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  • 1
    ISSN: 1432-0789
    Keywords: Microbial biomass ; Dehydrogenase activity ; Phosphatase activity ; Turnover ; Farmyard manure ; Soil enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary We studied the build-up and turnover of microbial biomass following the addition of farmyard manure to an unmanured soil and to soils from a long-term experiment in which different levels of farmyard manure had been applied for the last 23 years. The application of farmyard manure at 15–90 t ha-1 to previously unmanured soil increased the microbial biomass during the first 3 months of incubation but a gradual decline occurred with further incubation for up to 12 months. Microbial biomass C was positively correlated with soil organic C and ranged from 1.8% to 2.2% of organic C after 12 months of farmyard manure applications. Biomass turnover increased with the application of farmyard manure, ranging from 0.81 to 0.87 year-1 with various levels of manure. Amendment of soils from the long-term manure experiment with various levels of farmyard manure led to a build-up and decline in biomass C as seen in the unmanured soils, but biomass C was higher in all treatments compared to the corresponding unmanured soil treatments. Biomass turnover was greater compared to the unmanured soil treatments and it decreased with increasing levels of farmyard manure. The average soil respiratory activity increased with increasing levels of farmyard manure, but respiratory activity per unit of biomass C decreased with increasing levels of manure. Enzyme activities were greater in long-term manured soils compared to unmanured soils amended with various levels of manure. There was a significant correlation between biomass C and enzyme activities.
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  • 2
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To identify viral genes involved in reactivation of herpes simplex virus from latency, intertypic HSV-1 strain McKrae/HSV-2 strain HG 52 recombinants were selected following cotransfection of intact McKrae DNA and XbaI or Hpal cleaved HG 52 DNA. Eleven separately obtained recombinants containing HG 52 inserts between 0.35–0.56 and/or 0.82–1.0 map units (mu) were isolated. It was noted that with HpaI digested HG 52 DNA, only recombinants containing type 2 inserts from Hpald (0.35–0.57) and/or containing an intact type 2 [S] region were isolated. Similarly with XbaI cleaved HG 52 DNA only recombinants containing type 2 sequences from XbaIc (0–0.45) were isolated. In effect, the type 2 insert always contained one or both origins of replication (ORIL/ORIS). In reciprocal experients isolation of two recombinants from cotransfection of HpaI cleaved McKrae DNA with intact HG 52 DNA confirmed this finding; one contained both copies of ORIS and the intervening short region sequences of McKrae, the other contained approximately 3 kb of McKrae in which ORIL is located. These results indicate that either (a) the presence of an origin of replication in a RE fragment amplifies the fragment thereby increasing its concentration and hence recombination potential with intact genomes; and/or (b) recombination and replication may be correlated. In either case isolation of recombinants containing ORIL and ORIS from the restricted DNA parent strongly suggests that both origins are functional in vitro.
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  • 3
    ISSN: 1432-2242
    Keywords: Brassica campestris ; B. juncea ; B. napus ; Diplotaxis siifolia ; Intergeneric hybrid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Attempts were made to obtain intergeneric hybrids between Diplotaxis siifolia, a wild species, and cultivars of Brassica (B. campestris, B. juncea, and B. napus). The crosses showed unilateral incompatibility. When the wild species was used as female parent, pollen germination and pollen tube growth were normal, but hybrid seeds aborted due to post-fertilization barriers. Reciprocal crosses (cultivars as female parent) showed strong pre-fertilization barriers; although pollen grains showed germination, pollen tubes failed to enter the stigma. Hybrids were realized in two of the crosses, D. siifolia x B. juncea and D. siifolia x B. napus, through ovary culture. The hybrids were multiplied in vitro by multiplication of axillary shoots, or somatic embryogenesis. Detailed studies were carried out on the hybrid D. siifolia x B. juncea. F1 hybrids had shrivelled anthers and were pollen sterile. Amphiploids of this hybrid showed 60% pollen fertility and produced seeds upon self-pollination as well as backcross pollination with the pollen of B. juncea.
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  • 4
    ISSN: 1433-3023
    Keywords: Estrogen receptors ; Pseudopregnancy ; Urogenital tissue
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To elucidate the possible role of progesterone in pregnancy-induced urinary incontinence, the concentration of nuclear estrogen receptors (E2R) was measured in the urogenital tissues of non-pregnant (controls) and on days 6, 12 and 18 of pseudopregnancy in the rabbit. Whereas in the uterus E2R levels decreased by at least five-fold by day 6 of pseudopregnancy, changed little through day 12 and increased again at day 18, in the vagina and urethra only a small and insignificant decrease and increase occurred at days 6–12 and day 18, respectively. The receptor affinity, as judged by the computed K D values, did not change significantly in any of the preparation during pseudopregnancy. Similar changes in the E2R density were observed in rabbits treated with progesterone. These data provide further and concrete evidence for the tissue specificity in the downregulation of E2R by progesterone.
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  • 5
    ISSN: 1432-0673
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract An analysis is presented for the problem of propagating acceleration waves in a binary, immiscible fluid mixture with compressible constituents. A purely mechanical theory is used to describe the behavior of the mixture, and the local volume fractions (concentrations) of the constituents appear among the independent variables in constitutive equations. These volume fractions are constrained by the condition that they sum to unity. The theory of singular surfaces is used to analyse the propagation of waves. A quartic equation is obtained whose solutions are the permissible wave speeds. Conditions for the growth or decay of the amplitude of the wave are also given.
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  • 6
    ISSN: 1432-0673
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
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  • 7
    ISSN: 1432-0673
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
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  • 8
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
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  • 9
    ISSN: 1432-0789
    Keywords: Nitrogen ; Green manure ; Sesbania sp. ; Wetland rice ; Oryza sativa L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Two annual species of Sesbania, S. aculeata and Sesbania sp. PL Se-17, were field evaluated as green manure for wetland rice in an alkaline soil. The two species were raised as a catch crop during summer in a wheat-rice rotation, and added as 24.7 and 20.8 t ha−1 of green matter, 116 and 98 kg N ha−1, respectively, after 45 days of growth. For the optimum green manuring effect on rice grain yield and N uptake, S. aculeata required 5 days of decomposition (after turning in and before rice transplantation), whereas no decomposition period was necessary for Sesbania sp. PL Se-17. The effect on grain yield and N uptake of rice was equivalent to an application of 122 and 78 kg ha−1 of chemical N, for the two species, respectively. There was no residual effect of the green manuring on the soil N status after rice harvest.
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  • 10
    ISSN: 1432-072X
    Keywords: Rhizobium isolates ; Uptake hydrogenase ; Native ecosystem ; Cow pea miscellany hosts ; Hup+ and Hup- Rhizobium strains ; Acetylene reduction activity (ARA) ; Competence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rhizobium strains nodulating summer legumes cow pea [Vigna unguiculata (L.)], green gram [V. radiata (L.) (Wilczek)], black gram [V. mungo (L.) (Hepper)] and cluster bean [Cyamopsis tetragonoloba (L.) (Taub)] and a winter legume chick pea [Cicer arietinum (L.)] were surveyed in the Northern Plains of India and screened for hydrogenase activity to determine distribution of Hup character in the native ecosystem. It was observed that 56% of the Rhizobium strains of summer legumes were Hup+ whereas that of the winter legume, chick pea, were all Hup-. Ex planta acetylene reduction activity was observed in most of the Hup+ but not in the Hup- strains of any of the host species. In summer legume, mixed inoculation of Hup+ and Hup- strains, under sterilized as well as unsterilized soil conditions, showed that the host species were predominantly nodulated with Hup+ strain.
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