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  • Triticum aestivum  (158)
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  • Springer  (310)
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 53 (1989), S. 287-296 
    ISSN: 1570-7458
    Schlagwort(e): European corn borer ; Ostrinia nubilalis ; maize ; water ; drought ; stress ; development ; models ; phytotron ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Des plants de maïs se développent dans un phytotron dans 4 conditions d'humidité du sol (de la saturation à la dessication) et à 3 températures constantes (20°, 25° & 30°C). Chaque pied est contaminé au moment de l'émission du pollen, par une ooplaque d'O. nubilalis Hübn. (ECB) de race européenne E. L'installation, la colonisation et le développement des chenilles sont notés lors de 12 périodes de prélèvements destructifs (4 par température). La vitesse de développement d'O. nubilalis est affectée par la température, main non par l'humidité du sol. Les 4 niveaux d'humidité du sol n'ont aucun effet sur la teneur en eau des tiges de maïs. En fait, les feuilles de maïs présentent une senescence précoce lorsqu'il y a déficit en eau dans le sol. La teneur en eau du sol agit sur l'installation, sur la distribution verticale, la dispersion et le lieu d'alimentation des chenilles; mais ces effets sont légers et ne modifient pas la vitesse de développement. L'environnement larvaire dans la tige de maïs est efficacement isolé des variations externes par l'aptitude de la plante à maintenir la teneur en eau des tiges relativement élevée et stable. Ainsi, des changements importants au niveau du sol n'ont pratiquement pas d'effets sur le développement d'O. nubilalis, malgré les conséquences brutales pour la plante. Cette étude montre que la vitesse de développement d'O. nubilalis est relativement insensible aux modifications de la teneur en eau du sol ainsi qu'aux effets de ce stress de sécheresse sévère sur le pied de maïs. La discussion porte sur l'importance de ces résultats pour la modélisation de la dynamique de l'insecte, la physiologie de la culture et les interactions entre insecte et plante.
    Notizen: Abstract Maize plants were grown under four moisture regimes (wet to extreme deficit) and three constant temperatures (20°, 25° & 30°C) in a phytotron. Each plant was infested with one E-race European corn borer [Ostrinia nubilalis (Hubn.)] (ECB) egg mass at pollen shed. ECB development, location, and establishment were recorded over the course of 12 destructive sample dates (4/temperature). ECB developmental rates were not significantly affected by soil moisture treatments, but were significantly affected by temperature. In spite of successful establishment of four distinctly different soil moisture regimes, the maize stalk tissue water levels were not significantly different among soil water treatments. Instead, the maize plants exhibited accelerated leaf senescence in response to the water deficit conditions. Among the soil water treatments, differences were found in larval establishment, vertical distribution and dispersion, and feeding site selection; however, those effects were slight and could not explain the similarity in ECB developmental rates observed in these treatments. In maize, the larval environment within the stalk was effectively insulated from changes in the external environment by the plant's ability to maintain a relatively high and stable stalk tissue water content. Thus, large changes to the soil environment had essentially no effect on ECB development, though drastic consequences for the plant. This study indicates that ECB rates of development are relatively insensitive to changes in the soil water environment as well as the associated changes in the maize plant that accompany severe drought stress. The significance of these findings to insect modelling, crop physiology, and insect-crop interactions is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of insect behavior 2 (1989), S. 849-852 
    ISSN: 1572-8889
    Schlagwort(e): alternative mating tactics ; temperature ; Stictia heros ; Sphecidae ; Costa Rica
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 45 (1989), S. 171-173 
    ISSN: 1420-9071
    Schlagwort(e): Estrogen receptor ; homogenization ; temperature ; nucleus ; uterus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Homogenization of rat uterus at elevated temperatures results in an increased nuclear localization of unoccupied estrogen receptor. This is a nonlinear effect which is accounted for by an increased population of KCl-resistant nuclear binding sites at the elevated homogenization temperatures.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 45 (1989), S. 349-351 
    ISSN: 1420-9071
    Schlagwort(e): Spermatogenesis ; temperature ; brain ; hibernation ; Helix aspersa
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Ablation of the brain from hibernatingHelix aspersa maintained at 25°C causes a significant increase in the proliferation of male cells in the gonad, whereas the ablation of the optic tentacles has no effect. The brain, therefore, produces a factor which specifically inhibits the multiplication of spermatogonia and spermatocytes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1570-7458
    Schlagwort(e): Coleoptera ; Cerambycidae ; Morimus funereus ; development ; laboratory conditions ; food quality ; temperature ; season
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé L'étude a porté sur les effets d'une température constante (23 °C), de la qualité de l'aliment,-B = aliment naturel, c'est-à-dire de l'écorce de chêne pulvérisée; B+C = aliment naturel enrichi avec de la poudre de biscuits sucrés-, et de la saison sur le développement larvaire de M. funereus L. La température de 23 °C a été défavorable aux larves récoltées en septembre dans des souches de chênes et élevées sur aliment B: les larves étaient mortes en 30 jours. Avec aliment B+C, l'effet défavorable a été neutralisé et le poids des larves augmenté de 543%, 897% et 1179% en 1, 2 et 3 mois. Des larves néonates d'été ou d'hiver se sont bien développées sur B+C, mais toutes les larves d'hiver étaient mortes sur B en 40 j. Des larves de mêmes parents, écloses à différentes époques de l'année, ont présenté des différences saisonnières du taux de survie et de la vitesse de développement lors de leur élevage à 23 °C sur B+C. Le développement le plus rapide et la meilleure survie ont été obtenus avec des larves écloses au début ou au milieu de l'été; tandis que le développement le plus lent et la plus mauvaise survie ont été obtenus avec les larves écloses à la fin de l'été. Les changements saisonniers synchrones des adultes et de leurs descendants, exprimés à différents niveaux d'organisation biologique, suggèrent l'existence d'un rythme annuel endogène qui dépend de l'expression de différents gènes au cours du cycle annuel.
    Notizen: Abstract The effects of constant temperature (23 °C), food quality (B, natural diet i.e. powdered oak bark; B+C, natural diet enriched with powdered sweet crackers) and season on larval development of the cerambycid Morimus funereus L. were studied. The temperature of 23 °C exerted an unfavourable effect on larvae collected from oak stumps in September and bred on B; i.e. the larvae died within 30 days. When the larvae consumed B+C the unfavourable effect of temperature was abolished and the larvae increased their weight by 543%, 897% and 1179% in 1, 2 and 3 months, respectively. Newly hatched summerand winter-larvae developed successfully on B+C, while all the winter-larvae died within 40 days on B. Larvae of an identical parentage hatched in different phases of the annual cycle and showed seasonal differences in the rate of development and survival when reared on B+C at 23 °C. The fastest development and the highest survival rate were observed in larvae which emerged in early- and midsummer, whereas the slowest development and the lowest survival rate were in those hatched in late summer. The synchronized seasonal changes of adults and their offspring, as expressed at different levels of biological organization, suggest the existence of an endogenous annual rhythm which is dependent upon the expression of different genes in the course of the annual cycle.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 52 (1989), S. 185-188 
    ISSN: 1570-7458
    Schlagwort(e): Heteroptera ; Dolycoris baccarum ; S. Norwegian population ; adult hibernal diapause ; diapause completion ; diapause activation ; diapause induction ; diapause prevention ; photoperiod ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    ISSN: 1570-7458
    Schlagwort(e): Developmental rates ; temperature ; parasitoid ; mealybug ; Hymenoptera ; Encyrtidae ; Epidinocarsis diversicornis ; Acerophagus coccois ; Homoptera ; Pseudococcidae ; Phenacoccus herreni ; cassava ; yucca
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Les vitesses de développement des oeufs et de tous les stades larvaires mâles et femelles de P. herreni Cox & Williams ont été déterminées à 18°, 20°, 22°, 25°, 30° et 35°C. La longévité des adultes mâles et femelles a été déterminée. Les vitesses de développement de la ponte à la formation du cocon et de celleci à l'émergence de E. diversicornis Howard, encyrtide parasite de P. herreni ont été déterminées à 18°, 20°, 25° et 30°C. Il en a été de même pour un second encyrtide parasite A. coccois Smith à 20°, 25° et 30°C. Les équations polynomiales des derniers carrés dérivés et les équations logistiques ont été ajustées pour chaque lot de données (à l'exception de A. coccois) de façon à ce qu'elles aient pu être interpolées pour analyser l'impact de ces parasites sur la dynamique de population de P. herreni. Les résultats de cette analyse sont présentés à part.
    Notizen: Abstract Developmental rates for Phenacoccus herreni Cox & Williams were determined at 18°, 20°, 22°, 25°, 30° and 35°C for the egg, all juvenile male and all juvenile female stadia. Longevity was determined for adult females and adult males. Developmental rates for the P. herreni parasitoid Epidinocarsis diversicornis (Howard) were determined at 18°, 20°, 25° and 30°C for the oviposition-to-mummy-formation period and the mummy-formation-to-adult-eclosion period. Developmental rates were determined for the P. herreni parasitoid Acerophagus coccois Smith for the same two life stages at 20°, 25° and 30°C. Least-squares-derived polynomial equations or logistic equations were fitted to each data set (except for A. coccois) so that rates could be interpolated for temperatures between observed points for use in an analysis of the impact of these parasitoids on population dynamics of P. herreni. Results of this analysis are presented separately.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 50 (1989), S. 185-193 
    ISSN: 1570-7458
    Schlagwort(e): temperature ; development ; simulation ; phenology ; budmoth ; Zeiraphera canadensis ; Tortricidae ; degree-days
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé La diapause des oeufs de Zeiraphera canadensis Mutuura et Freeman (Lepidoptera: Tortricidae) a été complétée après 15 semaines d'élevage à 0,5°C. A ce stade de leur développement, une température supérieure à 30°C leur est létale. Les relations entre la température et le développement des larves sur l'épinette blanche, Picea glauca (Moench) Voss, et des pupes ont été observées au laboratoire. Les temps de développement les plus courts ont été observés à 28°C. Les larves sont tolérantes à la chaleur et se développent à 32 C, une température qui est létale aux pupes. II y a peu de variabilité des taux de développement de tous les stades immatures. Ceci explique le haut degré de synchronie observé au sein de populations de cet insecte. Un modèle simulant la phénologie a été mis au point et calibré pour prédire la fréquence des divers stades du cycle vital sous des conditions de terrain. La processus de calibration a révélé que la température dans le microhabitat des oeufs est très semblable à celle de l'air, mais que les larves, retrouvées sous l'enveloppe des bourgeons, sont exposées à des températures pouvant excéder celle-ci de plusieurs degrés. Pour des fins de planification du synchronisme entre le développement de l'insecte et des programmes de suivi et de lutte, le nombre de degré-jours nécessaires pour atteindre 10% d'éclosion des oeufs ou 75% d'émergence des adultes ont été estimés à partir d'une température seuil de 4,4°C.
