bluuebunny/crossref_metadata_2025_split huggingface dataset:
Illustration of the Genetic Differences in Ozone Sensitivity Between the Varieties Nicotiana tabacum Bel W3 and Bel B Using Various Plant Systems
Authors: Städtler Sabine , Ziegler H. 
Published: February 2014

AbstractThe ozone‐sensitive tobacco variety Bel W3 was compared with the tolerant cv. Bel B using amphidiploid and amphihaploid genotypes of both. In search of the first genotypical differences, their reaction to acute ozone treatments was investigated with systems of decreasing degree of complexity: whole plants, grown under field, greenhouse and sterile conditions, excised tissues, calli, CCP, MCP and subcellular reactions. It was common to all systems that a fumigation, which clearly exceeds the threshold of the most tolerant material, led to equal reactions in all genotypes in respect of visible injury and membrane leaching. With whole plants and leaf discs growing conditions were found to influence the ozone threshold more than the genotype. Because the most resistant field‐grown plants vary widely in their reaction, only sterile or greenhouse grown genotypes were compared. With the exception of whole sterile plants (no genotypical threshold differences), amphihaploids were more susceptible to ozone than their respective amphidiploids as to threshold and sensitivity spectra in all systems investigated. Higher ozone thresholds were detected for Bel B in all systems with one exception: MCP exhibited a lower threshold but also a lower degree of damage in the first buffer range of the sensitivity spectrum than those of Bel W3. Post‐fumigation starch accumulation in mesophyll chloroplasts was the most prominent subcellular ozone reaction.
The Cyanelles (Organelles of a Low Evolutionary Scale) Possess a Phosphate‐Translocator and a Glucose‐Carrier in Cyanophora paradoxa
Authors: Schlichting R. , Bothe H. 
Published: February 2014

AbstractCyanelles from Cyanophora paradoxa can easily be isolated and assayed for their carrier composition by the silicone oil filtering technique. The present investigation demonstrates a Pi‐translocator transferring phosphate, dihydroxyacetone phosphate and 3‐phosphoglycerate in a counter exchange mode in cyanelles as in chloroplasts of higher plants. The uptake of Pi is inhibited by dihydroxyacetone phosphate, phosphoglycerate and glucose‐6‐P, only poorly by phosphoenolpyruvate and not by 2‐phosphoglycerate. The inhibitors pyridoxalphosphate and 4,4′diisothiocyanostilbene‐2,2K'disulfonic acid at low concentration also affect Pi‐uptake. Cyanelles probably transport photosynthate (reductant and ATP) by triosephosphates. This is the first demonstration of a phosphate translocator in an organism of a low evolutionary scale. Cyanelles also transport glucose which proceeds in two phases. In the lower concentration range (≤ 2.5 mM), glucose penetrates by facilitated diffusion, whereas transport follows first‐order kinetics at higher amounts (> 2.5 mM). In the low concentration range, glucose‐transport is affected by high concentrations of 3‐O‐methylglucose and fructose. The physiological role of the glucose‐transport carrier in Cyanophora is doubtful. It may function in transporting glucose into cyanelles if the carbon level inside them becomes limiting, e.g. in dark periods.
Evaluation of Comparative DNA Amplification Fingerprinting for Rapid Species Identification within the Genus Clusia
Authors: Böhm Martina , Löw R. , Haag‐Kerwer Angela , Lüttge U. , Rausch Th. 
Published: February 2014

AbstractUnderstanding the taxonomiy of the tropical genus Clusia (Fam. Clusiaceae, Ord. Theales) has been hampered by the difficulties inherent in studying tropical dioecious, succulent, arborescent, epi‐ or hemiepiphytic taxa. Species identification by morphological traits often requires the terminal inflorescences and/or the succulent capsular fruits. To allow species differentiation based exclusively on vegetative tissue, a frequent necessity during ecological field studies, a procedure has been developed for rapid isolation of genomic DNA from Clusia leaf tissue followed by DNA amplification fingerprinting with a set of single arbitrary oligomer primers (23–27 mers). Fingerprints obtained with independent DNA preparations from one individual as well as DNA preparations from several individuals of the same species were identical for the major amplification products, although minor bands were somewhat variable. Polymorphic fingerprints have been obtained with 3 different primers for 3 Clusia species (C. minor L., C. alata Pl. & Tr., C. multiflora H. B. K.), and the related Oedematopus obovatus Spruce ex. PL (Clusiaceae). The interspecific Randomly Amplified Polymorphic Markers (RAPDs) thus obtained allow a rapid identification of vegetative tissue samples collected in the field, and will assist in a revision of the controversial taxonomy of the genus Clusia.
Adaptation of the Photosynthetic Apparatus of Anacystis nidulans to Irradiance and CO2‐Concentration
Authors: Müller Claudia , Reuter W. , Wehrmeyer W. , Dau H. , Senger H. 
Published: February 2014

