bluuebunny/crossref_metadata_2025_split huggingface dataset:
Outward Extension of Spinules in Exine of Centrolepis aristata (Centrolepidaceae)
Authors: Rowley J. R. , Dunbar Anita 
Published: February 2014

AbstractSpinules extend outwards 0.2 to 0.3 μm into the plasmodial tapetum during periods of rapid growth of microspores of Centrolepis. Before and after these intervals spinules commonly protrude only ca 0.05 μm above the surface of the tectum. The extended spinules have a rod shaped core ca 40 nm in diameter. The surface of the core is surrounded by loops ca 30 nm in diameter arranged in a regular pattern.
Karyological Differentiation in Sapindaceae with Special Reference to Serjania and Cardiospermum
Authors: Hemmer W. , Morawetz W. 
Published: February 2014

AbstractNew chromosome counts for 9 species and 2 genera of Sapindaceae are presented and compared with a review of all available chromosome numbers of the family. In 4 species diploid numbers differing from previous reports are found. In 4 species of the tribe Paullinieae (S. diversiflora, S. subdentata, C. grandiflorum and C. halicacabum) detailed studies on interphase nucleus structure, condensing behaviour and chromosome banding patterns are presented. The karyological differentiation of Paullinieae is generally characterized by dysploid reduction of chromosome numbers and the increase of chromosome size. Sequential staining of nuclei with CMA/DAPI and Giemsa‐C‐banding demonstrates diversification of constitutive heterochromatin (= hc) and different types of chromatin organization in Serjania and Cardiospermum. The obvious lack of polyploid series and the karyological evolution within the family is discussed. The outstanding small genome size found in Cardiospermum halicacabum is considered to be due to a secondary loss of DNA in the course of the change to herbaceous growth.
Developmental Aspects of Ultrastructure and Histochemistry of the Stylar Transmitting Tissue of Nicotiana sylvestris
Authors: Kandasamy M. K. , Kristen U. 
Published: February 2014

AbstractThe structure and histochemistry of the solid style of Nicotiana sylvestris Speg. and Comes have been studied by light and electron microscopy. The transmitting tissue develops large intercellular spaces filled with secretions rich in proteins and carbohydrates during maturation. The cells possess large nuclei, numerous plastids with starch grains, mitochondria, ribosomes and well developed endoplasmic reticulum and golgi apparatus. The plastids in the stylar region immediately below the stigma produce electron‐dense osmiophilic substances which are probably transferred into the cytoplasm by a process resembling budding‐off of vesicles. The Golgi apparatus may use the starch grains as a source of sugars for the synthesis and secretion of extracellular polysaccharides. The structural and cytochemical differences between the glandular cells of the stigma and the stylar transmitting tissue are discussed.
Subcellular Distribution of Free Amino Acids in Relation to Protein Synthesis in Cells of Chara corallina
Authors: Mimura T. , Sakano K. , Moriyasu Y. , Tazawa M. 
Published: February 2014

