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  • Lepidoptera  (75)
  • nitrogen  (53)
  • Springer  (127)
  • American Geophysical Union
  • MDPI Publishing
  • Springer Science + Business Media
  • 1990-1994  (127)
  • 1993  (127)
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  • 1990-1994  (127)
Year
  • 1
    Electronic Resource
    Electronic Resource
    The mode of action ofBacillus thuringiensis crystal proteins (1993)
    Springer
    Entomologia experimentalis et applicata 69 (1993), S. 145-155 
    Details
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Diptera ; crystal proteins ; Cyt proteins ; pathogenesis ; cytotoxicity ; solubility ; receptor binding ; pore formation ; synergism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02380641
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  • 2
    Electronic Resource
    Electronic Resource
    Differential selection of host plants by twoPieris species: the role of oviposition stimulants and deterrents (1993)
    Springer
    Entomologia experimentalis et applicata 68 (1993), S. 59-69 
    Details
    ISSN: 1570-7458
    Keywords: oviposition ; Pieris rapae ; Pieris napi oleracea ; Cruciferae ; Lepidoptera ; Pieridae ; stimulant ; deterrent ; insect-plant interaction ; host range
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Oviposition responses ofPieris rapae L. andP. napi oleracea Harris to nine crucifers, one Capparidaceae and one Tropaeolaceae were directly compared under controlled conditions. Chemical fractions from these plants were also tested on both insects for the presence of oviposition stimulants or deterrents. The results showed that plant chemistry is a key factor in differential selection of potential hosts by thesePieris species. Some plant species were equally acceptable to bothPieris species. However,P. rapae preferred cabbage over most test plants whereasP. napi oleracea strongly preferred plant species that were avoided byP. rapae. The observed preferences were explained in most cases by the presence of stimulants and deterrents in extracts of the plants. The twoPieris species have apparently evolved differential sensitivities to the chemical stimuli that trigger or deter oviposition. The balance of positively and negatively interpreted sensory signals evoked by plant chemicals obviously plays an important role in acceptance or rejection of a plant by both species. The role of specific glucosinolates and differing structure-activity relationships is suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02380582
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  • 3
    Electronic Resource
    Electronic Resource
    Mating disruption for control of damage by codling moth in Virginia apple orchards (1993)
    Springer
    Entomologia experimentalis et applicata 67 (1993), S. 57-64 
    Details
    ISSN: 1570-7458
    Keywords: Cydia pomonella ; codling moth ; mating disruption ; (E,E)-8,10-dodecadien-1-ol ; pheromones ; apple ; Lepidoptera ; Tortricidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Polyethylene dispensers (Shin Etsu) containing 172 ml of the sex pheromone, (E, E)-8,10-dodecadien-1-ol (63%), dodecenol (31%) and tetradecenol (6%), of codling moth (CM),Cydia pomonella (L.), were placed in apple orchards in Virginia. Two blocks of about 2 ha each were treated in 1989, and three in 1990. Dispensers were placed in trees at a density of 1000/ha shortly after apple bloom. Male orientation to pheromone traps was almost totally disrupted (a few males were captured at high population densities). In 1989, the Daleville pheromone-treated block had 0.9% and 0.8% CM-injured fruit in the center and edge, respectively; 0% and 39.5% injured fruit were found in the conventional control and abandoned blocks, respectively. The Criglersville orchard (‘organically’ managed, with high CM density) CM harvest injury was 16.0%, 16.5%, 34.5%, and 26.5% in the pheromone-treated center and edge, organic control and abandoned blocks, respectively. In 1990, the Daleville CM harvest injury was 4.7%, 7.3%, 1.1%, 0.3% and 58%, in the pheromone-treated center and edge, control center and edge, and abandoned blocks, respectively (possible reasons for the high injury in this block are discussed). Harvest injury in the Fincastle pheromone-treated and control blocks were 0.7% and 0%, respectively. The Criglersville orchard yielded 17%, 19% and 20% CM-injured fruit at harvest in the pheromone-treated, organic control and abandoned blocks, respectively. Pheromone release rate was calculated as 37 mg/ha/h in 1989.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02382717
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  • 4
    Electronic Resource
    Electronic Resource
    Mating disruption to control damage by leafrollers in virginia apple orchards (1993)
    Springer
    Entomologia experimentalis et applicata 67 (1993), S. 47-56 
    Details
    ISSN: 1570-7458
    Keywords: Platynota flavedana ; variegated leafroller ; Platynota ideausalis ; tufted apple bud moth ; Argyrotaenia velutinana ; redbanded leafroller ; mating disruption ; pheromones ; apple ; Lepidoptera ; Tortricidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mating disruption for control of variegated leafroller (VLR),Platynota flavedana (Clemens), tufted apple bud moth (TBM),P. ideausalis Walker, and redbanded leafroller (RBL),Argyrotaenia velutinana (Walker), was studied in Virginia apple orchards in 1989 and 1990. In 1989, each dispenser (1000/ha) contained 190 mg of 67.2%E11–14:Ac, 28.8%Z11–14:Ac, 1.4%E11–14:OH, 0.6%Z11–14:OH, and 2%Z9–12:Ac (a putative generic leafroller disruption blend). Trap captures of VLR, TBM and RBL were reduced by 97%, 51% and 55%, respectively. Average leafroller injury in the interior and edge of the pheromone block was 3.8% and 2.7%, respectively. The conventional control and abandoned blocks had 0.05 and 27.5% injury, respectively. Dispensers containingE11–14:OH (70%) andZ11–14:OH (30%) (close to the natural blend of VLR), more effectively disrupted orientation to pheromone traps by bothPlatynota spp. than did the generic blend. In 1990, dispensers containing 150 mg ofE11–14:OH (70%) andZ11–14:OH (1000/ha) were placed in two 2-ha blocks and one 4-ha block. One pheromonetreated block was sprayed in August with phosmet for codling moth, not timed for leafrollers. Trap captures of VLR and TBM were reduced by almost 100% and 69%, respectively. RBL captures were not reduced by VLR pheromone permeation. Injury fromPlatynota spp. in pheromone block middles and edges ranged from 0.3–1.7% and 0.3–2.3%, respectively. Injury in conventional blocks ranged from 0–1.1%. RBL injury in pheromone block middles ranged from 0–6.1%, and in edges, 1.7–4.8%. Injury in control blocks ranged from 0–1.1%. Combined leafroller injury in an abandoned block was 18% (s.e. 0.3). Release rates averaged 30 and 32 mg/ha/h for the VLR and generic pheromone dispensers, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02382716
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of host plant leaf damage on cabbage looper moth attraction and oviposition (1993)
    Springer
    Entomologia experimentalis et applicata 67 (1993), S. 79-85 
    Details
    ISSN: 1570-7458
    Keywords: Insecta ; Lepidoptera ; Noctuidae ; host-finding ; behavior ; oviposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mated femaleTrichoplusia ni (Hubner) moths, when presented a choice of either undamaged cotton plants,Gossypium hirsutum L., or damaged plants (cut leaves or feedingT. ni larvae) in a flight tunnel, were most often attracted first to the damaged plants. However, these same moths oviposited primarily on the undamaged plants. In a similar test with cabbage plants,Brassica oleracea L., the presence of conspecific larvae decreased both attraction and oviposition. Cuts to cabbage leaves had no significant effect on attraction or oviposition. When presented one plant at a time, percentages of cabbage looper moths attracted were not affected by the presence of larvae on either cabbage or cotton plants, or by cuts to cabbage plant leaves. Percentages of moths attracted were, however, higher using cotton plants with cut leaves. The results suggest an important role for damage induced plant volatiles in host location as well as host acceptance byT. ni.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02382720
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of a host plant,Brassica juncea, on calling behaviour and egg maturation in the diamondback moth,Plutella xylostella (1993)
    Springer
    Entomologia experimentalis et applicata 68 (1993), S. 117-126 
    Details
    ISSN: 1570-7458
    Keywords: insect-plant interaction ; Lepidoptera ; Plutellidae ; crucifer ; sexual maturation ; reproductive diapause ; kairomone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The influence of the presence of seedlings of a host plant, Oriental mustard,Brassica juncea (L.) Coss., on the calling behaviour and egg maturation in the diamondback moth,Plutella xylostella (L.), was investigated. In the presence of plants, females began calling at a younger age, began calling earlier in the night, and spent more time calling. Females which were kept with plants until after their first night of calling and then were isolated from plants, subsequently called less, at a level not significantly different from females which had never been exposed to plants. Of all females, both with and without plants, which were dissected at the end of the first night of calling (n=150), 93% contained mature eggs. Heavier females were significantly more likely to have mature eggs at adult emergence, to begin calling at a younger age and to spend more time calling on their first night of calling. The number of developed eggs in calling females was not significantly different in the presence or absence of host plants on the first night of calling. However, by the second night, females in the presence of plants contained significantly more eggs, indicating that the presence of plants accelerated egg maturation, both before and after the onset of calling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02380530
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  • 7
    Electronic Resource
    Electronic Resource
    Influence of caterpillar-feeding damage on the foraging behavior of the paper waspMischocyttarus flavitarsis (Hymenoptera: Vespidae) (1993)
    Springer
    Journal of insect behavior 6 (1993), S. 771-781 
    Details
    ISSN: 1572-8889
    Keywords: foraging behavior ; caterpillar-feeding damage ; paper wasps ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experiments were performed to determine the effect of caterpillar feeding damage on wasp foraging behavior and to determine the relative importance of visual and olfactory plant cues for foraging wasps. In an experiment using caterpillar-damaged leaves, wasps took significantly more larvae from the previously damaged plants compared to the controls in the experiments with tobacco plants, but wasps did not distinguish between damaged and control plants in the experiments with tomato plants. Another experiment indicated that wasps use a combination of visual and olfactory cues of plant damage in their search for prey rather than just visual or olfactory cues alone. Furthermore, these results suggest that leaf shape may affect wasp detection of caterpillar feeding damage and thus detection of prey.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01201676
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  • 8
    Electronic Resource
    Electronic Resource
    Age-dependent physiological responses of last instarHelicoverpa zea larvae to oral and topical application of precocene II (1993)
    Springer
    Entomologia experimentalis et applicata 67 (1993), S. 199-207 
    Details
    ISSN: 1570-7458
    Keywords: Helicoverpa zea ; Lepidoptera ; Noctuidae ; precocene II ; growth inhibition ; excretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Newly-ecdysed last instar larvae ofH. zea grouped into 100-, 200-, 300-, or 400-mg categories were fed diet containing precocene II or given precocene II topically on the abdomen. The time for larvae to reach a maximal weight, time to pupation, growth rate, and the amount of precocene II excreted were calculated. Younger larvae of lower weights, which were fed or topically treated with precocene II required more time to reach their maximal weight, had a lower maximal weight, a lower growth rate, and required more time to pupate than control larvae. Older larvae represented by the largest weight category were less sensitive to precocene II, had a shorter delay in reaching maximal weight, and a shorter delay in the time to pupation than control larvae; larvae in the largest weight category that were fed precocene II also had smaller decreases in the growth rate. Growth rate declines for larvae given topical doses of precocene II, however, were largest for the oldest larvae. All larvae given a single topical dose excreted precocene II for several days and were most efficient at eliminating smaller doses; larger, older larvae excreted more precocene II than smaller, younger larvae. Age-dependent responses to precocene II indicate that growth and metabolic processes, as well as xenobiotic metabolism, change in last instar larvae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02383428
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  • 9
    Electronic Resource
    Electronic Resource
    Hormonal control of pheromone responsiveness in the male black cutwormAgrotis ipsilon (1993)
    Springer
    Cellular and molecular life sciences 49 (1993), S. 721-724 
    Details
    ISSN: 1420-9071
    Keywords: Lepidoptera ; Noctuidae ; Agrotis ipsilon ; black cutworm ; juvenile hormone ; allatectomy ; pheromone reception ; sexual behaviour ; tenoxycarb ; KK-42
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In Lepidoptera, reproduction is linked to chemical communication between conspecific partners. When exposed to the female sex pheromone, males respond by exhibiting typical sexual behaviour which leads to mating. Here we show that presence of the juvenile hormone producing gland (corpora allata) of the male black cutworm,Agrotis ipsilon, is necessary for pheromone responsiveness. Allatectomized males do not show any sexual behaviour, although their antennal olfactory system is functional. Allatectomized males implanted with active corpora allata recover full pheromone receptivity. It is suggested that reproductive processes are synchronized in males and females through endocrine control; timing of the mating activity could serve as an adaptive strategy linked to the migratory behaviour of this species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01923960
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  • 10
    Electronic Resource
    Electronic Resource
    Tangential medulla neurons in the mothManduca sexta. Structure and responses to optomotor stimuli (1993)
    Springer
    Journal of comparative physiology 173 (1993), S. 783-799 
    Details
    ISSN: 1432-1351
    Keywords: Insect vision ; Lepidoptera ; Medulla neurons ; Optomotor stimulation ; Direction selectivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract InManduca sexta, large tangential cells connect the medulla via the lobula valley (LoV) tract to the midbrain and the contralateral medulla. Tract neurons have been stained and recorded to determine their responses to optomotor stimulation. Neurons in the LoV-tract comprise a physiologically and anatomically heterogeneous population: 1. Motion insensitive medulla tangential (Mt) neurons arise from cell bodies in the ventral rind. Heterolateral cells arborize massively in both medullae and one or both halves of the midbrain. Mt-neurons respond to changes in light intensity. Physiological and anatomical evidence argues for their monocularity and transmission from the medulla on the side of the soma to the central brain and the contralateral medulla. 2. Motion sensitive neurons with cell bodies behind the protocerebral bridge connect the midbrain to the ipsior contralateral medulla. Direction-selective responses are characterized by excitation to motion in the preferred and inhibition in the opposite direction with maxima either in a horizontal or vertical direction. Peak values appear at contrast frequencies of appr. 3/s. The results suggest that these neurons are binocular and relay information from the midbrain to the medulla. They have been labelled as centrifugal medulla tangential (cMt) neurons. The possible roles for tract neurons in visually guided behaviour are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02451909
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  • 11
    Electronic Resource
    Electronic Resource
    Fertilization of millet cv. Souna III in Senegal: dry matter production and nutrient uptake (1993)
    Springer
    Nutrient cycling in agroecosystems 35 (1993), S. 217-226 
    Details
    ISSN: 1573-0867
    Keywords: calcium ; dry matter distribution ; fertilizer ; harvest index ; magnesium ; manure ; millet ; nitrogen ; nutrient uptake ; phosphorus ; potassium ; Senegal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In a fertilizer and manure experiment, millet was grown under four treatments (no fertilizer or manure, farmyard manure, chemical fertilizer, and both). Grain yield and total aboveground biomass production of the unfertilized plot were relatively high. The observed differences in total dry matter production must be attributed to differences in nutrient availability, as amount of rainfall and its distribution were favourable. Results show only small differences in distribution of dry matter among the various plant organs between the best and the non-fertilized treatments. Nutrient supply from natural sources, defined as crop content of N, P, and K at maturity without fertilizer application, amounted to 104, 16 and 103 kg ha−1, respectively, which are very high values. Total uptake of calcium and magnesium is related to that of potassium, as the combined content of these three elements is linearly related to total aboveground biomass production. Minimum removal of nitrogen and phosphorus per ton grain dry matter amounts to 29 and 4kg, respectively, and 9 kg potassium per ton total aboveground dry matter. A possible double function of phosphorus as element of structural biomass and for maintenance of electro-neutrality is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00750640
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  • 12
    Electronic Resource
    Electronic Resource
    Nitrogen availability of soluble and slow release nitrogen fertilizers as assessed by electroultrafiltration (1993)
    Springer
    Nutrient cycling in agroecosystems 34 (1993), S. 121-126 
    Details
    ISSN: 1573-0867
    Keywords: Controlled release fertilizers ; electroultrafiltration ; nitrogen ; ryegrass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The efficiency of different nitrogenous fertilizers under forced leaching conditions was determined in pot experiments using ryegrass as an indicator plant in a sandy loam soil. Treatments were: ON (unfertilized), AN (ammonium nitrate), U (urea), DAP (diammonium phosphate), T (Triabon), FK (Floranid Komplett) and CDU (crotonylidendiurea). N source effects on N uptake, and N leached (as % of N applied) were evaluated. Results show that the fertilizers which behaved best with regard to N uptake were FK followed by Triabon and AN. The most soluble fertilizers, AN and urea, gave the highest N leaching losses. Significant correlations between EUF-NI (rapidly soluble fraction) and leaching, as well as between EUF-N (I + II) and N uptake by the plant (where EUF-N II relates to the slowly soluble fraction) were obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00750106
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  • 13
    Electronic Resource
    Electronic Resource
    The potential of alley cropping in improvement of cultivation systems in the high rainfall areas of Zambia. III. Effects on soil chemical and physical properties (1993)
    Springer
    Agroforestry systems 21 (1993), S. 117-132 
    Details
    ISSN: 1572-9680
    Keywords: alley cropping ; maize ; nitrogen ; organic matter ; soil fertility ; Leucaena leucocephala ; Flemingia congesta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A detailed study of the soil chemical and physical properties in seven-year-old alley cropping trial containingLeucaena leucocephala andFlemingia congesta in Northern Zambia is described. There was a strong correlation between the maize yield and the total amount of nitrogen applied, both from prunings and fertiliser, suggesting that a major reason for the observed benefit from alley cropping, particularly withLeucaena, was due to an improvement in nitrogen supply.Leucaena produced significantly more biomass, and its leaves had higher concentrations of nitrogen, phosphorous and potassium and lower C/N and C/P ratios than did those ofFlemingia. There was also evidence that the trees had a beneficial effect on other soil chemical properties; under the hedgerows, particularly those ofLeucaena, there were higher levels of organic carbon, Mg, K and ECEC, and pH values were also highest. It is suggested that higher levels of organic carbon in the alley crop treatments were responsible for the improvements observed in soil physical properties. Lower bulk density, lower penetration resistance, and a higher infiltration rate and pore volume fraction were measured in the alley crops, although there was no significant change in the soil water release parameters. A deteriorating effect of constant applications of nitrogen fertiliser on soil fertility was observed; as the level of urea application increased, there were significant decreases in Mg, K and pH, increases in Al and soil acidity, and higher penetrometer resistance. These results highlight the urgent need for further research on biological methods of maintaining soil fertility.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00705224