AbstractHomocontinuous cultures of the cyanobacterium Anacystis nidulans (syn. Synechococcus sp. PCC 6301) were grown at white light intensities of 2 and 20 W/m2, and supplied with 0.03 and 3 % CO2 enriched air. The mutual influence of these growth factors on the development of the photosynthetic apparatus was studied by analyses of the pigment content, by low temperature absorbance and fluorescence spectroscopy, by analyses of oxygen evolution light‐saturation curves, and by SDS PAGE of isolated phycobilisomes.The two growth factors, light and CO2, distinctly affect the absorption cross section of the photosynthetic apparatus, which is expressed by its pigment pattern, excitation energy distribution and capacity. In response to low CO2 concentrations, the phycocyanin / allophycocyanin ratios were lower and one linker polypeptide L30R, of the phycobilisomes was no longer detectable in SDS PAGE. Apparently, low CO2 adaptation results in shorter phycobilisome rods. Specifically, upon adaptation to low light intensities, the chlorophyll and the phycocyanin content on a per cell basis increase by about 50% suggesting a parallel increase in the amount of phycobilisomes and photosystem core‐complexes. Low light adaptation and low CO2 adaptation both cause a shift of the excitation energy distribution in favor of photosystem I. Variations in the content of the “anchor” polypeptides L60CM and L75CM are possibly related to changes in the excitation energy transfer from phycobilisomes to the photosystem II and photosystem I core‐complexes.
Pollination in Geonoma macrostachys and Three Congeners, G. acaulis, G. gracilis, and G. interrupta
Authors: Listabarth Ch. 
Published: February 2014

AbstractA continuous 15 month study of the floral ecology of four syntopic understorey palm species of Genoma was conducted in Amazonian Peru lowland rainforest.The spicate inflorescences of G. macrostachys, G. acaulis and G. gracilis are strictly protandrous and the plants are functionally dioecious. Data suggest that in G. macrostachys and G. acaulis pollination is based on a mimicry system, the pistillate flowers mimicking the staminate ones in colour, shape and scent. Pollen‐collecting meliponine bees (Hymenoptera, Apidae, Meliponinae) and pollen‐feeding syrphid flies (Diptera, Syrphidae) which visit inflorescences during both sexual stages are the pollinators of G. macrostachys. Geonoma acaulis is pollinated by small pollen‐feeding weevils (Coleoptera, Curculionidae, Derelomini) that visit male and female spikes.Additionally, in G. macrostachys another pollinator type, viz. euglossine bees (Hymenoptera, Apidae, Euglossinae), which are attracted and rewarded by both types of flowers may account for long‐distance pollination.The palm G. gracilis shows a very distinct pollination system. Although opportunistic insect visitors are attracted to the inflorescences of this species it seems to be mainly anemophilous because pollen becomes powdery during an thesis.The branched inflorescences of G. interrupta are also protandrous, but unlike the other species of Geonoma observed, staminate and pistillate anthesis of individual flowers are, for the most, overlapping. A broad spectrum of visitors is attracted (bees, wasps, flies, and beetles), which all may act as pollinators. Outcrossing is especially encouraged during the purely female phase at the end of the flowering cycle when there are no more staminate flowers in the inflorescence.Effects on the reproductive biology and population structure of different pollination systems and breeding system are discussed.
The Bizarre Inflorescence of Norantea brasiliensis (Marcgraviaceae): Visits of Hovering and Perching Birds1
Authors: Sazima I. , Buzato Silvana , Sazima Marlies 
Published: February 2014

