ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Zea mays  (6)
  • reproduction  (5)
  • sunflower  (5)
  • Springer  (16)
  • Wiley
  • 1
    ISSN: 1432-0789
    Keywords: A. chroococcum ; Seed inoculation ; Zea mays ; Acetylene reduction assay ; Yield response ; Associative N2 fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Inoculated and non-inoculated seedlings of Zea mays were grown in agricultural soils under aseptic and non-sterile conditions. Acetylene reduction activity and microbial counts were determined after 7 and 30 days of growth. Irrespective of the soil type Azotobacter spp. were commonly isolated under maize cultivation. Inoculation of agricultural soils with a suspension of A. chroococcum led to an increase in Azotobacter numbers, although this effect diminished with time. Nitrogenase activity was detected on maize roots and increased in response to the inoculation with A. chroococcum, showing that this associative growth could be of primary importance for the plant. The results of assays for acetylene reduction activity indicated that the nitrogenase activity was associated only with the root systems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-0789
    Keywords: A. chroococcum ; Zea mays ; Yield response ; Fertilizer N ; Inoculation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Field experiments were conducted during 1985 and 1986 to examine the effect of Azotobacter chroococcum on the grain yield of maize. Application of 40 kg N ha−1 plus A. chroococcum caused a significant increase in maize yield. Azotobacter inoculation was more efficient at lower doses (40 kg N ha−1) than at high doses (80 kg N ha−1) of urea.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1573-3017
    Keywords: Daphnia magna ; sediment toxicity ; reproduction ; hormesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The ecotoxicity of sediments from ten contaminated sites of the Nervion river catchment were assessed with the three-brood chronic sediment bioassay of Daphnia magna. Three additional locations were used as reference sites and one site as control for every bioassay. Survival, number and biomass of neonates and final adult biomass were measured as chronic ecotoxicity endpoints. High mortality of daphnids was observed at one site where sediment was heavily contaminated by metals. At the remaining sites only sublethal reproductive responses were observed, including inhibition of maturity and hence of reproduction, brood delay, reduction in number of neonates and lower adult final biomass. Hormetic responses in adult final biomass and number of neonates per brood were observed where toxicant concentrations were low or were not bioavailable. Female fecundity increased with size in the controls but the reproductive effort is lower in daphnids exposed to contaminated sediments. This was interpreted as an auto-conservative strategy of the species.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1573-3017
    Keywords: Tubifex tubifex ; sediment bioassay ; hormesis ; growth ; reproduction ; egestion rates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Toxicity assessment based on sediment chronic bioassays with the aquatic worm Tubifex tubifex was performed at ten contaminated sites in the industrial area of Bilbao (Northern Spain). One control and three reference sites were also included. Tubifex bioassay measures both survival and reproduction impairment. These endpoints have been contrasted and discussed in relation to somatic growth and both individual and total biomass of cocoons. Survival was only affected at one site which was heavily contaminated by organic compounds, mainly PAHs. A group of four severely ecotoxic sediments was characterised by a drastic reduction in number and size of cocoons, and adult somatic growth. In other group of sediments, some significant increases were found for these variables. It is suggested that these increases represent an effect of hormesis. An index of reproductive effort was used to integrate the relationship between somatic growth and reproduction. Values of reproductive effort at the test sediments were lower than those at the control sediment, suggesting a conservative strategy of oligochaete worms which consisted in an investment into somatic line (growth) at the expenses of offspring. Rates of food consumption which were estimated from egestion rates, were low at the contaminated sites. This fact could be related to the low production levels found at these sites and may reflect avoidance feeding behaviour of the oligochaete worms within the sediments. At some reference sites, high production could have resulted from high nutritional quality of sediments, or to an hormetic effect due to low concentration of some chemicals. Results are discussed in relation to toxicity data from sediment three-brood bioassay with Daphnia magna Straus performed separately on the same sediments.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1617-4623
    Keywords: Key wordsUstilago maydis ; Zea mays ; Corn smut ; Meiosis ; Cell cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The heterobasidiomycetes responsible for plant smuts obligatorily require their hosts for the completion of the sexual cycle. Accordingly, the sexual cycle of these fungi could so far be studied only by infecting host plants. We have now induced Ustilago maydis, the causative agent of corn smut, to traverse the whole life cycle by growing mixtures of mating-compatible strains of the fungus on a porous membrane placed on top of embryogenic cell cultures of its host Zea mays. Under these conditions, mating, karyogamy and meiosis take place, and the fungus induces differentiation of the plant cells. These results suggest that embryogenic maize cells produce diffusible compounds needed for completion of the sexual cycle of U. maydis, as the plant does for the pathogen during infection.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1573-5117