    Notizen: Abstract Diapause requirements of eggs of Zeiraphera canadensis Mutuura and Freeman (Lepidoptera: Tortricidae) are satisfied by 15 weeks of storage at 0.5°C. Temperatures above 30°C are lethal for this life stage. Temperature-dependent development of larvae fed on white spruce, Picea glauca (Moench) Voss, and of pupae was observed under laboratory conditions. The shortest development times were observed at 28°C. Larvae are tolerant to heat, and developed at 32°C, a lethal temperature for pupae. There was little variation of development rates in all stages of the life cycle, explaining the high degree of phenological synchrony reported in populations of this species. A phenological model was developed and calibrated to simulate the relative abundance of the various immature stages under field conditions. The calibration process suggested that temperature in the microhabitat of eggs may be very close to air temperature, but that temperatures under bud caps where larvae are feeding may rise several degrees above air temperature. For the purposes of planning the timing of survey and control practices, degree-day requirements for 10% egg hatch and 75% adult emergence were estimated based on a 4.4°C threshold temperature.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    ISSN: 1432-0789
    Schlagwort(e): Wheat ; Paddy straw compost ; N and P enrichment ; Rock phosphate ; Pyrite ; Triticum aestivum ; Nutrient uptake
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary A nutrient-rich compost from paddy straw was prepared using urea and Mussoorie rock phosphate for N and P enrichment respectively. Inorganic N was partly conserved in the compost by the addition of pyrite. Citric-acid-soluble P also increased with the addition of pyrite. Compost containing about 1.6% total N and 3.3% total P was found to be a good source of P for a wheat crop and also supplied a significant amount of N to the plants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 20 (1989), S. 59-66 
    ISSN: 1573-0867
    Schlagwort(e): Ammonia volatilization ; nitrogen leaching ; denitrification ; time of N application ; wheat ; Triticum aestivum ; Triticale ; irrigation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Grain yield, nitrogen (N) assimilation, ammonia (NH3) volatilization, denitrification and fertilizer N distribution were examined in three commercially grown cereal crops; two were sown into conventionally tilled fields, while the third was direct drilled into an untilled field. The crops were top dressed with urea at establishment, tillering or ear initiation. Crop yield and N assimilation were measured in 16 m by 2.5 m plots receiving 0, 35, 70, 105, 140 or 175 kg N ha−1. A mass balance micrometeorological technique was used to measure NH3 volatilization, and other fertilizer N transformations and transfers were studied using15N labelled urea in microplots. On the conventionally tilled sites application of urea increased the grain yield of wheat from 3.9 to 5.5 t ha−1, when averaged over the five application rates, three application times and two sites. There were no site or application time effects. However, on the direct drilled site, time of application had a significant effect on grain yield. When urea was applied at establishment, grain yield was not significantly increased and the mean yield (2.81 t ha−1) was less than that obtained from treatments fertilized at tillering or ear initiation (4.09 and 4.0 t ha−1, respectively). Much of the variation in grain yield at the no-till site could be ascribed to differences in NH3 volatilization. At the no-till site, NH3 losses were equivalent to 24, 12 and 1% of the N applied at establishment, tillering and ear initiation, respectively. Negligible volatilization of NH3 occurred at the other sites. The surface soil at the no-till site had the highest urease activity and the soil was covered with alkaline ash resulting from stubble burning. Plant recovery of fertilizer N did not vary with application time on conventionally tilled sites (mean 62%). However, plant recovery of15N applied to the no-till site at establishment (35% of the applied N) was significantly less than that from plots where the application was delayed (45% at tillering and 55% at ear initiation, respectively). Leaching of N to below 300 mm depth was minimal (0 to 5% of the applied N). The calculated denitrification losses ranged from 1% to 14% of the applied N. The results show that the relative importance of NH3 volatilization, leaching and denitrification varied with site and fertilization time. The importance of the various N loss mechanisms needs to be taken into account when N fertilization strategies are being developed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Biodegradation 7 (1989), S. 159-193 
    ISSN: 1572-9729
    Schlagwort(e): Brachiopod biogeochemistry ; diagenesis ; secular isotopic variations ; carbon isotopes ; oxygen isotopes ; Sr/Ca ; temperature ; Recent ; Late Paleozoic
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Energietechnik , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Sr/Ca ratios in modern brachiopod shells reflect variations in ambient seawater, whereas their Na contents show no relationship with water depth or habitat. Their Mn and Fe contents are controlled, in part, by leaching of these elements from oxide coatings or the low input/sedimentation rate of detrital material into depositional areas such as Quatsino Sound. For most Carboniferous brachiopods from North America, the Mn and Fe contents are similar to those recorded by their Recent counterparts. The high Mn and Fe contents in the brachiopods from shales suggest several possibilities for these levels. One possibility is the leaching of Mn and Fe from oxide coatings/matrix which was not completely removed in the cleaning process, or the high levels in part reflect unusual depositional conditions (some degree of anoxia) for the local shaly environments. The Sr/Ca ratio of brachiopods and, by inference, complementary seawater, did not vary significantly during the Carboniferous. The Sr/Ca minimum observed in brachiopods of Mississippian age coincides with a dip in the 87Sr/86Sr curve and correlates with the Hercynian orogeny. This is attributed to the cycling of seawater through mid-ocean ridge basalts, and postulated exchange reactions account for variation in the composition of seawater-Ca. The unidirectional trend of heavier δ13C values from the Devonian to the Permian is intricately coupled with the evolution of the terrestrial biomass. In addition to expansion of terrestrial plants, burial of reduced carbon in the form of coal (organic matter) contributed to the observed shift. The start of the Permo-Pennsylvanian glaciation is marked by a negative excursion of the secular carbon trend, which is linked to weathering of reduced carbon and its return to the oceanic reservoir with its oxidized carbon. The oxygen isotope values reflect the unidirectional trend towards higher values of the carbon data with decreasing geologic age. Negative excursions of the trend may be related to extensive weathering of terrestrial and submarine rocks, whereas positive excursions may be related to hydrothermal alteration of submarine rocks and dehydration of oceanic crust during times of active sea-floor spreading. Oxygen-calculated water temperatures of unaltered brachiopod material are unrealistically high for all of the Devonian, and the Chesterian-Meramecian, Desmoinesian-Missourian, and Artinskian Epochs. During these times maximum water temperatures of 42° to 56°C are well above the thermal threshold of protein denaturation. This process, which is lethal to most higher organisms, demands an adjustment in oxygen of -2.5%. for samples older than Missourian, and of -1.250%. for samples spanning the Missourian-Artinskian interval. With these adjustments and salinity considerations made prior to calculations, water temperatures become reasonable for the Late Paleozoic epeiric, tropical seas of North America.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 45 (1989), S. 102-103 
    ISSN: 1420-9071
    Schlagwort(e): Djungarian hamster ; photoperiod ; temperature ; T3 ; T4 ; testosterone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effects of photoperiod, temperature and testosterone treatment on plasma T3 and T4 levels were investigated in the Djungarian hamster. Plasma T3 level was affected by temperature (25°C〈7°C) but not by photoperiod. Plasma T4 level was affected by photoperiod (short day 〈 long day) at 25°C. Administration of testosterone increased plasma T4 level under short photoperiod at 25°C. Thus, higher plasma T4 level under long photoperiod at 25°C might be induced by testosterone.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    ISSN: 1432-2145
    Schlagwort(e): Pollen development ; Triticum aestivum ; RH0007
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A study of pollen development in wheat was made using transmission electron microscopy (TEM). Microspores contain undifferentiated plastids and mitochondria that are dividing. Vacuolation occurs, probably due to the coalescence of small vacuoles budded off the endoplasmic reticulum (ER). As the pollen grain is formed and matures, the ER becomes distended with deposits of granular storage material. Mitochondria proliferate and become filled with cristae. Similarly, plastids divide and accumulate starch. The exine wall is deposited at a rapid rate throughout development, and the precursors appear to be synthesized in the tapetum. Tapetal cells become binucleate during the meiosis stage, and Ubisch bodies form on the plasma membrane surface that faces the locule. Tapetal plastids become surrounded by an electron-translucent halo. Rough ER is associated with the halo around the plastids and with the plasma membrane. We hypothesize that the sporopollenin precursors for both the Ubisch bodies and exine pollen wall are synthesized in the tapetal plastids and are transported to the tapetal cell surface via the ER. The microspore plastids appear to be involved in activities other than precursor synthesis: plastid proliferation in young microspores, and starch synthesis later in development. Plants treated with the chemical hybridizing agent RH0007 show a pattern of development similar to that shown by untreated control plants through the meiosis stage. In the young microspore stage the exine wall is deposited irregularly and is thinner than that of control plants. In many cases the microspores are seen to have wavy contours. With the onset of vacuolation, microspores become plasmolyzed and abort. The tapetal cells in RH0007-treated locules divide normally through the meiosis stage. Less sporopollenin is deposited in the Ubisch bodies, and the pattern is less regular than that of the control. In many cases, the tapetal cells expand into the locule. At the base of one of the locules treated with a dosage of RH0007 that causes 95% male sterility, several microspores survived and developed into pollen grains that were sterile. The conditions at the base of the locule may have reduced the osmotic stress on the microspores, allowing them to survive. Preliminary work showed that the extractable quantity of carotenoids in RHOOO7-treated anthers was slightly greater than in controls. We concluded that RH0007 appears to interfere with the polymerization of carotenoid precursors into the exine wall and Ubisch bodies, rather than interfering with the synthesis of the precursors.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    The journal of membrane biology 112 (1989), S. 277-289 
    ISSN: 1432-1424
    Schlagwort(e): myelinated nerve fiber ; gating current ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary Asymmetrical displacement currents and Na currents of single myelinated nerve fibers ofXenopus laevis were studied in the temperature range from 5 to 24°C. The time constant of the on-response atE=4 mV,τ on, was strongly temperature dependent, whereas the amount of displaced charge atE=39 mV, Qon, was only slightly temperature dependent. The mean Q10 forτ on -1 was 2.54, the mean Q10 for Qon was 1.07. The time constant of charge immobilization,τ i , atE=4 mV varied significantly (α=0.001) with temperature. The mean Q10 forτ i -1 was 2.71±0.38. The time constants of immobilization of gating charge and of fast inactivation of Na permeability were similar in the temperature range from 6 to 22°C. The Qoff/Qon ratio forE=4 mV pulses of 0.5 msec duration decreased with increasing temperature. The temperature dependence of the time constant of the off-response could not be described by a single Q10 value, since the Q10 depended on the duration of the test pulse. Increasing temperature shifted Qon (E) curves to more negative potentials by 0.51 mVK −1, but shiftedP Na (E) curves andh ∞ (E) curves to more positive potentials by 0.43 and 0.57 mV K−1, respectively.h ∞ (E=−70 mV) increased monotonously with increasing temperature. The present data indicate that considerable entropy changes may occur when the Na channel molecule passes from closed through open to inactivated states.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 78 (1989), S. 728-734 
    ISSN: 1432-2242
    Schlagwort(e): Esterases ; Genetic variability ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Genetic variability of endosperm esterase has been studied in 42 cultivars of Triticum aestivum L. 2n=6x=42. Different techniques, including sequential electrophoresis and electrofocusing, have been used with various substrates and esterase inhibitors. The electrophoretic patterns in each cultivar are described. Chromosomal location using the nullitetrasomic and ditelosomic lines of Chinese Spring was carried out in order to relate and/or locate the esterase genes to specific chromosomes. Most of the esterase isozymes located were in the long arm of the chromosomes of the homoeology group 3; but we have found six located in the short arms, five of them in the chromosome 3AS and one in the 3DS. This location increases the number of esterase genes described, because no esterase genes had been described so far in short arms of chromosomes of the homoeology group 3. The genetic control is discussed and, according to our results, between 12 and 15 loci, organized in five “compound loci”, control the endosperm esterases in wheat. Also one “modifier” gene modifying the mobility of two esterase bands and present in all the cultivars studied is postulated.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 78 (1989), S. 873-878 
    ISSN: 1432-2242
    Schlagwort(e): Heat shock proteins ; 2D electrophoresis ; Triticum aestivum ; Gene location ; Gene regulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The low molecular weight heat shock protein (HSP) profiles of the hexaploid wheat cultivar “Chinese Spring” and its ditelosomic series were characterized by isoelectric focusing polyacrylamide gel electrophoresis of denatured in vivo radiolabeled proteins. Comparisons of the ditelosomics (DTs) to the euploid “Chinese Spring” enabled the assignment of genes controlling 9 of the 13 targeted HSPs to seven chromosome arms. There did not appear to be a genome-specific action in the regulation of expression of these HSPs. There did appear to be a higher frequency of controlling genes within homoeologous DT lines 3, 4 and 7. Significant variation in protein quantity was evident among the DT lines for some HSPs, while other HSPs were remarkably stable in their expression across all DTs examined. The results are useful in identifying specific DT lines for the investigation of HSP functions in hexaploid wheat.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 77 (1989), S. 162-168 
    ISSN: 1432-2242
    Schlagwort(e): Triticum aestivum ; Agropyron ; (Elytrigia, Thinopyrum) ; Intergeneric hybridization ; Crossability ; Wide crosses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Intergeneric hybrids between Triticum aestivum L. and conventional rhizomatous Agropyron species were produced in variable frequencies. They were recovered in high percentage frequencies for T. aestivum cultivars with A. acutum (14.6%), A. intermedium (48.0%), A. pulcherrimum (53.3%), and A. trichophorum (46.6%). The crossability percentages with the highly crossable cultivar ‘Chinese Spring’ for these Agropyron species accessions were 33.12%, 65.0%, 53.3%, and 65.4%, respectively. Autosyndetic associations of two of their three genomes gave mean meiotic chromosome association data of 17.0 I (univalents) +1.53 II (ring bivalents) + 7.04 II (rod bivalents) +1.43 III (trivalents) +0.05 IV (quadrivalents) +0.01 IV (pentavalents) for A. acutum and of 21.8 I + 1.56 II (rings) +7.22 II (rods) +0.84 III + 0.04 IV for A. intermedium. Chromosome pairing at metaphase I was comparatively lower for A. pulcherrimum (34.4 I + 0.2 II (rings) +3.4 II (rods) +0.14 III) and A. trichophorum (36.7 I + 0.35 II (rings) +2.26 II (rods) + 0.04 III) hybrids with T. aestivum. Hybrids of wheat with A. campestre and A. repens were obtained in low frequency. Direct crossing did not permit T. aestivum/ A. desertorum hybridization. However, by utilizing the 2n=10x=70 A. repens/A. desertorum amphiploid as the pollen source, hybridization with T. aestivum did indeed occur. Aneuploidy was prevalent in this hybrid combination while all other hybrid combinations were apparently normal.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 78 (1989), S. 229-232 
    ISSN: 1432-2242
    Schlagwort(e): Triticum aestivum ; Puccinia recondita ; Adult plant resistance ; Resistance genes ; Durable resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Wheat genotypes, including backcross derivatives of ‘Thatcher’ carrying Lr10 and Lr23, substitution lines for Lr10 and Lr23 in Chinese Spring background and Chinese Spring and Thatcher were analysed against 21 pathotypes of leaf rust in seedling tests. Adult plant responses in all these stocks were observed in the field nurseries under exposure to the inoculum of the Indian virulent races of leaf rust. The seedling data demonstrated that both the substitution lines and the backcross derivatives for each gene carry identical pattern of infection for resistance. The high level of adult plant resistance in the substitution lines, in contrast to the backcross derivatives in Thatcher, has been postulated to be due to the combination of resistance contributed by Lr10 and adult plant Chinese Spring resistance or to Lr23 and Chinese Spring adult plant resistance. It has been suggested that genes Lr10 and Lr23 added to the Chinese Spring background provide sources for durable resistance, since Chinese Spring has continued to provide a moderate level of adult plant resistance to leaf rust for a very long time.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 78 (1989), S. 521-524 
    ISSN: 1432-2242
    Schlagwort(e): Triticum aestivum ; SCEs ; Auxin ; Cytokinin ; Tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In order to know the mutagenic effects of synthetic auxins (NAA, 2,4-D, and 2,4,5-T) and a cytokinin (kinetin) in vitro, sister chromatid exchanges (SCEs) were analyzed in cultured cells of a hexaploid wheat (Triticum aestivum L.). In the MS medium supplemented with 2.0 mg/l 2,4-D, the mean number of SCEs per cell was 15.2, and per pg of DNA, 0.42. No significant effect was found in the treatments of NAA or 2,4-D at concentrations of 0.5–10.0 mg/l, whereas more than 2.0 mg/l of 2,4,5-T induced dramatic increases of SCEs. Kinetin itself had no significant effect on SCE induction, but there was a tendency that SCEs induced by 2,4,5-T were suppressed by kinetin.
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 78 (1989), S. 625-632 
    ISSN: 1432-2242
    Schlagwort(e): Triticum aestivum ; Tissue culture ; Callus ; Monosomic analysis ; Regeneration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ability of immature embryos of wheat (Triticum aestivum L.) to respond in cell culture was examined in crosses between the ‘Wichita’ monosomic series and a highly regenerable line, ‘ND7532’. Segregation in disomic controls and 13 monosomic families showed a good fit to a monogenic ratio indicating a qualitative mode of inheritance. Segregation in the cross involving monosomic 2D showed a high frequency of regeneration (93.6%) and high callus growth rate (1.87 g/90 days) indicating that 2D is a critical chromosome. Modifying genes may be located on other chromosomes. Substitution of chromosomes from a low regenerable cultivar ‘Vona’ further indicated that the group 2 chromosomes, in particular chromosome 2D, possess genetic factors promoting callus growth and regeneration.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 152 (1989), S. 14-21 
    ISSN: 1615-6102
    Schlagwort(e): Differentiation ; Heterochronic lysis ; Polarity ; Root protophloem sieve elements ; Triticum aestivum ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied phycology 1 (1989), S. 59-65 
    ISSN: 1573-5176
    Schlagwort(e): temperature ; acclimation ; Eucheuma alvarezii ; Eucheuma isiforme
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Branch cultures ofEucheuma alvarezii Doty var.tambalang Doty, farmed in the Philippines, andE. isiforme (C. Agardh) J. Agardh var.denudatum Cheney, from the west coast of Florida, were gradually transferred through three temperature regimes over a 6-week period. Photosynthetic responses were measured under a series of irradiances (P-I curves) and temperatures to determine immediate responses of the plants before, during and after completion of the transfers. The Philippine variety did not show acclimation to 18 °C either after gradual transfer from the initial culture temperature of 25 °C or when abruptly transferred from 25 to 18 °C. The Florida variety did show acclimation to 25 °C when gradually transferred from 18 to 22 to 25 °C over the 6-week period, but not if abruptly transferred from 18 to 25 °C. The west coast variety ofE. isiforme from Florida shows a temperature acclimation ability that parallels the seasonal changes in water temperature of its habitat.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 119 (1989), S. 87-97 
    ISSN: 1573-5036
    Schlagwort(e): irradiance ; root development ; root growth ; shoot development ; shoot growth ; temperature ; thermal time ; winter wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Wheat plants were grown in columns of soil until early stem elongation at a wide range of constant root temperatures. Two light environments were imposed and three levels of nitrogen fertilizer added at sowing. Shoot and root development and growth were measured by destructive sampling to investigate the combined effects of temperature and changing nutrient and assimilate supply. Both mainstem leaf and root axis production were linearly related to thermal time above a base temperature of 0°C. Low irradiance affected the appearance of mainstem tillers and associated nodal root axes. Nitrogen had little effect on shoot or root development but increased shoot area between 6 and 8 mainstem leaves. Higher temperatures and supplementary light resulted in larger root systems when compared at equivalent times after sowing. Total root length and root dry weight increased exponentially with thermal time, based on the mean of 4 cm soil and 2 cm air temperatures, but no single relation existed for all temperature and light treatments. Total plant dry matter, root length and root dry weight increased linearly with accumulated, intercepted, photosynthetically active radiation. Root growth responded less than the shoot to supplementary light. Increasing temperature reduced the proportion of root weight to total plant weight.