AbstractThe pollination biology of Norantea brasiliensis (Marcgraviaceae) was studied in the rain forest of southeastern Brazil. This plant presents bizarre, brush‐type racemous inflorescences bearing numerous flowers and extrafloral cup‐shaped nectaries. Flower anthesis is diurnal, nectar production is continuous and copious, and the sticky pollen is readily removed by visitors during the first morning hours. The ruby‐coloured inflorescences were visited by eight species of hummingbirds (Trochilidae), and 10 species of passerine birds (three Coerebidae and seven Thraupidae). Hummingbirds hovered while probing for nectar and touched flowers occasionally, whereas passerine birds perched and made contact with flowers habitually. Due to differences in flower‐visiting and general foraging behaviour, perching birds act as better pollen vectors than hovering birds. The inflorescence of Norantea brasiliensis seems well fitted for pollination by passerine birds, and the hexose‐dominated nectar supports this idea. Pollination syndrome trends within Marcgraviaceae may stem from insect‐pollinated, condensed and spike‐like inflorescences which would give rise to bird‐pollinated, brush‐type inflorescences. From the same basic condensed inflorescence, bat‐pollinated umbelliform inflorescence may be derived from bird‐pollinated, pendulous and corymb‐like inflorescences. These postulated inflorescence types are found among the extant species of Marcgraviaceae.
Polyamines and Morphogenesis ‐ Effects of Methylglyoxal‐bis(guanylhydrazone)
Authors: Féray Annie , Hourmant A. , Penot M. , Caroff J. , Cann‐Moisan Christine 
Published: February 2014

AbstractThe effects of methylglyoxal‐bis(guanylhydrazone) (MGBG), an inhibitor of polyamine biosynthesis were studied on tuberization and cellular polyamine content using in vitro Solanum tuberosum (cv Binjte) plants.When MGBG was added to the culture medium, it produced a partial inhibition of the growth of stems and leaves; it totally blocked rhizogenesis and strongly stimulated tuber formation. Morphogenetic effects of MGBG were correlated to a 40 % decrease in free putrescine, spermidine, spermine content of the leaves and to a 28 % decrease in spermidine titer of the stems. In the tubers, this inhibitor did not change the free polyamine titer but increased by up to 85 % the titer of conjugated putrescine, spermidine, spermine. When the plants were grown in the dark, MGBG produced, like benzyladenine, a stimulation of the rate of tuberization and enhanced the content of conjugated polyamines in the tuber.These results support the hypothesis that polyamines play an important role in the morphogenesis of potato plants. The role of polyamine conjugation in tuber development is discussed.
Diurnal Pattern of Transpiration, Water Uptake and Water Budget of Succulents with Different CO2 Fixation Pathways
Authors: Flach Barbara M.‐T. , Eller B. M. 
Published: February 2014

AbstractThe water fluxes and the CO2 exchange of three leaf succulents, Othonna opima, Cotyledon orbiculata and Senecio medley‐woodii, with different leaf anatomy, growth form and CO2 fixation pathways (C3, CAM) were monitored with a gas exchange cuvette which was combined with a potometric system to quantify water uptake. Measurements, which are primarily valid for plants with a sufficient water supply, were made during 6 to 10 consecutive days under constant experimental conditions. Water uptake for 24 h exceeded water loss by transpiration only for a S, medley‐woodii plant with 10 expanding but only 7 mature leaves. In this case the gained water evidently is put into leaf expansion. All other plants showed balanced transpiration and water uptake rates. O. opima and C. orbiculata have a similar life form, similar water storage volumes and the same natural habitat but their diurnal water uptake patterns differ significantly. In the C3 plant O. opima water uptake increased when the transpiration increased or transpiration rates were higher than uptake rates and vice versa. On the contrary the CAM plant C. orbiculata transpired during the dark period at constant or decreasing rates but showed steadily increasing uptake rates. Senecio medley‐woodii‐ and C. orbiculata are CAM plants with similar diurnal water uptake patterns with its maximum in uptake during or towards the end of the CO2 dark fixation period. Water uptake of C. orbiculata was at its minimum at the end of the light period despite transpiration being maximal. The results were discussed considering the different CO2 fixation pathways. In the investigated CAM succulents, C. orbiculata and S. medley‐woodii, the CAM influenced water uptake throughout the whole day and not only during the CO2 dark fixation period.
Seasonal Changes in the Cambium of Trees. I. Sucrose Content in Thuja occidentalis
Authors: Krabel Doris , Bodson Monique , Eschrich W. 
Published: February 2014

AbstractCambium samples of Thuja occidentalis L. were collected at five different times, covering spring reactivation and early and late resting period, and used for sucrose determinations. Fragments of the different cell types ‐ xylem ray, cambial initials, sieve‐elements including phloem parenchyma cells, phloem ray ‐ were dissected from freeze‐dried radial sections and analyzed individually. Results show large differences in sucrose concentrations in the different cell types of the cambial layer. In addition, each cell type also shows seasonal fluctuations in sucrose content, whose amplitudes and patterns of variation appear specific for the particular cell type.
Organ‐ and Tissue‐specific Biosynthesis of Flavonoids in Seedlings of Oenothera odorata (Onagraceae)
Authors: Neumann G. , Schwemmle B. 
Published: February 2014