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  • 14
    Electronic Resource
    Electronic Resource
    Host-plant green-leaf volatiles synergize the synthetic sex pheromones of the corn earworm and codling moth (Lepidoptera) (1993)
    Springer
    Chemoecology 4 (1993), S. 145-152 
    Details
    ISSN: 1423-0445
    Keywords: pheromone synergists ; host-plant volatiles ; Lepidoptera ; Noctuidae ; Helicoverpa zea ; corn earworm ; Olethreutidae ; Cydia pomonella ; codling moth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The capture of adult male moths in female sex pheromone traps of two key agricultural pests, the corn earworm (Helicoverpa zea) and the codling moth (Cydia pomonella), is enhanced or synergized by a certain group of host-plant volatiles, the “green-leaf volatiles” (GLVs). Since female adults of both species call and release their sex pheromones while perched upon the leaves of their host-plants, the volatile constituents from the leaves of a number of host-plants were compared. Sex pheromone traps containing one of the prominent leaf volatiles of certainH. zea hosts, (Z)-3-hexenyl acetate, not only significantly increased the capture ofH. zea males but were preferred over traps baited only with sex pheromone. Similarly, traps baited with synthetic sex pheromome ofC. pomonella plus a blend of GLVs captured significantly more males than traps baited only with sex pheromone. Since male moths are not captured in traps baited only with these GLVs, it appears that these GLVs act as pheromone synergists which increase or enhance the attraction or arrestment of male moths in pheromone traps.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01256549
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  • 15
    Electronic Resource
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    What controls levels of dissolved phosphate and ammonium in surface waters? (1993)
    Springer
    Aquatic sciences 55 (1993), S. 132-142 
    Details
    ISSN: 1420-9055
    Keywords: nitrogen ; phosphorus ; uptake ; regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dissolved inorganic nutrient pools are small relative to particulate pools, and dissolved pools turnover rapidly. It has been observed that pools change little from day to day on the sampling scales usually employed. A simple model is presented where uptake and regeneration rates balance to cause a local steady state concentration for dissolved inorganic nutrients. Enrichment and dilution perturbation experiments with lake water support the idea of steady state nutrient concentrations. Although inorganic nutrient concentrations are often controlled by biota, the absolute concentrations present tell little about the activity of that biota.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00877441
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  • 16
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    Terpenes and phenolics in response to nitrogen fertilization: A test of the carbon/nutrient balance hypothesis (1993)
    Springer
    Chemoecology 4 (1993), S. 3-7 
    Details
    ISSN: 1423-0445
    Keywords: carbon/nutrient balance hypothesis ; carbon allocation ; fertilization ; phenolics ; nitrogen ; terpene ; Abies grandis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrogen fertilization resulted in a linear increase in the growth ofAbies grandis seedlings, but linear decrease in foliage concentrations of phenolic compounds. These data are consistent with the inverse relationship between growth and production of carbonbased secondary chemicals predicted by the carbon/nutrient balance (CNB) hypothesis. However, in contrast to predictions of the CNB hypothesis, nitrogen fertilization had no effect on foliage terpene concentrations. The results suggest that not all carbon-based chemicals respond in the same manner to environmental variation, and that the carbon/nutrient balance hypothesis does not adequately explain all patterns of environmentally-induced variation in secondary metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01245890
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  • 17
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    Leaf variation in iridoid glycoside content ofPlantago lanceolata (Plantaginaceae) and oviposition of the buckeye,Junonia coenia (Nymphalidae) (1993)
    Springer
    Chemoecology 4 (1993), S. 72-78 
    Details
    ISSN: 1423-0445
    Keywords: insect-plant interactions ; intraplant variation ; chemical variation ; oviposition ; iridoid glycoside ; catalpol ; aucubin ; Lepidoptera ; Junonia coenia ; Plantaginaceae ; Plantago lanceolata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Chemical analysis of each individual leaf of fivePlantago lanceolata (Plantaginaceae) plants showed that iridoid glycoside content increased from undetectable in the oldest photosynthetic leaves to over 9% dry weight in the youngest leaves. The relative proportion of the two iridoid glycosides inP. lanceolata also changed with leaf age: older leaves had significantly more aucubin, whereas the youngest leaves had primarily or solely catalpol. Oviposition tests with femaleJunonia coenia (Nymphalidae) butterflies, showed that they laid most of their eggs on new leaves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01241676
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  • 18
    Electronic Resource
    Electronic Resource
    Green leaf volatiles enhance sex attractant pheromone of the tobacco budworm,Heliothis virescens (Lep.: Noctuidae) (1993)
    Springer
    Chemoecology 4 (1993), S. 175-177 
    Details
    ISSN: 1423-0445
    Keywords: green leaf volatiles ; cotton ; synergist ; behaviour ; sex attractant ; pheromone ; Lepidoptera ; Noctuidae ; Heliothis virescens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Components of the green leaf volatile complex (Z-3-hexenyl acetate andE-2-hexenyl acetate) were shown to enhance responses of tobacco budworm,Heliothis virescens, males to the sex attractant pheromone of conspecific females in the field. The results are discussed with regard to green leaf volatiles which enhance the attractant pheromone of a cohabiting species, and serve as attractants of a parasitoid of conspecific larvae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01256553
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  • 19
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    Insecticidal and growth-reducing activity of foliar extracts from Meliaceae (1993)
    Springer
    Chemoecology 4 (1993), S. 165-173 
    Details
    ISSN: 1423-0445
    Keywords: growth inhibition ; phytochemical prospecting ; Meliaceae ; Lepidoptera ; Noctuidae ; Peridroma saucia ; Orthoptera ; Acrididae ; Melanoplus sanguinipes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Thirty-one species in twenty genera of the plant family Meliaceae were assayed for the production of growth-inhibiting phytochemicals, using the generalist herbivorePeridroma saucia. Most species were inhibitory when methanolic extracts were incorporated into artificial diets at concentrations at or below those occurring naturally. In general members of the subfamily Melioideae were more inhibitory than members of the Swietenioideae. Extracts of deciduous species with short leaf lifetimes were significantly more inhibitory than those of evergreen species with longer leaf lifetimes. In a smaller sample of species, evergreen species showed a trend towards having tougher leaves than deciduous species. These results support the resource availability hypothesis of Coleyet al. (1985), and suggest that life history attributes may be of some value in selecting plants for phytochemical prospecting.
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    URL: http://dx.doi.org/10.1007/BF01256552
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    Inter-specific avoidance of egg-associated semiochemicals in four tortricids (1993)
    Springer
    Cellular and molecular life sciences 49 (1993), S. 998-1001 
    Details
    ISSN: 1420-9071
    Keywords: Lepidoptera ; Tortricidae ; synomone ; pheromone ; behavior ; oviposition ; Lobesia botrana ; Cydia pomonella ; Cydia molesta ; Eupoecilia ambiguella ; fatty acids ; esters of fatty acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Oviposition of four tortricid pests of vineyards (the European grapevine moth and the grape berry moth) and fruit orchards (the codling moth and the oriental fruit moth) is deterred by a blend of straight chain fatty acids and esters of fatty acids that have been identified in the eggs of one of them: the European grapevine moth (EGVM)Lobesia botrana. This is the first evidence of inter-specific recognition of an egg-like signal in moths. We demonstrate that oviposition site selection is influenced by population density, avoidance of deterrent being most important when females are isolated. Inter-specific egg recognition might be an important phenomenon, especially in species competing for a common food resource. We propose the term ‘oviposition regulating synomone’ for molecules and blends that affect the inter-specific spacing of eggs.
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    URL: http://dx.doi.org/10.1007/BF02125648
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    Determinants of predation on phytophagous insects: the importance of diet breadth (1993)
    Springer
    Oecologia 96 (1993), S. 575-582 
    Details
    ISSN: 1432-1939
    Keywords: Diet specialization ; Host plant chemistry ; Lepidoptera ; Paraponera clavata ; Predation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To evaluate the role of predation in the evolution of diet specialization and to determine the effectiveness of various larval defenses, we offered lepidopteran larvae to colonies of the tropical ant Paraponera clavata. We recorded behavioral and physical characteristics of prey items and used log-linear models to analyze their importance as deterrents to predation by P. clavata. The most important determinant of probability of prey rejection by P. clavata was a prey's diet breadth; specialists were rejected by the ants significantly more than generalists. Other less important, but significant, predictors of prey rejection included ontogeny, morphology and chemistry. Late instar caterpillars were rejected more frequently than early instars, hairy caterpillars were rejected more frequently than caterpillars with other morphologies, and one caterpillar species with an unpalatable extract was rejected more frequently than two species with palatable extracts.
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    URL: http://dx.doi.org/10.1007/BF00320516
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    Propheromones derived from codlemone (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 1-9 
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    ISSN: 1573-1561
    Keywords: Insect pheromones ; C. pomonella ; C. nigricana ; Lepidoptera ; Tortricidae ; propheromone ; codlemone ; conjugated dienes ; pheromone protection ; pheromone release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Tricarbonyl [(8,9,10,11-η-8,10-dodecadien-l-ol] iron and the corresponding acetate prepared from 8,10-dodecadien-1-ol or its acetate, comprise the protected double-bond system of the molecule. After coming in contact with ambient oxygen, the iron complexes in question slowly release the corresponding pheromones of, for example, the codling moth,Cydia pomonella, and the pea moth,Cydia nigricana in highE,E purity and amounts that are sufficient for pest monitoring. A simple dispenser for propheromone application is proposed. Results of release rates in laboratory conditions and field trials are given.
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    Effect of rearing temperature on pheromone component ratio in potato tuberworm moth,Phthorimaea operculella, (Lepidoptera: Gelechiidae) (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 71-81 
    Details
    ISSN: 1573-1561
    Keywords: Sex pheromone ; pheromone components ratio ; (E,Z,Z)-4,7,10-tridecatrienyl acetate ; (E,Z)-4,7-tridecadienyl acetate ; rearing temperature ; Lepidoptera ; Gelechiidae ; potato tuberworm moth ; Phthorimaea operculella
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The ratio of two components in the sex pheromone of the potato tuberworm moth,Phthorimaea operculella, was influenced by the rearing temperature. The percentage of the (E,Z,Z)-4,7,10-tridecatrienyl acetate dropped as the rearing temperature was raised. The total amount of the pheromone did not change parallel with the change of ratio. The critical period sensitive to temperature seemed to be the pupal stage. Temperature in the larval stage may also influence the ratio slightly. The biological significance of the phenomenon was also discussed.
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    Relative importance of infochemicals from first and second trophic level in long-range host location by the larval parasitoidCotesia glomerata (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 47-59 
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    ISSN: 1573-1561
    Keywords: Hymenoptera ; Braconidae ; Lepidoptera ; Pieridae ; Cruciferae ; tritrophic interactions ; foraging behavior ; host-habitat location ; herbivoreinduced synomones ; flight chamber ; infochemicals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Recently parasitoids were hypothesized to encounter a reliability-detectability problem relating to chemical stimuli from the first and second trophic level, when searching for hosts. The relative role of infochemicals originating from the host,Pieris brassicae (second trophic level), and its food plant, cabbage (first trophic level), have been investigated with respect to long-range host location by the larval parasitoidCotesia glomerata. Flight-chamber dual choice tests showed that uninfested cabbage plants are least attractive to female wasps. Host larvae and their feces were more attractive than clean plants but far less attractive than artificially damaged and herbivore-damaged plants. The plant-host complex, with host larvae actively feeding on the plant, was the most attractive odor source for the parasitoids. The data indicate that one of the solutionsC. glomerata uses to solve the reliability-detectability problem is to respond to infochemicals that are emitted from herbivore-damaged plants. Whether these infochemicals are herbivore-induced synomones that are produced by the plant remains to be demonstrated. Infochemicals emitted by the herbivore or its by-products are of little importance in the foraging behavior ofC. glomerata.
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    Diterpene resin acids: Major active principles in tall oil against Variegated cutworm,Peridroma saucia (Lepidoptera: Noctuidae) (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 1075-1084 
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    ISSN: 1573-1561
    Keywords: Tall oil ; resin acids ; abietic acid ; dehydroabietic acid ; isopimaric acid ; Peridroma saucia ; Lepidoptera ; Noctuidae ; variegated cutworm ; bioactivity ; natural insecticide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Tall oil, a by-product of the kraft process for pulping softwood, has been shown to have insecticidal properties. In the present study, the active principles in tall oil against the variegated cutworm,Peridroma saucia Hübner, were investigated. GC-MS analysis showed that abietic, dehydroabietic, and isopimaric acids were major resin acid components of crude tall oil and depitched tall oil. When crude tall oil samples of differing resin acid composition were incorporated into artificial diet at a concentration of 2.0% fresh weight, they suppressed larval growth by 45–60% compared to controls. This suppression was significantly (P≤0.05) correlated with the equivalent contents of abietic, dehydroabietic, isopimaric, and total resin acids. These results were also evident from a diet choice test, showing that the second-instar larvae obviously selected diets with low levels of resin acids when different diets were randomly arranged in a Petri dish. Bioassays with pure resin acids (abietic, dehydroabietic, and isopimaric acids) demonstrated that all individual chemicals have similar bioactivity against this insect. Comparison of the bioactivities of depitched tall oil and an equivalent mixture of pure resin acids in thePeridroma chronic growth bioassay indicated that pure resin acids and depitched tall oil share a common mode of action to this insect. This study confirms that resin acids are major active principles in tall oil against the variegated cutworm, but other chemicals likely also contribute to the bioactivity of tall oil.
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    Host recognition by entomopathogenic nematodes: Behavioral response to contact with host feces (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 1219-1231 
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    ISSN: 1573-1561
    Keywords: Host recognition behavior ; entomopathogenic nematodes ; feces ; Spodoptera exigua ; Lepidoptera ; Noctuidae ; Popillia japonica ; Coleoptera ; Scarabaeidae ; Blattella germanica ; Blatteria ; BlattellidaeAcheata domesticus ; Orthoptera ; Gryllidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Host recognition by entomopathogenic nematodes may occur through contact with insects' excretory products, cuticle, or gut contents. We analyzed the behavioral responses of four species of entomopathogenic nematodes during contact with feces of natural or experimental hosts. Host recognition by nematodes was manifested in alterations in the frequency and/or duration of one or more search parameters including forward crawling, headwaving, body-waving, stopping, backward crawling, head-rubbing, and headthrusting.Heterorhabditis bacteriophora andSteinernema glaseri showed behavioral responses to contact with feces of their natural hosts,Spodoptera exigua (Lepidoptera) andPopillia japonica (Coleoptera), and to the experimental hosts,Acheata domesticus (Orthoptera) andBlatella germanica (Blatteria).Steinernema carpocapsae responded only toB. germanica feces, whereas5. scapterisci did not significantly respond to any of the insect species. During contact with cockroach feces, all nematodes, exceptS. scapterisci, showed avoidance behavior. We suggest that ammonia present in cockroach feces is inhibitory to nematodes. Specific host recognition by entomopathogenic nematodes may be an important mechanism to maintain host affinities.
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    Effects of nitrogen and Douglas-fir allelochemicals on development of the gypsy moth,Lymantria dispar (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 1245-1263 
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    ISSN: 1573-1561
    Keywords: Artificial diet ; herbivory ; nitrogen ; Lymantria dispar ; Lepidoptera ; Lymantriidae ; monoterpenes ; nutritional ecology ; phenolics ; Pseudotsuga menziesii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Two experiments were conducted to examine the influence of foliar nitrogen, terpenes, and phenolics of Douglas-fir on the development of gypsy moth larvae. In the first experiment, foliar concentrations of nitrogen and allelochemicals were manipulated by fertilizing 3-year-old potted seedlings with 0 or 200 ppm nitrogen. Concentrations of foliar nitrogen (0.33–2.38%) were negatively correlated with the phenolics (15.8–24.4 mg/g). Sixth-instar larvae previously reared on current-year Douglas-fir needles were allowed to feed on these seedlings. Pupal weights (312.8–995.6 mg) were positively correlated with levels of foliar nitrogen, negatively correlated with amounts of foliar phenolics, and uncorrelated with terpene concentrations. In the second experiment, terpene and phenolic extracts from Douglas-fir foliage were incorporated at natural levels into artificial diets with high and low levels of protein nitrogen. Neonate larvae grew faster and were larger on the high nitrogen control diet (4.1–4.5%), however, fourth instars performed better on the control diet with low nitrogen levels (2.5–2.7%). Foliar terpenes incorporated into diet had little effect on neonate fitness, but may induce subtle physiological changes in later instar larvae. Phenolics, alone or in combination with terpenes, excessively suppressed growth and survival, with no individuals living through the fourth instar, regardless of the nitrogen level. Incorporating foliar phenolic extracts into artificial diet caused unnatural levels of toxicity and failed to clarify the effects of Douglas-fir phenolics on gypsy moth fitness. Foliar nitrogen is a key factor influencing gypsy moth development on Douglas fir, but may be mitigated to some degree by phenolics.
