Patagonia ; Tierra del Fuego ; Falkland Islands
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    Notes: Abstract Based on a simple multivariate analysis of the morphology of theAgropyron pubiflorum complex—A. patagonicum, A. antarcticum, A. fuegianum, andA. magellanicum—the variation pattern is shown to be clinal, and all taxa are included in a single, variable species. Currently the majority of species ofAgropyron is included inElymus and the correct name of this species isE. glaucescens.
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    Plant systematics and evolution 166 (1989), S. 79-89 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Liliaceae ; Hyacinthaceae ; Ornithogalum tenuifolium ; Evolution of karyotypes ; bimodal karyotypes ; DNA content ; Feulgen densitometry ; hybrids ; meiotic chromosome pairing ; fitness
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    Notes: Abstract Hypotheses on the evolution of the karyotypes of 8 chromosome races (2n = 4, 6, 8, 10, 12, 16-two forms, 26) within theOrnithogalum tenuifolium complex are discussed. Four of the karyotypes are strictly bimodal: 2n = 8 (6 long and two short chromosomes), 2n = 10 (6 long and 4 short chromosomes), 2n = 12 (6 long and 6 short chromosomes) and 2n = 16 (12 long and 4 short chromosomes). The hypotheses are tested by means of measurements of nuclear DNA content, studies of meiosis and pollen fertility of hybrids, and comparisons of karyotype morphology. The results indicate that the E. African 2n = 12 chromosome race is the most primitive and has given rise to the other chromosome races. The 2n = 6 race is found to have a significantly higher fitness than the 2n = 12 race.
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    Plant systematics and evolution 166 (1989), S. 141-158 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Proteaceae ; Conospermum taxifolium ; C. longifolium ; Biosystematics ; numerical taxonomy ; morphology ; allozymes ; electrophoresis ; Flora of Australia
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    Notes: Abstract A morphometric analysis of 18 attributes of 110 plants of theConospermum taxifolium complex suggests that it consists of three polythetically distinct taxa, corresponding to the traditional concepts ofC. taxifolium Smith s. str.,C. ericifolium Smith andC. ellipticum Smith. Discrimination is possible on the basis of leaf but not flower attributes. Analysis of allozymic variation indicates that the taxa are also genotypically differentiated.C. ericifolium andC. ellipticum are geographically isolated from each other but not fromC. taxifolium, andC. taxifolium is usually ecologically segregated from the other two taxa. Where this ecological segregation breaks down, morphological intermediates sometimes occur as the result of hybridization.
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    Plant systematics and evolution 166 (1989), S. 173-181 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Eragrostis curvula ; Lovegrasses ; Esterase isozymes ; disc electrophoresis ; biosystematics
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    Notes: Abstract The biosystematic relationships of the apomictic complexEragrostis curvula s. lato, is investigated by disc electrophoresis of seed extracts to obtain esterase patterns of 23 accessions representing the morphological variants of this complex: curvula, conferta, robusta, chloromelas and lehmanniana. The zymograms thus obtained were classified into four groups on the basis of the presence of certain bands taken as characteristic and constant markers. Within each group variations were found in strict accordance with the morphological and cytogenetic data available on the complex. Cluster analysis showed similarity levels between the strains studied, representing different genomic groups. The esterase pattern proved useful as an additional criterion for identifying the individual taxa making up the complex and for evaluating their reciprocal relationships.
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    Plant systematics and evolution 167 (1989), S. 43-57 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Chenopodiaceae ; Chenopodium ; Taxonomic trees ; phenograms ; cladograms ; natural classifications ; predictivity ; information content ; probability of trees
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    Notes: Abstract The contribution ofJ. S. L. Gilmour to numerical taxonomy is reviewed. His important concept of natural classification, as being general-purpose classifications with high predictivity, led to the development of ideas of information content, unit characters and equal character-weighting. The concept of predicitivity is extended to taxonomic trees (phenograms or cladograms). Under certain assumption of random sampling of characters it is shown that the probability of recovering the correct tree topology or tree-form may be small if characters are few. There may be very many topologies or tree-forms, every one of which has individually a low probability. It is, however, possible to estimate the aggregate probability of trees which have more than some specified resemblance to the “correct” tree. The practical prospects of estimating the distribution of tree probabilities are discussed.