AbstractIn developing Oenothera odorata seedlings, phytochrome‐mediated accumulation of various flavonoids (mainly glycosides of cyanidin and quercetin) is detectable, subsequent to a transient induction of the key enzymes of the general phenylpropanoid metabolism, L‐phenylalanine ammonia lyase (PAL) and of flavonoid biosynthesis, chalcone synthase (CHS). Organ‐ and tissue‐specific distribution of these enzymes and of the flavonoid end products was investigated in seedlings, irradiated with continuous far‐red light.Anthocyanins and quercetin glycosides are mainly localized in both the upper and lower epidermis of the cotyledons and to a lesser extent also in the epidermal cell layer of the hypocotyl. An obvious organ‐specific distribution was observed for the anthocyanins: cyanidin‐3,5‐O‐diglucoside accumulates in the epidermal cells of the cotyledons, whereas cyanidin‐3‐O‐glucoside is restricted to the epidermis of the hypocotyl. By contrast the pattern of quercetin glycosides is the same in the cotyledons and in the hypocotyl. The methylated flavonol aglycone 3‐0‐methylquercetin was found to be localized in the seed coat. According to this organ‐ and tissue‐specific pattern of flavonoids, immunochemical and immunohistochemical detection of PAL and CHS revealed a predominant localization of theenzymes in the epidermal layers of the cotyledons and the hypocotyl but also in the cells surrounding the vascular bundles. The role of compartmentation in regulation of flavonoid biosynthesis and putative functions of flavonoid compounds are discussed.
A Note on the Evolution of the Stamens in the Laurales, with Emphasis on the Lauraceae
Authors: Rohwer J. G. 
Published: February 2014

AbstractThe number of pollen sacs per anther and their position have traditionally been among the most important systematic characters in the Lauraceae. Opinions differ, however, about the evolutionary direction in these characters. This paper is intended to draw attention to little known morphological features of the stamens, in particular to transitions between disporangiate and tetrasporangiate anthers. In addition, the phylogenetic derivation of the stamen appendages is discussed. It is hypothesized that branched androecial structures may be primitive within the Laurales, if not in the angiosperms as a whole.
Nuclear and Organelle DNA Replication during Spore Germination in Bryophytes and Equisetum
Authors: Thoni Carola , Schnepf E. 
Published: February 2014

AbstractIn contrast to ferns, the spore nuclei of the moss, Funaria hygrometrica, are in the G2 phase. They do not incorporate the thymidine analogue BUdr before the first mitosis. When spores germinate in the presence of aphidicolin, an inhibitor of the (nuclear) DNA polymerase alpha, they give rise to two‐celled, negatively phototropic protonemata, consisting of relatively long and thin cells. Determinations of nuclear DNA content further confirm the presence of G2‐nuclei in Funaria spores. Spores of Pogonatum urnigerum and of Equisetum hyemale likewise contain G2‐nuclei, as shown by BUdr incorporation or experiments with aphidicolin, respectively. In germinating Funaria spores, the organelle DNA is synthesized very early and independent of nuclear DNA. A gradient in replication of organelle DNA is found only in the long tip cells which are formed in the presence of aphidicolin.
Regulation of NADP‐Dependent Glyceraldehyde 3‐Phosphate Dehydrogenase Activity in Spinach Chloroplasts*
Authors: Baalmann Elisabeth , Backhausen J. E. , Kitzmann C. , Scheibe Renate 
Published: February 2014