AbstractThe influence of protein‐synthesis inhibitors on the subcellular distribution of free amino acids was studied in internodal cells of Chara corallina. Use of an intracellular perfusion technique allowed separate measurements of amino acids in the vacuole, in the flowing sol endoplasm and in the gel layer. The sol endoplasm predominantly represents the cytosol, while the gel layer is occupied, for the most part, by chloroplasts.When cells were treated with 0.5 mM chloramphenicol (CRP) in the dark, both the total concentration of amino acids and the subcellular distribution were almost the same as in cells without treatment. In the light, however, the subcellular distribution changed dramatically, although the total concentration of amino acids was unchanged. The vacuolar concentration of amino acids was 3 times greater in CRP‐treated cells than in the control. The concentrations of amino acids in the sol endoplasm and in the gel layer were only half of those in the control. Amino acid permeability of the chloroplast envelope, measured using the perfused internodal cells, slightly increased after the CRP treatment in the light.Time‐dependent changes in concentrations of amino acids in the CRP‐treated cells were also measured in the light. The total concentration of amino acids in the cytoplasm gradually decreased, while that in the vacuole increased commensurately. The concentration and/or subcellular distribution of alanine, glutamine, glutamate and glycine changed dramatically. The concentration of alanine increased considerably both in the vacuole and in the cytoplasm. The cytoplasmic concentration of glutamine increased transiently within 1 −2 h after treatment with CRP. The cytoplasmic concentrations of glutamate and glycine decreased. Although the concentrations of some amino acids changed so markedly both in the vacuole and cytoplasm, only small differences in the activities of glutamic‐pyruvic transaminase, glutamic‐oxaloacetic transaminase and glutamine synthetase were detected between the control and the CRP‐treated cells.
Ein Beitrag zur Systematik und Entwicklungsbiologie höherer Pilze: Hefe‐Typen der Basidiomyceten. Teil II: Microbotryum‐Typ
Authors: Prillinger H. , Deml G. , Dörfler Ch. , Laaser G. , Lockau W. 
Published: February 2014

AbstractIn this and three further papers 205 yeasts and yeast states of Basidiomycetes and presumed relatives were investigated comparatively on the basis of the carbohydrate (neutral sugars) pattern of purified cell walls, urease‐activity, diazonium blue B reaction on the production of extracellular amyloid compounds (EAS), fermentation of carbohydrates, and ubiquinone data. A clustering leading to the Protomyces‐, the Microbotryum‐, the Ustilago‐, the Dacrymyces‐, and the Tremella‐type became apparent, especially from the qualitative and quantitative cell wall carbohydrate pattern.The different yeast types correspond well with 5S rRNA clusters known from the literature. 31 strains clustering within the Microbotryum‐type comprise the phragmobasidial smut fungi of dicotyledonous hosts (Microbotryum. Sphacelotheca), the phragmobasidial Rhodosporidium‐ and Leucosporidium‐species including some anamorph Rhodotorula‐species, which lack an oxidative degradation of myo‐inositol, the genera Sporobolomyces and Sporidiobolus, the Septobasidiales and some simple septate Auriculariales e.g. Agaricostilbum, Platygloea. Main characteristics of the Microbotryum‐type are: 1. The absence of extracellular amyloid compounds. 2. The dominance of mannose and the presence of fucose as cell wall constituents. 3. A positive DBB‐reaction and splitting of urea. Four Ustilago species parasitic on dicotyledonous hosts were transfered to Microbotryum (M. scabiosae, M. scorzonerae, M. cordae, M. vinosum) as a consequence from cell wall carbohydrate composition, production of rhodotorulic acid, and 5S rRNA sequence data from the literature.The predominance of mannose in the cell wall — otherwise only known from ascomycetous yeasts –, a type A secondary structure of 5S rRNA, a simple unifactorial mating system in all parasitic smut species suggest that the Microbotryum‐type might be ancestral to the Ustilago‐type. An evolution of simple (“siphonal”) holobasidia from “pseudotrichal” phragmobasidia will be discussed.
Excretion of Sugars by Chlorella Species Capable and Incapable of Symbiosis with Hydra viridis
Authors: Kessler E. , Kauer G. , Rahat M. 
Published: February 2014

