bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phenotypic Similarity and Genetic Relationship Among Populations of Microseris bigelovii (Asteraceae: Lactuceae)
Authors: Bachmann K. 
Published: February 2014

AbstractTwelve inbred strains have been derived from 10 representative populations of the North American annual M. bigelovii. The distribution and correlation of 21 phenotypic characters distinguishing these strains has been studied. The genetic similarity of these strains has been previously determined using nu clear DNA polymorphisms. Genetically similar strains (always geographic near neighbors) share phenotypic character states but these involve different characters in different cases. A few character state differences are correlated across all strains via early rosette growth rate, timing of reproduction, or overall capitulum size. Most character states recombine freely. This is evidence for effective gene flow (probably by achene dispersal) among these isolated populations.
Changes in the Constitution of Thylakoid Membranes in Spruce Needles During an Open‐top Chamber Experiment
Authors: Flammersfeld U. , Wild A. 
Published: February 2014

AbstractThe goal of the presented paper was to study the emission effects of natural air pollutants on the protein complexes of the thylakoid membrane. The tests were carried out in the frame of a long‐term experiment in which spruce trees kept in open‐top chambers with unfiltered ambient‐air were compared to spruce trees in chambers with purified‐air. The reaction centres of photosystem I (P‐700), cytochrome f, cytochrome b‐563, cytochrome b‐559, as well as the oxidation speed of the antennae chlorophylls were quantified.The concentrations of the cytochromes f and b‐563 indicate a marked annual rhythm with decreased concentrations during the summer months. The spruce trees in chambers with ambient‐air showed a smaller amount of the studied redox components in relation to 1000 molecules of chlorophyll than did the spruce trees in chambers exposed to purified‐air. In addition, increased oxidation speed of antennae chlorophylls could be observed on the isolated thylakoid membranes of the spruce trees in chambers with ambient‐air conditions. A relationship between the oxidation speed and the ozone concentration of the ambient air could be observed, i.e. with increasing ozone levels the oxidation of the antennae chlorophylls accelerated. However, the damage occurred only with a temporary delay (the so‐called memory effect).In case of the cytochromes f and b‐563 (components of the cytochrome b6f‐complex), a chamber effect related to changed light conditions became obvious when comparing spruce trees kept in chambers to trees left in their natural surrounding. The reduced photosynthetically active radiation — it is reduced in the chambers by 10 − 30% — led to a decrease of both cytochromes.In spite of the effects due to the chambers, the results indicate that ozone could be an effective damage factor and this will be of importance with regard to the situation in the low mountain range of Germany.
The Specific Mineral Metabolism of Selected Plant Species and its Ecological Implications
Authors: Kinzel H. , Lechner Ilse 
Published: February 2014

AbstractIn order to assess and compare the species‐specific mineral metabolism of various plants, we raised eight selected species from different families under identical nutritional conditions. Five different nutrient solutions with varying Ca/K ratios were used. After two months of growth, the leaves were harvested, arranged according to age, and analyzed with respect to their K, Ca, and Mg contents. The ion ratios, the changes of ion contents with increasing age, the differences in water‐ and acid‐soluble Ca (calcium oxalate), and the dependence of ion uptake on variations of ion concentrations in the solutions revealed a species‐specific (“physiotypic”) feature of mineral metabolism. These features are discussed taking into consideration the ecological demands of the investigated species, and assuming that the physiological peculiarities of a species should affect its ecological behavior.
A Comparative Study of Internal Light Environment in Bifacial Leaves of Different Plants
Authors: Remisotosku A. Martinez v. , McClendon J. H. , Fukshansky L. 
Published: February 2014

AbstractParameters of light propagation in plant leaves — absorption and scattering coefficients, asymmetry of scattering — have been estimated on the basis of measured transmission and emission as well as internal fluxes. This estimation has been carried through by solving the inverse problem of the 4‐flux radiative transfer — a theory considering forward and backward diffuse as well as directed components of the overall radiation in a multiple scattering sample. Using the gained parameters, light flux gradients in a two‐layered model leaf have been calculated at different wavelengths. Monte Carlo simulation of absorption spectra performed with the parameters obtained with this treatment is in a good agreement with experimental spectra, thus substantiating the theory. Parallel calculations with the two‐flux (Kubelka‐Munk) theory provide an estimation of the accuracy and applicability of this more simple treatment. Calculations have been performed for three different plants: Catalpa bignonioides, Tilia americana and Vitis riparia.
Peroxidase Catalyzed Dimerization and Demethylation of Protoberberine Alkaloids*
Authors: Bauer W. , Stadler R. , Zenk M. H. 
Published: February 2014

