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
  • 1
    ISSN: 1573-5060
    Keywords: aphids ; cereal breeding ; DIBOA ; Diuraphis noxia ; hydroxamic acids ; pest resistance ; Poaceae ; Schizaphis graminum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Hydroxamic acids are secondary metabolites typical of Poaceae that play a role in cereal resistance against pests and pathogens. The content of the hydroxamic acid aglucones DIBOA (2,4-dihydroxy-1,4-benzoxazin-3-one) and DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one) was evaluated in wild Poaceae belonging to the tribes Triticeae (genera Hordeum and Elymus) and Aveneae (genera Deschampsia and Phalaris). The concentration of DIBOA in seedling extracts of the wild barleys Hordeum chilense, H. brevisubulatum subsp. violaceum and H. bulbosum was negatively correlated with parameters related to performance of the cereal aphids Schizaphis graminum and Diuraphis noxia. The relevance of the results obtained for breeding programs aimed at increasing cereal resistance against aphids is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1573-1561
    Keywords: Wheat ; hydroxamic acids ; DIMBOA ; plant resistance ; cereal aphids ; Homoptera ; Aphididae ; aphid predators ; Eriopis connexa ; Coleoptera ; Coccinellidae ; tritrophic interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one), a secondary metabolite found in cereal extracts, confers resistance in wheat to aphids. Its effect on beneficial organisms was tested on larvae of the aphid predatorEriopis connexa Germar. Larvae were fed until pupation on artificial diets to which different concentrations of DIMBOA (2–200μg/g diet) were added, as well as on aphids that had been feeding on wheat seedlings with different DIMBOA levels (140–440 μg/g fresh tissue). In diets, the effect of DIMBOA was greatest on survival of third-instar larvae and on the duration of the second and fourth instars. When aphids were provided as food, those that had fed on a wheat cultivar with an intermediate DIMBOA level led to a significantly longer larval duration in the predator than did those that fed on either low or high DIMBOA cultivars. Shortest predator development times were obtained with aphid prey that had fed on high DIMBOA seedlings. Higher DIMBOA levels in the plant appear to reduce aphid feeding rates (and rates of DIMBOA ingestion), decreasing aphid survival and minimizing the effect of the toxin on the predator.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1573-1561
    Keywords: Defoliation ; regrowth ; induced responses ; chemical defense ; hydroxamic acids ; rye ; Secale cereale ; Poaceae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The effect of defoliation and consecutive defoliation (condefoliation) of rye seedlings on the allocation patterns of biomass and hydroxamic acids (Hx) was evaluated five days after treatment. Growth of condefoliated seedlings was lower than that of defoliated and nondefoliated ones. Concentration of Hx decreased in shoots of condefoliated seedlings compared to nondefoliated ones, while concentration of Hx in root exudates increased. Allocation of Hx to roots and root exudates increased at the expense of allocation to the shoots in condefoliated seedlings. The ratio of Hx-aglucone to Hx-glucoside was higher in shoots of defoliated and condefoliated seedlings. The decrease in quantity of defense in shoots was accompanied by an increase in its quality, given that aglucones are more toxic than glucosides. The increase in concentration of Hx—an allelopathic compound also involved in mineral uptake by roots—in root exudates of condefoliated seedlings was suggested to lead to an advantage in the acquisition of resources for the regeneration of lost biomass.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1573-1561
    Keywords: Temperature ; photoperiod ; hydroxamic acids ; growth ; defense ; secondary metabolites ; wheat ; Gramineae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The effects of temperature and photoperiod on accumulation of hydroxamic acids (Hx) in wheat (Triticum aestivum L.) seedlings were evaluated under laboratory conditions. Hx concentrations were significantly higher at higher temperatures. No such clear trend was found for the photoperiod effect. The significant effect of temperature and photoperiod on growth rate of seedlings and the significant positive correlation between growth rate prior to analysis and levels of Hx, suggested that environmental effects on Hx accumulation were at least partially mediated through their effect on plant growth rate. After uncoupling the effect of environmental conditions from the effect of plant growth rate by statistical means the effect of temperature on Hx was no longer significant. Therefore, temperature effect was fully mediated by plant growth rate. Implications of the patterns found are discussed in issues of plant-defense general theories.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1573-1561