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    Cardenolides fromErysimum cheiranthoides: Feeding deterrents toPieris rapae larvae (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 1355-1369 
    Details
    ISSN: 1573-1561
    Keywords: Pieris rapae ; Erysimum cheiranthoides ; feeding deterrents ; cardenolides ; digitoxigenin 3-O-β-D-glucoside ; glucodigigulomethyloside ; glucodigifucoside ; erychroside ; cheirotoxin ; strophanthidin glycosides ; digitoxigenin glycosides ; Lepidoptera ; Pyridae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Larvae of the cabbage butterfly,Pieris rapae, refuse to feed on the wild mustard,Erysimum cheiranthoides, due to the presence of alcoholextractable deterrents. The active components were extracted inton-BuOH, and this extract was separated into four fractions (I–IV) by reverse-phase HPLC. Fractions III and IV retained the feeding deterrent activity. The activity of fraction III was found to be due to the cardenolide diglycosides 1 and 2, which were previously reported as oviposition deterrents for gravidP. rapae butterflies. Three active compounds were isolated from fraction IV by column chromatography on silica gel followed by reverse-phase HPLC. These compounds were identified as a monoglycoside, digitoxigenin 3-O-β-D-glucoside (4), and two diglycosides, glucodigigulomethyloside (5) and glucodigifucoside (6). An additional cardenolide isolated from fraction II was identified as cheirotoxin (7). All compounds were identified by UV, NMR (1H and13C), and mass spectrometry, as well as hydrolysis experiments. The feeding deterrent activity of these compounds was compared with that of related commercially available chemicals and other compounds isolated fromE. cheiranthoides.
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    2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one (N-O-Me-DIMBOA), a possible toxic factor in corn to the southwestern corn borer (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 531-542 
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    ISSN: 1573-1561
    Keywords: Corn ; Zea mays (L.) ; southwestern bora borer ; Diatraea grandiosella ; Dyar ; Lepidoptera ; Pyralidae ; feeding resistance ; 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one ; N-O-Me-DIMBOA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The southwestern corn borer (SWCB),Diatraea grandiosella Dyar, is a major pest of corn,Zea mays L., in the southern United States. The damage to corn is caused primarily by larval feeding on leaf, ear, and stem tissues. In this study, 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one (N-O-Me-DIMBOA) was identified by MS and NMR as present in corn whorl surface waxes. This compound has evidently not been isolated previously, but its glucoside has been reported in corn, wheat, andCoix lachryma. It is present in the waxes in a higher concentration than DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one) and 6-MBOA (6-methoxybenzoxazolinone). It was toxic to the SWCB in a stress diet, but it was less toxic to this insect than 6-MBOA when incorporated in the standard rearing diet. Nevertheless, it may have some role in the resistance of corn to the SWCB because the total surface wax content is higher in resistant lines than in susceptible lines.
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    Pyrrolizidine alkaloids in the arctiid mothHyalurga syma (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 669-679 
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    ISSN: 1573-1561
    Keywords: Pyrrolizidine alkaloids ; alkaloid sequestration ; alkaloid transformation ; Boraginaceae ; Heliotropium transalpinum, Heliotropium peruvianum ; Lepidoptera ; Arctiidae ; Pericopinae ; Hyalurga syma ; chemical defense ; Araneidae ; Nephila clavipes ; orb-weaving spider
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The arctiid mothHyalurga syma (subfamily Pericopinae) sequesters pyrrolizidine alkaloids (PAs) from its larval food plantHeliotropium transalpinum (Boraginaceae). Colorimetric quantification of total PAs in the larvae, pupae, and adults ofHyalurga revealed mean values of about 286–445μg per individual (1.4–2.6% of dry weight). The PA mixtures found in the moth and its larval food plant were evaluated by GC-MS. Food-piant leaves were found to contain the diastereoisomeric retronecine esters indicine (IIIa), intermedine (IIIb), and lycopsamine (IIIc), and the heliotridine ester rinderine (IIId) only as minor constituents, whereas 3′-acetylrinderine (IVc) (68% of total PAs) and the respective 3′-acetyl esters of indicine (IVa) and intermedine (IVb) (both 17%) were the major alkaloids. Supinine (IIa) is detectable in traces only. The PA mixtures in eggs, larvae, pupae, and imagines ofHyalurga were identical: indicine, intermedine, and lycopsamine accompanied by considerable amounts of supinine and amabiline or coromandalinine (IIb/IIc) were the major components. Only larvae were found to store small quantities of a 3′-acetyl derivative. Rinderine and its 3′-acetyl ester were never found in the insects. Low concentrations of the arctiidspecific PA callimorphine (I) were present in larvae, pupae, and imagines. The differences in the PA patterns of the insects and their larval food plant suggest thatHyalurga is capable of modifying plant-derived PAs by inversion of the 7-OH configuration (conversion of the necine base heliotridine into retronecine), and perhaps the inversion of the 3′-OH [conversion of (+)-trachelanthic acid into (−)-viridifloric acid], although the possibility of a selective sequestration of the respective retronecine esters cannot be excluded. Some trials with the orb-weaving spiderNephila clavipes, a common neotropical predator, showed that both freshly emerged and field-caught adults ofHyalurga syma are liberated unharmed by the spider. The liberation could be related to the presence of PAs in the moths.
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    Structure-activity correlations among analogs of the currant clearwing moth pheromone (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 735-750 
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    ISSN: 1573-1561
    Keywords: Pheromone analogs ; (E,Z)-2,13-octadecadien-1-yl acetate ; EAG ; gas chromatography ; vapor pressure ; currant clearwing moth ; Synanthedon tipuliformis Clerk ; Lepidoptera ; Sesiidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Eleven analogs of (E,Z)-2,13-octadecadien-1-yl acetate1, a main pheromone component of the currant clearwing moth,Synanthedon tipuliformis Clerk (Lepidoptera: Sesiidae) were synthesized and tested for their biological activities by electroantennography (EAG). To correct the EAG data for differences in volatility of the analogs, their vapor pressures were estimated by a gas chromatographic method. All structural changes in the parent molecule were found to reduce the biological activity to various degrees. The most active analog tested was the carbamate12, whose activity was almost comparable to that of the pheromone component1. Structure-activity correlations showed that hydrophobic, steric, and electronic effects of chain terminal groups might be responsible for variations in biological activity of the conformationally unchanged (E,Z)-2,13-analogs
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    Trail and arena marking by caterpillars ofArchips cerasivoranus (lepidoptera: Tortricidae) (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 1479-1489 
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    ISSN: 1573-1561
    Keywords: Archips cerasivoranus ; Yponomeuta cagnagella ; trail following ; silk ; trail pheromone ; Lepidoptera ; Tortricidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The activity ofArchips cerasivoranus caterpillars is largely limited to their colonial silk web and trails. Silk pulled directly from the spinnerets of caterpillars and wound onto paper strips to form artificial trails elicited locomotion from the larvae. Trails made from extracts of silk and silk glands also elicited locomotion. These and other observations reported here indicate that the caterpillars are responsive to a water-soluble pheromone that is a component of the silk strand. Marker pheromones appear not to be secreted from other regions of the body, as has been reported for some other trail-following caterpillars.
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    Nitrogen release from decomposing seaweeds: species and temperature effects (1993)
    Springer
    Journal of applied phycology 5 (1993), S. 175-181 
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    ISSN: 1573-5176
    Keywords: decomposition ; Gracilaria ; nitrogen ; nutrients ; temperature ; Ulva
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This study determined the rate at which nitrogen accumulated in seaweeds is released during decomposition and the effect of temperature on their rates of decomposition and nitrogen release. Gracilaria verrucosa and Ulva lactuca decomposed rapidly in outdoor mesocosms. Ulva, but not Gracilaria, became nitrogen-enriched during decomposition. Maximal weekly rates of nitrogen release were 5.91 ± 2.23 and 6.37 ± 2.59 g N m−2 d−1, respectively for Gracilaria and Ulva. Temperature had a significant effect on the decomposition rate of Gracilaria in a laboratory experiment: decomposition was greater at 30 °C than at 25 °C. No net decomposition was observed at 16 °C. Gracilaria became nitrogen enriched at 30 °C, but not at 16° or 25°. The release of stored nutrients from decaying seaweeds should be included in nutrient budgets and models when seaweed standing stocks are significant. Seaweed source-sink relationships are important ecologically and can be applied to attempts at using seaweeds as environmental monitors of anthropogenic eutrophication and to efforts of cultivating seaweeds for the improvement of water quality.
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    Effect of light intensity and ammonium-N on carotenogenesis ofTrentepohlia odorata andDunaliella bardawil (1993)
    Springer
    Journal of applied phycology 5 (1993), S. 547-549 
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    ISSN: 1573-5176
    Keywords: Trentepohlia odorata ; Dunaliella bardawil ; light intensity ; nitrogen ; growth ; carotenogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract AxenicTrentepohlia odorata was cultured at three different NH4Cl levels (3.5 × 10−2, 3.5 × 10−3, 3.5 × 10−4 M) and three different light intensities (48, 76, 122 µmol m−2 s−1). Chloride had no effect on growth over this range of concentration. High light intensity and high NH4Cl concentration enhanced the specific growth rate. The carotenoid content increased under a combination of high light intensity and low N concentration. WhenD. bardawil was exposed to the same combination of growth conditions, there was an increase in its carotenoid content. The light saturation and the light inhibition constants (K s andK i, respectively) for growth, and the saturation constant (K m) for NH4Cl were determined. TheK s andK i values were higher inT. odorata (66.7 and〉 122 σmol m−2 s−1, respectively) than inD. bardawil (5.1 and 14.7 µmol m−2 s−1, respectively). TheK m value determined at 122 µmol m−2 s−1, however, was lower inT. odorata (0.048 µM) than inD. bardawil (0.062 µM).
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    Culture ofGelidium sesquipedale (Clem.) Born.et Thur. in a chemostat system. Biomass production and metabolic responses affected by N flow (1993)
    Springer
    Journal of applied phycology 5 (1993), S. 405-415 
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    ISSN: 1573-5176
    Keywords: agar ; C:N ratio ; chemostat ; Gelidium ; nitrogen ; phycobiliproteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Gelidium sesquipedale is the most important raw material used for extraction of agar in Spain. Based on chemostats, a system of culture for macroalgae with a continuous flow of culture medium has been developed. A stressed morphotype from the South of Spain was cultured, and the effects of different rates of NO 3 − flow on growth and internal constituents were investigated in the laboratory. Cultivation was successful after optimizing factors affecting growth, such as irradiance level, renewal rate and water movement. Mass production was dependent on N supply. With a flow of 35 μmol NO3 − g−1 DW d−1, optimal values of growth (2.1% d−1) and biomass yield were obtained. In these conditions, biomass yield resembled the values observed in natural populations (about 500 g DW m−2 y−1). When the flow of N was reduced to 15 μmol NO 3 − g−1 DW d−1, growth rate and biomass yield were reduced three-fold, and were null when N was supplied as 7 μmol NO 3 − g−1 DW d−1. C:N ratio was an index of the physiological status of the tissue, remaining low when N was sufficient and raised to critical values when N supply was limited. Phycobiliproteins, kept at a constant irradiance level, were affected by N supply, acting as an internal nitrogen reserve, unlike chlorophylla. An effective phycobiliprotein synthesis took place when the flow of N was sufficient. Agar yield, on dry weight basis, was similar as a function of N flow, whereas agar yield of the culture was higher when N was sufficient as a result of growth not being limited by N. This system of culture, commonly used in microalgal studies, may have an important use in macroalgae as a system to obtain biomass of high quality as well as a good tool for physiological studies in conditions of continuous and controlled flow of nutrients.
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    Methods for measuring biological nitrogen fixation in grain legumes (1993)
    Springer
    Plant and soil 152 (1993), S. 19-23 
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    ISSN: 1573-5036
    Keywords: acetylene reduction ; difference method ; legumes ; 15N isotope method ; nitrogen ; nitrogen fixation ; Rhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract To assure proper management and fully realize the benefits of the legume-Rhizobium symbiosis it is necessary to be able to quantify the amount of nitrogen fixed. Having measured the effectiveness of atmospheric N2 fixation the macro- or micro-symbionts as well as agronomic factors can be manipulated with the objective to maximize biological nitrogen fixation. A suitable method to quantify nitrogen fixation is therefore necessary in any programme aiming at increasing N2 fixation, like the one being reported in this volume. There are several methods available to quantify nitrogen fixation and most of the commonly used ones are described in the present paper listing their advantages and disadvantages.
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    URL: http://dx.doi.org/10.1007/BF00016330
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    Modelling nutrient responses in the field (1993)
    Springer
    Plant and soil 155-156 (1993), S. 57-66 
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    ISSN: 1573-5036
    Keywords: nitrogen ; wheat ; simulation ; yield-response curve
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Models of the yield responses of crops to applied nutrients are a recent addition to the methods available for making fertilizer recommendations. They have a place in integrating nutrient information with information on other factors which affect yield and its response to added nutrients. This review deals with nitrogen models classified into three groups: those which predict yield-response curves based on empirical factors; those which simulate the yield response from complex simulation models of many processes regulating crop growth and the soil environment; and those which aim to simulate yield and selected processes based on simplified functional relationships which apply to a target region or industry. Three case studies representing the three classes of model are drawn from research on dryland wheat in different parts of Australia. They show examples in which models provide information which is unobtainable from experimental procedures and which provide information useful to farmers in making decisions about fertilizers. Suggestions are made for future developments in crop-nutrient modelling including further comparisons of models, linkage of models with tissue tests, modelling co-limiting nutrients, deciding on the appropriate level of detail within a model and the need for methods for calibrating and testing models on attributes other than yield alone.
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    URL: http://dx.doi.org/10.1007/BF00024984
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    Estimation of potentially mineralisable nitrogen in soil by KCl extraction (1993)
    Springer
    Plant and soil 157 (1993), S. 167-174 
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    ISSN: 1573-5036
    Keywords: extraction ; mineralisation ; nitrogen ; potassium chloride ; uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The mineral nitrogen extractable from 12 Scottish arable soils by boiling for 1 hour with 1 M KCl solution was compared with the quantities taken up by ryegrass, barley and oats in pot tests. High correlations were obtained for ryegrass and oats (r2=0.85 and 0.79, respectively), with a slightly lower correlation (r2=0.64) for barley. When the results for one anomalous soil were eliminated from the analysis, all r2 values were 0.81 or higher. The results confirmed earlier work indicating that this method may prove useful for predicting crop uptake of soil-derived nitrogen.
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    URL: http://dx.doi.org/10.1007/BF00011045
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    Non-structural carbohydrate: Analysis by near infrared reflectance spectroscopy and its importance as an indicator of plant growth (1993)
    Springer
    Plant and soil 155-156 (1993), S. 243-246 
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    ISSN: 1573-5036
    Keywords: fructans ; NIR ; nitrogen ; non-structural carbohydrates ; rice ; starch ; stress ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Plant shoot samples are frequently analysed to assess if crops require additional nitrogen or mineral elements to maintain satisfactory growth. If plant growth is limited by temperature, water stress, disease, lodging or a mineral deficiency, non-structural carbohydrates (NSC) may be accumulated in, or depleted from, tissues especially those in the lower stems. Plant testing laboratories do not routinely analyse NSC to assist in the identification of plant stress probably because skilled technicians and time are required for the wet chemical determination. In this paper we report that routine determination of NSC is possible using near-infrared reflectance spectroscopy; the errors of determination are comparable with traditional chemical methods. The concentration of NSC in the shoots of rice grown in south eastern Australia ranges from 1.6 to 22.8%, as starch. In the shoots of wheat grown in eastern Australia the range is from 2.4 to 35.2%, as fructans. In both crops the NSC content is highly inversely correlated with the shoot nitrogen content. Based on data from commercial wheat and rice crops we suggest that the ratio between nitrogen and NSC can be used to identify crops in which growth has been limited by a stress other than nitrogen and so are unlikely to show the predicted response to an application of nitrogen fertilizer.
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    URL: http://dx.doi.org/10.1007/BF00025029
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    Nuclear magnetic resonance studies of the location and function of plant nutrients in vivo (1993)
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    Plant and soil 155-156 (1993), S. 45-55 
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    ISSN: 1573-5036
    Keywords: compartmentation ; cytoplasm ; 39K NMR ; maize ; nitrogen ; 14N NMR ; 15N NMR ; pea ; phosphorus ; potassium ; 31P NMR ; vacuole
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The cytoplasmic and vacuolar pools of ammonium, inorganic phosphate and potassium can be studied non-invasively in plant tissues using high resolution nuclear magnetic resonance spectroscopy. The techniques that allow these pools to be discriminated in vivo are described and their application to plants is reviewed with reference to the phosphorus, nitrogen and potassium nutrition of root tissues.
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    URL: http://dx.doi.org/10.1007/BF00024983
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    Changes in the amino acid composition and protein modification in phloem sap of rice (1993)
    Springer
    Plant and soil 155-156 (1993), S. 171-174 
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    ISSN: 1573-5036
    Keywords: amino acid ; nitrogen ; phloem sap ; phosphorylation ; protein ; rice (Oryza sativa L.)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Pure phloem sap was collected from insects feeding on rice (Oryza sativa L.) leaves by a laser technique similar to the aphid stylet technique. Rapid circulation of nitrogen in the sieve tubes was demonstrated directly using 15N as a tracer. Application to the roots of the metabolic inhibitors of amino acids, aminooxyacetate and methioninesulfoximine, changed the amino acid composition in the sieve tubes. Feeding methionine to leaf tips resulted in its bulk transfer into the sieve tubes. In vitro experiments confirmed the existence of protein kinases in the pure rice phloem sap. The phosphorylation status of the sieve tube sap proteins was affected by the light regime. The possibility that changes in chemical composition or protein modification such as phosphorylation in the sieve tubes might affect plant growth are discussed. Analysis of pure phloem sap collected from rice plants by insect laser technique has shown dynamic changes in the chemical composition and the quality of proteins in the sap.