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 119 (1989), S. 99-110 
    ISSN: 1573-5036
    Schlagwort(e): Irradiance ; root development ; root growth ; temperature ; thermal time ; winter wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Winter wheat was sown on 2 dates with 3 levels of nitrogen fiertiliser (0, 50 and 200 kg N ha−1) in one year and on 2 sites in a followign season. Shoot and root development and growth were measured between emergence and anthesis in the first season and emergence and 7 mainstem leaves in the second. Differences in temperature and light regime led to significant differences in shoot and root development and growth between sowing dates. A thermal time-scale, based on soil surface or air temperatures, with a base of 0°C, adequately described the production of mainstem leaves and nodal root axes over all treatments. Autumn applied nitrogen had little effect on development. Shoot growth and green area index increased exponentially with thermal time prior to spring nitrogen application and the completion of canopy development. Early-sown crops had larger root systems than late-sown crops prior to winter and this divergence was retained until anthesis. The relationship between root growth and thermal time was little better than with days after sowing and was not improved by either varying the site of temperature measurement or the base temperature used for calculation. Differences in soil texture and drainage, between sites, led to significant changes in root length distribution. Although spring applied nitrogen generally increased root length, its effects were inconsistent. There was a curvilinear relation between root length and the amount of photosynthetically active radiation (PAR) intercepted; this relation was unaffected by sowing date or nitrogen treatment. The amount of root produced per unit PAR decreased as the season progressed, reflecting the decrease in the proportion of total dry matter partitioned to the root system.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 119 (1989), S. 199-204 
    ISSN: 1573-5036
    Schlagwort(e): copper sources ; grain yield ; methods of application ; park wheat ; stem melanosis ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Park wheat (Triticum aestivum cv. Park) is susceptible to stem melanosis when grown on Cu-deficient soils. Three field experiments were conducted to evaluate the effectiveness of various Cu sources, using different methods and rates of application for reducing the incidence of stem melanosis and increasing the grain yield of Park wheat on a Cu-deficient Black Chernozemic soil in central Alberta. A fourth experiment determined the residual effect of Cu over 4 years. In the first experiment, Park wheat had less disease and higher grain yield when Cu-chelate solution at 2 and 4 kg Cu ha−1 or Cu-sulfate solution at 10 and 20 kg Cu ha−1 was applied to the soil surface and incorporated to a depth of 8 cm or was applied at these rates as a foliar spray. The foliar application, however, was phytotoxic and delayed maturity by approximately two weeks. Sidebanding Cu (4 cm to the side and 4 cm below the seed row) was least effective. In the second experiment, Cu-sulfate solution incorporated into the soil was more effective than the soil incorporated granular Cu-sulfate in reducing disease incidence and increasing grain yield in the year of application. In the following year the granular Cu was as effective as solution Cu. The third experiment showed that Cu seed dressings did not have any effect on disease incidence or grain yield of Park wheat. In the fourth experiment, the residual effect of Cu-chelate was evident four years after application. The grain yield in the fourth year was about four times that of the control.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 40 (1989), S. 161-167 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; bread wheat ; near-isogenic lines ; phenotypic similarity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The degree of phenotypic similarity of Centana and its near-isogenic lines (NILs) has been investigated. Some NILs have a disease reaction, a gliadin pattern and a yield level which differs from Centana. This means that they still possess many donor genes. One of the NILs, Shortana, must be a derivative of a backcross line crossed with an unknown genotype resulting in a good yielding variety.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 40 (1989), S. 259-264 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; bread wheat ; Triticum turgidum durum ; durum wheat ; pentaploid hybrids ; homoeologous pairing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The meiotic behavior of 22Triticum turgidum durum × Triticum aestivum L. cv. Chinese Spring (2n=35 chromosomes, AABBD genomes) F1 hybrids has been analyzed and compared with that of the same cultivars hybridized withT. turgidum durum cv. Senatore Capelli. The multivalent associations observed in the hybrids may be attributed to a large extent to homoeologous pairing. Our study shows that not all the chromosomes of the D genome have the same affinity with their homoeologues of the A or B genomes. We have also concluded that there is no correlation between the percentage of the cells with multivalent associations and the mean of chiasmata per cell (attached arm).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 41 (1989), S. 65-69 
    ISSN: 1573-5060
    Schlagwort(e): Fragaria ; Potentilla ; intergeneric hybrids ; pollen storage ; temperature ; relative humidity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Low temperature and humidity were used for the storage of pollen of four species of Fragaria (2n=14, 42 and 56) and two species of Potentilla (2n=14). The stainability of Fragaria pollen was assessed over a number of years by use of aceto-carmine stain and its viability by cross-pollinations; stainability of Potentilla pollen was assessed by acetocarmine. Fragaria pollen so stored remained stainable for seven years and showed the ability to set seed for three years. over the latter period, aceto-carmine staining gave a reasonable prediction of seed set produced by the stored pollen of Fragaria and so is of value in estimating pollen viability in that genus. Potentilla pollen remained stainable for three years.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 41 (1989), S. 235-246 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; bread wheat ; landrace groups ; classification ; primary landrace ; secondary landrace ; Austria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Using 49 morphological characteristics sixty-six accessions originating from 15 populations of bread wheat, together with 8 selections from landraces and 5 improved varieties were classified in five groups: group 1: Alpiner Bartwizen (including Hausbergweizen), Attergauer Bartweizen, which are marked by awned white ears; group 2: Awned Sipbachzeller (and its selection Otterbacher Bartweizen) and marked by awned red ears. This group also includes some awned derivatives of hybrids between group 1 and group 3; group 3: Sipbachzeller wheat, including Innviertler wheat and the selections Ritzlhofer Alt, Achleitner and Wieselburger roter Kolben; group 4: Tassilo and Tassilo-variants, and group 5: Dickkopf (Squarehead) types with lax ear, probably being derivatives of hybrids between group 3 and Dickkopf types. Most populations were contaminated with foreign material. The contamination may have been caused by the farmer who actually mixed varieties, or may have originated on the farmer's field.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 42 (1989), S. 41-44 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; frost resistance ; locus Fr1 ; recombinant lines ; chromosome 5A
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary A gene for frost resistance on chromosome 5A of wheat was located using single chromosome recombinant lines from the cross between the substitution line Hobbit (Triticum spelta 5A) and Hobbit. In this sample of recombinant lines the locus for frost resistance, designated Fr1, is completely linked to the locus Vrn1 controlling vernalisation requirement. The results can be explained by a pleiotropic action of the Vrn1 locus or close genetic linkage between Vrn1 and Fr1. Further detailed study is necessary to resolve these alternative hypotheses.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 31
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; dwarfing genes ; drought stress ; yield ; yield components
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Near-isogenic tall (no dwarfing gene), semidwarf (Rht1 or Rht2) and dwarf (Rht1 + Rht2 or Rht3) spring wheat lines were evaluated for yield and yield components under irrigated and rainfed conditions. Under irrigated conditions, the dwarf and the semidwarf lines exhibited a significant yield advantage over the tall lines. Under rainfed conditions, the semidwarf lines outyielded the tall as well as the dwarf lines. Percent yield reduction in response to drought stress was highest with the dwarfs and lowest with the tall lines. Dry matter production of the tall lines and that of the semidwarf lines did not differ significantly and both produced significantly more dry matter than the dwarf lines under irrigated as well as rainfed conditions. Plant height and kernel weight decreased with increasing degree of dwarfness while number of kernels per spikelet, harvest index and days to heading increased under both moisture regimes. The dwarfing genes did not have any significant influence on number of tillers/m2 and spikelets per spike in either moisture regime.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 43 (1989), S. 41-45 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; chromosome substitution ; frost resistance ; hardening
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The highly frost resistant wheat variety Cheyenne (donor) and the poorly frost resistant variety Chinese Spring (recipient) were frozen at −9° C and −11° C at various stages of hardening, as were a number of substitution lines of these two varieties (CS/Ch 3A, CS/Ch 5A, CS/Ch 7A, CS/Ch 2B, CS/Ch 4B, CS/Ch 5B, CS/Ch 4D, CS/Ch 5D). Chromosomes 5A, 5B, 5D, 4B and 7A of Cheyenne increased the frost resistance of the recipient variety to varying extents. However, the frost resistance changed not only as a function of the different chromosomes, but also as a function of the duration of hardening, indicating that genes responsible for frost resistance are expressed differently during different phases of the hardening process.
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  • 33
    ISSN: 1573-5060
    Schlagwort(e): Triticum durum ; durum wheat ; Triticum aestivum ; wheat germplasm ; collection ; yield components ; drought response ; canopy temperature ; osmotic adjustment ; phenology ; Israel
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Diverse landraces of wheat, collected from the semi-arid (150 to 250 mm of total annual rainfall) Northern Negev desert in Israel were considered as a potential genetic resource of drought resistance for wheat breeding. These materials were therefore evaluated for their reponses to drought stress in agronomical and physiological terms. Up to 68 landraces, comprising of Triticum durum, T. aestivum, and T. compactum were tested in two field drought environments, in one favourable field environment, under post-anthesis chemical plant desiccation which revealed the capacity for grain filling from mobilized stem reserves, under a controlled drought stress in a rainout shelter and in the growth chamber under polyethylene glycol (PEG)-induced water stress. Biomass, grain yield and its components, harvest index, plant phenology, canopy temperatures, kernel weight loss by chemical plant desiccation, growth reduction by PEG-induced drought stress and osmotic adjustment were evaluated in the various experiments. Landraces varied significantly for all parameters of drought response as measured in the different experiments, which was in accordance to their documented large morphological diversity. Variation in grain yield among landraces under an increasing drought stress after tillering was largely affected by spike number per unit area. Kernel weight contributed very little to yield variation among landraces under stress, probably because these tall (average of 131 cm) landraces generally excelled in their capacity to support kernel growth by stem reserve mobilization under stress. Yield under stress was reduced with a longer growth duration of landraces only under early planting but not under late planting. Landraces were generally late flowering but they were still considered well adapted phenologically to their native region where they were always planted late. Landraces differed significantly in canopy temperature under drought stress. Canopy temperature under stress in the rainout shelter was negatively correlated across landraces with grain yield (r=0.67**) and biomass (r=0.64**) under stress. Canopy temperature under stress in the rainout shelter was also positively correlated across landraces (r=0.50**) with canopy temperature in one stress field environment. Osmotic adjustment in PEG-stressed plants was negatively correlated (r=−0.60**) with percent growth reduction by PEG-induced water stress. It was not correlated with yield under stress in any of the experiments. In terms of yield under stress, canopy temperatures and stem reserve utilization for grain filling, the most drought resistant landrace was the ‘Juljuli’ population of T.durum.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 44 (1989), S. 65-72 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Puccinia recondita ; leaf rust resistance ; alien gene transfers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Nine transfers of leaf rust (Puccinia recondita Rob. ex Desm.) resistance to wheat (Triticum aestivum L.) from Agropyron elongatum Host. Beauv., Triticum speltoides Tausch and rye (Secale cereale L.) were backcrossed up to 10 times to commercial wheat cultivars. The objective was to study the effect of the transfers on agronomic and quality characters and to make them available in desirable genetic backgrounds. The results varied greatly for different transfers. In four cases no promising material was obtained even after nine backcrosses. However, for the remaining five transfers material with potential as a new cultivar was obtained.
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  • 35
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Puccinia recondita f. sp. tritici ; wheat leaf rust ; partial resistance ; latency period ; gene action ; oligogenic inheritance ; transgressive segregation ; number of genes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Crosses were made between the highly susceptible Little Club and the partially resistant cultivars Westphal 12A, Akabozu and BH 1146 to obtain F1, F2 and backcross generations. Latency period (LP) was determined in plants inoculated at the young flag leaf stage with a monospore culture of race ‘Flamingo’ of wheat leaf rust. Broad sense heritability of LP in the F2 averaged 0.8. The genes showed partial to almost complete recessive inheritance. Scaling tests indicated that additive gene action was the most important factor in the inheritance of partial resistance. The tests showed that there were no indications for additive x additive, additive x dominance or dominance x dominance interactions. The number of effective factors was estimated as one or two for Akabozu, three or more for Westphal 12A, and two or three for BH 1146. BH 1146 also possessed a (semi-)dominant gene for a lower infection type which was temperature sensitive in its expression. The genes of the various parents had unequal effect on LP.
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  • 36
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Puccinia recondita f. sp. tritici ; wheat leaf rust ; partial resistance ; latency period ; oligogenic inheritance ; transgressive segregation ; number of genes ; heritability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Three partially resistant spring wheat cultivars, with a long latency period were crossed among each other and with the highly susceptible Little Club, with a very short latency period. Parents, F3 and F5 plants have been inoculated with the leaf rust race Flamingo in the young flag leaf stage to determine the latency period. From the crosses with Little Club, it was concluded that Westphal 12A carries three, Akabozu two and BH 1146 two or three genes for a longer latency period. BH 1146 appears to carry also one hypersensitive resistance gene. Transgressive segregation occurred in crosses between partially resistant cultivars. From crosses between the partially resistant cultivars, it was concluded that the genes in Akabozu and Westphal 12A are different, while those in Akabozu and BH 1146 are at least partly different. The possibilities of accumulation of LP-prolonging genes are discussed.
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  • 37
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; anther culture ; callus initiation ; cytoplasm ; cytoplasmic male sterility
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Nuclear and cytoplasmic factors affect tissue culture response in wheat (Triticum aestivum), and cytoplasmic male sterility may enhance callus initiation in anther culture. Three wheat nuclear genotypes, each in normal and two alien cytoplasms conferring cytoplasmic male sterility, were evaluated for callus initiation frequency in anther culture. Nuclear genotype had the greatest effect on callus initiation, but cytoplasm and nucleus X cytoplasm interaction also produced significant effects. The nuclear genotype of ‘Chris’ outperformed ‘Butte’ and ‘Coteau’ in all cytoplasms. Ordinary wheat and Triticum timopheevi cytoplasms outperformed Aegilops speltoides cytoplasm. Cytoplasmic male sterility did not increase callus initiation. This suggests manipulating the nuclear genotype is the best strategy for improving the capacity of wheat to initiate callus in anther culture.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Photosynthesis research 21 (1989), S. 17-26 
    ISSN: 1573-5079
    Schlagwort(e): chlorophyll fluorescence ; herbicide binding ; photoinhibition ; photosynthesis ; photosystem II ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The time courses of some Photosystem II (PS II) parameters have been monitored during in-vivo and in-vitro photoinhibition of spinach chloroplasts, at room temperature and at 10 °C or 0 °C. Exposing leaf discs of low-light grown spinach at 25 °C to high light led to photoinhibition of chloroplasts in-vivo as manifested by a parallel decrease in the number of functional PS II centres, the variable chlorophyll fluorescence at 77K (F v /F m ), and the number of atrazine-binding sites. When the photoinhibitory treatment was given at 10 °C, the former two parameters declined in parallel but the loss of atrazine-binding sites occurred more slowly and to a lesser extent. During in-vitro photoinhibition of chloroplast thylakoids at 25 °C, the loss of functional PS II centres proceeded slightly more rapidly than the loss of atrazine-binding sites, and this difference in rate was further increased when the thylakoids were photoinhibited at 0 °C. During the recovery phase of leaf discs (up to 9 h) the increases in F v /F m preceded that of the number of functional PS II centres, while only a further decline in the number of atrazine-binding sites was observed. The recovery of variable chlorophyll fluorescence and the concentration of functional PS II centres occurred more rapidly at 25 °C than at 10 °C. These results suggest that the photoinhibition of PS II function is a relatively temperature-independent early photochemical event, whereas the changes in the concentration of herbicide-binding sites appear to be a more complex biochemical process which can occur with a delayed time course.