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  • 86
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    Keywords: Angiosperms ; Ranunculaceae ; Ranunculus auricomus agg. ; Ranunculus marsicus ; Cytofluorimetry ; polyploidy ; agamic complex
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    Notes: Abstract A cytofluorimetric method for DNA amount determination on nuclei released from fixed leaves has been successfully tested on samples belonging to the polyploid series ofRanunculus marsicus Guss & Ten. (sect.Auricomus). The procedure was devised to screen rapidly for different ploidy levels within topodemes and progenies.
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    Plant systematics and evolution 168 (1989), S. 7-18 
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    Keywords: Angiosperms ; Fagaceae ; Castanea ; Lithocarpus ; Comparative morphology ; cupule ; ontogenetic development
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    Notes: Abstract Two contradicting theories have been proposed for the morphological nature of fagaceous cupules; the intercalary growth theory and the higher order dichasial branch theory. All the previous ontogenetic studies insist on the latter one, but the genera investigated have been rather restricted and have not covered all the cupule types. A comparative study of the ontogenetic development of cupules inCastanea crenata andLithocarpus edulis, which are representatives of fundamentally different cupule types, revealed that both the theories are incomplete. InL. edulis, the higher order dichasial branches contribute to cupule formation along the anterior portions of the lateral flowers. However, along the adaxial portion of the central flower, the cupule develops as an intercalary growth, represented by rapid increase of tangentially oblong epidermal cells. InCastanea, intercalary growth is not clearly observable, for presumably, the flowers are surrounded by a well-developed partial inflorescence mound from the beginning of development.
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    Plant systematics and evolution 166 (1989), S. 159-171 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Triticeae ; Biosystematics ; genome analysis ; chromosome homology ; phylogenetic reconstruction ; classification
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    Notes: Abstract The implications of genome analysis for evolutionary theory and systematics are treated. The precise relationship between the theoretical and operational definitions of chromosome homology is shown to be uncertain. It is pointed out that genera defined by genome analysis may be either monophyletic or non-monophyletic, and that the genus is not a basic unit of evolution. Characters obtained by genome analysis may be useful in a phylogenetic context, provided they are treated as all other characters.
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    Plant systematics and evolution 166 (1989), S. 243-248 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Viscaceae ; Viscum ; Nuclear DNA content ; DNA denaturation ; DNA reassociation ; host-specific DNA organization ; subspecific genome differentiation
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    Notes: Abstract The nuclear DNA content and composition with respect to base composition and the proportion of repetitive DNA was studied in the host-specific mistletoe subspecies,Viscum album subsp.album, V. a. subsp.abietis andV. a. subsp.laxum, using DNA ofLoranthus europaeus as a standard. Small but not significant differences were found between the 2C DNA contents and the base composition but significant differences were detected in the patterns of sequence organization. This infraspecific variation is briefly discussed in the light of differences known to occur in the patterns of lectins and viscotoxins, immunostimulating and cancerostatic effects.
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    Plant systematics and evolution 166 (1989), S. 253-264 
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    Keywords: Angiosperms ; orchids ; Pleione ; P. bulbocodioides ; P. formosana ; P. yunnanensis ; P. humilis ; P. forrestii ; Chromosome banding ; Feulgen staining ; karyotype analysis ; epiphytic ; semi-terrestrial ; terrestrial habitats
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    Notes: Abstract Karyotypic and heterochromatin studies suggest a basic division of the orchid genusPleione into two groups, one represented by the clearly epiphytic species and the other including both species with terrestrial trends as well as those that are truly terrestrial. The epiphytic group possesses only (sub) metacentric chromosomes and is characterised by a considerable amount of terminal heterochromatin while the terrestrial group has some subtelocentric chromosomes and only small amounts of centromeric heterochromatin. It is concluded that a major phyletic split in the mode of chromosome change occurred during the transition from the epiphytic to the terrestrial habitat.