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    Mineral nutrient disorders of root crops of the Pacific: Preliminary observations on sweet potato (Ipomoea batatas) (1993)
    Springer
    Plant and soil 155-156 (1993), S. 263-267 
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    ISSN: 1573-5036
    Keywords: critical concentration ; magnesium ; manganese ; nitrogen ; phosphorus ; potassium ; solution culture ; zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Solution culture was used to characterise deficiencies or toxicities of several essential elements in Ipomoea batatas cv. Wanmun, and to define the critical concentrations of these elements in young mature leaves during vegetative growth. Tentative critical concentrations for deficiency, expressed on the basis of dry weight of leaf blade, were: nitrogen 3.8%, phosphorus 0.17%, potassium 2.4%, magnesium 0.12%, manganese 20μg/g and zinc 10μg/g. For manganese and zinc toxicities it was possible only to designate the range within which the critical concentration occurred. Visible symptoms are briefly described.
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    Molecular biological approaches to plant nutrition (1993)
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    Plant and soil 155-156 (1993), S. 21-31 
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    ISSN: 1573-5036
    Keywords: nitrogen ; sulphur-nutrition ; gene cloning ; gene expression ; regulation ; crop improvement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In the last decade, understanding of ion transport has grown sufficiently to pose sensible questions about the molecular nature of the processes and their regulation. Techniques for identifying and cloning genes and for genetic transformation provide the means for answering these questions. Transport of ions across membranes is obviously a major aspect of mineral nutrition since it occurs during initial absorption, compartmentation and mobilisation of nutrients. Here, we will briefly review the types of transport protein involved and show how molecular biology and recombinant DNA technology have revealed something of their structure. Strategies used to identify the genes for transporters are discussed and reference is made to areas in which the availability of cloned genes will facilitate future studies. Mineral nutrition involves, however, more than membrane transport. The absorption rates of major nutrients are quite strictly regulated by biochemical factors which vary with the rate at which nutrients are used in growth. Nitrogen, sulphur and phosphate nutrition in micro-organisms are regulated by the interaction of various DNA-binding proteins with the promoter regions of genes for key enzymes in the assimilatory pathways and the specific ion permeases. The expression of the regulatory protein or its activity can be modified by metabolites, such as glutamine. Some evidence supports the idea that higher plants also have groups of genes with a common regulation of expression. An attempt is made to identify some reasonable objectives, which should increase understanding of the regulation of nutrient transport.
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    Variation in 15N enrichment of crimson clover labeled under field conditions (1993)
    Springer
    Plant and soil 152 (1993), S. 255-260 
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    ISSN: 1573-5036
    Keywords: crimson clover ; field labeling ; legume ; nitrogen ; 15N ; variability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Plant material labeled with 15N is often used to determine recovery of N from green manure crops by subsequent crops. In this study, 15N enriched crimson clover (Trifolium incarnatum L.) was grown at a field site where it was to be utilized in a subsequent experiment. A foliar spray of (NH4)2SO4 (99 atom % excess 15N) was applied to a 1.2 m × 8.8 m plot of crimson clover at a rate of 10 kg N ha−1 in early March 1990, immediately prior to the period of rapid vegetative growth. Clover shoots harvested in April contained 1.72 atom % excess 15N. Total N concentration of enriched clover was similar to that in adjacent untreated clover. Clover shoots contained 20% of the applied 15N, and an additional 27% was recovered from the surface soil horizon (0 to 15 cm). A gradient was observed across the plot, with clover enrichment increasing from 1.3 to 2.2 atom % excess 15N. Recovery of applied 15N in soil was highest in the subplots with lowest clover enrichment. Variability in 15N enrichment was also observed among plant parts: leaves from the basal half of shoots had 2.2 atom % excess 15N; while leaves from the terminal half of shoots, terminal stems, and basal stems had between 1.1 and 1.4 atom % excess 15N.
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    Allocation of carbon and nitrogen as a function of the internal nitrogen status of a plant: Modelling allocation under non-steady-state situations (1993)
    Springer
    Plant and soil 155-156 (1993), S. 183-186 
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    ISSN: 1573-5036
    Keywords: allocation ; carbon ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In this paper we model allocation of carbon and nitrogen to roots and leaves as a function of the nitrogen status of a plant. Under steady-state conditions, allocation of carbon and nitrogen to leaves is exponentially (positively) correlated with plant nitrogen concentration, whereas allocation to roots is correlated negatively, also in an exponential manner. Allocation functions derived under steady-state conditions are used to simulate biomass partitioning under non-steady-state nutrient conditions. Upon nitrogen deprivation, measured and simulated values are rather similar with time, suggesting that allocation functions derived under steady-state conditions also hold under non-steady-state conditions.
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    URL: http://dx.doi.org/10.1007/BF00025014
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    Effects of sowing time and plant age on critical nitrogen concentrations in canola (Brassica napus L.) (1993)
    Springer
    Plant and soil 155-156 (1993), S. 387-390 
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    ISSN: 1573-5036
    Keywords: Brassica napus L. ; canola ; critical concentrations ; nitrate ; nitrogen ; sowing time
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Critical concentrations of NO3-N in fresh petiole tissue and total N in the dried lamina were determined for the youngest mature leaf (YML) of field-grown canola. For dry matter yield of canola sown on 4 May, critical NO3-N concentration in the YML petiole at the rosette stage (RS) was 1.46 mg/g fresh wt. At the flower-buds-visible stage (BV) it was 0.45 mg/g fresh wt. For seed yield the values were 1.72 and 0.53 mg/g fresh wt. Critical total N concentration in the YML lamina for dry matter yield were 69 mg/g dry wt. at RS and 57 at BV. For seed yield they were 71 and 59 mg/g dry wt. Critical NO3-N concentrations in the YML petiole of canola sown on 30 May were reduced by 50%; critical total-N concentrations in the YML lamina were not reduced to the same extent. Despite the reductions in critical N concentrations in the YML, critical N fertilizer rates for vegetative growth and seed yield were unaffected by sowing date or plant growth stage.
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    Iron-deficiency chlorosis in Scots pine growing on acid soils (1993)
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    Plant and soil 153 (1993), S. 255-263 
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    ISSN: 1573-5036
    Keywords: acid soil ; chlorosis ; iron deficiency ; nitrogen ; Pinus sylvestris
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Scots pine (Pinus sylvestris L.) trees growing on acidic soils may show a special type of chlorosis. The current needles are yellowish and the discolouration is most pronounced at the needle base. The disease bears resemblance to iron chlorosis in trees on calcareous soils. In order to investigate the cause of the chlorosis, needle and soil samples were collected in 41 stands in the southern, central and eastern parts of the Netherlands. Needles of the chlorotic trees had low levels of chlorophylls and carotenoids and high ratios of carotenoids to chlorophylls and of chlorophyll a to chlorophyll b. These symptoms occur in plants suffering from iron deficiency. The current needles of chlorotic trees contained on average 14 mg kg−1 Fe, whereas unaffected trees from the same stands contained 24 mg kg−1. Healthy trees from stands without chlorotic trees had needle iron levels of 29 mg kg−1. Spraying the needles of chlorotic trees with ferric-EDTA containing solutions resulted in partly regreening within a few weeks. Chlorotic needles showed also high nitrogen and cadmium levels. Soils of chlorotic stands contained large amounts of extractable inorganic nitrogen and phosphorus. The possible causal relationships between the observed iron deficiency and the differences in elemental composition of needles and soils are discussed.
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    Effects of fertilization levels in two farming systems on senescence and nutrient contents in potato leaves (1993)
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    Plant and soil 154 (1993), S. 81-88 
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    ISSN: 1573-5036
    Keywords: farming system ; fertilization ; magnesium ; nitrogen ; potassium ; potato ; proteolytic enzymes ; senescence ; Solanum tuberosum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The influence of fertilization on senescence and nutrient remobilization in potato leaves was investigated in two farming systems on a soil with a poor potassium availability. The ‘Conventional’ farming system followed good local practices including industrial products, while in the ‘Bio-Dynamic’ farming system industrial fertilizers and synthetic pesticides were avoided. Potassium concentrations in the dry matter of mature leaves varied over a wide range. Nitrogen compounds (protein, chlorophyll) were less affected, and phosphorus concentrations in the dry matter were similar. Magnesium and potassium concentrations in the leaves were negatively correlated. In both farming systems senescence was advanced in plants with a low nutrient supply. Alkaline pyrophosphatase and aminopeptidase activities (in general highest in expanding and mature leaves) were lower and endopeptidase activities peaked earlier on plots with low fertilizer levels. A high percentage of potassium was remobilized from senescing leaves on unfertilized plots, but the phosphorus concentration remained high at the end of the season. The results suggest that the differential net remobilization of nitrogen, phosphorus and potassium depended on actual source/sink relations in the plants.
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    Estimation of potentially mineralisable nitrogen in soil by KCl extraction (1993)
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    Plant and soil 157 (1993), S. 175-184 
    Details
    ISSN: 1573-5036
    Keywords: barley ; extraction ; malting quality ; mineralisation ; nitrogen ; 15N-labelling ; potassium chloride ; uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The potentially mineralisable nitrogen extracted from 10 soils by two methods involving boiling with dilute KCl were compared with the actual uptake of soil N by spring barley in the field, as determined with the use of 15N-labelled fertiliser. Generally good correlations were found for those soils which had previously been cropped with cereals (defined in Great Britain as either ‘N-Index zero’, or ‘low nitrogen status’ soils, for fertiliser recommendations), with the results obtained by the more severe of the two methods being somewhat better than by the other method. When organic matter content was also taken into account, correlations were improved. Mineral nitrogen in the soil at sowing was highly correlated with potentially mineralisable nitrogen, and with uptake, but this relationship did not hold for soil samples taken in January, well before the likely sowing date. This suggested that early measurement of soil mineral nitrogen (when decisions on cropping are normally made) was not a practicable method for determinining spring fertiliser applications, and that the measure of potentially mineralisable nitrogen appeared more promising in this regard.
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    Decay rate and substrate quality of fine roots and foliage of two tropical tree species in the Luquillo Experimental Forest, Puerto Rico (1993)
    Springer
    Plant and soil 150 (1993), S. 233-245 
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    ISSN: 1573-5036
    Keywords: decomposition ; fine roots ; lignin ; litterbags ; nitrogen ; polyphenols ; substrate quality ; trees ; tropical montane rain forest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Decomposition rates, initial chemical composition, and the relationship between initial chemistry and mass loss of fine roots and foliage were determined for two woody tropical species, Prestoea montana and Dacryodes excelsa, over a gradient of sites in two watersheds in the Luquillo Experimental Forest, Puerto Rico. At all locations, fine roots decayed significantly more slowly than foliage during the initial 6 months. Substrate quality of the initial tissue showed marked differences between roots and foliage when using cell wall chemistry, secondary chemistry and total elemental analysis as indices. Quantity of acid detergent fiber (ADF) (non-digestible cell wall fiber) and lignin content were higher for roots than leaves: D. excelsa roots had 55.3% ADF and 28.7% lignin while leaves had 36.2% ADF and 11.8% lignin; P. montana roots had 68.0% ADF and 26.8% lignin while leaves had 48.5% ADF and 16.1% lignin. Aluminum concentrations were higher in fine roots (843 mg kg−1 in D. excelsa, 1500 mg kg−1 in P. montana) than leaves (244 mg kg−1 in D. excelsa, 422 mg kg−1 in P. montana), while calcium concentrations were higher in foliage (5.5 mg g−1 in D. excelsa, 7.8 mg g−1 in P. montana) than roots (3.4 mg g−1 in D. excelsa, 3.1 mg g−1 in P. montana). Nitrogen did not show any trend with tissue or species type. A linear model between mass remaining after 6 months and initial tissue chemistry could be developed only for calcium (r2=0.64).
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    Leaf expansion, photosynthesis, and water relations of sunflower plants grown on compacted soil (1993)
    Springer
    Plant and soil 149 (1993), S. 175-184 
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    ISSN: 1573-5036
    Keywords: compaction ; Helianthus annuus L. ; leaf expansion ; nitrogen ; osmotic potential ; photosynthesis ; root growth ; soil strength ; turgor ; water potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Leaf expansion and growth response of sunflower (Helianthus annuus, L.) to soil compaction were investigated in relation to compaction effects on water relations, nitrogen nutrition, and photosynthesis. A series of field experiments were conducted with plants grown in 20 cm-diameter cylinders with soil bulk densities ranging from 1.2 to 1.7 g cm−3 at the 0–20 cm depth (equivalent to 0.8 to 2.4 MPa soil strength measured with a soil penetrometer). Relative leaf expansion rate (RLER) decreased linearly with increasing soil strength. Smaller plant size in compacted treatments was due not only to slower expansion rates, but also smaller maximum size of individual leaves. Sensitivity of leaf expansion to soil strength was best illustrated by a reduction in RLER and maximum size of the first leaf to emerge in a treatment with only the lower 10–20 cm of the profile compacted (bulk density of 1.7 g cm−3). Root growth was less affected than shoot growth by compaction and root:shoot ratios of compacted treatments were significantly higher than the control. Soil compaction had no significant effect on pre-dawn or midday leaf water potential, osmotic potential or leaf turgor. Specific leaf weight was usually higher in plants grown on compacted soil, and leaf nitrogen and photosynthesis per unit leaf area were either unaffected by treatment or significantly higher in compacted treatments. The results suggest that early growth reduction of sunflower plants grown on compacted soil was more sink- than source-limited with regard to water, nitrogen, and carbon supply. Further evaluation of this hypothesis will require verification that these whole-leaf measurements provided a sufficiently accurate approximation of treatment effects on the dynamic equilibria of expanding cells.
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    Grain protein and grain yield of tritordeum in comparison to wheat and triticale (1993)
    Springer
    Plant and soil 153 (1993), S. 287-293 
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    ISSN: 1573-5036
    Keywords: grain protein concentration ; grain yield ; nitrogen ; tritordeum ; triticale ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The new species of cereal × Tritordeum Ascherson et Graebner (Hordeum chilense Roem. et Shultz × Triticum ssp.) has a grain protein concentration (GPC) of up to 25%. The relationship between GPC and yield, and the factors responsible for the high GPC of tritordeum were examined and compared in field experiments. Three experimental tritordeum lines, two early and a later released (recombined and secondary tritordeums) were compared to wheat (cv. Cajeme) and triticale cultivars (cv. Trujillo). GPC's were 19%–22% for recombined tritordeums, 16% for the secondary tritordeum, 12–15% for wheats and 11% for triticale. Grain yields of the recombined and secondary tridordeum were 17–33% and 45–57% that of the wheats and triticale, respectively. Reducing grain sink size by spikelet removal resulted in an increased GPC of remaining grains. Considering all species together there were a strong inverse relationship between GPC and grain yield (GY) per main ear (GPC=26−4.76 ln GY; r2=0.82). In another experiment, frost damage to an early sown treatment of wheat reduced sink size. Harvest index (HI) of early sown wheat was reduced from 0.45 to 0.19, values comparable to that of tritordeum. Having similar HI, the GPC of the early sown wheat was the same as an early sown tritordeum (around 18%). Data for total N uptake and the N concentration of plant tissue during the growing season indicated that enhanced N uptake and remobilisation were not responsible for tritordeum's high GPC. These results suggest that the high GPC of the early lines of tritordeum is a consequence of the small grain yield concentrating the grain protein.
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    A comparison of the effects of subsoiling on plant uptake and leaching losses of sulphur and nitrogen from a simulated urine patch (1993)
    Springer
    Plant and soil 155-156 (1993), S. 375-378 
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    ISSN: 1573-5036
    Keywords: clover ; grass ; leaching ; lysimeter ; nitrogen ; 15N ; nutrient balances ; nutrient uptake ; pasture ; subsoiling ; sulphur ; 35S
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Synthetic cow urine labelled with 35S and 15N was applied to large, undisturbed, monolith lysimeters sampled from subsoiled and non-subsoiled areas of a grass/clover pasture. For one year following the urine application, the lysimeters were subjected to a combination of natural rainfall, simulated rainfall and simulated flood irrigations. Drainage from the lysimeters was sampled regularly and monthly (approx.) pasture cuts taken. At the end of the year, the lysimeters were destructively sampled in 50 mm depth increments for soil analysis. Leachates, plant samples and soil samples were analysed for 35S and 15N. There were no significant differences in plant uptake of 35S and 15N between the subsoiled and nonsubsoiled lysimeters. Initially grass showed a higher degree of labelling than clover. Total amounts of 35S and 15N leached from the subsoiled lysimeters were approximately twice that leached from the nonsubsoiled ones. Leaching patterns differed substantially between the two nutrients. Total recoveries of 35S (in plants, leachates and soil extracts) accounted for 82% of the applied 35S for the subsoiled lysimeters and 72% for non-subsoiled ones. The unrecovered 35S is considered to have been incorporated into soil organic matter. Total recoveries of 15N (in plants, soil and leachates) were similar to those for 35S, but unrecovered 15N is attributed to loss by denitrification.
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    Detritus and nutrient dynamics in the shore zone of lakes: a review (1993)
    Springer
    Hydrobiologia 251 (1993), S. 49-58 
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    ISSN: 1573-5117
    Keywords: lake littoral ; detritus ; macrophytes ; decomposition ; nitrogen ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The importance of detritus varies greatly among shore zones of lakes, but in a large majority of these regions detrital pathways prevail. Aside from a great spatial and seasonal variability, macrophytes and bottom sediments appear to be dominant stores of nutrients in these habitats. Macrophytes hold a central position in nutrient cycling in the shore-littoral lake zones. They are the main source of autochthonous detritus as they prevail in the total biomass of littoral organisms, and they are only rarely available as direct food of consumers. Various processes and interactions determine the role of macrophytes in nutrients dynamics. These are: the intensity of nutrient uptake and translocation, release of nutrients by healthy plants and from decomposing plants, exchange of elements between macrophytes and their periphyton, as well as interception of seston by macrophyte stands. Particular plant species differ in their time of dying and susceptibility to decomposition. The changes in decomposing material (size structure of particles and nutrient content) mean that detritus in various stages of decomposition differs in its role in trophic dynamics of shore-littoral lake zones. Several types of shore regions as regards detritus sources and retention level are discussed.