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 40 (1989), S. 103-109 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; triticale ; wheat-triticale hybrids ; Secale cereale ; rye ; Gaeumannomyces graminis ; take-all ; resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Fifteen triticale and wheat-triticale hybrid lines were evaluated for resistance to the take-all fungus Gaeumannomyces graminis var. tritici and compared with five wheat and two rye lines in inoculated field and pot trials. The triticale and wheat-triticale hybrid lines varied in rye chromosome number and degree of resistance expressed. One line, Venus with seven pairs of rye chromosomes consistently showed levels of resistance intermediate between wheat and rye. A trend was observed where increasing rye chromosome content led to greater resistance but exceptions showed that variation within triticales could not be ascribed to rye chromosome content alone.
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 40 (1989), S. 121-126 
    ISSN: 1573-5060
    Schlagwort(e): Chrysanthemum morifolium ; chrysanthemum ; tolerance ; temperature ; days to flower ; breeding ; component analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Twenty seven clones of chrysanthemum, 19 of which were selected at low temperature, were flowered at 10, 14, 18 and 22°C. The number of days to flower in response to temperature could, for each genotype, be described by a parabola with the parameters: optimum temperature, days to flower at the optimum temperature and curvature which represents the sensitivity to temperature. The low-temperature selections did not have a reduced optimum temperature but reduced sensitivity to temperature accounted for most of the ability to flower at low temperature. The parameters may vary independently. Examples are given to show how these parameters can be combined to construct genotypes with a required temperature response.
    Materialart: Digitale Medien
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  • 41
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; gliadins ; electrophoresis ; cultivar identification ; breeding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The process of the separation of gliadin proteins of wheat, using polyacrylamide gel electrophoresis, was studied in detail. It was shown that electrophoresis is a dynamic process during which the pH of the gel changes together with the potassium ion concentration. The most positive effect on the separation of the gliadins was generated by a moving front, which is a boundary between regions with a low concentration of K+ ions and a low pH, and region with a high concentration of K+ ions and a high pH, after optimization of the concentrations of the cations and anions in the electrode solutions. The finding was exploited for the development of an extremely simple electrophoresis system, in which buffers were not needed for obtaining a high resolution. The system was further improved by applying a stacking gel. The advantages of this system are discussed. This new approach may be useful for improving electrophoresis systems for other applications.
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 43 (1989), S. 53-57 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; bread wheat ; gibberellic acid insensitivity ; identification of dwarfing genes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary GA-insensitive Rht genes of 18 Japanese modern varieties and landraces were identified. Out of 12 modern varieties tested 6 carried only Rht1, and the other 6 carried only Rht2. No varieties carried both Rht1 and Rht2 or Rht3. The geographical distribution of the Rht genotypes in the Japanese modern varieties was clearly localized. All 6 landraces tested carried only Rht2.
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  • 43
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; Scalavatis bread wheat ; durum-like hexaploid wheat ; contamination ; variation ; groups ; cluster analysis ; relationship ; Cyprus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The mutual resemblance of 81 hexaploid wheat plants contaminating durum fields on Cyprus was investigated by determining their phenotypes of gliadins, glutenins and peroxidase. Three groups were generated by clustering programs. Group 1 consists of plants with ears resembling those of durum plants, plants of groups 2 and 3 have a bread wheat appearance. Suggestions on the origin of these three groups are made. Group 1 may derive from (back)crosses between hexaploid and durum plants since time immemorial. If so, the hexaploid plants would have served as ‘donor’ of the D genomes, and durum plants as the ‘recurrent parent’. Groups 2 and 3 may derive from two introductions, either from two countries, or from the same country, but then in different periods.
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 44 (1989), S. 143-150 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Triticum durum ; durum ; environmental correlations ; grain yield ; plant height ; tiller number ; grain size
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Environmental correlation coefficients were computed among all pairs of five traits, namely grain yield, heading date, number of tillers per m2, plant height and 1000-grain weight (grain size) using 30 Triticum durum and 30 Triticum aestivum varieties grown in 18 environments. Grain yield was significantly correlated with the other four traits in almost all of the varieties. The mean correlation coefficient over all varieties ranged from 0.58 to −0.83 for durum wheat and 0.66 to 0.88 for aestivum wheat. The correlation coefficients between heading date and the other traits were also significant, ranging from −0.45 to −0.79 in durum wheat and −0.61 to −0.85 in aestivum wheat. The correlation coefficient between number of tillers with plant height and 1000-grain weight were the smallest, 0.19−0.32 in durum wheat and 0.39−0.60 in aestivum wheat. It was concluded that agronomic practices favouring early and good stand establishment in the dry regions will favour the yield components and important adaptive traits, which contribute towards larger yields. Significant differences were found among genotypes in the environmental correlation coefficients and the associated changes in one trait as a result of changes in other traits.
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 44 (1989), S. 187-195 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Puccinia recondita f. sp. tritici ; wheat leaf rust ; partial resistance ; latency period ; infection frequency ; urediosorus size ; growth stage ; component analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Latency period (LP), infection frequency (IF) and urediosorus size (US) of leaf rust were determined on primary leaves and young flag leaves of 18 spring wheat cultivars. A large growth stage effect and a large cultivar effect on all three components were observed. Partial resistance as measured by the three components was generally better expressed in the adult plant stage than in the seedling stage. Associated variation of the components was observed: long LP, low IF and small US tended to go together. The association was not complete, cultivars with clear deviations of this association for one of the components were found suggesting the existence of at least partly different genetic factors controlling the respective components. LP measured on flag leaves gave the most reliable results and, therefore, could best be used as a selection criterion in breeding programs for partial resistance.
    Materialart: Digitale Medien
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  • 46
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Puccinia recondita f.sp. tritici ; leaf rust ; temperature sensitivity ; latency period ; infection frequency ; urediosorus size ; growth stage
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Three components of partial resistance (PR) were studied at three post-infection temperatures using seven spring wheat genotypes differing in level of PR and two different wheat leaf rust races. The components were latency period (LP), infection frequency (IF) and urediosorus size (US). The expression of LP was more sensitive to temperature than the expression of the other two components. LP-prolonging genes were better expressed at low temperatures than at high temperatures and cultivar differences tended to increase with decreasing temperature in both seedling and adult plant stages. The reaction of IF to temperature differed from that of LP and US, probably because IF is regulated by another mechanism than LP and US. It is recommended to perform PR-screening tests at low rather than at high temperatures. If temperatures are maintained at about 8–13°C (night-day), seedlings can be used to screen for PR instead of the more expensive adult plant tests. The effectiveness of PR in seedling stage at low temperatures suggests that the seedling stage may have epidemiological significance as the low temperatures (8–13°C) are relevant for seedlings in the field.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 44 (1989), S. 225-234 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; winter wheat ; breeding ; phenology ; vernalization ; Vrn genes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary An international survey of wheat breeders and scientists was conducted to determine whether there was a common understanding of the term ‘winter wheat’. Response to photoperiod was mentioned by only seven of the 30 survey respondents. It was consequently suggested that it be excluded from any definition. Response to vernalization was mentioned by 28 of the 30 respondents. However, there was considerable variation in the method of quantifying this response and the degree of response necessary for wheat to be called ‘winter’. It was concluded that the only objective and internationally consistent definition of ‘winter wheat’ was a ‘genetic’ definition based on the complement of Vrn genes a wheat possesses. Varieties not possessing any of the dominant Vrn alleles appear to take a distinctively longer and more variable time to head when grown under non-vernalizing, long day conditions. These are ‘genetically winter’ wheats.
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 44 (1989), S. 273-282 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; race-specificity ; Puccinia recondita f.sp. tritici ; wheat leaf rust ; partial resistance ; hypersensitive resistance ; latency period ; disease severity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Partial resistance (PR) in wheat to wheat leaf rust (Puccinia recondita f.sp. tritici) is characterized by a slow epidemic build-up despite a susceptible infection type. Two greenhouse tests and two field tests, in which 11 spring wheat cultivars were exposed to five wheat leaf rust races, revealed some indication for race-specificity of PR. In the greenhouse, the expression of PR was highly dependent on the environment. Significant cultivar-race interactions in the first experiment were lost in the second experiment probably due to cultivar-environment and cultivar-race-environment interactions. In the polycyclic field tests several factors played a role in explaining the inconsistency of the cultivar-race interactions, such as differences in initial inoculum, genotypic differences in earliness, interplot interference or environmental conditions. One cultivar-race combination showed a significant but small interaction towards susceptibility in both field experiments. The interaction was probably too small to detect in the monocyclic greenhouse tests. The results do not conflict with the idea that a gene-for-gene relationship could exist between PR-genes in the host and genes in the pathogen. Some problems with regard to the selection of PR in wheat to wheat leaf rust are discussed.
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 44 (1989), S. 241-245 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Puccinia recondita f.sp. tritici ; leaf rust ; partial resistance ; environmental stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Five spring wheat cultivars differing in partial resistance (PR) to wheat leaf rust were tested at Wageningen (the Netherlands) on a sandy and a clay site, El Batan (CIMMYT, Mexico) and Ponta Grossa (Brazil) over two years. The cultivars were Skalavatis 56, Little Club (both very susceptible), Westphal 12A, Akabozu and BH 1146 (all three with high levels of PR). The results showed that PR was expressed at all four locations in both years. The level of expression was influenced by the environment but the cultivar ranking was hardly affected. Selection for PR in the field can therefore be carried out over a wide range of environments.
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 44 (1989), S. 247-258 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Puccinia recondita f.sp. tritici ; leaf rust ; epidemiological parameters ; microfield ; race nursery ; partial resistance ; components of resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Eighteen spring wheat cultivars were tested in microfields and race nurseries for their partial resistance PR to wheat leaf rust under low and high disease pressure respectively. Large differences existed between the 18 cultivars, Skalavatis 56 being the most susceptible and Ponta Grossa 1 being the most resistant cultivar. Of the three epidemic parameters, disease severity (DS) at the time that the susceptible check was severely diseased and area under the transformed disease severity curve (AUTC) and the logistic growth rate (r), AUTC and DS were highly correlated. Both seemed to be reliable estimators of PR but DS should be preferred for economical reasons. The logistic growth rate seemed to be unsuitable as an estimator of partial resistance. High and low disease pressure gave similar cultivar ranking. PR can be screened and selected equally well in race nurseries with low space, low time and low cost input as in microfields with high space, time and cost input. Cultivar differences in development rate had a large impact on the cultivar differences for amount of disease and can therefore greatly bias the estimation of cultivar resistance. The resistance of early cultivars tended to be underestimated whereas the resistance of late cultivars tended to be overestimated. The effect of differences in developmental rate was most pronounced in the flag leaf. It is advisable to avoid the assessment of disease levels on the flag leaf only and to incorporate in the tests several susceptible and resistant checks that cover the range of development rates in the material to be selected, because otherwise selection for resistance will tend to select also for lateness. Regression of the epidemiological parameters on three components of partial resistance revealed that latency period (LP) is an important factor in determining the resistance observed in the field explaining on average 67% of the observed variation. Adding infection frequency (IF) and urediosorus size (US) to the linear model increased the proportion of the observed variation in the field explained by the components to 80%. This result supports the idea that the components of PR inherit independently, at least, in part.
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  • 51
    ISSN: 1573-5117
    Schlagwort(e): Acanthocyclops ; productivity ; temperature ; food limitation ; generation time
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The generation time of the predatory cyclopoid copepod Acanthocyclops robustus was estimated on 11 occasions during the years 1980 to 1982 in Alderfen Broad. In a multiple regression model, generation time was found to be uncorrelated with temperature, positively correlated (p 〈 0.05) with the densities of Bosmina longirostris and rotifers, and negatively correlated (p 〈 0.001) with the density of nauplii of the calanoid copepod Eudiaptomus gracilis. It is suggested that generation time was determined largely by the availability of calanoid nauplii as prey, even though these constituted only 2% of zooplankton standing biomass.
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 184 (1989), S. 79-88 
    ISSN: 1573-5117
    Schlagwort(e): Cyclopoid copepods ; development times ; eggs ; instars ; temperature ; diapause
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The duration times of eggs, combined naupliar instars and of the different copepodite stages of five species of cyclopoid copepods — Acanthocyclops robustus, Cyclops vicinus, Diacyclops bicuspidatus, Mesocyclops leuckarti, and Thermocyclops crassus — were investigated at five different temperatures. The five species can be divided in two groups: two species, C. vicinus and D. bicuspidatus, adapted to cold water conditions and three species, A. robustus, M. leuckarti and T. crassus adapted to warm water conditions. The cold water species showed a faster egg development than M. leuckarti and T. crassus at 5–15 °C. The eggs and instars of the warm water species M. leuckarti tend to develop faster than those of the former two species at higher temperatures. A. robustus showed the shortest egg and instar development at 10–25 °C. The warm water species T. crassus produced no eggs at 10 °C and temperatures below. At higher temperatures (20, 25 °C) the egg and instar duration times were similar or longer than those of the other species. When cultured in total darkness a great part of the CIV respectively CV copepodites of the summer forms entered arrest and the percentage of copepodites that showed an arrest of development was highest at lowest temperatures. The present results are compared with data from literature and differences are discussed.
    Materialart: Digitale Medien
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 186-187 (1989), S. 81-102 
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; rate of population increase ; life span ; temperature ; salinity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A review of temperature and salinity effects on rotifer population dynamics is presented together with original data of these effects for three clones of Brachionus plicatilis. There is a clear relationship between temperature and the intrinsic rate of increase, r: an increase of temperature — within the natural environmental range — produces an exponential increase of r, and the slope of the response depends on the genotype. The effect of salinity is also genetically dependent; the highest r for each clone is observed at the salinity close to that of its environmental origin. The response of r to temperature is mainly a consequence of the response of the individual rates of development and reproductive timing. The effect of temperature on fecundity (number of descendents per individual life time) is negligible when temperature values are within the normal habitat ranges. On the other hand, salinity seems to affect primarily fecundity. The interaction salinity-temperature may be important in clones or species living in fluctuating environments with positive response to the more frequent combinations found in the corresponding habitats.