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    Plant systematics and evolution 167 (1989), S. 113-127 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Boraginaceae ; Symphytum ; S. officinale agg. ; Chemotaxonomy ; pyrrolizidine alkaloids ; isobauerenol
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    Notes: Abstract In a chemotaxonomic study of the genusSymphytum pyrrolizidine alkaloids and triterpenes were used as chemotaxonomical markers. A micro-extraction methods was developed for screening compounds of very small pieces of herbarium material. The occurrence of the pyrrolizidine alkaloids symphytine and (acetyl-)lycopsamine is very general forSymphytum taxa. Echimidine is present in someS. officinale L. plants and inS. tanaicense Steven. The triterpene isobauerenol is present inS. officinale, S. bohemicum Schmidt,S. tanaicense and inS. officinale var.lanceolatum Weinm. The chemotaxonomic hypothesis, proposed byGadella and collaborators, based on the presence of the triterpene isobauerenol inS. officinale and its absence inS. asperum Lepech. and the presence of the pyrrolizidine alkaloid echimidine inS. asperum and its absence inS. officinale, can no longer be applied absolutely to theS. officinale species complex. The pyrrolizidine alkaloid and triterpene pattern ofS. officinale (2n = 24) andS. bohemicum (2n = 24) is identical.S. bohemicum is morphologically, cytologically and phytochemically very similar toS. officinale. Furthermore, it readily crosses with the white flowered W. European diploids ofS. officinale. Therefore it seems likely that these two taxa are conspecific.S. tanaicense shows a pyrrolizidine alkaloid and triterpene pattern similar toS. officinale (2n = 40). Also on morphological and cytological grounds they are very similar. It seems highly probable thatS. tanaicense is conspecific withS. officinale (2n = 40) and represents an intraspecific variant only.S. officinale var.lanceolatum contained no pyrrolizidine alkaloids but did contain isobauerenol. This feature points to an origin fromS. officinale.
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    Plant systematics and evolution 167 (1989), S. 149-164 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Cichorium intybus ; Tapetum ; pollen ; exine ; pollenkitt
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    Notes: Abstract The tapetal development ofCichorium intybus L. is investigated using LM and TEM and discussed in relation to the development in other species. During the second meiotic division the tapetal cells become binucleate and lose their cell walls. They intrude the loculus at the time of microspore release from the meiotic callose walls, which means that a locular cavity is never present in this species. During pollen development they tightly junct the exine, especially near the tips of the spines. During the two-celled pollen grain stage they degenerate and most of their content turns into pollenkitt. Until anther dehiscence they keep their individuality, which means that these intruding tapetal cells never fuse to form a periplasmodium. The ultrastructural cytoplasmatic changes during this development are discussed in relation to possible functions.
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    Plant systematics and evolution 168 (1989), S. 59-69 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Fabaceae ; pigeonpea ; Cajanus cajan ; Sex allocation ; mating systems ; fruit and seed set
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sex allocation theory predicts that: (1) resources allocated to androecium should decrease with an increase in selfing, (2) a decrease in androecium biomass should be accompanied by an increase in the biomass of pistils, and (3) a decrease in androecium biomass should be coupled with a decrease in flower size, specifically corolla biomass. Another predicted change in reproductive traits associated with variation in selfing concerns seed to ovule ratios, but does not directly stem from sex allocation theory. It has been postulated that seed to ovule ratios should be positively correlated with the amount of selfing. These predictions were tested for six accessions of pigeonpea,Cajanus cajan L., that differed in selfing rates. The results were remarkably in accordance with the predictions. We conclude that sex allocation theory provides a powerful tool to understand the evolution of many reproductive traits in plants.
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  • 94
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    Plant systematics and evolution 168 (1989), S. 87-94 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Apiaceae ; Pimpinella major ; P. saxifraga ; P. alpina ; Asteraceae ; Solidago virgaurea ; S. canadensis ; S. gigantea ; Exploratory data analysis (EDA) ; classification algorithm ; MOBCENTR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract MOBCENTR is a classification algorithm combining features of classification about mobile centres, Ward algorithm and of the Hard-Isodata method. The results of this new algorithm and of Ward algorithm are compared by morphological characters of species ofSolidago andPimpinella.
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  • 95
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    Plant systematics and evolution 168 (1989), S. 181-193 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Ranunculaceae ; Adonis ; Taxonomy ; distribution ; cytology ; chromosome numbers ; meiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The five annual species ofAdonis L., sect.Adonis, growing in Israel, form a series of diploid, tetraploid and hexaploid species. Their somatic chromosome numbers are 2n = 16 inA. annua L.,A. dentata Del. andA. palaestina Boiss., 2n = 32 inA. microcarpa DC., 2n = 48 inA. aestivalis L.; counts forA. dentata, A. palaestina andA. microcarpa are new records. There are indications that alloploidization may have been involved in the process of speciation in sect.Adonis. A taxonomic survey of the 8 species of the section reveals that a higher ploidy level is usually combined with a larger distribution area.