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    Frost formation in the ecotonal zone and its role for release of nutrients (1993)
    Springer
    Hydrobiologia 251 (1993), S. 65-72 
    Details
    ISSN: 1573-5117
    Keywords: Frozen littoral ; frost heave ; nutrient release ; nitrogen ; phosphorus ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In winter, the littoral substrate of ecotonal zones along north Swedish rivers and lakes freezes. Even if the littoral is flooded at freeze-up, the ice freezes solid to the shore substrate due to low temperature combined with a gradual decrease in water level during winter. Frost conditions were studied during an 8-year period along eight littoral transects in the River Vindelälven and adjacent riverside lagoons. Heavy frost heave with formation of needle ice was observed in several places. Nutrient release was suggested to take place due to the frost process. Sediment was taken to a laboratory experiment where samples with sediment and water were kept under unfrozen and frozen conditions during six months. N (total-N) and Ca were significantly released to the water, while P (total-P) did not show any clear movement from the frozen sediment. The results indicate that frost processes in ecotonal zones are involved in the movement of nutrients between sediment and water.
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    Transport and retention of matter in riparian ecotones (1993)
    Springer
    Hydrobiologia 251 (1993), S. 95-101 
    Details
    ISSN: 1573-5117
    Keywords: Land/stream ecotones ; bank runoff ; aerial drift ; retention ; carbon ; nitrogen ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ‘stream’ ecosystem is described as a three-layered system, vertically as well as horizontally. The land/stream ecotone is defined as the area where lotic and edaphic characters overlap at the time of observation. The study site — ‘Oberer Seebach’, near the Biological Station Lunz — and the methods employed are described. Only a surprisingly small fraction (less than 10 %) of total imports is transported across the surface ecotones. The driving variables determining bank runoff and aerial drift are described and discussed. The importance of channel areas which are periodically flooded is stressed.
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    Influence of nitrogen and phosphorus fertilizers on amount and nutrient content of litterfall in a regrowth eucalypt forest (1993)
    Springer
    New forests 7 (1993), S. 33-47 
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    ISSN: 1573-5095
    Keywords: eucalypt ; regrowth forest ; litter ; litterfall ; fertilizer ; nitrogen ; nutrient cycling ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of fertilizer treatment on nutrient transfers to the forest floor were examined in regrowth Eucalyptus diversicolor F. Muell. forest. Dry weight and nutrient content of leaf litterfall and total litterfall were measured for 3 years in a stand to which two levels of N (0, 200 kg ha-1 year-1) were applied each year at each of three levels of a single initial application of P (0, 30, 200 kg ha-1). Annual accessions of litter to the forest floor were significantly increased by additions of both N (by 17%, 18% and 21% in the 3 years) and 200 kg P ha-1 (by 8%, 8% and 4% in the 3 years) but there was no interaction between effects of N and P treatments. Fertilizer application also had a significant effect on the nutrient content of leaf litterfall and total litterfall. Concentration of N in leaf litterfall was 9% to 23% greater on plots treated with N fertilizer compared to untreated plots. The amounts of N in litterfall were about 30% greater on N-treated compared to untreated plots. On plots treated with 200 kg P ha-1, P concentrations in leaf litter were 50% to 100% greater than in litter from plots receiving no P. Application of 200 kg P ha-1 increased the amounts of P in annual litterfall by 32% to 87%. The greatest increase in P accessions occurred soon after fertilizer treatment. The amounts of Ca, K, and Na in litterfall were also significantly increased by fertilizer application. For Ca and K this was due partly to increases in element concentrations in litterfall following application of treatments. The effect of fertilizers on internal recycling of plant nutrients and on litter accumulation and nutrient dynamics in forest floor litter is discussed.
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    Retention of nitrogen and phosphorus in a Danish lowland river system: implications for the export from the watershed (1993)
    Springer
    Hydrobiologia 251 (1993), S. 123-135 
    Details
    ISSN: 1573-5117
    Keywords: retention ; core-sampling ; phosphorus ; nitrogen ; resuspension ; export
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In a Danish lowland river system intensive measurements were made, in four 80 m reaches, of the nitrogen (N) and phosphorus (P) stored in the stream sediment. The results were used for calculation of the total retention in the river system during two summers (June to August). In addition, the mobilization of nutrients from the stream bottom in autumn 1987 was compared with the export from the watershed. During the study period (June 1987 to September 1988) the amounts of N and P stored in stream reaches were determined fortnightly using a core-sample technique. In reaches dominated by submersed macrophytes, 25–40 g N m−2 and 20–30 g P m−2 were stored during two summers, against only 10–15g N and P m−2 for sandy and gravely reaches. In riparian zones with emergent macrophytes the retention was even higher than in the submersed macrophytes. Gross retention exceeded net retention by a factor of two to three. Net retention of P in the river system during the summer of 1987 was equal to the summer export from the watershed. On an annual basis, retention in the summer constituted 20% of the P export. In contrast, retention in the summer of 1988 amounted to 60% of the total P export during the same period (38% reduction) and 22% in comparison with the annual export. The corresponding figures for N were lower, showing reductions of 16% and 12% of the export of total N in the two summer periods, and about 1% of the annual exports. In September 1987 6.4% of the total N export and 65% of the total P export from the watershed consisted of resuspended material. In 1987 the N and P retained during the summer was almost completely resuspended during storm events during September to November.
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    Transpiration by an emergent macrophyte: source of water and implications for nutrient supply (1993)
    Springer
    Hydrobiologia 271 (1993), S. 97-108 
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    ISSN: 1573-5117
    Keywords: Myriophyllum aquaticum ; parrotfeather ; nitrogen ; phosphorus ; mass flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The contribution of sediment interstitial water and the water column to the transpiration stream of Myriophyllum aquaticum (Vellozo) Verdcourt was determined to estimate the significance of mass flow in supply of sediment nutrients for plant growth. Sediment interstitial water accounted for about 2% of the water transpired over a 37 day period. Because of the small volume of water that originated in the sediment we concluded that mass flow did not significantly enhance nutrient supply to the roots of M. aquaticum. Relative growth rate (RGR) of adventitious, water roots was greater than whole plant RGR, and RGR of sediment roots was not significantly different from zero, indicating a shift in the biomass allocation after emergence of the apical meristem into the air. Water use, measured by the transpiration coefficient, averaged 260 ml H2O mg DW-1, which is similar to C-4 terrestrial plants. M. aquaticum has leaf characteristics commonly associated with xerophytic habitats. These characteristics may be necessary if a high transpiration rate and a mechanical requirement for high cell turgor pressure, required by a reliance upon hydrostatic pressure for support of the aerial stems, are mutually exclusive because of morphological constraints on hydraulic conductivity.
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    Importance of flood zones for nitrogen and phosphorus dynamics in the Danube Delta (1993)
    Springer
    Hydrobiologia 251 (1993), S. 143-148 
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    ISSN: 1573-5117
    Keywords: Danube Delta ; flood zones ; phosphorus ; nitrogen ; eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The change of concentration of total reactive phosphorus (TRP) and dissolved inorganic nitrogen (DIN) was studied in the lower Danube river and in selected lakes situated in the wetland area of the Danube Delta. The differences Danube Delta in nutrient concentration in the river waters entering the delta and the delta in different sites (especially lakes) of the wetland area are considered to reflect retention in the system. The highest retention was found in periods of moderate and low water level when the surface-to-volume ratio of the lakes was high. In these periods the in-lake concentration of TRP and DIN could be as low as 11 and 23% of the values found in the inflowing river.
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    Simulated effects of precipitation and nitrogen on Serengeti grassland productivity (1993)
    Springer
    Biogeochemistry 22 (1993), S. 157-178 
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    ISSN: 1573-515X
    Keywords: Serengeti ; productivity ; precipitation ; nitrogen ; grazing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract In the Serengeti National Park, Tanzania, precipitation and soil nitrogen vary greatly between northwestern tallgrass areas and southeastern shortgrass areas, with the tallgrass having higher total precipitation and lower soil fertility. We used a model of grassland productivity, carbon/nitrogen cycling, and abiotic factors to test the hypothesis that tallgrass productivity is limited primarily by nitrogen availability while shortgrass productivity is limited by water. Under observed grazing intensities and ungrazed conditions, precipitation exerted primary control over grassland productivity for both regions, with differences in soil texture mediating soil water availability to the grasses. Mineral nitrogen availability interacted with water availability to influence productivity at precipitation levels ⩾ 130% of the mean. Nitrogen mineralization and precipitation were positively related for each grassland type, however, nitrification varied both between grassland types and between grazed and ungrazed conditions. Combined mineralization and nitrification could not maintain soil mineral nitrogen levels in the face of plant nitrogen uptake stimulated by increased precipitation, thus providing the mechanism by which nitrogen becomes a secondary limiting factor for both grasslands. Model experiments indicated that the pattern of primary limitation by precipitation and secondary limitation by nitrogen was robust to model assumptions concerning ungulate deposition of urine and dung nitrogen to the soil.
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    Electrophysiological and behavioral responses of turnip moth males,Agrotis segetum to fluorinated pheromone analogs (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 143-157 
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    ISSN: 1573-1561
    Keywords: Agrotis segetum ; Lepidoptera ; Noctuidae ; (Z)-5-decenyl acetate ; fluorinated analogs ; behavioral activity ; electrophysiological activity ; flight tunnel ; single sensillum recording ; field test ; lipophobicity ; lipid solubility ; structure-activity analysis ; pheromone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The electrophysiological and behavioral responses of maleAgrotis segetum to fluorinated analogs of (Z)-5-decenyl acetate (Z5-10∶OAc) were investigated. The single sensillum recordings showed that 4,4-difluoro-(Z)-5-decenyl acetate (4,4-F2), 7,7-difluoro-(Z)-5-decenyl acetate (7,7-F2), 10,10,10-trifluoro-(Z)-5-decenyl acetate (10,10,10-F3) and 7,7,8,8-tetrafluoro-(Z)-5-decenyl acetate (7,7,8,8-F4) were each 100-fold less active than the natural Z5-10 ∶ OAc, whereas the 7,7,8,8,9,9,10,10,10-nonafluoro-(Z)-5-decenyl acetate (F9) analog was essentially inactive. A mixture of Z5-10 ∶ OAc, Z7-12 ∶ OAc, and Z9-14 ∶ OAc on a filter paper dispenser was as attractive as female gland extracts when tested in a flight tunnel. With Z5-10∶OAc omitted, the two-component mixture elicited a significantly lower male response. Four analogs, 7,7-F2, 10,10,10-F3, 7,7,8,8-F4, and F9, were added separately to the two-component mixture to replace Z5-10∶OAc. The responses elicited by the mixtures containing the 7,7-F2, 10,10,10-F3, and 7,7,8,8-F4 analogs did not differ significantly from that of the natural three-component mixture and the two-component mixture, whereas the mixture containing F9 elicited a significantly lower male response, as low as the response to the two-component mixture. In a field test the mixtures containing 10,10,10-F3 and 7,7,8,8-F4 were significantly more active than the two-component mixture, but still less active than the natural three-component mixture. It appears that field tests provided greater discrimination among pheromone analogs in assessing their behavioral activity than the flight-tunnel test did. Structure-activity analyses demonstrate the importance of the lipophilic interaction between the terminal alkyl chain and the receptor site for the activity of the stimulus. The lipophobicity of the fluorinated analogs impedes a productive receptor interaction.
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    Constituents of wing gland and abdominal hair pencil secretions of male African sugarcane borer,Eldana saccharina walker (Lepidoptera: Pyralidae) (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 2255-2277 
    Details
    ISSN: 1573-1561
    Keywords: Eldana saccharina ; Lepidoptera ; Pyralidae ; exocrine secretions ; sex pheromone ; aggregation pheromone ; electroantennograms ; electroantennographic detection ; NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In addition totrans-3,7-dimethyl-6-octen-4-olide (eldanolide), vanillin, and 4-hydroxybenzaldehyde, identified by French workers in the wing gland and abdominal hair pencil secretions of the male African sugarcane borer,Eldana saccharina, we have, in an earlier note, reported the presence of several other terpenoid, aromatic, and unbranched-chain compounds such as, (Z)-3,7-dimethylocta-2,6-dienoic acid, 6,10,14-trimethyl-2-pentadecanol, 4-hydroxy-3-methoxybenzyl alcohol, 1-octadecane thiol, 16-hexadecanolide, and 18-octadecanolide in these secretions. In the present paper experimental details and spectral evidence supporting the identification of these compounds, as well as the identification of (Z)-9-hexadecenal and cw-3,7-di-methyl-6-octen-4-olide (cis-eldanolide), are reported. Using electroantennography it was found that male and female antennae reacted approximately equally strongly to both secretions. This result was confirmed in analyses of the secretions using coupled gas chromatography-electroantennography and it was found that male as well as female antennae responded to eldanolide. Vanillin, substituted phenols related to vanillin, and some oxygenated monoterpenes elicited weak responses in male and female antennae. In some analyses 6,10,14-trimethyl-2-pentadecanol, present in the secretions of the insect, gave a strong antennal response. The results obtained in dynamic and static headspace determinations showed that several of the organic compounds present in the glandular secretions are released in detectable quantities and are present in widely varying quantitative ratios in the effluvia of individual calling male moths.
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    Diel rhythms of calling behavior and pheromone production of oriental tobacco budworm moth,Helicoverpa assulta (Lepidoptera: Noctuidae) (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 2953-2963 
    Details
    ISSN: 1573-1561
    Keywords: Helicoverpa assulta ; sex pheromone ; calling ; diel periodicity ; Lepidoptera ; Noctuidae ; (Z)-9-hexadecenal ; hexadecanal ; (Z)-11-hexadecenal ; (Z)-9-hexadecenyl acetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Both calling behavior and titer of (Z)-9-hexadecenal (Z9-16: Al), the major sex pheromone component ofHelicoverpa assulta, in pheromone glands showed distinct diel periodicity, and these two were synchronous. Calling was most actively performed and the pheromone titer reached a maximum from 2 to 6 h after lights-off. During photophase, no calling was shown and only a relatively small amount of Z9-16:A1 was detected. However, there was a time lag of a few days between peak calling activity and maximum pheromone titer. The pheromone titer was maximal from age 1 day to age 5 days and thereafter decreased while calling was most actively performed after age 3 days. Titers of three minor components, hexadecenal, (Z)-11-hexadecenal, and (Z)-9-hexadecenyl acetate, showed similar daily fluctuation patterns to that of Z9-16:Al, but relative to the titer of Z9-16:Al, the titer of the two aldehyde components remained relatively constant whereas that ofZ9-16:Ac increased in the late scotophase.
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    Sex pheromone catabolism in the redbanded leafroller moth (1993)
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    Journal of chemical ecology 19 (1993), S. 751-762 
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    ISSN: 1573-1561
    Keywords: Lepidoptera ; Tortricidae ; Argyrotaenia velutinana ; tritiated pheromone ; 11-tetradecenyl acetate ; sensory biochemistry ; catabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Tritium-labeled components of the red-banded leaf-roller female sex pheromone, (Z)- and (E)-[11,12-3H2]-11-tetradecenyl acetate (57 Ci/mmol), applied to antennae of males and females were degraded causing formation of tritiated 11-tetradecenol, 11-tetradecenoic acid, and water. Results indicate that the catabolic pathway involves acetate hydrolysis, oxidation of alcohol to fatty acid, and degradation of the acid viaβ-oxidation. Both geometric isomers were degraded equally well by males but degradation proceeded comparatively less rapidly with female antennae. It is surmised that under natural conditions of olfactory sensing, sex pheromone impinging upon the moth's antennae is probably subject to a similar catabolic fate.
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    (6Z,9Z-3R,4S)-Epoxy-heptadecadiene: major sex pheromone component of the larch looper,Semiothisa sexmaculata (Packard) (Lepidoptera: Geometridae) (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 843-850 
    Details
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Geometridae ; Semiothisa ; S. sexmaculata ; S. marmorata ; S. neptaria ; sex pheromone ; sex attractant ; enantiomer ; (3Z,6Z,9Z)-heptadecatriene ; (6Z,9Z-3R,4S)-epoxy-heptadecadiene ; (6Z,9Z-3S,4R)-epoxy-heptadecadiene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Gas chromatographic-electroantennographic analysis (GC-EAD) of female larch looper,Semiothisa sexmaculata (Packard), gland extracts revealed two EAD-active compounds. Retention index calculations, GC-mass spectroscopy in selected ion monitoring mode, and GC-EAD analysis of authentic standards identified the compounds as (3Z,6Z,9Z)-heptadecatriene (3Z,6Z,9Z-17∶H) and (6Z,9Z)-cis-3,4-epoxy-heptadecadiene (6Z,9Z-cis-3,4-epoxy-17∶H). Chirality determination of the monoepoxydiene in gland extracts was impeded by small quantities, but field experiments indicated that maleS. sexmaculata were most strongly attracted to enantiomerically enriched 6Z,9Z-3R,4S-epoxy-17∶H (69% ee), while maleS. neptaria (Guenée) responded well to various blends of theR,S- and S,R-epoxide enantiomers. Binary combinations of theR,S-epoxide enantiomer with 3Z,6Z,9Z-17∶H significantly inhibited response by maleS. sexmaculata, but strongly enhanced attraction of sympatric maleS. marmorata Ferguson. Enantiomerically enriched 6Z,9Z-3R,4S-epoxy-17∶H can be used as a trap bait to monitor populations of the larch-defoliatingS. sexmaculata. Whether 6Z,9Z-3R,4S-epoxy-17∶H serves as single component sex pheromone inS. sexmaculata or small amounts of 6Z,9Z-3S,4R-epoxy-17∶H synergize or suppress optimal attraction, will be tested as chirally pure monoepoxydienes become available.