AbstractThe excretion of some sugars (maltose, glucose, and glucose‐6‐phosphate) was studied at pH 2.5–6.0 in 38 strains of Chlorella belonging to 15 species of which 7 are capable and 8 incapable of symbiosis with Hydra viridis. A high rate of maltose excretion below pH 4.0 (Cernichiari et al., 1969) was found only in C. vulgaris (non‐symbiotic) and C. mirabilis (non‐symbiotic). The other Chlorella species are characterized by quite different patterns of sugar excretion. C. spec. (= “C. paramecii”; symbiotic) excretes very high amounts of maltose in the whole range from pH 2.5–6.0. C. kessleri (symbiotic), C. luteoviridis (symbiotic), and C. fusca var. fusca (non‐symbiotic) show a predominant excretion of glucose‐6‐phosphate from pH 2.5–6.0. Some strains also exhibit a high excretion of glucose above pH 4.0 (C. spec. = “C. paramecii”) or below pH 3.0 (C. fusca var. vacuolata). Several species, e.g. C. saccharophila var. saccharophila (symbiotic), C. sorokiniana (non‐symbiotic), and C. protothecoides (symbiotic), excrete only very small amounts of sugars. There is no obvious correlation between sugar excretion and the ability or inability of the Chlorella species to form stable symbioses with Hydra viridis.
Untersuchungen zur Konstruktion des Bestäubungsapparates von Thalia geniculata (Marantaceen); Investigations on the Construction of the Pollination Apparatus of Thalia geniculata (Marantaceae)
Authors: Claßen‐Bockhoff Regine 
Published: February 2014

ZusammenfassungDer Bestäubungsmechanismus der Blüte von Thalia geniculata wird im Zusammenhang mit speziellen Blütenstrukturen (schiefe Leiste, Schwiele, Häutchen, Trigger, Narbenfortsatz) erläutert. Im Gegensatz zu anderen Marantaceen‐Gattungen verläuft die Griffelbewegung nicht bogen‐, sondern S‐förmig. Der Griffel steht aktiv unter Spannung und ist nur an einer Stelle reizbar. Mittels Zeitlupenaufnahmen wird die Bewegung rekonstruiert: Sie verläuft in 3 Phasen und dauert etwa 0,03 Sek. Die enorm hohe Geschwindigkeit der Griffelbewegung und die Tatsache, daß die Blüte nur eine einzige Bestäubungschance besitzt, verlangen präzise Synorganisations‐ und Synchronisationsprozesse, die im einzelnen dargestellt werden.AbstractThe pollination mechanism of the flower, Thalia geniculata, and the unusual construction of the style and staminodes is illustrated. As early as the bud stage, pollen of the single stamen is deposited onto the pollen tray at the top of the style. Special structures of the staminodes — “oblique ledge” (schiefe Leiste, sL), “callosity” (Schwiele, Schw) and “hood” (Kapuze, Ka) — are in the optimal position for pollination. The style functions only as a secondary pollen presenter. It is under active tension and only sensitive at a defined site. The proboscis of a visiting insect is guided into the flower by special structures: “callosity”, “pellicle” (Häutchen, H) and an appendage to the stigma (Narbenfortsatz, Nf). The insect touches the style and starts its explosive S‐shaped movement via a trigger mechanism. Slow motion pictures (5000 pictures/s) show that the revolving movement occurs in 3 phases in approximately 0.03 s. During this very short time the style becomes erect, scrapes the pollen from the proboscis into its stigmatic cave and deposits its own pollen onto the proboscis in the form of a sticky paste.In Th. geniculata the 2 flowers of a partial inflorescence together form one attractive symmetrical, melittophilous blossom. They are pollinated, by Xylocopidae (even in SE Asia, where the plant is not indigenous). Each flower has only a single chance to be pollinated. If xenogamy fails, self‐pollination is possible.
Early Effects of Penconazole on H+ and K+ Transport, Electrolyte Leakage and Transmembrane Electrical Potential in Egeria densa Leaves
Authors: Marrè Maria‐Teresa , Albergoni F. G. , Venegoni A. , Moroni A. 
Published: February 2014