AbstractA peroxidase which catalyzes, in essentially quantitative yield, the dimerization of jatrotthizine to 4,4′‐bisjatrorrhizine was isolated and partly characterized from Berberis stolonifera cell cultures. This peroxidase also mediates the demethylation of a variety of 10‐ or 3‐O‐CH3 substituted tetrahydroprotoberberines and their quarternary analogues. A survey of more than 30 cell culture species, using seven different alkaloids, demonstrated the presence of this catalytic activity mainly in the plant families Berberidaceae and Ranunculaceae, while it was absent in the Papaveraceae. Caution is justified when employing alkaloids labelled at their [‐O‐CH3] groups for enzymatic assays except when peroxidases (even without addition of H2O2) are not present.
Quantification of Visible Structural Changes of the V0V1‐ATPase in the Leaf‐tonoplast of Mesembryanthemum crystallinum by Freeze‐fracture Replicas Prepared During the C3‐Photosynthesis to CAM Transition*
Authors: Klink Rebecca , Lüttge U. 
Published: February 2014

AbstractPlants of the annual facultative halophyte and facultative CAM‐plant, Mesembryanthemum crystallinum L., were irrigated with a solution containing NaCl when they had developed 3 leaf pairs. This treatment induced CAM and the plants were then watered with 400 mM NaCl until the end of the experiment of 37 days. A separate set of plants was simultaneously maintained as non‐salt treated controls. Tonoplast vesicles were prepared from the leaves at regular intervals during the time‐course of the experiment. Three samples of each preparation were freezed fractured, and carbon/platinum‐replicas taken. On a total of 1400 fracture faces the diameters and densities per unit area of intramembraneous particles were measured. The results show an increase in the average diameter of particles from 6.5 nm to 8.5 nm and an increase of the relative amount of fracture faces with high particle densities related to the total of fracture faces obtained; both of which kinetically correlated to CAM induction. This increase in size and density of particles, which are known to belong to the H+‐transporting ATPase of the tonoplast. shows independently of and in addition to protein analyses, that an increased amount of ATPase‐protein is incorporated into the membrane during CAM induction. Some possible explanations for the increase in ATPase particle size are discussed.
Ion‐selective Microelectrodes: Their Use and Importance in Modern Plant Cell Biology
Authors: Felle H. H. 
Published: February 2014

AbstractThe exact ion gradients across cellular membranes and their changes due to metabolic or transport processes can be best studied with the use of ion‐selective microelectrodes. The last decade of research using ion‐selective microelectrodes in intact cells has proven this technique to be indispensable for the investigation of a variety of physiological questions of regulatory processes, membrane transport, cellular signalling, developmental biology and plant nutrition. Their application to selected problems has led to numerous exciting observations, many of which have changed our view concerning cellular responses to environmental stimuli and in many instances have led to a new understanding of plant cell physiology. Since, with these electrodes, intracellular as well as extracellular free ion concentrations can be simultaneously detected with electrical transport parameters such as membrane potential and membrane conductance, they can be powerful tools in the hands of many plant cell biologists.
NPA Inhibits Secretion of Amylases by Barley Aleurone Cells and Auxins can Overcome this Inhibition
Authors: Klämbt D. 
Published: February 2014

AbstractPolar cell growth is regulated by auxin (Klämbt et al., 1992). It is essentially dependent upon exocytosis. Is exocytosis directly regulated by auxin?Aleurone cells secrete amylases, as well as other hydrolases, by exocytosis. In preliminary experiments, with 22 h of incubation, increasing concentration of N‐1‐naphthylphthalamic acid (NPA) parallels the inhibition of amylase secretion.A model system for secretion was designed. Barley aleurone layers, previously incubated in 1 μM GA3 for 16 h, then washed extensively in the presence of 10 μM NPA for 10 min, were incubated finally for 2 h in GA3, NPA and/or auxins. NPA inhibits amylase secretion. Auxins completely abolished secretion inhibition at the optimal concentration of 1 μM.Aleurone layers contain 1.5 to 3 μM endogenous indole‐3‐acetic acid (IAA) and have a high capacity to accumulate and retain IAA. A 7‐fold accumulation occurred within 3 h after application of 20 μM radiolabeled IAA. A loss of about 10% could be measured within the following 4 h period in fresh media, independent of the presence of NPA.The inhibition of amylase secretion by NPA is not due to an inhibition of protein biosynthesis which was tested by the use of [35S]‐methionine.
Photosynthesis of Marine Macroalgae from Antarctica: Light and Temperature Requirements
Authors: Wiencke C. , Rahmel J. , Karsten U. , Weykam G. , Kirst G. O. 
Published: February 2014