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    Structure-activity relationships for analogs of (+)-(E)-endo-Β-bergamoten-12-oic acid, an oviposition stimulant ofHelicoverpa zea (Boddie) (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 11-27 
    Details
    ISSN: 1573-1561
    Keywords: Oviposition ; insect chemoreception ; corn earworm ; Helicoverpa zea ; Lepidoptera ; Noctuidae ; Lycopersicon hirsutum ; host-plant selection ; sesquiterpenes ; carboxylic acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Β-Bergamotenoic acid, a compound previously shown to stimulate oviposition inH. zea, was converted into a set of bicyclic analogs and tested with a set of acyclic side chain analogs to ascertain the molecular structure that maximizes insect behavioral response. While changes in the bicyclic ring elicited no variation in response, alteration in the side chain structure ofΒ-bergamotenoic acid resulted in significant changes in moth preference. Free rotation about the C-C bond proximal to the carboxylic acid group appears to be an important structural factor, since saturation of the side chain double bond significantly increased activity. The carboxylic acid group seems to be required for strong oviposition stimulation, since analogs lacking the carboxylic acid group exhibited no significant oviposition activity. Oviposition preference ofH. zea was also influenced by the length of the hydrocarbon chain to which the carboxylic acid is attached. While hexanoic acid was found inactive, the ovipositional preference for the heptanoic and octanoic acids was greatest for the one 8-carbon tested. This and other work suggest that carboxylic acids of specific chain lengths influence the oviposition behavior of bothHelicoverpa andHeliothis species and may be associated with host-plant selection. The potential use of this information in designing integrated pest management strategies for control ofH. zea is discussed.
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    Effect of relative humidity conditions on responsiveness of European corn borer (Ostrinia nubilalis) males to female sex pheromone in a wind tunnel (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 61-69 
    Details
    ISSN: 1573-1561
    Keywords: European corn borer ; Ostrinia nubilalis ; Lepidoptera ; Pyralidae ; male responsiveness ; relative humidity ; wind tunnel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The responsiveness pf 3-day-old European corn borer males to three concentrations of 97∶3 Z∶E 11-tetradecenyl acetate, the female sex pheromone, was studied over a range of relative humidities (43–100%) in a wind tunnel. The proportion of males taking flight and reaching the source decreased, while the proportion exhibiting in-flight arrestment of upwind progress increased under high humidity conditions at all three concentrations of pheromone tested. The relationships between relative humidity and these behaviors were best described by polynomial equations.
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    Effects of α-Terthienyl on the midgut detoxification enzymes of the European corn borer,Ostrinia nubilalis (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 2047-2054 
    Details
    ISSN: 1573-1561
    Keywords: Ostrinia nubilalis ; European corn borer ; Pyralideae ; Lepidoptera ; cytochrome P-450 ; cytochrome b5 ; cytochromec reductase ; glutathioneS-transferase ; α-terthienyl ; phototoxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The biochemical basis for the tolerance of the European corn borer,Ostrinia nubilalis, to the phototoxinα-terthienyl was investigated by measuring the midgut polysubstrate monooxygenases and glutathioneS-transferase activities.α-Terthienyl administered in the diet to the corn borers increased the level of cytochromeb 5, NADH-cytochromec reductase,O-demethylase, and glutathioneS-transferase activities. The induced detoxification enzyme activities should enable the corn borer to metabolizeα-terthienyl more efficiently and therefore render the corn borer highly tolerant toα-terthienyl.
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    Chemical and ultrastructural analysis of corn cuticular lipids and their effect on feeding by fall armyworm larvae (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 2055-2074 
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    ISSN: 1573-1561
    Keywords: Spodoptera frugiperda ; Lepidoptera ; Noctuidae ; Zea mays ; scanning electron microscopy ; cuticular lipids ; host-plant resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The cuticular lipid composition of lower and upper leaves of five genotypes of field-grown corn,Zea mays L., was determined by combined gas chromatography-mass spectrometry. Surface lipids of the upper leaves had a higher proportion ofn-alkanes (45–52%) than the lower leaves, while the lower leaves had higher percentages of fatty alcohols (12–18%) than the upper leaves. Scanning electron microscopy showed that the upper leaves of two corn genotypes, MpSWCB-4 and Cacahuacintle X's, had a smooth amorphous appearance, while the lower leaves had a dense array of wax crystals.Spodoptera frugiperda (J.E. Smith) larvae weighed more and developed more rapidly when they were reared on diet containing corn foliage from which the cuticular lipids had been removed than when they were fed untreated foliage. However, growth was not inhibited when larvae were fed diet containing the cuticular lipid extracts or individual cuticular lipid components.
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    C18 Dienes as attractants for eighteen clearwing (Sesiidae), tineid (Tineidae), and choreutid (Choreutidae) moth species (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 799-813 
    Details
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Sesiidae ; Tineidae ; Choreutidae ; (E2,Z13)-octadecadien-1-ol/acetate ; 3,13-octadecadien-1-ol/acetate ; isomers ; stereoselective synthesis ; sex attractants ; inhibitors ; field trapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract By screening singly and binary mixed 2,13- and 3,13-octadecadien-yl acetates and alcohols (2,13- and 3,13-18: Ac/OH)in Lithuania, Armenia, Azerbaijan, Turkmenistan, Ukraine, and the far east of Russia, sex attractants were discovered for 12 Sesiidae, four Tineidae, and one Choreutidae moth species. Males ofSesia yezoensis andBembecia puella as well asNemapogon flavifrons were attracted by mixture ofZ3,Z13-18:Ac/OH in a ratio of 9∶1,Pyropteron sp. n. by the same mixture (ratio 1∶9),Bembecia romanovi andB. zuwandica byZ3,Z13-18:Ac andE3,Z13-18:Ac (9∶1),Synanthedon caucasicum by the same mixture in the opposite ratio (1∶9),B. scopigera by 23,213-18:Ac andE2,Z13-18:OH in a ratio 9∶1,Synasphecia triannuliformis byZ3,Z13-18:OH andE3,Z13-18:OH (9∶1),Similipepsis takizawai andArchimeessia sp. n. by E3,Z13-18:OH andE2,Z13-18:Ac (1∶1),Prochoreutis sechestediana by a mixture ofE3,Z13-18:Ac plusE2,Z13-18:OH (1∶),Microsphecia brosiformis by E3,Z13-18:Ac,Synanthedon conopiformis by the analogous alcohol,Synanthedon scoliaeformis andNemaxera betulinella byE2,Z13-18:Ac,Triaxomera fulvimitrella byZ3,Z13-18:Ac. An analogous alcohol component is essential for the attraction ofB. ichneumoniformis males. Inhibitors forB. romanovi, B. scopigera andB. zuwandica attraction were discovered. Preliminary data on attractants for six other species as well as on the diurnal rhythm of sexual activity of three species are presented. A new method for the stereoselective synthesis of 3,13–18:Ac/OH andE2,Z13-18:Ac/OH is described.
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    URL: http://dx.doi.org/10.1007/BF00985010
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    Oviposition stimulants for the black swallowtail butterfly: Identification of electrophysiologically active compounds in carrot volatiles (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 919-937 
    Details
    ISSN: 1573-1561
    Keywords: Papilio polyxenes ; Papilionidae ; Lepidoptera ; Daucus carota ; Apiaceae ; host-plant selection ; oviposition behavior ; electroantennogram ; combined GC-EAG ; plant volatiles ; sabinene hydrate ; 4-terpineol ; bomyl acetate ; (Z)-3-hexenyl acetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Headspace volatiles were collected from undamaged foliage of carrot,Daucus carota, a host-plant species of the black swallowtail butterfly,Papilio polyxenes. The volatiles were fractionated over silica on an open column, and the fractions were tested in behavioral assays withP. polyxenes females in laboratory experiments. The polar fractions, as well as the total mixture of volatiles, increased the landing frequency and the number of eggs laid on model plants with leaves bearing contact-oviposition stimulants. The nonpolar fraction, containing the most abundant compounds in carrot odor, was not stimulatory. Gas Chromatographic (GC) separation of the fractions was coupled with electroantennogram (EAG) recordings to identify the compounds perceived byP. polyxenes females. The EAG activity corresponded to the behavioral activity of the fractions. None of the nonpolar compounds, identified as various monoterpenes, evoked a major EAG response, but several constituents of the polar fractions elicited high EAG responses. Sabinene hydrate (both stereoisomers), 4-terpineol, bomyl acetate, and (Z)-3-hexenyl acetate were identified by GC-MS as active compounds.
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    URL: http://dx.doi.org/10.1007/BF00992528
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    Quantification of insect growth and its use in screening of naturally occurring insect control agents (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 1109-1118 
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    ISSN: 1573-1561
    Keywords: Bioassay ; tobacco budworm ; Heliothis virescens ; beet armyworm ; Spodoptera exigua ; Lepidoptera ; Noctuidae ; insect growth inhibitors ; allelochemicals ; quassinoids ; chaparrin ; chaparrinone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In studies of the effects of allelochemicals or other factors on the development of different insect species, comparison of growth-inhibiting activities is difficult using the parameters currently employed. We introduce two new parameters, growth index (GI) and relative growth index (RGI), which can unify the quantification of insect development. This quantification can also eliminate the effects of different growth characteristics due to the genetic differences between insect species. By measuring growth-inhibiting effects of two phytochemicals, chaparrin and chaparrinone, on the tobacco budworm,Heliothis virescens, and the beet armyworm,Spodoptera exigua, bioassay procedures and GI and RGI calculations are demonstrated.
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    Chirality of 5,11-dimethylheptadecane, the major sex pheromone component of the hemlock looper,Lambdina fiscellaria (Lepidoptera: Geometridae) (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 1057-1062 
    Details
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Geometridae ; eastern hemlock looper ; western hemlock looper ; sex pheromone ; pheromone chirality ; dimethylated hydrocarbons ; field trapping ; electrophysiological recordings ; (5R, 11S)-5 ; 11-di-methylheptadecane ; (55,11R-5 ; 11-dimethylheptadecane ; (5R, 11R-5 ; 11-di-methylheptadecane ; (5S,11S)-5 ; 11-dimethyIheptadecane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Of the four possible stereoisomers of 5,11-dimethylheptadecane, the major sex pheromone component of the eastern hemlock looper (EHL),Lambdina fiscellaria fiscellaria Guen., and the western hemlock looper (WHL),Lambdina fiscellaria lugubrosa Hulst, (5R,11S)-5,11-dimethylheptadecane was the only stereoisomer eliciting electrophysiological responses by male EHL and WHL antennae. In field bioassays with EHL and WHL populations, traps baited with (5R,11S)-5, 11-dimethylheptadecane caught as many males as did traps baited with all four stereoisomers combined or a synthetic mixture of 5,11-dimethylheptadecanes. Catches in traps baited with the other three stereoisomers did not significantly differ from those in the unbaited control traps. We conclude that male antennae lack chemoreceptors for the other three stereoisomers of 5,11-dimethylheptadecane and hypothesize that only (5R,115)-5,11-dimethylheptadecane is produced by female EHLs and WHLs.
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    URL: http://dx.doi.org/10.1007/BF00987368
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    Chemical correlates of α-tocopherol (Vitamin E) alteredMalacosoma disstria herbivory inFraxinus pennsylvanica var.Subintegerrinia, green ash (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 1205-1217 
    Details
    ISSN: 1573-1561
    Keywords: α-Tocopherol ; vitamin E ; elicitor ; alterable resistance ; antiherbivory ; ash tree ; Malacosoma disstria ; forest tent caterpillar ; Lepidoptera ; Lasiocampidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The antioxidant α-tocopherol (vitamin E), applied in a basal trunk band to the green ash tree,Fraxinus pennsylvanica var.subintergerrinia, elicited an alteration of foliar feeding byMalacosoma disstria larvae (Lepidoptera: Lasiocampidae). The bioassayed effects were dependent on the dosage of elicitor, the time after elicitation, and the position in the tree. Leaves for chemical analysis were collected from trees receiving two dosages and at two intervals after elicitation. Compounds in the ethyl acetate extractables from the ash tree leaves were separated by TLC and HPLC. TLC separations showed differences in the nonhydrolyzed extractables attributable to elicitor dosage and time after elicitation. TLC-resolved differences were also evident among acid-hydrolyzed samples. HPLC-resolved profiles revealed eight peaks in the nonhydrolyzed extractables that were quantitatively negatively correlated with larval feeding preference between elicited versus control foliage on at least one of the two sampling dates. Results from this study and other investigations reported in the literature indicate that the antioxidantα-tocopherol (vitamin E) can function as an environmental-stress elicitor of alterable defensive chemistry in green ash and other plants.
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    URL: http://dx.doi.org/10.1007/BF00987381
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    3,13-Dimethylheptadecane: Major sex pheromone component of the western false hemlock looper,Nepytia freemani Munroe (Lepidoptera: Geometridae) (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 1501-1510 
    Details
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Geometridae ; sex pheromone ; 3,13-dimethylheptadecane ; 3,13-dimethylhexadecane ; 3, 13-dimethyloctadecane ; 5,13-dimethylheptadecane ; 3,11 -dimethylhexadecane ; 3, 11-dimethylpentadecane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract 3,13-Dimethylheptadecane (3,13-dime-17Hy) is the major sex pheromone component of the western false hemlock looper (WFHL),Nepytia freemani Munroe. It was identified in extracts of female pheromone glands by coupled gas chromatographic-electroantennographic detection (GC-EAD) and coupled GC-mass spectroscopy (GC-MS). Traps baited with 100μg of 3,13-dime-17Hy attracted large numbers of male WFHL. Of five additional candidate pheromone dimethylated hydrocarbons, only 3,13-dimethylhexadecane attracted male WFHL. However, neither 3,13-dime-16Hy nor the other four compounds enhanced attraction to 3,13-dime-17Hy when tested in binary or ternary combination at respective ratios of 100∶10, 100∶1, or 100∶1∶1. Identification of the complete WFHL sex pheromone requires structural elucidation of all 12 EAD-active components in gland extracts, determination of their chirality, and field testing of antennally active isomers in appropriate combinations and ratios. Stereoisomeric 3,13-dime-17Hy as trap bait may already be used to monitor WFHL populations.
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    Determination of release rates of pheromone dispensers by air sampling with C-18 bonded silica (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 2513-2519 
    Details
    ISSN: 1573-1561
    Keywords: Sex pheromone ; release rate ; pheromone dispenser ; mating disruption ; Lobesia botrana ; Cydia pomonella ; Lepidoptera ; Tortricidae ; (E,E)-8,10-dodecadien-l-ol ; (E,Z)-7,9-dodecadienyl acetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Release rates of pheromones from commercial dispensers for mating disruption inLobesia botrana andCydia pomonella have been measured by sampling an air stream with C-18 bonded silica (Sep-Pak cartridges) followed by extraction and gas chromatographic analysis. The flow chamber is made from inexpensive materials that can be replaced when contaminated. The results correspond with those obtained by gravimetry; the method supplies additional information on the composition of the airborne material.
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    Interactions amongHeliothis virescens larvae, cotton condensed tannin and the CryIA(c) δ-endotoxin ofBacillus thuringiensis (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 2485-2499 
    Details
    ISSN: 1573-1561
    Keywords: Bacillus thuringiensis subsp.kurstaki strain HD-73 ; insecticidal proteins ; cotton condensed tannin ; Heliothis virescens ; Lepidoptera ; Noctuidae ; relative growth rate ; relative consumption rate ; bioassays ; Gossypium hirsutum ; tritrophic interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The potential interactions among a plant-produced allelochemical, a phytophagous insect, and an endotoxin produced byBacillus thuringiensis were investigated using purified cotton condensed tannins, the CryIA(c)δ-endotoxin fromB. thuringiensis subsp.kurstaki strain HD-73, and larvae ofHeliothis virescens. Purified condensed tannin from cotton fed to neonateH. virescens reduced feeding and mortality caused by insecticidal crystals ofB. thuringiensis. In fifth instars, tannin reduced relative growth rate (RGR), relative consumption rate (RCR), but antagonized the effects of the crystalδ-endotoxin. Tannin did not deter feeding of fifth instars in choice tests with cellulose-ester disks. Masking tannin from interacting with the dietary ingredients of artificial diets and crystal protein by encapsulation in alginate gel suggested that tannin adversely affected feeding after ingestion.These results suggest that insect control tactics that employδ-endotoxins in microbial insecticides and transgenic cotton plants may not be compatible when used in conjunction with plants containing high tannin concentrations.
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    Evidence for a multicomponent sex pheromone inEriborus terebrans (Gravenhorst) (HYM.: Ichneumonidae), a larval parasitoid of the European corn borer (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 2563-2576 
    Details
    ISSN: 1573-1561
    Keywords: Sex pheromone ; multicomponent pheromone ; parasitoid ; bioassay ; Hymenoptera ; Ichneumonidae ; Eriborus terebrans ; Lepidoptera ; Pyralidae ; Ostrinia nubilalis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Sex pheromone activity ofEriborus terebrans (Gravenhorst) (Hymenoptera: Ichneumonidae) was recovered from acetone rinses of flasks that previously contained females. The acetone flask rinses elicited the following male responses: upwind anemotaxis, casting, hovering, landing, wingfanning, and mating attempts with other nearby males. Activity of the acetone flask rinse lasted up to four days on a glass substrate. Polar component and nonpolar components were demonstrated in the acetone flask rinse. The polar component elicited male behavioral responses similar to those by the acetone flask rinse, although retention of males at the pheromone source and the period of wing-fanning were of shorter duration. Chromatography data and chemical derivatization indicated that the polar component had the properties of a carboxylic acid with an additional oxygen-containing functional group. The non-polar component acted as a synergist since it was inactive alone but increased male behavioral responses when added to the polar component. Florisil open column chromatography suggested that the nonpolar component was a hydrocarbon(s).