    Materialart: Digitale Medien
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 186-187 (1989), S. 129-136 
    ISSN: 1573-5117
    Schlagwort(e): Hexarthra ; salinity ; alkalinity ; wind action ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In Neusiedler See, a shallow alkaline lake with fluctuating water level and salinity, four species of Hexarthra occur: H. mira, H. fennica, H. jenkinae (occasional) and H. polyodonta. The analysis of longterm data reveals a general phenological pattern which does not change from year to year. They first occur in May, develop a maximum in June/July, sometimes a second one in August/September and disappear in October. But the species succession is different in the various years, occasionally only one species (H. mira or H. polyodonta) being present. There is a fairly consistent relation between the chemical conditions and the prevalent species; an increase in salinity favours the development of H. polyodonta. Low temperature and wind generated suspended particles have a negative influence on the development of the Hexarthra populations. Smaller populations of Hexarthra are in a relation to the occurrence of Leptodora indicating predation pressure of the latter species. In Neusiedler See the Hexarthra populations seem to be controlled to a great extent by abiotic factors, but predation by Leptodora and most probably by young fish seems to play an important role too.
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  • 55
    ISSN: 1573-5117
    Schlagwort(e): Rotifera ; resting eggs ; light ; temperature ; hatching ; mixis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The marine rotifer Brachionus plicatilis typicus (Clone 8105A, Univ. of Tokyo) was cultured in 500 ml beakers to form resting eggs. Tetraselmis tetrathele was used as a culture food. Just after formation, resting eggs were exposed to various temperature (5–25 °C) and light regimes (24L: OD and OL : 24D). When eggs were exposed to light just after formation, the eggs hatched sporadically over a month. No hatching was observed for six months when eggs were preserved under dark conditions regardless of the temperature. These eggs hatched simultaneously after being exposed to light and eggs preserved at 5 °C showed twice as high hatching rate (40%) as that of eggs preserved at 15–25 °C (24%). Clones from resting eggs that were kept under different temperature and light regimes were reared individually to the third generation. Incubation at 25 °C with lighting produced the highest (5.4% and 5.2 %) rate of mictic females during their 2nd and 3rd generations, respectively. The lowest rates (0 and 1.5%) were found when the eggs were kept at 5 °C in total darkness for six months. A lower rate of amictic female production was found in clones with higher rates of mixis.
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 186-187 (1989), S. 209-214 
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; distribution ; temperature ; oxygen content
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Lunzer Obersee, a small lake located at an altitude of 1100 m above sea level, was investigated from July 1985 to October 1987. The rotifer community consists of 7 dominant species, 7 subdominant species and 34 species which occasionally occurred in the plankton. The dominant species show rather different demands in relation to temperature and oxygen content; e.g.: Filinia hofmanni was found at a wide range of oxygen concentrations (0.6–13.3 mg O2l−1) and low temperatures (4–6 °O, living in the upper water layers (1–7 m) during spring and in the deeper, anoxic zone in summer. In contrast, Asplanchna priodonta was found at rather high oxygen contents (〉 9 mg O2 l−1), ), and showed a wide range of temperature tolerance (4–15 °C). On the basis of field data the temperature and oxygen requirements of several species are described and discussed.
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 186-187 (1989), S. 363-369 
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; temperature ; food concentration ; bioenergetic parameters
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The influence of temperature and food quality was studied on the following energy balance parameters of B. angularis: ingestion, production, growth and mortality. The ingestion rate rises to an optimum at 15 and 20 °C and decreases at 25 °C. The other rates increase continuously over the 5–25 °C range. The Q10-values of production rate are higher than those of ingestion rate. Temperature also modifies the relationship between food concentration and bioenergetic rates. They react according to a Monod function (production at all temperatures, growth at 10 °C) or decrease at high concentrations (growth at 15° and 20 °C.)
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 186-187 (1989), S. 381-386 
    ISSN: 1573-5117
    Schlagwort(e): biometric analysis ; resting eggs ; rotifers ; salinity ; temperature ; genetic variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of temperature and salinity on resting egg size of two Brachionus plicatilis (Rotifers) clones was investigated. Clones were selected according to their different behaviour in laying resting eggs: one clone ejects them, whereas they remain inside the females body in the other clone. The difference in resting eggs size between the two clones is noticeable, although the difference is not as great as that between female body size. An important temperature-salinity interaction on resting egg size has been observed. The general inverse relationship between size and temperature is only true at lower temperatures. At high temperatures size varies around the mean although could be greater than at intermediate temperatures. This is more evident at the intermediate salinity tested which is considered to be the closest to the optimum in our experiments. This pattern of variation suggests that mean size is bigger than expected, in relation to temperature and salinity, when these factors have values close to the extremes of their range, normally found in nature, and to which adaptative mechanisms can evolve. Size is bigger at the salinity — temperature low - low and high - high combinations which are the most commonly found in the temperate environments.
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 172 (1989), S. 39-49 
    ISSN: 1573-5117
    Schlagwort(e): Antarctica ; bacteria ; biofilms ; cyanobacteria ; microbial mats ; Nostoc ; Phormidium ; photosynthesis ; respiration ; stream algae ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Water temperatures in southern Victoria Land streams fluctuated over the range 0 to 10 lay close to freezing. In a series of controlled assays at Fryxell Stream, Taylor Valley, the benthic microbial mats showed strongly positive metabolic responses to increases in temperature well above ambient. Rates of polysaccharide and lipid biosynthesis increased with temperature over the range 0 to 25 °C. Between 0 and 10 °C, Q10 values for the cyanobacterial mats were 1.7 to 3.2 for gross photosynthesis, 2.5 to 5.7 for respiration, 2.2 to 2.5 for acetate incorporation into lipid, 1.9 to 3.8 for glucose catabolism, and 1.9 to 2.8 for thymidine incorporation. Respiration accounted for a high percentage of gross photosynthesis, and a net respiratory loss of carbon from three communities was either induced or worsened by an increase in temperature from 0 to 10 °C. The chlorophyll a content of Nostoc disc incubated for one month in darkness decreased by 27% at 5 °C, but by 99% at 25 °C. This set of assays suggests that the cyanobacterial mats contained large amounts of chlorophyll a and carbon associated with inactive or senescing cells. This unusual standing stock could probably not persist under warmer conditions, which would promote both increased respiratory losses and faster rates of bacterial decomposition.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 173 (1989), S. 219-229 
    ISSN: 1573-5117
    Schlagwort(e): aquatic fungi ; temperature ; seasonal periodicity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The occurrence, distribution and seasonal periodicity of 49 species of aquatic fungi belonging to the orders Chytridiales, Lagenidiales, Blastocladiales, Saprolegniales and Peronosporales from two tanks of Kurukshetra, India, is described. Seasonal periodicity was found to be governed by temperature.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 174 (1989), S. 89-97 
    ISSN: 1573-5117
    Schlagwort(e): carbon ; Illinois ; light ; nitrate ; nutrient limitation ; periphyton ; phosphate ; streams ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Factors limiting periphyton accrual in east-central Illinois agricultural streams were investigated. Nutrient-diffusing substrata were used to examine periphyton macronutrient limitation in streams in two agricultural watersheds. Substrata consisted of sand-agar mixtures with one of six experimental treatments. Macronutrients included carbon, nitrate, phosphate and combinations of the three. Substrata were collected after a 5 and 9 day period and analyzed for chlorophyll a. None of the treatments were significantly greater than the controls at any of the seven stations, thus we conclude that periphyton in these streams was not nutrient limited. Highest periphyton colonization/growth rates were associated with the smaller upstream reaches, while lower rates occurred in the larger downstream reaches. Multiple regression showed that most of the variance in the rate of chlorophyll a accrual after five days was explained through water temperature and turbidity (r2 = 0.91); whereas, stream nitrate and phosphate concentrations accounted for no significant portion of the variance. We conclude that instream primary production in agricultural streams of central Illinois is limited by temperature and light.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 62
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 179 (1989), S. 17-24 
    ISSN: 1573-5117
    Schlagwort(e): profiles ; resolution ; monitoring ; temperature ; oxygen ; spate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Longitudinal profiles of water quality along a well-mixed tidal river are, ideally, based on simultaneous measurements at fixed stations distributed along the river. The resolution of the profiles is limited by the density of the stations. However, for a given number of stations the resolution is greatly increased if water quality date can be extrapolated upstream and downstream of the stations, making use of velocity data; the resolution is then determined by the density of the extrapolated data points, which may be an order of magnitude higher than the density of the stations. A 15-km length of river was investigated using 5 current meters equipped to measure depth, temperature, conductivity and dissolved oxygen. Data were recorded simultaneously every 10 minutes. When the average cross-sectional speed was 0.25 ms−1 (typical of tidal conditions), the extrapolated data points were 150 m apart, so the resolution of the resulting profiles (7 per kilometre) was much higher than that of the stations alone (0.3 per kilometre). The extrapolation process required a means of deducing the average cross-sectional speed from the speed measured at a given station. The key to this was provided by temperature data recorded during the onset of a spate, when tidal flow was suspended and the average cross-sectional speed was uniformly about 0.75 ms −1 at four of the stations. Profiles of temperature and dissolved oxygen were generated by this method; the resolution was about 2 data points km−1 during the onset of the spate, and 6 points km−1 during tidal flow.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 175 (1989), S. 223-231 
    ISSN: 1573-5117
    Schlagwort(e): Rotifera ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Information on the distribution of 225 species of planktic, periphytic and benthic rotifers from diverse waters in south and central Sweden was analyzed for temperature preference and tolerance. Most rotifers have a very wide tolerance range. Certainly differences in temperature dependence exist between separate species. However, these differences are, in a regional material like this, generally less distinct than what has been found for the distribution within individual lakes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 116 (1989), S. 69-76 
    ISSN: 1573-5036
    Schlagwort(e): oxidation ; soil ; sulphur ; temperature ; tetrathionate ; thiosulphate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The rate of oxidation of micronized elemental sulphur in three soils was measured over a range of temperatures between 2 and 20°C. Temperature had a marked effect with a Q10 (temperature coefficient) between 1.9–3.1. The period for 50% oxidation varied between 6–10 days at 20°C to between 36–42 days at 2°C. All the oxidation curves showed an initial lag. At 20°C the oxidation rate was four times that of flowers of sulphur and was related to the smaller particle size. Additives (wetting and dispersing agents) in the commercial micronized sulphur preparation used (‘Thiovit’) were inhibitory at high concentrations but stimulatory at low concentrations. The significance to field conditions is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 120 (1989), S. 95-101 
    ISSN: 1573-5036
    Schlagwort(e): allelopathy ; lyophilization ; Oryza sativa ; phytoxicity ; rhizosphere soil ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Using a wheat seed bio assay, the phytotoxicity of extracts obtained from wheat and rice rhizosphere soils was determined. The wheat rhizosphere soil extract was found to show phytotoxic effects. More allelopathic materials were found from the wheat-rice rotation soils than from the rice soil. Extracts obtained under basic conditions (pH 8) were found to be more inhibitory than those obtained by acid extraction (pH 5). Wheat straw was found also to contain phytotoxic substances. A comparison of two methods in concentrating the aqueous extracts, rotary evaporation and lyophilization, indicates that the former contained more substances with phytotoxic effects.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 18 (1989), S. 167-179 
    ISSN: 1573-5044
    Schlagwort(e): Vicia faba L. ; in vitro propagation ; temperature ; nitrogen ; activated charcoal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The influences of nitrogen sources, culture temperature and activated charcoal supplements were studied in relation to the rooting ability of V. faba cuttings. The interaction of these factors led to quantitative and qualitative modifications of the culture responses. Low temperatures (14–18°C) were suitable for in vitro culture, limiting the formation of phenolics in plant material and making activated charcoal supplement unnecessary. Nitrogen supplements contributed in modifying the different plant responses, in accordance with temperature. Multiple shoot formation was obtained from the cotyledonary node and from the stem nodes cultivated in the presence of 6-benzylaminopurine (BAP). BAP at 4 mg l-1 was the most effective concentration in promoting high rates of shoot development. The original position of stem nodes was found to determine the explant response to plant growth regulator treatments, possibly due to the effect of residual apical dominance.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Journal of bioenergetics and biomembranes 21 (1989), S. 115-135 
    ISSN: 1573-6881
    Schlagwort(e): Membrane fluidity ; fish membranes ; homeoviscous adaptation ; temperature ; hydrostatic pressure ; acclimation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Physik
    Notizen: Abstract The homoeostatic regulation of bilayer order is a property of functional importance. Arguably, it is best studied in those organisms which experience and must overcome disturbances in bilayer order which may be imposed by variations in temperature of hydrostatic pressure. This article reviews our recent work on the adaptations of order in brain membranes of those fish which acclimate to seasonal changes in temperature or which have evolved in extreme thermal or abyssal habitats. The effects of temperature and pressure upon hydrocarbon order and phase state are reviewed to indicate the magnitude of the disturbances experienced by animals in their environments over the seasonal or evolutionary timescale. Acclimation of fish to altered temperature leads to a partial correction of order, while comparison of fish from extreme cold environments with those from temperate or tropical waters reveals a more complete adaptation. Fish from the deep sea also display adaptations of bilayer order which largely overcome the ordering effects of pressure.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 68
    ISSN: 1573-5087
    Schlagwort(e): Abscisic acid ; dormancy ; batatasin-I ; phthalic acid ; temperature ; Dioscorea floribunda
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In the tubers of medicinal yam (Dioscorea floribunda Mart. & Gal.) abscisic acid (ABA) content was high in all the parts during the dormant condition in the winter, but it decreased to a very low level in the actively growing plants. ABA content of the entire tuber was negatively correlated with temperature and photoperiod. Growth inhibitors including batatasin-I and phthalic acid were identified in the dormant tuber.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 69
    ISSN: 1573-5044
    Schlagwort(e): anther culture ; Triticum aestivum ; donor plant environment ; incubation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Four different growth environments (field, two phytotron greenhouses and one growth chamber) were compared, using two genotypes of spring wheat, one recalcitrant and one responsive. Field-grown plants gave inferior results. Large improvements could be made by improving the conditions, embryoid frequencies in the two genotypes reaching 77.1% and 183.9% per 100 anthers, respectively. High light intensity during the induction phase strongly suppressed induction in both genotypes, but stimulated regeneration of green plants in the recalcitrant genotype, which had the lowest regeneration ability. Weak, diffuse light did not inhibit induction while the positive effect on regeneration was maintained. Also, another recalcitrant genotype was grown in the field, together with two F1-hybrids (recalcitrant x recalcitrant and recalcitrant x responsive). Evidence for a three-factor system was obtained.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 70
    ISSN: 1573-5044
    Schlagwort(e): wheat ; Triticum aestivum ; ABA ; ABA analogs ; somatic embryogenesis ; precocious germination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Zygotic embryos from ten spring wheat (Triticum aestivum L.) genotypes were tested for embryogenic callus induction in the presence or absence of externally supplied (±)-abscisic acid (ABA) and two of its analogs, methyl abscisate and methyl epoxy-beta-ionylideneacetate. (±)-ABA and its analogs suppressed precocious germination of cultured late-stage embryos and promoted embryogenic callus induction. A significantly greater number of plants was regenerated from calli induced in the presence of ABA and ABA analogs. Early-stage embryos when cultured in the presence of (±)-ABA showed a negative response. Possible roles of ABA with respect to the expression of somatic embryogenesis are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 18 (1989), S. 227-230 
    ISSN: 1573-5044
    Schlagwort(e): sterility ; diploid ; haploid ; pollen plants ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The fertility of plants from wheat anther culture was studied. It was found that one half of the 36 plants with diploid root tips didn't set seeds at all, and that 41 of the 42 plants with haploid root tips were completely sterile. It was surprising that sterility was so widely distributed even among the plants with diploid root tips.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Pharmaceutical research 6 (1989), S. 697-701 
    ISSN: 1573-904X
    Schlagwort(e): ultrasound ; phonophoresis ; temperature ; ibuprofen ; human skin ; in vitro percutaneous absorption
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The objective of this study was to develop an in vitro method to investigate the effect of ultrasound on the in vitro absorption of ibuprofen from a propylene glycol/water vehicle through human epidermis. A diffusion cell was modified so ultrasound could be applied to the vehicle and skin. Since ultrasound can increase the temperature underneath the area of application, control representing temperature effects ran concurrently to the ultrasound experiment. The results demonstrate that ultrasound can increase the penetration of ibuprofen through human skin. This increase in diffusion was greater than for controls where an equivalent increase in temperature was utilized. The results also indicate that evaporation of vehicle components may alter the skin/vehicle partition coefficient, decreasing the effects of ultrasound on the penetration of ibuprofen through the skin.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    European journal of plant pathology 95 (1989), S. 85-105 
    ISSN: 1573-8469
    Schlagwort(e): Triticum aestivum ; Erysiphe graminis ; vertical distribution ; triadimefon ; AUDPC-value ; economic thresshold ; seed number
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Beschreibung / Inhaltsverzeichnis: Samenvatting Opbrengstderving van wintertarwe door meeldauw werd bestudeerd in 11 veldproeven in Nederland. De schade bedroeg gemiddeld 0.013 (SE=0.003) kg are−1 per puistdag meeldauw per blad, vanaf het tweede-knoop stadium tot begin deegrijp bij opbrengstniveaus van 70 tot 90 kg are−1, in de blanco. Bij een ziektestress van 0 tot 2000 puistdagen meeldauw per blad werd geen afwijking van een rechtlijnig verband gevonden. De schaderelatie werd niet significant beïnvloed door de verschillende jaren, rassen of grondsoorten. Het effect van meeldauw op enkele opbrengstcomponenten werd aangetoond. Meeldauwprofielen in de onbehandelde veldjes konden worden beschreven met de vergelijking: CM=CLAb, waarin CM het cumulatieve aantal puistjes is en CLA het cumulatieve bladoppervlak, beide berekend van bovenin het bladerdek naar beneden, de totalen gestandaardiseerd op één. De gradiënt parameter b bedroeg gemiddeld 3.4 (SE=0.9). Waargenomen verschillen in steilte van de meeldauwprofielen beïnvloedde de schaderelatie niet aantoonbaar.