AbstractActivation of NAD(P)‐glyceraldehyde 3‐phosphate dehydrogenase (NADP‐GAPDH, EC 1.2.1.13) can be achieved in isolated chloroplasts in the light, or in the dark upon addition of dithiothreitol (DTT) and/or 3‐phosphoglycerate plus ATP. Activation in darkened chloroplasts is only partial with DTT or 3‐phosphoglycerate plus ATP alone, but complete when both effectors are added. In the light, full activation is only achieved upon addition of ATP. The time‐course of activation appears to depend upon the actual concentration of 1,3‐bisphosphoglycerate (1,3bisPGA) inside the chloroplasts. The Ka values for 1,3bisPGA are in the same range as has been determined for the purified enzyme, namely around 20 μM for the dark form (in the absence of DTT) and around 1 μM for the light form or in the presence of DTT. In contrast, the Ka value for ATP is 1 to 2 mM for both the oxidized and the reduced enzyme forms. The observed activation of NADP‐GAPDH is strongly paralleled by an increase of 3PGA, and consequently of 1,3bisPGA in the illuminated chloroplast, while the ATP level remains constant or declines. Activation by 1,3bisPGA is accompanied by dissociation of the 600 kDa form to the 150 kDa form, while reduction alone does not induce a shift in molecular mass as documented by fast gel filtration on Superdex 200. Thus partial activation by DTT in the dark is due to an increased activity of the 600 kDa form, while the activation state in the light is the result of a partial conversion of the 600 kDa form into the more active 150 kDa form. The principle of this activation is a fast reduction of the enzyme by the ferredoxin/thioredoxin system, resulting in a lowered Kavalue for 1,3bisPGA, and thus adjusting the properties of the enzyme to the stromal 1,3bisPGA level. The occurrence of a 300 kDa oligomer mainly during inactivation has also been observed. From these results a model is constructed that describes the reversible interconversion of various activation and aggregation states of NADP‐GAPDH as observed upon light/dark transitions in isolated spinach chloroplasts.
Molecules and Morphology, Phylogenetics and Genetics
Authors: Kadereit J. W. 
Published: February 2014

AbstractVarious explanations can be offered for the incongruence between phylogenetic hypotheses resulting from morphological and molecular data sets. Of these, the possibility that incongruence may result from the mutation of major morphogenetic genes leading to dramatic morphological divergence unaccompanied by equivalent change of the phylogenetic marker molecule(s) used is discussed in detail. As evidence for this hypothesis, several examples for such incongruence are surveyed. It seems possible that in many cases the genetic basis of the morphological characters responsible for the incongruence found may be simple, and that the genes involved may be homologous to genes known from mutant systems.It is suggested that: 1. the systematic documentation of incongruence between molecular and morphological phylogenies may help to assess the frequency of evolutionary change through the mutation of major morphogenetic genes, and that 2. the identification of major morphological characters distinguishing closely related taxa with mutant phenotypes known from mutant systems eventually may allow an experimental approach to the problem of evolutionary change resulting from major genes. Natural taxa suspected to be the result of such processes could be changed morphologically through transformation with the relevant genes.
A Phagomyxa‐like Endoparasite of the Centric Marine Diatom Bellerochea malleus: A Phagotrophic Plasmodiophoromycete1
Authors: Schnepf E. 
Published: February 2014

AbstractIn September 1993 the marine centric diatom, Bellerochea malleus (Brightwell) Heurck, collected in the Wadden Sea near List/Sylt, was parasitized by a Phagomyxa algarum‐like organism. Karling (1944) reported Phagomyxa algarum Karling in North Carolina as a parasite of the filamentous brown algae Ectocarpus and Pylaiella. The Bellerochea parasite develops an endocytoplasmic Plasmodium and incorporates host cytoplasm into a large, central digestion vacuole, by a form of phagocytosis. Later on, the Plasmodium cleaves to form a zoosporangiosorus. Each zoosporangium is surrounded by a thin wall. It releases zoospores (2.5 × 4 μm) with two unequal flagella, an anterior (4 μm long) and a posterior (8 μm long). Cystosori and cysts could not be detected. The ultrastructure of the zoosporangia and zoospores was investigated, with particular attention to the flagellar apparatus and its rearrangement during zoospore release. This process is very similar to that recorded for zoospores of the plasmodiophoromycete Polymyxa graminis Ledigham (Barr and Allan, 1982). The Bellerochea parasite is closely related to or identical with Phagomyxa algarum. The taxonomic position of Phagomyxa is discussed. In spite of its phagotrophic nutrition and the possible lack of cystosori and cysts, Phagomyxa should be regarded as a member of the Plasmodiophoromycota (or Plasmodiophorida) but not included in a separate order Phagomyxida as proposed by Cavalier‐Smith (1993a).
Chronology of Phytoparasitic Fungi Introduced to Germany and Adjacent Countries
Authors: Kreisel H. , Scholler M. 
Published: February 2014

AbstractA chronologically arranged list of 59 taxa of phytoparasitic micromycetes, introduced to Germany after 1750, is presented. Another list enumerates 15 fungal taxa which have been introduced to other parts of Europe but may be expected in Germany, too. Most of the enumerated newcomers are members of the orders Pucciniales and Erysiphales. The new terms archaeomycete, neomycete, and ephemeromycete are proposed.