    Keywords: Defense ; herbivory ; aphids ; wheat ; Gramineae ; hydroxamic acids ; Defense theory ; Carbon/Nutrient theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Hydroxamic acids (Hx) are natural products of Gramineae that are associated with cereal resistance to pests. We aimed at characterizing the induction of Hx accumulation in seedlings of wheat,Triticum aestivum, by short-term infestation of the cereal aphid,Rhopalosiphum padi. A load of 25 aphids increased significantly the Hx levels in the infested primary leaf in comparison with control levels. Lower loads did not increase Hx concentration. Aphid infestation lasting 16 hr did not elicit induction of Hx, even after a time-lag of 32 hr to allow the expression of any induced response. Forty-eight hours was the minimum duration of aphid infestation required to trigger Hx induction. The age of the infested tissue (the primary leaf) did not affect induction. Similar increases of Hx were found in unfolding, expanding, and totally expanded primary leaves. It was determined that the regime of nutrient supply (N-intensive nutritive solutions at low and high concentration) to wheat seedlings had no effect on the magnitude of the aphid-induced Hx (N-based secondary metabolites). Results obtained are discussed in the framework of general theories of plant defense allocation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1573-1561
    Keywords: Aphid ; experience ; probing behavior ; sieve elements ; salivation ; cell punctures ; hydroxamic acids ; EPG ; Sitobion fragariae ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We hypothesized that aphids after previous exposure to hydroxamic acids (Hx), a family of secondary plant compounds deleterious to aphids, are able to reduce their subsequent exposure to them. This hypothesis was tested by evaluating the time to produce salivation into a sieve element (SSE) by the aphid Sitobion fragariae on seedlings of two wheat cultivars of Triticum aestivum differing in their concentration of Hx. The total time to produce a first SSE was significantly longer in the high-Hx cultivar; however, the subsequent, second SSE (first SSE after interruption of probing) in this cultivar was significantly reduced, reaching the level observed in the low-Hx plants. Therefore, a strategy to reduce the exposure to secondary compounds was observed only in the second SSE in high-Hx plants. When the experimental plant was replaced by a new unattacked plant after the first SSE, aphids did not change the behavior described, thus excluding an aphid-induced plant susceptibility. The number of cell punctures and accumulated duration was not affected by previous exposure to Hx, either in low or high Hx cultivars. Total time and pathway time but not cell punctures, seem to be the variables affected by previous exposure to Hx.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1573-1561
    Keywords: Sitobion avenae ; aphids ; hydroxamic acids ; DIMBOA ; detoxification ; cytochrome P-450 monooxygenases ; NADPH cytochrome c reductase ; glutathione S-transferases ; esterases ; catalase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Hydroxamic acids (Hx) are wheat secondary metabolites conferring resistance for cereals against aphids. The activity of five enzymatic systems were evaluated in the aphid Sitobion avenae reared on the high-Hx wheat cultivar Chagual and the low-Hx wheat cultivar Huayún for 10 generations. Enzyme solutions were prepared from aphid homogenates and assayed for mixed function oxidases (including cytochrome P-450 monooxygenases and NADPH cytochrome c reductase), glutathione S-transferases, esterases, and catalase. Specific activities per aphid individual of cytochrome P-450 monooxygenases, NADPH cytochrome c reductase, glutathione S-transferases, and esterases were significantly increased in wheat cultivars relative to oat (only marginal increase of esterases in Chagual). Aphids fed on cv. Huayún showed an overall higher induction of enzymatic systems than those fed on cv. Chagual. Comparison of these results with reported effects of Hx on detoxifying enzymes in other insects, including aphids, support the hypothesis that these enzymatic pathways play an important role in the detoxification of toxic host-plant secondary metabolites.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1570-7458
    Keywords: wheat ; aphids ; hydroxamic acids ; DIMBOA ; DIMBOA-glucoside ; EPG ; electrical penetration graph ; feeding deterrents ; antixenosis ; plant resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Feeding behaviour of five species of cereal aphids in wheat seedlings differing in hydroxamic acid (Hx) levels, was monitored via electrical penetration graphs (EPG). Aphid species could be grouped as sensitive to the feeding deterrent effect of Hx in the seedlings (Rhopalosiphum padi, Schizaphis graminum, Sitobion avenae, andMetopolophium dirhodum) or insensitive to them (Rhopalosiphum maidis). However, when feeding behaviour was studied in artificial diets containing Hx, all species were equally sensitive to Hx. The behavour ofR. maidis was further compared with that ofR. padi through detailed EPG analysis. It was found that the insensitivity ofR. maidis to Hx in seedlings may be due to a feeding strategy avoiding contact with the compounds by decreasing the number of cellular punctures in live tissues other than sieve elements during its way to the phloem.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 37 (1988), S. 289-293 
    ISSN: 1573-5060
    Keywords: Triticum ; hydroxamic acids ; 1,4-benzoxazin-3-ones ; plant resistance ; wheat breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Fifty-five accessions of Triticum species were analyzed for content of hydroxamic acids (Hx), a natural resistance factor against various organisms. Hx were found in all accessions analyzed. Extreme values were found in wild diploid species: highest in T. speltoides (16.0 mmol/kg fr. wt) and lowest in T. tauschii (0.21). Modern polyploid wheats sharing the same genome did not show substantial variations in Hx levels. The data suggest possible sources of high Hx levels for wheat breeding programs.
    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...