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    Chirality of synergistic sex pheromone components of the western hemlock looperLambdina fiscellaria lugubrosa (HULST) (Lepidoptera: Geometridae) (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 2547-2561 
    Details
    ISSN: 1573-1561
    Keywords: Sex pheromone ; enantiomer ; Lepidoptera ; Geometridae ; western hemlock looper ; (5R)-2,5-dimethylheptadecane ; (5S)-2,5-dimethylheptadecane ; (7R)-7-methylheptadecane ; (7S)-7-methylheptadecane ; chirality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Bakers' yeast reduction of (2E)-3-(2′-furanyl)-2-methyl-2-propenal yielded the synthetic intermediate, (2S)-3-(2′-furanyl)-2-methylpropanol, of high chiral purity (〉97% ee) for the synthesis of the enantiomers of 2,5-dimethylheptadecane and 7-methylheptadecane, two synergistic sex pheromone components of the western hemlock looper (WHL),Lambdina fiscellaria lugubrosa Hulst. In electrophysiological bioassays, (7S)- but not (7R)-7-methylheptadecane elicited strong antennal responses by male WHL antennae. In field trapping experiments, addition of (7S)- but not (7R)-7-methylheptadecane to (5R,11S)-5,11-dimethylheptadecane, the major sex pheromone component of WHL, increased attraction. Attraction to (5R,11S)-5,11-dimethylheptadecane in combination with (7S)-7-methyiheptadecane was further enhanced by the addition of (5S)- but not (5R)-2,5-dimethylheptadecane. Similarly, attraction to (5R,11S)-5,11-dimethylheptadecane combined with (5S)-2,5-dimethylheptadecane increased when 7S- but not (7R)-7-methylheptadecane was added as a third component. We conclude that (7S)-7-methylheptadecane and (5S)-2,5-dimethylheptadecane are the synergistic sex pheromone components of WHL. The synthetic methodology described is applicable to the synthesis of chiral methyl-branched pheromones in other orders of the Insecta, particularly Coleoptera, Diptera and Orthoptera.
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    Species discrimination in five species of winter-flying geometrids (Lepidoptera) based on chirality of semiochemicals and flight season (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 2721-2735 
    Details
    ISSN: 1573-1561
    Keywords: Chirality ; enantiomers ; sex pheromones ; (3Z,9Z)-(6R,7S)-epoxynonadecadiene ; (3Z,9Z)-(6S,7R)-epoxynonadecadiene ; (6Z,9Z)-(3S,4R)-epoxynonadecadiene ; Colotois pennaria ; Erannis defoliaria ; Agriopis aurantiaria ; A. marginaria ; A. leucophearia ; Lepidoptera ; Geometridae ; electroantennogram ; field trapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Enantiomer separation of (6Z,9Z)-cis-3,4-epoxynonadecadiene and (3Z,9Z)-cis-6,7-epoxynonadecadiene could be achieved using chiral high-resolution gas chromatography and a cyclodextrin-bond column. (3Z,9Z)-(6R,7S)-Epoxynonadecadiene was identified from ovipositor extracts ofColotois pen-Naria, while inErannis defoliaria the 6S,7R-enantiomer was found. In field trapping tests pure synthetic enantiomers caught only conspecific males of these species. (3Z,6Z,9Z)-Nonadecatriene was found in both species, while the presence of (3Z,6Z,9Z)-heneicosatriene was indicated inC. Pennaria only. A 10∶10∶3 blend of (3Z,9Z)-(6R,7S)-epoxynonadecadiene, (3Z,6Z,9Z)-heneicosatriene, and (3Z,6Z,9Z)-nonadecatriene was found to be optimal for catchingC. Pennaria, whileE. Defoliaria males were optimally caught by a 1∶1 mixture of (3Z,9Z)-(6S,7R)-epoxynonadecadiene and (3Z,6Z,9Z)-nona-decatriene. (6Z,9Z)-(3S,4R)-Epoxynonadecadiene was identified from ovipositor extracts ofAgriopis (Erannis) aurantiaria. In field tests the pure enantiomer proved to be a highly specific sex attractant for both the late autumn/early winter flyingA. Aurantiaria and the late winter/early spring flyingA. Leucophearia. Males ofAgriopis marginaria, which fly in late winter/early spring, were attracted to (3Z,9Z)-(6S,7R)-epoxynonadecadiene. The addition of (3Z,6Z,9Z)-nonadecatriene to theS,R-enantiomer increased captures. Optimal catches were recorded with a 10∶3 epoxide-hydrocarbon blend. Enantiomer specificity in all species was confirmed in EAG measurements.
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    Developmental inhibition ofSpodoptera litura (Fab.) larvae by a novel caffeoylquinic acid from the wild groundnut,Arachis paraguariensis (Chod et Hassl.) (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 2917-2933 
    Details
    ISSN: 1573-1561
    Keywords: Spodoptera litura ; Lepidoptera ; Noctuidae ; Arachis paraguariensis ; wild groundnuts ; caffeoylquinic acids ; resistance ; rutin ; quercetin ; phenolics ; growth inhibition ; Arachis hypogaea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A novel compound, 1-caffeoyl-4-deoxyquinic acid (1-CdQA) has been identified along with 3-caffeoylquinic acid (3-CQA) and 5-caffeoylquinic acid (5-CQA) (syn. chlorogenic acid) in the foliage ofArachis paraguariensis, a wild species of groundnut that is highly resistant to attack by the larvae ofSpodoptera litura. When neonate larvae were fed on diets treated with 3-CQA or 1-CdQA, their development was severely inhibited compared to larvae on untreated diets, and the effects were similar in nature and magnitude to those observed for larvae feeding on diets treated with 5-CQA, rutin, and quercetin. The effects of all the compounds were dose related, and their optimal concentration was approximately 3 mM, which corresponds to the total foliar concentration of both caffeoylquinic acids and quercetin diglycosides inA. paraguariensis. After 24 h, the development of third stadium larvae feeding on diets treated with 5-CQA, rutin and 1-CdQA was promoted compared to larvae on control diets, but after 96 hr larvae feeding on treated diets had gained significantly less weight than those on the control diets. 1-CdQA, 3-CQA, and quercetin dyglycosides (previously identified in the foliage ofA. paraguariensis) are considered to be valuable components in resistance of groundnuts toS. litura and may provide useful genetic markers in future breeding for resistance to this pest.
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    Sugar beet crown borer,Hulstia undulatella (Clemens) 1: Identification and field tests of female sex pheromone gland components (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 433-440 
    Details
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Pyralidae ; Phycitinae ; Hulstia undulatella ; sex pheromone ; (Z)-9-tetradecen-1-ol acetate ; (Z)-9-tetradecen-1-ol ; (Z)-11-hexa-decen-1-ol acetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Electroantennogram profiles of saturated and monounsaturated 12-, 14-, and 16-carbon acetates, and 12- and 14-carbon alcohols implicated (Z)-9-tetradecen-1-ol acetate (Z9-14: Ac) as a component of the female sex pheromone ofHulstia undulatella (Clemens). Gas chromatography-mass spectrometric analysis of extract of the female sex pheromone glands showed the presence of Z9-14:Ac (8.5 ng/female), (Z)-9-tetradecen-1-ol (Z9-14:OH), and (Z)-11-hexadecen-1-ol acetate (Z11-16:Ac) in a ratio of 100∶4∶21, respectively. In tests in sugar beet fields, Z9-14:Ac alone produced some trap catch. Addition of Z9-14: OH did not increase catch while addition of Z11-16:Ac eliminated catch, but addition of both Z9-14:OH and Z11-16: Ac increased catch sevenfold. A combination of Z9-14: OH and Z11-16: Ac without Z9-14: Ac did not produce trap catch. A lure of 200 μg Z9-14:Ac+16 μg Z9-14:OH+42 μg Z11-16:Ac is suggested for use in monitoring traps.
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    Soil nutrient depletion by agricultural production in Southern Mali (1993)
    Springer
    Nutrient cycling in agroecosystems 36 (1993), S. 79-90 
    Details
    ISSN: 1573-0867
    Keywords: agriculture ; Sahel ; Sudan ; Mali ; cotton ; fertilization ; nutrient ; soil ; soil degradation ; depletion ; nutrient ; nutrient balance ; nitrogen ; phosphorus ; potassium ; calcium ; magnesium ; acidification ; sustainability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The degree of soil mining by agricultural production in Southern Mali is assessed by calculating nutrient balances: differences between the amount of plant nutrients exported from the cultivated fields, and those added to the fields. Export processes include extraction by crops, losses due to leaching, to erosion, and to volatilization and denitrification. Inputs include applications of fertilizer and manure, restitution of crop residues, nitrogen fixation, atmospheric deposition of nutrients in rain and dust, and enrichment by weathering of soil minerals. Nutrient balances are calculated for N, P, K, Ca, and Mg. Both pessimistic and optimistic estimates are given. The resulting figures indicate, even when the most optimistic estimates are used, large deficits for nitrogen, potassium and magnesium. For the region as a whole, the calculated deficits are -25 kg N/ha,-20 kg K/ha, and -5 kg Mg/ha. Further, acidification is to be expected, in particular in areas where cotton is grown. The deficits are caused by traditional cereal crops, but also by cotton and especially by groundnut. The latter two crops are fertilized, but insufficiently. It is important to note, that the negative figures are not automatic recommendations for application of a specific amount of additional fertilizer. For phosphorus and calcium the balance of the region as a whole appears to be about in equilibrium, but locally large variations may occur. Erosion and denitrification are important causes of nutrient loss, accounting respectively for 17 and 22% of total nitrogen exports. Atmospheric deposition and weathering of minerals in the soil are still important nutrient inputs that contribute as much as nutrients as organic and mineral fertilizer combined. Nutrient depletion is very large in comparison to the amount of fertilizer applied. Drastic options, such as doubling the application of fertilizer or manure, or halving erosion losses, even if feasible, would still not be enough to make up for the calculated deficits. The annual value of withdrawn nutrients, if related to prices of fertilizers, varies between 10,000 and 15,000 FCFA/ha (40-60 US $/ha). Since the estimated average gross margin from farming in this area is 34,000 FCFA/ha (123 US $/ha), soil mining appears to provide an amount equal to 40% of farmers' total income from agricultural activities.
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    Environment, seed rate, and N rate influence on yield of winter barley (1993)
    Springer
    Nutrient cycling in agroecosystems 34 (1993), S. 59-65 
    Details
    ISSN: 1573-0867
    Keywords: Barley ; environment ; nitrogen ; seeding rate ; yield ; yield components
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This study was conducted to determine the effects of rainfall and temperature during the growing season, seed rate, and N rate on grain yield and yield components of winter barley (Hordeum vulgare L.) on a Typic Haploxeralf soil in Santa Olalla (Toledo), Spain in 1986/7, 1987/8, and 1988/9. Two experiments were conducted each year using the 6-rowed variety ‘Barbarrosa’ and the 2-rowed variety ‘Reinette’. Both experiments used seed rates of 80, 160, and 240 kg ha−1 as whole plot treatments, and N rates of 0, 40, 80, 120, and 160 kg ha−1 as subplots. Responses to N depended on both the quantity and distribution of rainfall during the growing season, and temperature during grain fill. In the high rainfall, moderate grain-fill temperature year, increasing the N rate from 0 to 160 kg ha−1 increased grain yields (by 2.3 t ha−1), straw yields and the harvest index while maintaining the kernel weight for both varieties. In the low rainfall, high grain-fill temperature year, N rate had little influence on grain yield, but increased the straw yield, which reduced the harvest index, and also decreased kernel weight. Seed rate had no influence on grain yields even though wide variation in N rates, rainfall and temperatures occurred in the three-year study. Results from this study indicated that strategies to reduce (or avoid) water/high temperature stress during grain fill are necessary to assure more uniform yield responses to N application across years. However, decisions about seed rate can be made independently for conditions similar to those in this study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00749961
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    The effect of cattle foot traffic on soil compaction in a silvo-pastoral system (1993)
    Springer
    Agroforestry systems 21 (1993), S. 1-10 
    Details
    ISSN: 1572-9680
    Keywords: silvo-pasture ; compaction ; cattle traffic ; penetrometer ; bulk density ; nitrogen ; seedlings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This paper reports on the extent of soil compaction due to cattle traffic around hardwood and softwood tree seedlings established in existing pasture, and subject to cattle pressure. A higher soil penetrometer resistance in the grazed areas pointed to a significant change in soil structure (i.e. dry bulk density) as a result of cattle traffic in the area. In a related experiment comparing the effect of three different levels of soil compaction on tree seedling growth and nitrogen cycling it was found that water infiltration and nitrogen uptake were reduced in soils treated with a medium and high level of compactive effort. This resulted in a slower rate of growth of the tree seedlings. The addition of an additional nitrogen source improved seedling growth in both the medium and high density compactive treatments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00704922
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    How do non-differentiating bacteria adapt to starvation? (1993)
    Springer
    Antonie van Leeuwenhoek 63 (1993), S. 333-341 
    Details
    ISSN: 1572-9699
    Keywords: survival ; starvation ; stress ; Vibrio ; carbon ; nitrogen ; phosphorus ; protein synthesis ; carbon starvation stimulon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Non-differentiating bacteria adapt to starvation induced growth arrest by a complex turn-on/turn-off pattern of protein synthesis. This response shows distinct similarities with those of spore formation in differentiating organisms. A substantial amount of information on the non-growth biology of non-differentiating bacteria can be derived from studies onVibrio strains. One important result is that carbon rather than nitrogen or phosphorus starvation leads to the development of a starvation and stress resistant cell in these organisms. Hence, we have attempted to characterize the carbon starvation stimulon. By the use of two-dimensional gel electrophoresis of pulse-labelled cells and transposon mutagenesis, using reporter gene constructs, the identity and function of some members of the carbon starvation stimulon have been elucidated. Moreover, regulatory genes of the starvation response have been identified with these techniques. Current studies primarily address the identity and function of these genes. The role of transcript modification and stability for both long term persistence during starvation as well as the efficient recovery of cells which occurs upon nutrient addition is also addressed. It is suggested that an understanding of the functionality of the translational machinery is essential for the understanding of these adaptive pathways. This contribution also discusses the diversity of the differentiation-like response to starvation in different bacteria and whether a general starvation induced programme exists.
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    URL: http://dx.doi.org/10.1007/BF00871228
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    Nitrogen mass balances and denitrification rates in central Ontario Lakes (1993)
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    Biodegradation 20 (1993), S. 195-212 
    Details
    ISSN: 1572-9729
    Keywords: denitrification ; lake ; mass balance ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Nitrogen mass balances for seven unproductive lakes and 20 forested catchments in central Ontario were measured between 1977 and 1989. Average annual lake denitrification rates calculated with the N/P ratio method were strongly correlated with summer anoxic factor (extent of surficial sediment anoxia) whereas denitrification rates calculated with a210Pb sediment N accumulation method were poorly correlated with the anoxic factor suggesting that the N/P method is superior. Substantial denitrification occurred in all lakes — an average of 36% of TN inputs or 75% of the net gain. On a regional area-weighted basis, 67% of bulk atmospheric TN deposition was stored or denitrified terrestrially, 12% was denitrified in lakes, 4% was stored in lake sediments, and 17% was exported from lakes. N/P ratios were generally less in streams than in precipitation suggesting preferential N retention in catchments, whereas the N/P ratios in lake outputs were slightly higher than lake input ratios, suggesting preferential P retention in lakes. This is consistent with the notion that P-limited lakes can exist adjacent to N-limited forests.
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    URL: http://dx.doi.org/10.1007/BF00000787
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    Synthesis of aluminum nitride in transferred arc plasma furnaces (1993)
    Springer
    Plasma chemistry and plasma processing 13 (1993), S. 613-632 
    Details
    ISSN: 1572-8986
    Keywords: Aluminum nitride ; aluminum ; nitrogen ; hydrogen ; ammonia ; thermal plasma ; transferred plasma ; emission spectroscopy ; sintering ; ultrafine powder ; nanophase ; composite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Ultrafine particles of aluminum tnitride (AIN) arc produced by a transferred an plasma. Two devices are used: a transferred arc plasma on aluminum natal in nitrogen or nitrogenlammonia atmospheres, and a item concept of transferred arc plasma when, DC anode and cathode ares are coupled together above an alumintun melt. Equilibrium chemical compositions mere calculated. The temperature distributions in the plasma are measured hr emission spectroscopy Flit, powder, made from 99.8%, aluminum ingot, it as analyzed and confirmed to be 99.3%, of hexagonal phase aluminum nitride. In othertests, from 99.99% aluminum ingot, a translucent AIN vinter was obtained. The densification behavior was assessed by hot pressing and by pressureless sintering, with and without additives. The thermal conductivities are given.