    Notizen: Abstract Damage by mildew to winter wheat was studied in 11 field experiments in the Netherlands. Damage is described by the simple function: −0.013 (SE=0.003) kg are−1 per pustule-day of mildew per leaf, from second node stage to early dough at yield levels of 70 to 90 kg are−1, in diseasefree plots. No deviations from linearity at disease stresses from zero to two thousand pustuledays per leaf were observed. Years, cultivars or soil types did not affect the damage function significantly. The effects of mildew on some yield components were suggested. Mildew profiles in untreated plots could be described by the equation: CM=CLAb, in which CM and CLA are the cumulative pustule number and the cumulative leaf area, respectively, calculated both from top to bottom of the canopy, and totals standardized at unity. Estimates of the gradient parameter b aveaged 3.4 (SE=0.9). Observed differences in steepness of the profiles did not affect the damage function significantly.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 74
    ISSN: 1573-8248
    Schlagwort(e): Telenomus reynoldsi ; functional response ; Holling disc equation ; random parasite equation ; temperature ; Telenomus reynoldsi ; réponse fonctionnelle ; équation de Holling ; équation de la recherche au hasard de l'hôte ; température
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Beschreibung / Inhaltsverzeichnis: Résumé La réponse fonctionnelle deTelenomus reynoldsi Gordh et Coker à l'augmentation de la densité des œufs deGeocoris punctipes (Say) a été déterminée à 5 températures constantes en utilisant des boîtes de Pétri. Les courbes obtenues à toutes les températures étaient de Type II. Les durées du parasitisme (Th) et les taux de recherche de l'hôte (a) ont été estimés et comparés en utilisant l'équation «disc» de Holling. Le taux maximum du parasitisme (1/Th) s'est accru linéairement de 9 à 15 hôtes/jour avec l'accroissement de la température. La meilleure représentation de la relation entre le taux de recherche de l'hôte et la température a été obtenue par une équation quadratique. Le taux de recherche de l'hôte variait de 205 à 888 cm2/jour; il était maximum à 32° C. En utilisant l'équation du «random parasite» (parasite recherchant son hôte au hasard), l'analyse de la réponse fonctionnelle dans un terrain plus complexe contenant une plante artificielle, a conduit à des estimations plus précises du taux de recherche de l'hôte et du taux maximum du parasitisme, qui peuvent être utilisées pour décrire ces activités dans la nature. Le taux de la recherche de l'hôte était de 6680 cm2/jour, tandis que le taux maximum du parasitisme était de 13 hôtes/jour.
    Notizen: Abstract The functional response ofTelenomus reynoldsi Gordh & Coker was determined at 5 constant temperatures using a dish arena. Functional response curves at all temperatures were of Holling's Type II. Handling rate increased linearly with increasing temperature, whereas the relationship of search rate to temperature was best described by a quadratic model. Search rate was highest at 32°C. Using Rogers' random parasite equation, analysis of the functional response in a more complex arena containing an artificial plant provided estimates of search and handling rates that may be more appropriate in the field environment. Search rate was 6,680 cm2/day. Handling rate was 13 hosts/day.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    BioControl 34 (1989), S. 201-208 
    ISSN: 1573-8248
    Schlagwort(e): Notonecta ; embryos ; temperature ; Notonecta ; embryon ; température ; Notonecta ; embriones ; temperatura
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Beschreibung / Inhaltsverzeichnis: Résumé Les œufs deNotonecta unifasciata Guérin à différents stades de développment embryonnaire maintenus dans l'eau à des températures variables (2,2–25 °C) et durant de 4 à 12 semaines révèlent une viabilité maximale (〉80 %) à la température la plus forte. Cependant, la viabilité optimale sans développement se situait à 14.4 °C avec des embryons âgés de 8 jours (〉35 %). Un court stockage (4 semaines) à 14.4 °C augmente d'une façon significative la viabilité de l'œuf. La survie était faible (〈20 %) aux 2 températures les plus basses. Des œufs maintenus à 14.4 °C durant 12 semaines et supportant environ 50 % de mortalité peuvent être un procédé pratique de lutte biologique.
    Kurzfassung: Resúmen Huevecillos deNotonecta unifasciata mantenidos en varios estadios del desarrollo embrionarios y a varias temperaturas (2.2–25.6 °C) por 4–12 semanas, demostraron la mayor viabilidad (〉80 %) a la temperatura más alta. Sín embargo, la óptima viabilidad cuando no hubo desarrollo, se realizó en embriones de ocho días de edad, mantenidos a 14.4 °C. Almacenamiento de corto tiempo (cuatro semanas) a 14.4 °C se produjo un significante aumento de viabilidad. Superviviencia fué baja (〈20 %) a temperaturas menos de 8.3 °C. Se ofrece que huevecillos almacenados a 14.4 °C por 12 semanas, cuales se realizan un 50 % mortalidad, puede servir en la ejecución del control biológico.
    Notizen: Abstract Notonecta unifasciata Guerin eggs maintained at different stages of embryonic development in water at variable temperatures (2.2–25.6 °C) and for periods of 4–12 weeks revealed maximum viability (〉80 %) at the highest temperature. However, optimum nondevelopmental viability was at 14.4 °C with eight-day-old embryos (〉35 %). Short term (4 weeks) storage at 14.4 °C significantly increased egg viability. Survival was poor (〈20 %) at the 2 lowest temperatures. Eggs held at 14.4 °C for 12 weeks and sustainingca. 50 % mortality, may be a practical procedure for biological control.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 76
    ISSN: 1573-8248
    Schlagwort(e): Anagyrus pseudococci ; Leptomastix dactylopii ; Leptomastidea abnormis ; temperature ; adult longevity ; progeny production ; Anagyrus pseudococci ; Leptomastix dactylopii ; Leptomastidea abnormis ; température ; longévité des adultes ; descendance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Beschreibung / Inhaltsverzeichnis: Résumé La descendance augmente et la longévité de l'adulte décroît quand la température augmente entre 18°C et 30°C pour les 3 parasitoïdes de pseudococcines,Anagyrus pseudococci, (Girault),Leptomastix dactylopii Howard etLeptomastidea abnormis Girault. La distribution de Weibull donnait une bonne adaptation aux courbes de suvies pour les 3 parasitoïdes et la comparaison statistique à différentes températures des paramètresb etc de Weibull permettaient des changements dans l'échelle et la forme des courbes. En général les ♀♀ des 3 espèces vivaient plus longtemps que les ♂♂, excepté aux fortes températures. Les femelles deL. abnormis avaient leur descendance maximale à 24°C et la maintenaient à ce niveau jusqu'à 34°C. Elles vivaient plus longtemps que les 2 autres espèces de parasitoïdes à 30°C et manifestaient une courbe de survie de type I dans la gamme de températures examinées.A. pseudococci etL. dactylopii réclamaient tous deux de fortes températures (30°C) pour atteindre leur descendance maximale, mais vivaient moins longtemps à cette température. A 30°C les importante de la population qui mourrait dans les tous premiers jours.L. dactylopii vivait le plus longtemps à 26°C, les femelles manifestant une courbe de survie de type I à toutes les températures, tandis que les courbes de survie des mâles passaient du type I au type II à 30°C. Les implications de ces observations dans la dynamique des populations des différents parasitoïdes sont discutées brièvement.
    Notizen: Abstract Progeny production increased and adult longevity decreased with rising temperature within the range 18°C to 30°C for the 3 mealybug parasitoidsAnagyrus pseudococci (Girault),Leptomastix dactylopii Howard andLeptomastidea abnormis (Girault). The Weibull distribution gave a good fit to survival curves for the 3 parasitoids and statistical comparison of Weibullb andc parameters at different temperatures allowed changes in the scale and shape of the curves to be detected. In general, ♀♀ lived longer than ♂♂ for all 3 species, except at high temperature. FemaleL. abnormis attained their maximum progeny production at 24°C and maintained this level up to 34°C. They lived longer than the other 2 parasitoid species at 30°C and showed a type I survival curve throuhout the range of temperatures examined.A. pseudococci andL. dactylopii both required high temperatures (30°C) to attain their maximal progeny production, but werepseudococci tended towards type II, with a larger proportion of the population dying within the first few days.L. dactylopii lived longest at 26°C, with ♀♀ showing a type I survival curve at all temperatures and ♂ survival curves changing from type I to type II at 30°C. The implications of these findings for the population dynamics of the different parasitoids are briefly discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 48 (1988), S. 73-84 
    ISSN: 1570-7458
    Schlagwort(e): Liriomyza trifolii ; Agromyzidae ; Diptera ; temperature ; thresholds ; life history ; feeding ; intrinsic rate of increase ; tomato ; host-plant suitability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé La vitesse de développement, la mortalité, l'alimentation, la fécondité et la longévité de L. trifolii (Burgess) élevés sur plants de tomates du cultivar ‘Moneydor’ ont été examinées au laboratoire sous 3 températures constantes (15°C, 20°C et 25°C) et une thermopériode (16/22°C, moyenne 19,5°C). Les taux de développement et les seuils de chaque stade ont été déterminés à partir des droites de régressions. Aucune corrélation n'a été mise en évidence entre ces variables biologiques et la taille des pupes. De plus, certaines données sur la biologie de L. trifolii sont fournies et discutées. Le taux intrinsèque d'accroissement, rm a varié de-0,0023 oeuf viable/femelle/jour à 15°C à 0,1254 oeuf viable/femelle/jour à 25°C et la reproduction nette de 1 oeuf femelle viable/femelle à 15°C à 26 oeufs femelles viables/femelle à 25°C. La durée d'une génération a varié de 48 jours à 15°C à 24 j à 25°C. 90% de la ponte a eu lieu dans les 115 premiers degrés jours de la vie imaginale à 20 et 25°C. La fécondité et la longévité étaient fortement liées au nombre de piqûres nutritionnelles. Ces résultats montrent que la tomate est un hôte convenable permettant aux populations de L. trifolii de se développer lorsque la température est supérieure à 16°C.
    Notizen: Abstract The effects of three constant (15°C, 20°C and 25°C) and one alternating (16–22°C, mean 19.5°C) temperatures on development, mortality, feeding, fecundity and longevity of Liriomyza trifolii (Burgess) on tomato plants cv. ‘Moneydor’ were examined in the laboratory. Development rates and thresholds for each instar were estimated by means of linear regression. No correlation was found between life history variables and pupal length. Further, data on the biology of L. trifolii are given and discussed. The intrinsic rate of increase, rm, varied from-0.0023 viable female eggs/⧫/day at 15°C to 0.1254 eggs/⧫/day at 25°C and net reproduction from one viable female egg/⧫ at 15°C to 26 eggs/⧫ at 20°C. Generation time varied from 48 days at 15°C to 24 days at 25°C. Ninety % oviposition occurred within the first 115 degree-days of adult life at both 20°C and 25°C. Fecundity and longevity were highly correlated with the number of feeding punctures. The data indicate that tomato is a suitable host plant allowing populations of L. trifolii to increase if temperatures are above 16°C.
    Materialart: Digitale Medien
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 46 (1988), S. 19-28 
    ISSN: 1570-7458
    Schlagwort(e): Hymenoptera ; Encyrtidae ; parasitoids ; Pseudococcidae ; mealybugs ; Anagyrus pseudococci ; Leptomastix dactylopii ; Leptomastidea abnormis ; temperature ; predicting development ; thresholds ; temperate glasshouses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Les vitesses de développement de 3 parasitoïdes de cochenilles ont été étudiées dans les conditions de température de serre, avec thermopériode ou en température constante. En conditions constantes, la vitesse augmente jusqu'à 35°C, mais est létale à 40°C. Avec thermopériode, une thermophase de 40°C peut être tolérée pendant 12 heures. Les vitesses de développement sous thermopériodes pourraient être calculées à partir des données obtenues en conditions constantes, modifiées en fonction des durées respectives des cryophases et thermophases. Une méthode originale est présentée pour obtenir les seuils inférieurs de développement, en utilisant des thermopériodes, et pour calculer les vitesses de développement à températures élevées. Une méthode de régression polynomiale, non vérifiée préalablement, a été utilisée pour prévoir les durées moyennes des développements sous serre. Ces estimations sont beaucoup plus sûres que les prédictions basées sur le concept de degré-jour (Do), lorsque les températures extrêmes durent longtemps, mais en serre chaude elles ne présentent aucune différence significative. De plus, une méthode d'évaluation des 95% d'émergences, a donné de bonnes estimations des premières et dermières émergences en conditions périodiques.