AbstractThe photosynthetic performance of macroalgae isolated in Antarctica was studied in the laboratory. Species investigated were the brown algae Himantothallus grandifolius, Desmarestia anceps, Ascoseira mirabilis, the red algae Palmaria decipiens, Iridaea cordata, Gigartina skottsbergii, and the green algae Enteromorpha bulbosa, Acrosiphonia arcta, Ulothrix subflaccida and U. implexa. Unialgal cultures of the brown and red algae were maintained at 0°C, the green algae were cultivated at 10°C. IK values were between 18 and 53 μmol m−2 s−1 characteristic or low light adapted algae. Only the two Ulothrix species showed higher IK values between 70 and 74 μmol m−2 s−1. Photosynthesis compensated dark respiration at very low photon fluence rates between 1.6 and 10.6 μmol m−2 s−1. Values of α were high: between 0.4 and 1.1 μmol O2 g−1 FW h−1 (μmol m−2 s−1)−1 in the brown and red algae and between 2.1 and 4.9 μmol O2 g−1 FW h−1 (μmol m−2 s−1)−1 in the green algal species. At 0°C Pmax values of the brown and red algae ranged from 6.8 to 19.1 μmol O2 g−1 FW h−1 and were similarly high or higher than those of comparable Arctic‐cold temperate species. Optimum temperatures for photosynthesis were 5 to 10°C in A. mirabilis, 10°C in H. grandifolius, 15°C in G. skottsbergii and 20°C or higher in D. anceps and I. cordata. P: R ratios strongly decreased in most brown and red algae with increasing temperatures due to different Q10 values for photosynthesis (1.4 to 2.5) and dark respiration (2.5 to 4.1). These features indicate considerable physiological adaptation to the prevailing low light conditions and temperatures of Antarctic waters. In this respect the lower depth distribution limits and the northern distribution boundaries of these species partly depend on the physiological properties described here.
Somatic Hybrids of Sunflower (Helianthus annuus L.) Identified at the Callus Stage by Isoenzyme Analysis
Authors: Barth S. , Woeste D. , Schnabl Heide 
Published: February 2014

AbstractDark grown hypocotyl protoplasts from Helianthus annuus L. cvs. Cerflor and Euroflor were electrically fused to produce somatic hybrids. Following fusion, the protoplasts were cultivated in agarose droplets for four weeks. Macroscopic visible calli (0.1‐0.3 mm) were transferred onto solid medium and calli reaching a size of 3 mm were collected. Their isoenzyme patterns were analysed based on two different isoenzymes that allow discrimination between the two cultivars used for fusion. From the examined calli, about 26 % showed an isoenzyme pattern of putative binary heterokaryocytes. The isoenzyme pattern of the non‐fused control revealed less than 5% of possibly chimeric colonies.
ATPase Activities and Membrane Fine Structure of Rhizodermal Cells from Sorghum and Spartina Roots Grown Under Mild Salt Stress
Authors: Koyro H.‐W. , Stelzer R. , Huchzermeyer B. 
Published: February 2014