AbstractThe early effects of penconazole (PCZ) at relatively high concentration (10−4 to 5 × 10−4 M) on changes in pH and in titratable acidity of the medium, transmembrane electrical potential difference (Em), electrolyte leakage and cell morphology were investigated in Egeria densa leaves. At the lowest (10−4 M) concentration and in the presence of a very low (10 μM) K+ concentration, triazole induced an early, moderate hyperpolarization of Em, associated with a decrease of net K+ uptake, suggesting some increase in the passive permeability to K+. This Em hyperpolarization was no longer detectable at high (2 mM) K+out concentration. At high PCZ concentrations (3 × 10−4 M and 5 × 10−4 M) the early hyperpolarization detectable in the presence of a low K+out concentration became transient, and was followed by a marked depolarization. PCZ, at these concentrations, suppressed acidification of the medium, stimulated electrolyte leakage and, in the mesophyll cells, induced some shrinking of the cytoplasm and its disconnection from the cell walls. These results are interpreted as due to an early effect of this triazole leading to the disorganization of the plasma membrane.
Dynamic Organization of Plant Microtubules at the Three Distinct Transition Points During the Cell Cycle Progression of Synchronized Tobacco BY‐2 Cells
Authors: Hasezawa S. , Nagata T. 
Published: February 2014

AbstractDynamic changes of microtubule (MT) configuration have been examined during the cell cycle progression in tobacco BY‐2 cells, which have been highly synchronized by aphidicolin treatment. Although it has been shown previously that four cell cycle stages display characteristic features of MTs (Hasezawa et al., 1991), distinct changes of MT configuration were observed at the interfaces of G2/M, M/G1 and G1/S, and the frequency of appearance of such distinct structures were quantitatively examined. Among others, it is the first observation that at M/G1 disintegrating phragmoplasts coexisted with short MTs in the perinuclear envelopes, but the MTs disappeared in the later stage, when cortical MTs were organizing. Thus it is supposed that cortical MTs originate from the transiently observed short MTs in the perinuclear region. This observation offered also an experimental system to analyze the molecular changes of MTs at the three interfaces during cell cycle progression in plant cells, as the mass culture of tobacco BY‐2 cells is readily available.
The Formation of Free Lipid Radicals During the Electromanipulation of Protoplasts (Vicia faba)
Authors: Biedinger Ursula , Bickert Chr , Youngman R. J. , Schnabl Heide 
Published: February 2014

AbstractMembrane lipid degradation of plant protoplasts of Vicia faba was characterized by the determination of ethane formation after electrofusion and electropermeabilization. Incubation of protoplasts with ascorbate or α‐tocopherol before electromanipulation led to a decrease in ethane production. Fusion product yield could be increased by incubation with α‐tocopherol.Using a simple model system, we investigated the active species involved in lipid peroxidation under conditions typically used for electromanipulation. The formation of lipid free radicals by electric pulses could be demonstrated.
Cytosolic Ca2+‐Concentrations and Distributions in Rhizoids of Chara fragilis Desv. Determined by Ratio Analysis of the Fluorescent Probe Indo‐1
Authors: Hodick D. , Gilroy S. , Fricker M. D. , Trewavas A. J. 
Published: February 2014

AbstractRhizoids of Charafragilis Desv. were iontophoretically loaded with the Ca2+‐sensitive ratio dye indo‐1. After loading, the rhizoids regained their preinjection‐membrane potential within 2 to 5 min and survived the procedure for more than 24 h, but their growth in length was permanently inhibited. Microfluorimetric measurements of the indo‐1 fluorescence‐ratio showed spontaneous fluctuations of the cytoplasmic Ca2+‐concentration, usually declining from high values after loading to 425 ± 80 nM (± SD, n = 7) as determined by in‐vitro calibration. Increasing the extracellular K+‐concentration (0.1 mM to 10 mM) or Ca2+‐concentration (1 mM to 10 mM) led to increases of 100 to 200 nM in cytoplasmic Ca2+‐concentration. The spatial distribution of cytosolic Ca2+ in the rhizoid tips was visualised in ratio images computed from low‐light video‐pictures. These images showed a fairly homogeneous distribution of Ca2+ throughout the tip cytoplasm with concentrations being in the same range as determined by microfluorimetry. A tip‐to‐base gradient in cytoplasmic Ca2+, thought to be a prerequisite for cell polarity and tip growth, was found in only 1 out of 16 successfully microinjected cells. Additionally, a progressive compartmentalization of the fluorochrome indo‐1, probably in the proplastids and the very abundant endoplasmic reticulum of the rhizoids, was observed.
Calcium Oxalate Crystal Formation and Growth in Two Legume Species as Altered by Strontium
Authors: Zindler‐Frank Elisabeth 
Published: February 2014