    Notizen: Abstract Developmental rates of three encyrtid mealybug parasitoids were examined under constant, cycling and glasshouse temperatures. Under constant conditions the rate of development increased with rising temperature up to 35°C, but a constant 40°C was lethal. Under cycling conditions, 12 h periods at 40°C could be tolerated. Developmental rates under cycling conditions could be calculated from constant temperature data, by incrementing development on an h/h basis. A new technique was developed to determine the lower thresholds for development, using cycling regimes and to calculate the rates of development over short periods at high temperature. A previously untested polynomial regression technique was used to predict mean developmental periods under glasshouse conditions. These predictions were considerably more accurate than day-degree (Do) predictions when substantial periods at extreme temperatures were involved, but not significantly different from day-degree predictions under ‘hot-house’ conditions. In addition a method was developed to calculate a 95% range for emergence, which gave consistently good estimates of first and last eclosion observed under fluctuating conditions.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 47 (1988), S. 173-182 
    ISSN: 1570-7458
    Schlagwort(e): Bembidion lampros ; Pterostichus cupreus ; Carabidae ; Coleoptera ; behaviour ; temperature ; searching ; consumption ; cereal aphid ; Rhopalosiphum padi ; prey ; density ; barley
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Les taux maximum de consommation de R. padi L. à différentes températures ont été déterminés au laboratoire chez deux carabes, B. lampros Herbstet P. cupreus L. La consommation moyenne a augmenté avec la température chez les deux espèces, B. lampros consommant un maximum de 15,9 larves des stades 1 à 3 et 9,1 pucerons adultes aptères, à 25°C. P. cupreus a été particulièrement vorace et a consommé 125,3 adultes aptères par jour à 20°C. Le comportement des deux espèces a été observé en filmant en vidéo des carabes à jeun, maintenus à différentes températures constantes, dans des enceintes semées en orge de printemps. Des éléments du comportement, communs aux deux espèces, ont été définis: 1) immabilité, 2) marche et course, 3) recherche, 4) affrontement. P. cupreus a été plus actif à toutes les températures, B. lamprosa été inactif au-dessous de 10°C. La part de temps consacrée à la recherche, le nombre de plantes prospectées, et la vitesse ont augmenté avec la température chez les deux espèces. Dans des enceintes similaires colonisées par R. padi, P. cupreus a significativement augmenté le temps consacré à la recherche dans les enceintes, parallèlement à l'augmentation de la densité des pucerons. Après la découverte d'une colonie de pucerons, P. cupreus escalade et prospecte la plante et ses voisines immédiates; tandis que les plantes des enceintes sans pucerons sont rarement escaladées. B. lampros n'a pas été observé escaladant des plantes d'enceintes avec ou sans pucerons, et il n'a pas accru son temps de prospection en fonction de la densité de pucerons. Les quelques B. lampros qui ont capturé des pucerons l'ont fait lorsque ceux-ci marchaient sur la surface du sol. La discussion a porté sur l'efficacité relative des deux carabes comme prédateurs de R. padi, et les résultats ont été comparés à ceux d'études du même type, menées ailleurs, avec des prédateurs de Sitobion avenae sur blé d'hiver.
    Notizen: Abstract Maximum consumption rates were determined for two carabids, Bembidion lampros Herbst. and Pterostichus cupreus L., feeding on the cereal aphid Rhopalosiphum padi L. at different temperatures in the laboratory. Mean daily consumption increased with increasing temperature for both species, B. lampros consuming a maximum of 16 1–3 instar nymphs and 9 apterous adult aphids at 25°C. P. cupreus was particularly voracious and consumed 125 apterous adult R. padi per day at 20°C. The behaviour of both species was analysed by video filming starved beetles, maintained at different constant temperatures, in arenas sown with spring barley. The behavioural components (1) still; (2) run/walk; (3) search and (4) confrontation were identified and were common to both species. P. cupreus was more active over the temperature range tested; B. lampros was inactive under 10°C. The proportion of time spent searching, number of plants searched, and velocity increased with increasing temperature for both species. When observed in similar arenas seeded with R. padi colonies, individuals of P. cupreus significantly increased their time spent searching in arenas with increasing aphid density. Following discovery of an aphid colony, individuals climbed and searched the host plant and its nearest neighbours. Plants in aphid free arenas were rarely climbed. B. lampros was not observed climbing in either aphid free arenas or in arenas with increasing aphid densities, and did not significantly increase its time spent searching in response to increased prey density. The few B. lampros that found aphids caught them walking on the soil surface. The relative efficiences of these two carabids as predators of R. padi are discussed, and the results are compared with similar studies elsewhere with predators of Sitobion avenae on winter wheat.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 7 (1988), S. 67-70 
    ISSN: 1432-0789
    Schlagwort(e): Root activity ; Soil C mineralization ; 14C-labelled plant material ; Decomposition stages ; Wheat ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Two different soils were amended with 14C-labelled plant material and incubated under controlled laboratory conditions for 2 years. Half the samples were cropped with wheat (Triticum aestivum) 10 times in succession. At flowering, the wheat was harvested and the roots removed from the soil, and a new crop was started. Thus, the soil was continuously occupied by predominantly active root systems. The remaining samples were maintained without plants under the same conditions. The aim of the experiment was to study the effects of active roots on C-mineralization rates during different stages of decomposition and during long-term incubation. During the first 200 days, corresponding to the active decomposition stages, the roots weakly reduced 14C mineralization. With a lower level of decomposition, when more than 60% of the initial 14C was mineralized and when the available nutrients were markedly exhausted by plant uptake, the roots stimulated 14C mineralization.[/ p]
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 81
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 7 (1988), S. 71-78 
    ISSN: 1432-0789
    Schlagwort(e): Root activity ; Rhizosphere ; C metabolism ; Microbial biomass ; Microbial activity ; Wheat ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Two different soils were amended with 14C-labelled plant material and incubated under controlled laboratory conditions for 2 years. Half the samples were cropped with wheat (Triticum aestivum) 10 times in succession. At flowering, the wheat was harvested and the old roots removed from the soil, so that the soil was continuously occupied by predominantly active root systems. The remaining samples were maintained without plants under the same conditions. During the initial stages of high microbial activity, due to decomposition of the labile compounds, the size of the total microbial biomass was comparable for both treatments, and the metabolic quotient (qCO2-C = mg CO2-C·mg−1 Biomass C·h−1) was increased by the plants. During the subsequent low-activity decomposition stages, after the labile compounds had been progressively mineralized, the biomass was multiplied by a factor of 2–4 in the presence of plants compared to the bare soils. Nevertheless, qCO2-C tended to reach similar low values with both treatments. The 14C-labelled biomass was reduced by the presence of roots and qCO2-14C was increased. The significance of these results obtained from a model experiment is discussed in terms of (1) the variation in the substrate originating from the roots and controlled by the plant physiology, (2) nutrient availability for plants and microorganisms, (3) soil biotic capacities and (4) increased microbial turnover rates induced by the roots.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 6 (1988), S. 315-321 
    ISSN: 1432-0789
    Schlagwort(e): Biopores ; Root growth ; Transpiration ; Simulations ; Mechanical impedance ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The use of vertical biopores by wheat (Triticum aestivum) seminal roots for easy access to the subsoil and the consequences for plant water supply and yield has been investigated by computer simulation. Parameters included were: biopore density and diameter, depth of cultivation and strength of the subsoil — all under a wide range of seasonal weather conditions. The model predicts that biopores add significantly to root penetration at depth, even at a density of 0.1% v/v of small, vertical pores, while 1.5% to 2.0% v/v can ensure maximum root penetration. When the growing season is shorter a larger number of biopores is needed to ensure timely root penetration to depth. With shallow tillage, biopores occur closer to the soil surface, and their importance is increased. Deeper root penetration invariably gives greater water uptake and transpiration, but may have a negative effect on grain yield, especially under the driest climatic conditions. An increase in early water use may result in less soil water being available during the grain-filling period. The effect of biopores on plant transpiration varies from year to year, depending on the amount of rain and its distribution in time, and on the amount of soil water stored at time of sowing.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 83
    ISSN: 1432-0983
    Schlagwort(e): Triticum aestivum ; Plant mitochondrial DNA ; Ribosomal genes ; Sequence rearrangements
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The nucleotide sequence of the wheat mitochondrial 26S ribosomal RNA gene and flanking regions was determined and compared with mitochondrial 26S rRNA genes from maize and Oenothera. All three genes exhibit a high degree of homology except within two variable regions. When the plant mitochondrial 26S rRNA genes are compared with Escherichia coli 23S rRNA and chloroplast 23S and 4.5S rRNA genes, a third variable region is apparent close to the 3′ end of the gene. The 5′ and 3′ ends of the wheat mitochondrial gene were determined by S1 nuclease mapping. Computer analysis of the wheat mitochondrial gene revealed several small sequences present either in the 5′ region of the 26S rRNA gene or in the 18S rRNA gene.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 84
    ISSN: 1432-0983
    Schlagwort(e): Triticum aestivum ; Genomic variability ; Mitochondrial DNA ; Somatic tissue culture ; Regeneration ability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Embryogenic and non-embryogenic long-term callus cultures of hexaploid wheat exhibit differences in the organization of their mitochondrial genome. Embryogenic and non-embryogenic fractions of callus cultures initiated from immature embryos of the wheat cultivar “Chinese Spring” have been isolated and subsequently subcultured. DNA-DNA hybridization experiments using labelled cloned wheat mitochondrial DNA fragments have shown that the mitochondrial DNA organization of embryogenic subcultures derived from embryogenic parts of “Chinese Spring” calli is closely related to that of the initial “Chinese Spring” calli, while non-embryogenic subcultures derived from non-embryogenic fragments of “Chinese Spring” calli exhibit a mitochondrial DNA organization similar to that found in non-embryogenic calli derived from cultivar “Aquila”. In addition, somatic tissue cultures initiated from three other non-embryogenic wheat cultivars (“Talent”, “Thésée” and “Capitole”) display mitochondrial DNA arrangements similar to those found in cultivar “Aquila”. These results strongly suggest that, in wheat callus cultures, a particular mitochondrial genome organization is correlated with the ability of cultured cells to regenerate whole plants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 17 (1988), S. 251-266 
    ISSN: 1573-0867
    Schlagwort(e): Zinc ; controlled-release ; diffusion ; pH ; temperature ; phosphate ; clay ; sand ; moisture content
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The emission and movement of zinc from planar arrangements of controlled-release (C.R.) thermoplastic matrix zinc fertilizer formulations was studied in cylindrical diffusion cells packed with a clay or a sand. The influences of a number of soil characteristics known to affect zinc diffusion were also investigated. Zinc emission was initially (over 2 days) very rapid. The rate declined markedly thereafter. Morphologically distinct C.R. zinc formulations released zinc at different rates. Zinc moved appreciably and consistently further in the sand than in the clay. Of the soil characteristics studied, increasing phosphate levels had no effect upon zinc emission or mobility in either soil. Increasing pH in the sand did not affect zinc emission, but decreased zinc mobility. Conversely, in the two soils, increasing temperature stimulated zinc emission, but had little influence on zinc mobility. At higher water contents, zinc release was increased in both soils. However, zinc movement was only increased in the sand.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 86
    ISSN: 1420-9136
    Schlagwort(e): Middle atmosphere ; temperature ; neutral and ion composition ; turbulent transfer ; model
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Using a numerical model for temperature and neutral and ion composition behaviour at middle atmospheric heights, an analysis has been made of the dependence of atmospheric structural parameters on temperature, solar activity, and on turbulent transfer intensity. For mesospheric heights, an inverse dependence of the nitric oxide density on the temperature has been found. It is thus possible to explain experimentally obtained temperature variations over a cyclc of solar activity at mesospheric and lower thermospheric heights. Numerical simulation results indicate that the temperature in the height range ∼75–120 km depends considerably on both the absolute values of turbulent transfer coefficients and their vertical gradients.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Sexual plant reproduction 1 (1988), S. 217-222 
    ISSN: 1432-2145
    Schlagwort(e): Triticum aestivum ; Cytology ; In vitroandrogenesis ; Fluorescent microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Two winter wheat genotypes (‘Diószegi 200’ and ‘Mv 15’) were compared for their in vitro androgenic capacity. On average, the induction frequency of embryogenic structures was 71.7% in ‘Diószegi 200’ and only 4.3% in ‘Mv 15’. The haploid induction ability of the two genotypes differed considerably, with ‘Diószegi 200’ being much higher. The difference in the in vitro inductability of the microspores may result from genetic differences which are manifested in the survival rate of the microspores during the culture period and their adaptability to in vitro conditions. Special DNA fluorochrornes were suitable for studying the different pathways of in vitro androgenesis. Our data indicate that the repeated equal divisions of the microspore nucleus might lead to pollen embryo formation, and subsequent divisions of the vegetative portion of the pollen grain after the first asymmetric microspore mitosis can result in pollen callus formation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 26 (1988), S. 287-301 
    ISSN: 1573-4927
    Schlagwort(e): shikimate dehydrogenase ; electrophoresis ; isoelectric focusing ; isozymest ; Triticeae ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Starch gel electrophoresis and polyacrylamide gel isoelectric focusing (IEF) were used to investigate the genetic control of Triticeae shikimate dehydrogenase-1 (SKDH-1). Studies of wheat-alien species chromosome addition lines established thatSkdh-1 ofHordeum vulgare cv. Betzes is located in chromosome 5H,Skdh-V1 ofDasypyrum villosum in 5V,Skdh-R1 ofSecale cereale cvs. Dakold and King II in 5R, andSkdh-S 11 ofTriticum longissimum in 5S1S. Also, the chromosomal locations of the genes that encode SKDH-1 inT. aestivum cv. Chinese Spring,T. umbellulatum, andS. cereale cv. Imperial, determined earlier using zone electrophoresis, were reconfirmed using IEF. Zone electrophoresis and IEF do not differ markedly in their ability to detect the expression of alienSkdh-1 genes in wheat-alien species chromosome addition lines. However, IEF may be superior to zone electrophoresis as a technique for detecting and analyzing SKDH-1 genetic variants within Triticeae species; among the species studied, IEF generally resolved two or more isozymes perSkdh-1 allele present, while zone electrophoresis resolved only one.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 11 (1988), S. 311-319 
    ISSN: 1573-5028
    Schlagwort(e): chloroplast gene ; iron-sulphur protein ; psaC ; Pisum sativum ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The gene for the 8 kDa subunit of photosystem I has been located in the small single copy region of wheat chloroplast DNA by coupled transcription-translation of cloned fragments of DNA and by DNA sequence analysis. The pea gene for this subunit was located in pea chloroplast DNA by using the wheat gene as a probe. The location was confirmed by immunoprecipitation of the products of coupled transcription-translation of cloned DNA with antiserum raised against the small subunits of pea photosystem I and by DNA sequence analysis. The deduced amino acid sequences of the pea and wheat proteins are identical in seventy-six out of the eighty-one amino acid residues. There are nine conserved cysteine residues, eight of which are arranged in the primary structure in a similar way to those in bacterial ferredoxins containing two 4Fe-4S centres, suggesting that the polypeptide binds iron sulphur centres A and B of photosystem I.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    The journal of membrane biology 103 (1988), S. 149-158 