AbstractThe study aims at correlations between ultrastructure of rhizodermal membranes and ATPase activities of two gramineous C4‐species effected by salinization of the growth medium.Comparative investigations were done with drought‐resistant Sorghum and drought‐sensitive, salt tolerant Spartina plants grown under steady‐state conditions without or with 40 mol m−3 NaCl. Both species sustained this treatment and showed marked influences of salt on growth but not on root respiration. Generally, the intramembraneous particle (IMP) frequencies, found on freeze‐fracture replicates of rhizodermal plasmic fracture faces of the plasmalemma (PPF) and tonoplast (TPF), were higher in Sorghum than in Spartina. NaCl leads in both species to an increase of the rhizodermal IMP frequency in the TPF (∼150%) and PPF (∼120%).The activities of T‐ and P‐ATPase were determined for membrane vesicles from crude extracts and from isolated protoplasts of roots, respectively; the results from both preparations were the same. The vanadate‐sensitive tissue ATPase activities increased under salt stress ∼ 5 times in Sorghum and ∼ 2 times in Spartina whilst the nitrate and azide‐sensitive tissue ATPase activities increased ∼ 6 times only in Sorghum.The combination of the results from the membrane fine structures with the biochemical tests points out that salt‐effected increases of ATPase activities of Sorghum roots were ∼4 times higher than the increases of IMP frequencies on rhizodermal membranes; in Spartina this effect is less intense.It is concluded that a salty environment leads to a higher ATPase activity per IMP in both species. The stronger reaction of Sorghum is explainable by the increase in K+/Na+ selectivity of the plasma membrane under salt stress. This is not the case for Spartina because the roots of this species include salt which subsequently is sequestered by the salt glands of the leaves.
Cortical Microtubule Organization and Internodal Cell Maturation in Chara corallina
Authors: Wasteneys G. O. , Williamson R. E. 
Published: February 2014

SummaryThe arrangement of cortical microtubules, as documented by immunofluorescence and immunogold‐silver enhancement, changes during the growth and maturation of giant internodal cells of Chara corallina, a process taking approximately 45 days. Transverse microtubules are found throughout growth along with a subset of distinctly non‐transverse microtubules. During the second half of the growing period, when relative growth rates are diminishing, these non‐transverse microtubules become more abundant but a few days prior to growth cessation, they are mostly absent. At about the time of growth cessation the microtubules, while retaining their locally parallel alignment, begin to show increasing deviation from the transverse axis. Eventually, a mosaic of locally parallel yet variably oriented fields of microtubules forms. Many days after growth stops, microtubules become shorter and less numerous and lose parallel alignment, leading to the formation of a random MT pattern.
Involvement of Ubiquitin in Phosphoenolpyruvate Carboxylase Degradation
Authors: Schulz Margot , Klockenbring T. , Hunte Carola , Schnabl Heide 
Published: February 2014

AbstractWestern immunoblot analysis of protein extracts prepared from epidermal peels, whole leaves, and mesophyll protoplasts with ubiquitin and PEPCase antibodies indicated ubiquitinated PEPCase bands and degradation products only in crude extracts which have been obtained in the presence of the proteolysis inhibitors leupeptin and hemin. After ammonium sulfate precipitation and further purification, PEPCase forms were stable and not ubiquitinated. It is assumed, that only a certain part of PEPCase is degraded via the ubiquitin‐dependent proteolysis.
Modulation of Gene Activity During Photomorphogenesis of Gametophytes of the Fern, Onoclea sensibilis
Authors: Raghavan V. 
Published: February 2014

AbstractGametophytes of the sensitive fern, Onoclea sensibilis grow as filaments in the dark and in red light and assume planar morphology in blue light. RNA content and the synthesis of different RNA fractions as monitored by [3H]‐uridine incorporation and chromatography on oligo(dT)‐cellulose column, were consistently low in the dark‐grown gametophytes, high in blue light and intermediate in red light. No new mRNAs were detected in the translation products primed by poly(A)+ RNA isolated from gametophytes grown under any conditions. Of the nearly 30 polypeptide bands identified in the in vitro profile, some increased in intensity in blue light, while most continued to decay in the dark and in red light. An increase in the intensity of the polypeptide bands was detected when dark‐ or red light‐grown gametophytes were returned to blue light. Abundance of mRNA of the gene for the large subunit of maize ribulose‐1,5‐bis‐phosphate carboxylase/oxygenase (rbcL) remained more or less unchanged during growth of gametophytes in blue light but declined to very low or undetectable levels in red light and in the dark. Transfer of gametophytes from the dark or red light to blue light led to the reappearance of rbcL mRNA. Within the limits of detectability, these observations indicate that light quality or dark condition does not affect the expression of the genome, but modifies its relative transcriptional activity. Overall, the results support the hypothesis that changes in the rate of synthesis or degradation of certain mRNAs are associated with the growth patterns of gametophytes of O. sensibilis in the different environments.
Analysis of the Growth Response of Air‐Grown Rice Coleoptiles to Submergence
Authors: Kutschera U. , Hoss R. , Fröhlich M. , Hoson T. 
Published: February 2014