SummaryYoung plants of Phaseolus and Canavalia were grown in nutrient solutions where calcium had been partially or totally replaced by either strontium or sodium. The deleterious effect of this replacement on growth and development was greater with strontium than with sodium. As the calcium content of the nutrient solution was decreased fewer calcium oxalate crystals were formed in leaf tissues. There were fewer crystals formed when calcium was replaced by strontium than by sodium. Changes in solubility characteristics of the crystals indicated that they had incorporated strontium.
Ricinoleic Acid Catabolism in Peroxisomes
Authors: Gerbling Heidrun , Gerhardt B. 
Published: February 2014

AbstractPeroxisomes from castor bean endosperm and mung bean hypocotyl completely degrade ricinoleic acid (12‐D‐hydroxy‐9‐cis‐octadecenoic acid) to acetyl‐CoA. Concomitant NADH formation occurred with a stoichiometry of 9 nmol NADH formed per 1 nmol ricinoleate degraded. At the C8‐intermediate level, where the hydroxy group of ricinoleic acid forms a barrier to β‐oxidation, 2‐hydroxyoctanoate and 2‐oxooctanoate were detected as intermediates. 2‐Hydroxyoctanoate was oxidized to 2‐oxooctanoate with H2O2 producing a reaction exhibiting 1:1 stoichiometry of the products. The peroxisomes appeared to oxidize both isomers of racemic 2‐hydroxyoctanoate. 2‐Oxooctanoate was metabolized to heptanoyl‐CoA (propionyl‐CoA and acetyl‐CoA) in a NAD‐dependent, but ATP‐independent, reaction. Heptanoate was not detected as an intermediate. Imidazole, an inhibitor of α‐oxidation, did not effect the degradation of ricinoleate or 2‐oxooctanoate. Arsenite, an inhibitor of oxidative decarboxylation, inhibited the metabolism of ricinoleate at the C8‐intermediate level, according to the accumulation of 2‐oxooctanoate and the stoichiometry of concomitant NADH formation. Arsenite completely inhibited the metabolism of 2‐oxooctanoate. It is concluded that the barrier caused by the hydroxy group of ricinoleic acid and prevention of β‐oxidation at the C8‐intermediate level, is circumvented by an α‐hydroxy acid oxidase reaction followed by an oxidative decarboxylation allowing return to the β‐oxidation track.
The Tonoplast Localization of Two Basic Isoperoxidases of High pI in Lupinus
Authors: Barceló A. Ros , Ferrer M. A. , Florenciano E. García , Muñoz R. 
Published: February 2014

AbstractThe ultrastructural localization of peroxidase (EC 1.11.1.7) activity in cambial initial and xylem parenchyma cells of etiolated Lupinus albus hypocotyls (cv. Multolupa) revealed that, unlike phloem tissues, most of the enzymatic activity is located as dark electron‐dense deposits on the tonoplast. Subcellular fractionation studies of plasmolyzed hypocotyls revealed that this enzymatic activity is apparently due to two basic peroxidase isoenzymes of isoelectric points 9.5 and 9.7 for B3 and B4, respectively. These isoenzymes are found mainly in young (5‐day old) seedlings, and are probably involved, as indicated by other authors, in the metabolism of quinolizidine alkaloids in Lupinus species.
The Biomechanics of Tree Fork Design
Authors: Mattheck C. , Vorberg U. 
Published: February 2014