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  • 96
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    Plant systematics and evolution 162 (1989), S. 5-61 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Nypa ; Ctenolophon ; Bombacaceae ; Olacaceae ; Symplocos ; Alangium ; Nepenthes ; Pachysandra andSarcococca ; Restionaceae ; Chloranthaceae ; Austrobaileyaceae ; Paleogeography ; paleochorology ; chorology ; Neophyticum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract After presenting the methodological bases of historical phytogeography (paleochorology; Fig. 1), a new paleographic map series is introduced (Fig. 2). They serve for ten examples of paleochorological analyses, in which the major phases of the development of a group in space and time are documented. In addition to purely tropical taxa (Nypa, Ctenolophon), others which originated in the warm and humid N. Tethyan belt (Bombacaceae p.p.,Olacaceae p.p.,Symplocos, Alangium, Nepenthes) or which presently occur as eastern N. American/E. Asian disjuncts (Sarcococca andPachysandra) are discussed (Figs. 3–14). Finally, analyses of two very old angiosperm groups with complicated paleochorological patterns (Restionaceae andAscarina, Chloranthaceae p.p.; Figs. 15–16) are presented.
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  • 97
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    Plant systematics and evolution 162 (1989), S. 63-78 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Myrtaceae ; Proteaceae ; Casuarinaceae ; Lauraceae ; Nothofagus ; etc. ; Tertiary floras of Australia ; evolution of the Australian flora
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The evolution of the Australian flora through the Tertiary has not been reviewed by a megafossil palaeobotanist for almost a century. Based on material available and published studies, the Australian Tertiary can be considered in three units: Eocene, Oligo-Miocene, and Pliocene. Key taxa in the Eocene includeCasuarinaceae, Proteaceae, Fagaceae, Podocarpaceae, andLauraceae. Many known Eocene deposits are interpreted as warm, humid rainforests. Oligo-Miocene floras reflect a climatic deterioration, with greater occurrence of sclerophylly and xerophylly. A reduction of tropical taxa is seen with an increase ofMyrtaceae and earliest records ofMimosaceae, Chenopodiaceae, andPoaceae. These trends continue into the Pliocene, which is not well represented in Australia. Problems needing to be addressed include the discrepancy between the pollen and megafossil records ofNothofagus, the origins of Australia's wet tropical taxa, and the role of fire in the early evolution of the Australian flora.
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  • 98
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    Plant systematics and evolution 165 (1989), S. 91-94 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Heliopsis scabra ; Rudbeckia vulgaris ; Flowers ; UV patterns during anthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pseudanthia ofHeliopsis scabra andRudbeckia vulgaris (Asteraceae) were examined during the anthesis for differences in their UV patterns. Distinct changes in the reflectance and absorbance properties could be observed. The results suggest a close correlation between different stages of floral development and pollinator attraction.
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  • 99
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    Plant systematics and evolution 165 (1989), S. 85-89 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Alliaceae ; Allium cepa ; Leucoplast ; chloroplast ; plastids ; plastid metamorphosis (transformation)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The greening of the upper part of the outerAllium cepa L. bulb scales, in particular along the vascular regions, is limited to the hypodermal cells in which typical leucoplasts are transformed to normal and functional chloroplasts. This process is light dependent and cannot afterwards be reversed or modified by darkness. The changes in fine structure are described and briefly discussed.
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  • 100
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    Plant systematics and evolution 165 (1989), S. 101-136 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Rubiaceae ; Rubieae ; Crucianella sect.Roseae ; C. platyphylla (spec. nova) ; C. gilanica (with subspp. and stat. nov.) ; C. suaveolens andC. sintenisii ; Systematic revision ; eco-geographical analysis ; Flora Iranica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The perennial taxa ofCrucianella in Asia form a coherent group, apparently diploid (x = 11) and outbreeding throughout, and should be placed into sect.Roseae. This Irano-Turanian group has its centre of diversity in the mountain systems south of the Caspian Sea and reaches with outposts NE. and E. Anatolia, NE. Iraq, S. Iran and C. Asia. Four species and 13 subspecies (within the polymorphicC. gilanica) are recognized, described (partly as new), and illustrated (Figs. 1–6). Conspectus, keys and distribution maps (Figs. 7 and 8) as well as plesio- and apomorphic character states and data on size of areas are provided (Table 1). There is an obvious correlation between more plesiomorphic taxa with smaller areas in the distribution centre of the group, and more apomorphic taxa with larger areas towards its periphery (Fig. 9). These findings are linked to a working hypothesis on the evolution of the group.
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