AbstractThe effect of submergence of air‐grown rice seedlings (Oryza sativa L. var. Sasanishiki) on coleoptile growth and ultrastructure, extensibility and chemical composition of the cell walls was investigated. The lag‐time between start of submergence and the onset of the enhancement of growth was less than 4 h. The growth response was associated with a drastic thinning of the cell walls and an increase in wall extensibility. At the outer epidermal wall of both air‐grown and submerged coleoptiles electron‐dense (osmiophilic) particles were detected. During submergence, the net accumulation of cellulose and hemicellulose was reduced, but the increase in pectic substances was unaffected. Submergence caused an 80% inhibition of the net accumulation of wall‐bound phenolics (ferulic‐ and diferulic acid) compared with air‐grown controls. The osmotic concentration of the tissue saps was not affected by submergence. Our results support the hypothesis that rapid coleoptile elongation under water is caused by an inhibition of the formation of phenolic cross‐links between matrix polysaccharides via diferulate, which results in a mechanical stiffening of the cell walls in the air‐grown coleoptile.
Variation and Evolution of Karyotype Characters in Palm Subfamily Coryphoideae s.l.
Authors: Röser M. 
Published: February 2014

AbstractKaryological data are presented for 13 genera of palm subfamily Coryphoideae s.l. Chromosome numbers of 4 species and of genus Guihaia (G. argyrata, 2n = 36) are new. Apart from the prevailing chromosome number of 2n = 36, subfam. Coryphoideae s.l. shows extreme heterogeneity with respect to chromosome size and morphology, organization of constitutive heterochromatin (C‐banding, fluorochrome staining), interphase nucleus structures and prophase condensation patterns. Five karyologically differing groups of genera can be distinguished (Coccothrinax‐group, Guihaia, Livistona‐group incl. Sabal, Phoenix, and Bismarckia). Chromosome evolution probably has gone from medium sized to very small chromosomes with an average length of less than 1.5 μm; hc‐distribution from evenly distributed throughout the karyotype to accumulated in few chromosomes; from simple banding patterns to complicated ones (hc‐elaboration). Karyotypes with chromosomes of continuously decreasing size, similar morphology, and uniform prophase condensation probably gave rise to almost bimodal karyotypes with non‐uniform, heteropycnotic chromosomal structures. Changes in the organization of interphase nuclei are corresponding. Karyotype differentiation is compared to major evolutionary events in floral and vegetative morphology of subfam. Coryphoideae s.l. Karyologically, genera Phoenix and Bismarckia are isolated and the relations to the remaining part of the subfamily are not clear.
Reconstitution into Liposomes of the Tonoplast ATP‐ and Pyrophosphate‐Dependent Proton Pumps from Rubus hispidus Cell Cultures
Authors: Perotti E. , Chanson A. 
Published: February 2014

AbstractThe ATP‐ and pyrophosphate‐dependent proton pumps from tonoplast‐enriched vesicles prepared from Rubus hispidus cell cultures were solubilized in the presence of polyoxyethylene(9,10)p‐t‐octylphenol (Triton X‐100) and reconstituted into liposomes of soybean phospholipids, using Bio‐Beads SM‐2 to remove the detergent. The specific activity of the two pumps was greatly increased by the solubilization‐reconstitution procedure. Identical characteristics were found for pyrophosphate‐dependent proton transport in native and reconstituted vesicles. On the other hand, the ATP‐dependent proton transport of the reconstituted vesicles was no longer inhibited by KNO3.
Paxillus involutus — Pinus sylvestris Mycorrhizae from Heavily Polluted Forest.
Authors: Turnau K. , Kottke I. , Oberwinkler F. 
Published: February 2014

AbstractThe electron‐opaque granules localized in vacuoles of Paxillus involutus hyphae associated with Pinus sylvestris mycorrhizae, collected from heavily polluted sites were analysed by electron spectroscopic imaging (ESI) and electron energy loss spectroscopy (EELS) connected with the electron microscope (TEM 902, Zeiss). On the basis of the elemental composition two kinds of granules were distinguished. The first, similar in appearance to polyphosphate granules, described already for several fungi, was characterized by high contents of phosphorus accompanied by sulphur, calcium and often aluminium. More common, however, was the second sort of granules containing more nitrogen, sulphur and cadmium, while the amount of phosphorus was much lower. The data reveal accumulation of cadmium inside fungal vacuoles and suggest the possibility of detoxification of heavy metal by the symbiotic fungus.