AbstractTwo biomechanically different types of tree fork are described: the “compression fork” where the two jointed stems are pressed against each other at the contact face by the action of reaction wood, and the “tension fork” where the two connected stems are bent away from each other by gravity or wind action leading to tensile stresses in the connective zone.It is well known that trees permanently try to improve their own designs by adaptive growth in order to maintain a state of constant mechanical stress at the tree surface. In the case of these two different types of tree fork, adaptive growth also takes different ways in order to avoid high localized stress peaks which could lead to failure of the tree under wind loading.In this paper only the tension fork is assessed with respect to its shape optimization by computer simulation of adaptive growth. It is shown that the tensile fork is shape optimized in a very perfect way in order to avoid any dangerous localized stress peaks (notch stresses) which could lead to failure of the tree.
Ion Transport and the Transpiration Stream
Authors: Smith J. A. C. 
Published: February 2014

AbstractIn a long‐term experiment with maize grown at different humidities, Tanner and Beevers (1990) demonstrated that the amount of water lost by the plants in transpiration (plus guttation) could be reduced by a factor of three without any adverse effect on growth. As a consequence, the authors questioned the importance of the transpiration stream in supplying the shoot with minerals, arguing that there are other causes of mass flow in the xylem (such as Münch counterflow from phloem to xylem, and water consumed by growing sink tissues) that may, in the limit, be capable on their own of providing the shoot with minerals. This hypothesis is discussed here in the light of recent work on xylem water relations. It is shown to involve the incorrect premise that, if transpiration were required for long‐distance ion transport, plants should grow less well at high humidity. Instead, solute flux to the shoot can be demonstrated by experiment to remain constant over a wide range of transpiration rates, since the concentration of solutes in the xylem sap varies inversely with transpiration rate. Independent evidence suggests that the non‐transpirational component of mass flow in the xylem is small and is unlikely to be able to provide the shoot adequately with minerals in the absence of transpiration. A simple corollary of this view is that plant growth should be reduced at very low transpiration rates, a prediction that should be testable at sufficiently high humidities under carefully controlled conditions.
Sucrose Utilization of the Ectomycorrhizal Fungi Amanita muscaria and Hebeloma crustuliniforme Depends on the Cell Wall‐bound Invertase Activity of their Host Picea abies
Authors: Salzer P. , Hager A. 
Published: February 2014

AbstractThe role of apoplastic invertase (β‐d‐fructofuranoside — fructohydrolase, EC 3.2.1.26) of the host Picea abies for carbohydrate uptake and growth of two of its natural ectomycorrhiza partners was studied. For that purpose, hyphae of Amanita muscaria (Pers. ex Fries) Hock. and Hebeloma crustuliniforme (Bull. ex Fries) Quell., as well as roots and suspension cultured cells of Picea abies (L.) Karst. were used. Apoplastic invertase activity was demonstrated on roots and suspension cultured cells of spruce (in the latter case with 21.7 nkat (g fresh weight)−1). Inhibition of the root cell wall invertase activity (pH optimum 4.5) by increasing the apoplastic pH allowed determination of the permanent release of sucrose from the root. However, under in vivo conditions at a lower cell wall pH the hydrolysation products glucose and fructose were predominantly found. In contrast to spruce cells and certain fungi, such as Saccharomyces (Novick et al., 1981) or Phycomyces (Ruiz‐Herrera et al., 1989) invertase activity of the mycorrhizal fungi Hebeloma and Amanita was negligibly low. Furthermore, sucrose could not be consumed by Amanita and Hebeloma. As a consequence, cultures of these mycorrhizal fungi starved when kept on media with sucrose as sole carbohydrate source. But addition of invertase initiated hyphal growth immediately. Studies on carbohydrate uptake of host and fungal cells confirmed that the monosaccharides glucose and fructose were readily incorporated by spruce and fungal cells, with a clear preference for glucose. From these results it is suggested that apoplastic invertase activity of the host Picea abies is a precondition for the utilization of sucrose by the studied mycorrhizal fungi during the nutritional interaction of the symbiotic partners.