    ISSN: 1432-1424
    Schlagwort(e): H+ pump ; K+ channel ; light ; Nitella ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary At membrane potentials different fromE K, the temperature effect on membrane potential ofNitella consists of two components. One of them changes its sign atE K, the other one does not. This leads to the assignment of these components to changes in the K+ channel and in the H+ pump, respectively. It is shown that the fast time constant (3 to 30 sec) of the temperature effect on the H+ pump measured as a change in membrane potential and that of the temperature effect on the K+ channel measured as a change in resistance (having about twice the value of that of the pump) are sensitive to light intensity. Both time constants measured inNitella become smaller if light intensity increases from 0 to 15 Wm−2. This supports the suggestion of Fisahn and Hansen (J. Exp. Bot. 37:440–460, 1986) that temperature acts on plasmalemma transport via photosynthesis via the same mechanism as light does.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 91
    Digitale Medien
    Digitale Medien
    Springer
    The journal of membrane biology 101 (1988), S. 67-72 
    ISSN: 1432-1424
    Schlagwort(e): hemolysis ; membrane ; erythrocyte ; pyrexia ; phospholipid ; phase transition ; unilamellar ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary Rates of human red blood cell hemolysis were measured as a function of temperature. Three distinct temperature intervals for hemolysis were noted: a) At temperatures equal to or less than 37°C no hemolysis was observed for the duration of the incubation (30 hr). b) For temperatures exceeding 45°C hemolysis rates are rapid and are accompanied by gross changes in cellular morphology. The activation energy for hemolysis is 80 kcal/mole; this value is characteristic of protein denaturation and enzyme inactivation suggesting that these processes contribute to hemolysis at these high temperatures. c) Between 38 and 45°C the energy of activation is 29 kcal/mole, indicating that a fundamentally different process than protein inactivation is responsible for hemolysis at these relatively low temperatures. A mechanism based on the concept of the critical bilayer assembly temperature of cell membranes (N.L. Gershfeld,Biophys. J. 50:457–461, 1986) accounts for hemolysis at these relatively mild temperatures: The unilamellar state of the membrane is stable at 37°C, but is transformed to a multibilayer when the temperature is raised; hemolysis results because formation of the multibilayer requires exposing lipid-free areas of the erythrocyte surface. An analysis of the activation energy for hemolysis is presented that is consistent with the proposed unilamellar-multibilayer transformation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 31 (1988), S. 379-383 
    ISSN: 1871-4528
    Schlagwort(e): rooting ; temperature ; daylength ; transplanting ; yield
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A series of experiments were conducted in Vietnam to develop a system whereby detached sprouts from physiologically old green sprouted seed tubers could be used to grow potatoes. Three node segments from the mid or basal portion of the detached sprout produced the greatest percentage of shoots and roots. Growth was best in a medium of equal parts of sub-soil, pig manure and brick kiln ash. Sprout cuttings produced plantlets ready for transplanting in 14–20 days with mean daily temperatures of 22 to 24°C. When transplanted in mid-November, yields from sprout cuttings in field experiments were 10 to 18 t/ha which were 33% lower than from healthy seed tubers but more than the national average yield using degenerated seed tubers. Tubers produced by plants grown from sprout stored well and gave good yields when replanted the following year.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 93
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 160 (1988), S. 77-89 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Poaceae ; Triticeae ; Triticum aestivum ; T. timopheevi ; T. monococcum ; Dasypyrum villosum ; B, G, S, A, V genomes ; Nor-loci ; DNA-DNA hybridization ; spacer rDNA sequences ; molecular evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract TheNor-loci of polyploid wheats and their putative diploid progenitor species were assayed by probing isolated nuclear DNA with ribosomal DNA spacer sequences (spacer rDNA sequences, isolated by cloning), from theNor-loci of genomes B (Triticum aestivum), G (T. timopheevi), B (syn. S,T. speltoides), A (T. monococcum) and V (Dasypyrum villosum). DNA samples for analysis were digested with the restriction endonuclease Taq 1 and assayed by DNA-DNA hybridization under standard (37°C) and high stringency (64°C) conditions. The assay procedure emphasized differences between the divergent spacer sequences of the polyploid species and allowed relative homologies to the respective sequences in diploid species to be established. — The studies indicated thatT. timopheevi andT. speltoides contain different sets of spacer rDNA sequences which were readily distinguishable and, in the case ofT. timopheevi, assigned toNor-loci on different chromosomes. This contrast with the spacer rDNA sequences of the majorNor-loci on chromosomes 1 B and 6 B inT. aestivum, which were difficult to distinguish and were deduced to contain very similar sequences. Among the diploid progenitor species only the spacer rDNA fromT. speltoides shared close homology with polyploid wheat species. OneNor-locus inT. timopheevi (on chromosome 6 G) did not show close homology with any of the rDNA spacer probes available. — The data suggestsT. speltoides was the origin of someNor-loci for both theT. timopheevi andT. turgidum lines of tetraploid wheats. The possibility that the 6GNor-locus inT. timopheevi may have derived from an unknown diploid species by introgressive hybridization is discussed. The spacer rDNA sequence probe fromT. monococcum shared good homology with some accessions ofD. villosum and a line ofT. dicoccoides; the implications of this finding for evolution of present-day wheats are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 94
    ISSN: 1435-1536
    Schlagwort(e): Circular dichroism ; gelatin ; sodium alkyl sulphates ; aqueousgelatinsolutions ; secondary structure ; pH ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract The modification of the triple helical structure in aqueous gelatin solutions by changing pH and adding alkyl sulphates at 298 K and after rechilling the solution to 283 K was investigated by CD-measurement. At 298 K the triple helical content at the IEP of the gelatin has its maximum value. It is only weakly affected by adding sodium dodecyl sulphate (SDDS) at concentrations 〈10−4 M/dm3. The unfolding of the triple helix affected by pH and SDDS is reversible by rechilling the solution. The triple helical content of gelatin solutions decreases at SDDS concentrations higher than 10−4 M/dm3. In all cases the decrease of the amount of triple helical structure is connected with an increase of the cis-configuration in single chains and leads to chain reversals. At sufficiently high SDDS concentrationsβ-sheets are formed. These changes are thermally irreversible. Sodium decyl sulphate (SDS) has a more minor influence than SDDS except in the range of the c.m.c. of SDS. At sufficiently high SDS concentrations,β-turns appear.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 95
    ISSN: 1573-5036
    Schlagwort(e): arctic ; Eriophorum ; pH ; phosphatases ; phosphorus ; PNPPase ; root enzymes ; temperature ; tundra
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Eriophorum vaginatum L. subsp.spissum (Fern.) Hult., a dominant plant in arctic tundra ecosystems, has acid phosphatase activity evenly distributed along its root surface from the root tip to a distance at least 16 cm from the tip. These root surface phosphatases have optimal activity from pH 3.5 to 4.0; mean soil pH for soil samples collected with roots was 3.69. Apparent energy of activation and Q10 values (14.0 kcal mol−1 and 2.2, respectively) do not provide evidence for temperature acclimation, but substantial phosphatase activity was measured at 1°C. Kinetic parameters determined for this root surface phosphatase were as follows: Km=9.23 mM, Vmax=1.61×10−3 μmoles mm−2h−1. The presence of inorganic phosphorus in the assay medium did not inhibit root surface phosphatase activity except at very high concentrations (100 mM); even then, only slight inhibition was detected (7 to 19%). A comparison of hydrolysis rates with inorganic phosphate assimilation rates measured forE. vaginatum indicates that organic phosphate hydrolysis may occur at approximately one third the rate of inorganic phosphate absorption. Calculations show that inorganic phosphate produced by root surface phosphatase activity may satisfy 65% of the annual phosphate demand ofE. vaginatum. Since arctic tundra soils are typically higher in dissolved organic phosphorus compounds than in inorganic phosphate, root surface phosphatase activity may make a considerable contribution to the phosphate nutrition of this widespread and abundant arctic plant.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 39 (1988), S. 137-144 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Hordeum vulgare ; barley ; boron toxicity ; variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The growth and yield of seven wheat and two barley cultivars or lines, previously found to show different degrees of boron tolerance under field conditions, were compared in a pot experiment at a range of soil boron treatments. Soil treatments ranged up to 150 mg/kg applied B. Extractable B in soils ranged up to 103 mg/kg. At the highest B treatment seedling emergence was delayed, but the percentage emergence was not reduced. The degree of boron toxicity symptom expression varied between the wheat cultivars and lines, with the two most tolerant, Halberd and (Wq*KP)*WmH)/6/12, displaying the least symptoms. The concentration of boron applied to the soil which produced a significant depression of growth and yield varied between cultivars. For example, the yield of (Wq*KP)*WmH)/6/12 was not affected at the 100 mg/kg applied boron treatment, while the grain yield for (Wl*MMC)/W1/10 was significantly reduced at the 25 mg/kg treatment. There was a linear increase in boron concentration in tillers at the boot-stage with increasing concentration of boron in the soil. The most boron tolerant genotypes had the lowest tissue boron concentrations in each of the treatments. Halberd and (Wq*KP)*WmH)/6/12 had approximately half the boron concentrations of the more sensitive genotypes at the 25 and 50 mg/kg treatments. Differential tolerance of boron within the tissue was also observed. Both Stirling and (Wl*MMC)/W1/10 had significantly reduced total dry matter and grain yields at the 25 mg/kg treatment, while the concentrations of boron in boot stage tillers at this treatment were 118 and 100 mg/kg, respectively. On the other hand, Halberd and (Wq*KP)*WmH)/6/12 had tissue boron concentrations of 144 and 131 mg/kg, respectively, at the 50 mg/kg treatment but yield was unaffected. The relative responses in the pot experiment, for wheat, were in close agreement with field results. Halberd and (Wq*KP)*WmH)/6/12 had the highest grain yields, with the lowest concentrations of boron in the grain when grown under high boron conditions in the field. In pots these two genotypes proved to be the most tolerant of boron. For barley the advantage in grain yield in the field, expressed by WI-2584 compared with Stirling, was not repeated in pots. WI-2584 was, however, more tolerant than Stirling on the basis of total dry matter production. The results show that useful variation in boron tolerance exists among wheat, and that breeding should be able to provide cultivars tolerant to high levels of boron.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 109 (1988), S. 139-140 
    ISSN: 1573-5036
    Schlagwort(e): emergence ; germination ; Glycine max ; soybean ; seed ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract ‘Bragg’ and ‘Cobb’ soybean [Glycine max (L.) Merr.] seeds were germinated in sand at temperatures ranging from 25 to 40°C. Emergence decreased with increasing temperature above 37°C, with virtually no emergence at 40°C. Emergence of 12 other cultivars at 38°C ranged from 25 to 95%. ‘Foster and ‘Coker 338’ were more sensitive to high temperature than the other cultivars.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 109 (1988), S. 227-234 
    ISSN: 1573-5036
    Schlagwort(e): acetylene reduction ; diurnal cycles ; nitrogen fixation ; oxygen permeability ; photosynthesis ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract While diurnal cycles in nitrogen fixation rates are sometimes assumed to result from diurnal variation in photosynthetically active radiation, contradicting evidence exists that indicate soil temperature is the primary environmental influence. These studies assessed the significance of temperature on soybean nitrogen fixation under field conditions. Two groups of intact field-grown soybean plants, one at ambient and the other exposed to a 10°C diurnal variation in soil temperature, were nondestructively assayed for acetylene reduction rates. Activity was closely associated with soil temperature (R2=0.85), even when temperature was 12 h out of phase with ambient. Data were also obtained to determine if the effects of rhizosphere temperature on nitrogen fixation are mediated through an effect on the nodule oxygen permeability. Nodule oxygen permeability of intact, aeroponically grown soybean was closely correlated with the diurnal changes in temperature (R2=0.90).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; soft red winter wheat ; Leptosphaeria nodorum ; Septoria nodorum ; septoria nodorum blotch ; glume blotch ; components of partial resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Seven soft red winter wheat cultivars were evaluated for partial resistance to Leptosphaeria nodorum under field conditions. The results demonstrate that resistance is available among cultivars that are adapted to the southeastern U.S. and that resistance is long lasting. Resistant cultivars had longer incubation and latent periods, slower rates of lesion development, and reduced the level of sporulation of L. nodorum. Seedlings of susceptible cultivars sustained severe disease with dew periods as short as 48 hr in greenhouse tests. One resistant cultivar sustained little damage with dew period as long as 144 hr. Latent period was shortest on the second leaf below the flag leaf (F-2 leaf) of all cultivars and longest on the flag leaf which reflected the effect of microclimate and leaf age. The range in length of latent period on the flag, F-1, and F-2 leaves of resistant cultivars was less than that for susceptible cultivars. Differences between cultivars were greatest (up to 6.8 days) for the F-2 leaf. A delay in production of inoculum on the F-2 and lower leaves of resistant cultivars should delay infection of the flag leaf and spike. The greatest differentiation among cultivars for sporulation of L. nodorum was on upper leaves at Feekes growth stage 11.2. ‘Oasis’ consistently had less sporulation than other cultivars at all sampling dates and leaf positions. The rate of disease progress up the plant (disease severity) and area under the disease progress curve were also least on ‘Oasis’. There were significant correlations among components of resistance and associated components suggesting that a single or interrelated mechanisms control expression of resistance. Overall, ‘Oasis’ was the most resistant cultivar followed by ‘Coker 762’ and ‘Coker 747’. There cultivars have remained resistant for ten or more years. ‘Stacy’ was intermediate in resistance and was the most variable of the seven cultivars for the components tested. ‘Holley’, ‘Omega 78’, and ‘Florida 301’ were highly susceptible by all criteria tested. Plant height was not a factor in resistance. The resistant cultivars are mostly later in maturity than the susceptible cultivars. In this study, crop maturity was similar under existing environmental conditions during the two seasons when most data were collected.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 38 (1988), S. 55-63 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; bread wheat ; gibberellic acid insensitivity ; semi-dwarfness
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Genetic analysis of a new weak source of GA-insensitivity derived from Saitama 27 showed that it was controlled by a single gene located on chromosome 4A and allelic to Rht1 and Rht3. the gene was shown to be present in many Italian and Yugoslavian varieties suggesting a selective advantage in some breeding programmes. Varietal comparisons indicated that the gene reduces height by around 11 per cent. This was combined with an increase in spikelet fertility and in the total number of grain developing in the ear. In this initial experiment a reduction in grain size eliminated the advantages of increased grain number. Following development of isogenic lines in a number of varietal backgrounds the true potential of the gene will be determined.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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