    Keywords: toxicity ; cultures ; oligochaetes ; T. tubifex ; growth ; reproduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Reproduction in Tubifex tubifex is being used as part of a suite of indicators of sediment toxicity in Canada and Spain, and reproduction of T. tubifex is being considered as a component of sediment objectives for environmental regulation and clean-up in the Canadian Great Lakes. The data being used to set these reproductive targets have been developed from a single culture of T. tubifex from Lake Erie. The plasticity of this particular species is well known and before it can be adopted widely as a test organism it is necessary to determine whether a single culture source should be used or if cultures derived from different populations respond similarly. A series of experiments with two cultures, one from Lake Erie the second from a small mountain stream in Northern Spain have shown that the Spanish worms appear to produce fewer cocoons per adult (mean 8.6 S.D. 1.0) than those from Lake Erie (mean 10.4 S.D. 0.3) at 22.5 °C, a standard test temperature. The number of young produced per adult by the Spanish culture is also lower (mean 19.0 S.D. 4.6) than the L. Erie population (mean 30.6 S.D. 2.3), however, the Spanish population has higher reproductions rates at a lower temperature. The Spanish worms also have lower and more variable growth rates than the Canadian population. There also appear to be slight differences in the sensitivities to toxicants, with the Canadian worms having higher LC50s for copper, chromium and cadmium. While there are differences in the responses in the two cultures these are not considered to be sufficient to invalidate the use of either population in a standard bioassay protocol as long as appropriate calibration and validation are undertaken.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1617-4623
    Keywords: Key words Transactivation ; Zea mays ; VP16 ; Nuclear receptors ; Heliothis EcR/GR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transformation with a chimeric receptor containing the glucocorticoid transactivation and DNA-binding domains fused to an ecdysteroid receptor ligand-binding domain permits ecdysone agonist-inducible gene expression in monocotyledonous plant cells. The inducible system is based on the specific activation of a chimeric receptor containing the ligand-binding domain of the Heliothis virescens ecdysteroid receptor and the inducer RH5992 (a 20-hydroxyecdysone agonist). RH5992 is an non-steroidal agrochemical with a high specificity for lepidopteran ecdysone receptors. Addition of RH5992 to transformed cells results in high levels of inducible expression in a ligand-specific manner, particularly when the effector receptor is coupled to the strong transactivator VP16. A chimeric construct containing the Drosophila ecdysone ligand-binding domain failed to activate reporter gene activity with RH5992, while activation was observed in the presence of muristeroneA. The system described provides the basis for an inducible gene expression system that is compatible with agricultural use.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1573-5028
    Keywords: elicitor ; hydroxyproline-rich glycoproteins ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Hrgp (hydroxyproline-rich glycoprotein) gene codes in maize for one of the most abundant proteins of the cell wall. HRGPs may contribute to the structural support of the wall and they have also been involved in plant defense mechanisms. This second aspect has been tested for the Hrgp gene in maize where, in contrast with the situation in dicot species, the gene is encoded by a single-copy sequence. Hrgp mRNA accumulation is induced in maize suspension-cultured cells by elicitors, isolated either from maize pathogenic or non-pathogenic fungi. The induction of Hrgp mRNA accumulation by elicitor extracted from Fusarium moniliforme has been studied in detail. The level of induction depends on elicitor concentration and remains high until at least 24 h. Ethylene and protein phosphorylation appear to be involved in the transduction pathway of Hrgp gene activation by the F. moniliforme elicitor but not by 5 µM methyl jasmonate or 1 mM salycilic acid. Different compounds known to participate in plant stress responses such as ascorbic acid or reduced glutathione have also a positive effect on Hrgp mRNA accumulation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1573-5060
    Keywords: Helianthus annuus ; fatty acids ; palmitic acid ; X-ray mutagenesis ; seed oil ; sunflower
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A new sunflower mutant, CAS-12, was obtained, which has both high palmitic (≈30%) and high oleic acid contents, and also a substantial amount of palmitoleic acid (≈7%). The mutant was selected after X-ray irradiation of dry seeds of the inbred line BSD-2-423, which had normal palmitic (≈3%) and high oleic (≈88%) acid levels. The increase of palmitic and palmitoleic acids occurred at the expense of the oleic acid content, which decreased to around 55% in respect to the original line. Linoleic acid content is always under 5%. Palmitic and palmitoleic acid levels were similar to those of the high palmitic mutant CAS-5 obtained in a previous programme from a low oleic line isogenic to BSD-2-423 using a similar mutagenic treatment. In that previous programme we also selected three high stearic acid mutants using chemical mutagenic treatment on the same sunflower line (RDF-1-532). We attempted to obtain mutants in other lines but were unsuccessful. The isolation of similar mutants in isogenic parental lines illustrates the importance of the genetic background in the development of specific mutants with an altered seed oil fatty acid composition. The oil of this mutant will increase the range of potential uses of sunflower oil.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1573-5036
    Keywords: Azotobacter chroococcum ; phytohormones ; root exudates ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Growth ofAzotobacter chroococcum in N-free medium was stimulated in the presence of maize root exudates. Our results show that the production of auxins, gibberellins and cytokinins were significantly stimulated when maize root exudates from 7 to 30 d old plants were added to the culture media.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...