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    URL: http://dx.doi.org/10.1007/BF01570134
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    Special Equations of State for Methane, Argon, and Nitrogen for the Temperature Range from 270 to 350 K at Pressures up to 30 MPa (1993)
    Springer
    International journal of thermophysics 14 (1993), S. 699-725 
    Details
    ISSN: 1572-9567
    Keywords: argon ; caloric properties ; density ; equation of state ; Helmholtz function ; methane ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In order to describe the thermodynamic behavior of methane, argon, and nitrogen in the so-called “natural-gas region,” namely, from 270 to 350 K at pressures up to 30 MPa as accurate as possible with equations of a very simple form, new equations of state for these three substances have been developed. These equations are in the form of a fundamental equation in the dimensionless Helmholtz energy; for calculating the pressure or the density, the corresponding equations explicit in pressure are also given. The residual parts of the Helmholtz function representing the behavior of the real gas contain 12 fitted coefficients for methane, 8 for argon, and 7 for nitrogen. The thermodynamic relations between the Helmholtz energy and the most important thermodynamic properties and the needed derivatives of the equations are explicitly given; to assist the user there is also a table with values for computer-program verification. The uncertainties when calculating the density ρ, the speed of sound w, the isobaric specific heat capacity c p, and the isochoric specific heat capacity c v are estimated as follows. For all three substances it is Δρ/ρ≤±0.02 % for p≤ 12 MPa and Δρ/ρ ≤ ±0.05% for higher pressures. For methane it is Δw/w≤±0.02% for p≤10 MPa and Δw/w≤+-0.1% for higher pressures; for argon it is Δw/w≲-0.1 % for p≤ 7 MPa, Δw/w≤±0.3 % for 7 〈p≤30 MPa; and for nitrogen it is Δw/w≤±0.1% for p≤1.5 MPa and Δw/w±0.5% for higher pressures. For all three substances it is Δc p/c p≤±1 % and ΔC v/C v≤±1 % in the entire range.
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    URL: http://dx.doi.org/10.1007/BF00502103
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    Storage and dynamics of organic matter in different springs of small floodplain streams (1993)
    Springer
    Hydrobiologia 251 (1993), S. 199-209 
    Details
    ISSN: 1573-5117
    Keywords: spring ; karst ; interstitial aquifer ; nitrogen ; carbon ; organic matter retention
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The flow of groundwater through the sediment layer (underflow or hyporheic zone) of streams and at the origin of streams can influence organic matter uptake dynamics of floodplain. The River Rhône floodplain has limestone foothills. Here we studied 2 karstic and 2 interstitial springs differing by aquifer geology. Organic matter, physico-chemical conditions were compared between these springs during two seasons (from March to September 1989) and at different depths (0, −20 cm, −40 cm). Temperatures indicated large differences in underflow between springs, in their relation to the surrounding environment, and between seasons. Springs are well oxygenated, with differences between layers. Cultivated fields supply interstitial springs with nitrates, and pools are nutrient traps. DOC was heterogeneous in space and time and correlates with VFPOC. Particulate nutrients were correlated with available surface area of sediment grains. Physical conditions of each spring were prominent in determining storage and turnover of organic matter. Each spring, by its own characteristics and dynamics regulating stability and turnover, had an effect or control on storage, transport and retention of organic matter (quality, quantity). These springs offer an example of the heterogeneity, and give a view of the diversity of patches within a floodplain. The data suggest that groundwater flow of springs may be a major factor in the functioning of floodplain tributaries.
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    URL: http://dx.doi.org/10.1007/BF00007179
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    Drainage history and land use pattern of a Swedish river system — their importance for understanding nitrogen and phosphorus load (1993)
    Springer
    Hydrobiologia 251 (1993), S. 285-296 
    Details
    ISSN: 1573-5117
    Keywords: land drainage ; nitrogen ; phosphorus ; areal coefficients ; agricultural streams ; riparian ecotones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During the 19th and the first half of the 20th century, approximately 300 km2 of lakes and wetlands, representing 29% of the River Kavlingean catchment in Southern Sweden, were drained to make land available for agriculture. Published accounts of nutrient loads from the catchment indicated that until the mid 20th century, factories and urban point sources were the major contributors of both nitrogen and phosphorus. By the middle of the 20th century, the construction of sewage treatment plants had effectively reduced phosphorus pollution. Concurrently, the land drained in the previous century underwent a more intense cultivation, with productivity being maintained by commercial fertilizers. Subsequently, net nutrient loads from agriculture continued to increase, reaching an annual load of 2652 tons total-nitrogen and 70 tons total-phosphorus for the River Kävlingeån. Whilst high nutrient leakage from agricultural watersheds may be a problem which is only recently recognized, it had its origins in nearly a hundred years of commonly accepted agricultural policy. To assess the importance of agriculture as the major source of nutrients to the River Kävlingeån system, three tributary catchment areas, differing in terms of their land use patterns (high, medium and low intensity of agricultural use), were studied and compared with literature figures. Results indicated that agricultural nutrient loss areal coefficients were substantially higher than the literature figures, demonstrating the role of agriculture as source of nutrients to the River Kävlingeån system. The agricultural land use policies of the last fifty years were revealed to be most important with regard to this role. Of such land use policies, the cultivation of the last 10–15% of land employed for agricultural use (primarily riparian ecotones) may be of most significance. The literature indicates that intense agricultural use of this final 10–15% may account for a ca. 50% increase in nitrogen loss. This suggests that one solution to the problem of agricultural diffuse pollution may lie in the restoration and sustainable management of riparian ecotones of agricultural streams.
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    URL: http://dx.doi.org/10.1007/BF00007188
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    Seasonal nitrogen dynamics in reed beds (Phragmites australis (Cav.) Trin. ex. Steudel) in relation to productivity (1993)
    Springer
    Hydrobiologia 251 (1993), S. 1-12 
    Details
    ISSN: 1573-5117
    Keywords: littoral ; reed-belt decline ; Phragmites australis ; nitrogen ; eutrophication ; productivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Shoot biomass and nitrogen, accumulated within above-ground plant biomass in autumn, correlate with nitrogen availability indicated by nitrogen content (% DM) of several shoot parts during the height of the growth period. A higher nitrogen percentage of the shoots is correlated with a higher shoot loss and subsequent substitution by branching and tillering during and continuing toward the end of the growth period. A delayed switch from the vegetative to the generative phase reduces the translocation of reserve material to the rhizome. Increasing nitrogen load is at least one of the factors causing instability and reed-belt decline.
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    URL: http://dx.doi.org/10.1007/BF00007158
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    Nitrogen and phosphor compounds in bottom sediments: mechanisms of accumulation, transformation and release (1993)
    Springer
    Hydrobiologia 252 (1993), S. 1-22 
    Details
    ISSN: 1573-5117
    Keywords: lakes ; reservoirs ; carbon ; nitrogen ; phosphate ; sediments ; accumulation ; eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This paper is an overview of Russian literature dealing with the accumulation, the transformations and the release of phosphate and nitrogen compounds in a great number of Russian lakes and reservoirs. A considerable data bank has been analysed. Special attention is given to the relations of N- and P-accumulation with the input and transformation of organic carbon, as well as to the release mechanisms, often in relation to eutrophication of the lakes and reservoirs. It is shown that the major input of organic matter into the sediments comes from autochthonous material, and is usually 〉 70 %. The relative importance of phytoplankton and macrophytes as sources of organic matter is discussed; it appears that trophic state, depth and other factors may have a large influence on this ratio. In shallow eutrophic lakes macrophytes may be the source of organic matter, which source can amount to 1.5–2.5 times that of phytoplankton. It is also shown that the C/N ratio is not a good indicator of the source of the organic matter, because their C/N ratios often are not very different. The decomposition rate of organic matter was analysed; it depends on trophic state and other factors. Sediment N accumulation is mostly (〉 90%) in organic form, and depends on nitrogen and organic matter inputs coming from phytoplankton or macrophytes. A correlation coefficient of 0.9–0.95 was found in 176 lakes. In 113 lakes the N accumulation was 0.11 x C accumulation, with C/N ratios between 7.4 and 12.9. Ammonification was rather constant in different groups of lakes; values were often about 20–25 mg m−2 d−1. The presence of the different forms of nitrogen in interstitial water and in adsorbed forms is discussed. The N in interstitial water is usually in the form of NH3. Sediment P-accumulation is usually in inorganic form and is related to primary production. Three different groups of sediments could be distinguished with C/P ratios of 31–100, of 101–350 and 〉 350. In hard water lakes P sedimentation was found to be 0.3–0.5 times that in soft water lakes with comparable primary production. The relative occurrence of apatite, non-apatite and residual P in sediments was calculated. In the interstitial water the P concentration appeared to be controlled by the input and decomposition of organic matter. The concentration of phosphate dissolved in the interstitial water of the top 2 cm layer is often 10–100 times lower than that of the dissolved N. The concentrations of interstitial phosphate are from a few μgl−1 up to 15 mgl−1, but the higher concentrations occur only rarely. Different types of vertical profiles of P compounds in the sediments were shown to be related with the presence of an oxidised zone, the presence of clay etc. Autochthonous apatite and non-apatite phosphates are more mobile than the allochthonous ones and are in equilibrium with interstitial phosphate. Accumulation of autochthonous apatite in sediments is controlled by decomposition of organic matter and accumulation of carbonates.
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    URL: http://dx.doi.org/10.1007/BF00000124
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    Nitrogen and phosphorus dynamics and retention in ecotones of Lake Titicaca, Bolivia/Peru (1993)
    Springer
    Hydrobiologia 251 (1993), S. 39-47 
    Details
    ISSN: 1573-5117
    Keywords: agriculture ; algae ; lake ; littoral ; macrophytes ; nitrogen ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We are studying present conditions and consequences of material movement from land to water in the Lake Titicaca basin, and how fluxes are affected by human activities. The principal objective of this research is to describe and explain the variability in the Andean Altiplano of (a) water, nutrient and sediment fluxes from land and (b) composition, nutrient limitation and other important features of nearshore lake communities, and compare the effects of different agricultural practices (especially traditional and modern) on these factors. We are focusing on a comparison of the impacts of two forms of agriculture in this region: ancient raised fields currently under rehabilitation, and flat pastures and fields, which are more common. Results of the first year of study indicate there is substantial variability in nitrogen and phosphorus dynamics in relation to ecotone complexity (simple vs. intermediate vs. complex). Raised field sites have the beneficial effect of reducing high available nutrient concentrations (nitrate and soluble reactive phosphorus) and sediment load (measured as turbidity) as the water passes through them enroute to the lake. Aquatic vegetation (algae and macrophytes) reflect well ambient total nitrogen and phosphorus concentrations. Experimental nutrient limitation bioassays indicate that nitrogen is the most important limiting nutrient, though there is important spatial variability within the landscape, and phosphorus as well as nitrogen can be limiting.
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    URL: http://dx.doi.org/10.1007/BF00007163
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    The application of the ecotone concept in defining nutrient management requirements for the upper Potomac River basin (1993)
    Springer
    Hydrobiologia 251 (1993), S. 341-349 
    Details
    ISSN: 1573-5117
    Keywords: nutrients ; ecotones ; Potomac River ; nitrogen ; watersheds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The utility of the ecotone concept in nutrient management studies of the Potomac River basin, a large USA watershed, is examined. The MAB hypothesis suggesting that ‘the influence of an ecotone or adjacent system is proportional to the length and scope of the interfaces’ (Naiman et al., 1989) is the major focus of this paper. The land-riverine ecotone appears to have a major influence on the total nitrogen balance and river export flux of nitrogen for the upper Potomac River basin. A method of converting conventional areal flux units into linear flux rates is suggested.
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    URL: http://dx.doi.org/10.1007/BF00007193
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    Availability and uptake of inorganic nitrogen in a mixed old-growth coniferous forest (1993)
    Springer
    Plant and soil 148 (1993), S. 163-174 
    Details
    ISSN: 1573-5036
    Keywords: ammonium ; nitrate ; nitrification ; nitrogen ; old-growth forest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Old-growth forest stands of mixed species composition provide the opportunity to study species-specific influences on soil properties. We monitored rates of nitrogen mineralization, nitrification and an index of ammonium and nitrate uptake in a mixed old-growth stand of Douglas-fir (Pseudotsuga menziesii), western hemlock (Tsuga heterophylla) and western redcedar (Thuja plicata) over a two-year period. Litter and mineral soil (0–10-cm depth) were sampled adjacent to ten large trees of each species. After initial characterization of litter and soil, buried bags were incubated in both layers for ca. 2-month intervals. Soil and litter pH was lowest near western hemlocks. Nitrification, nitrate concentrations, and percent uptake as nitrate differed among the tree species; rates were highest near western redcedars. For all species, percent nitrification and nitrate uptake rate were higher in soil than in litter. The results indicate species-specific effects on ammonium and nitrate production and uptake within this forest type.
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    URL: http://dx.doi.org/10.1007/BF00012854
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    Estimates of the residual nitrogen benefit of groundnut to maize in Northeast Thailand (1993)
    Springer
    Plant and soil 154 (1993), S. 267-277 
    Details
    ISSN: 1573-5036
    Keywords: added nitrogen interactions ; groundnut ; maize ; nitrogen ; 15N-isotope methodology ; residual effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Four cultivars of groundnut were grown in upland soil in Northeast Thailand to study the residual benefit of the stover to a subsequent maize crop. An N-balance estimate of the total residual N in the maize supplied by the groundnut was made. In addition three independent estimates were made of the residual benefits to maize when the groundnut stover was returned to the land and incorporated. The first estimate (Estimate 1) was an N-balance estimate. A dual labelling approach was used where 15N-labelled stover was added to unlabelled microplots (Estimate 2) or unlabelled stover was added to 15N-labelled soil microplots (Estimate 3). The nodulating groundnut cultivars fixed between 59–64% of their nitrogen (as estimated by the 15N isotope dilution method using non-nodulating groundnut as a non-fixing reference) producing between 100 and 130 kg N ha-1 in their stover. Although the following maize crop suffered from drought stress, maize grain N and dry weights were up to 80% and 65% greater respectively in the plots where the stover was returned as compared with the plots where the stover was removed. These benefits were comparable with applications of 75 kg N ha-1 nitrogen in the form of urea. The total residual N estimates of the contribution of the nodulated groundnut to the maize ranged from 16.4–27.5 kg N ha-1. Estimates of the residual N supplied by the stover and fallen leaves ranged from 11.9–21.3 kg N ha-1 using the N-balance method (Estimate 1), from 6.3–9.6 kg N ha-1 with the labelled stover method (Estimate 2) and from 0–11.4 kg N ha-1 with the labelled soil method. There was closest agreement between the two 15N based estimates suggesting that ‘apparent added nitrogen interactions’ in these soils may not be important and that N balance estimates can overestimate the residual N in crops following legumes, even in very poor soils. This work also indicates the considerable ability of local groundnut cultivars to fix atmospheric nitrogen and the potential benefits from returning and incorporating legume residues to the soil in the upland cropping systems of Northeast Thailand. The applicability of the 15N methodology used here and possible reasons for the discrepancies between estimates 1, 2 and 3 are discussed.
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    URL: http://dx.doi.org/10.1007/BF00012532
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    Productivity and adaptive capacity of winter wheat landraces and modern cultivars grown under low-fertility conditions (1993)
    Springer
    Euphytica 70 (1993), S. 27-33 
    Details
    ISSN: 1573-5060
    Keywords: Wheat ; Triticum aestivum ; landrace ; semidwarf ; phosphorus ; nitrogen ; fertilization ; genetic improvement ; breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In recent decades, most winter wheat (Triticum aestivum L.) breeding in the United States has been done in field nurseries in which the soil receives ample fertilization. To determine the effects of these breeding efforts on productivity under low-fertility conditions, we evaluated twenty-nine winter wheat genotypes (seven Asian landraces; thirteen standard-height U.S. cultivars released between 1874 and 1971; and nine semidwarf cultivars released between 1977 and 1988) under severe fertility stress at three Kansas, USA locations. Experiments included fertilized and unfertilized treatments. The modern, semidwarf cultivars yielded 18% and 20% more, on average, than landraces and standard-height cultivars under low and high fertility, respectively; however, only the latter difference reached the 5% significance level. At only one location (Hays) was there a significant genotype X fertility interaction: there, 89% of the semidwarf cultivars, only 8% of the standard cultivars, and 57% of the landraces responded to fertilization. The regression coefficient of mean grain yield (unfertilized) on year of introduction or release for standard and semidwarf cultivars was zero, indicating that a century of breeding has produced no genetic improvement in performance under these low-fertility conditions. Although we found that the usual yield advantage of modern cultivars is not expressed under very low fertility, we saw no evidence that older cultivars are superior under those conditions.
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    URL: http://dx.doi.org/10.1007/BF00029637
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    Mass loss and nitrogen dynamics in decomposing acid forest litter in the Netherlands at increased nitrogen deposition (1993)
    Springer
    Biogeochemistry 20 (1993), S. 45-62 
    Details
    ISSN: 1573-515X
    Keywords: atmospheric deposition ; forest ecosystems ; litter decomposition ; The Netherlands ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Litterbag experiments were carried out in five forest ecosystems in the Netherlands to study weight loss and nitrogen dynamics during the first two years of decomposition of leaf and needle litter. All forests were characterized by a relatively high atmospheric nitrogen input by throughfall, ranging from 22–55 kg N ha−1 yr−1. Correlation analysis of all seven leaf and needle litters revealed no significant relation between the measured litter quality indices (nitrogen and lignin concentration, lignin-to-nitrogen ratio) and the decomposition rate. A significant linear relation was found between initial lignin-to-nitrogen ratio and critical nitrogen concentration, suggesting an effect of litter quality on nitrogen dynamics. Comparison of the decomposition of oak leaves in a nitrogen-limited and a nitrogen-saturated forest suggested an increased nitrogen availability. The differences in capacities to retain atmospheric nitrogen inputs between these two sites could be explained by differences in net nitrogen immobilization in first year decomposing oak leaves: in the nitrogen-limited oak forest a major part (55%) of the nitrogen input by throughfall was immobilized in the first year oak leaf litter. The three coniferous forests consisted of two monocultures of Douglas fir and a mixed stand of Douglas fir and Scots pine. Despite comparable litter quality in the Douglas fir needles in all sites, completely different nitrogen dynamics were found.
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    URL: http://dx.doi.org/10.1007/BF00002805
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