ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • N2 fixation  (3)
  • 81.20.Lb
  • Cytochemistry
  • Lactation
  • Springer  (5)
  • 1990-1994  (5)
Collection
Keywords
Publisher
  • Springer  (5)
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Effect of successive cuttings on uptake and partitioning of 15N among plant parts of Leucaena leucocephala (1990)
    Springer
    Biology and fertility of soils 9 (1990), S. 37-42 
    Details
    ISSN: 1432-0789
    Keywords: Agroforestry ; Cutting ; Leucaena leucocephala ; N distribution ; N2 fixation ; N uptake ; 15N isotope ; Rhizobium spp.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary We studied the effect of three successive cuttings on N uptake and fixation and N distribution in Leucaena leucocephala. Two isolines, uninoculated or inoculated with three different Rhizobium strains, were grown for 36 weeks and cut every 12 weeks. The soil was labelled with 50 ppm KNO3 enriched with 10 atom % 15N excess soon after the first cutting. Except for the atom % 15N excess in branches of K28 at the second cutting, both the L. leucocephala isolines showed similar patterns of total N, fixed N2, and N from fertilizer distribution in different parts of the plant at each cutting. The Rhizobium strain did not influence the partitioning of 15N among the different plant parts. Significant differences in 15N enrichment occurred in different parts. Live nodules of both isolines showed the lowest atom % 15N excess values (0.087), followed by leaves (0.492), branches (0.552), stems (0.591), and roots (0.857). The roots contained about 60% of the total plant N and about 70% of the total N derived from fertilizer over the successive cuttings. The total N2 fixed in the roots was about 60% of that fixed in the whole plant, while the shoots contained only 20% of the fixed N2. We conclude that N reserves in roots and nodules constitute another N source that must be taken into account when estimating fixed N2 or the N balance after pruning or cutting plants. 15N enrichment declined up to about fivefold in the reference and the N2-fixing plants over 24 weeks following the 15N application. The proportion and the amounts of N derived from fertilizer decreased, while the amount derived from N2 fixation increased with time although its proportion remained constant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335859
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Evidence of a maternal foraging cycle resembling that of otariid seals in a small phocid, the harbor seal (1994)
    Springer
    Behavioral ecology and sociobiology 34 (1994), S. 95-104 
    Details
    ISSN: 1432-0762
    Keywords: Maternal strategy ; Lactation ; Foraging ; Pinnipeds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Lactation strategies in the two largest families of seals have been characterized as a phylogenetic dichotomy, with sea lions and fur seals (Otariidae) exhibiting foraging cycles and true seals (Phocidae) a strategy of fasting. We show that a lactating phocid, the harbor seal, Phoca vitulina, has a foraging cycle similar to that of otariids. Time-depth recorders attached to lactating harbor seal mothers revealed that 9 of 11 females began bouts of diving, averaging 12–40 m, by mid-lactation (12 days). During the remainder of lactation, females made an average of seven diving trips, lasting about 7 h. They returned to the rookery during the interval between successive bouts to nurse their pups. Diving was more frequent during daylight than at night and diving bouts increased in duration as lactation progressed. The diving behavior of females that had weaned their pups and previously collected data from stomach lavage, suggest that the bouts of diving represent successful foraging. We propose that the lactation strategy of the harbor seal is intermediate to that of the otariids and other phocids studied. The harbor seal has a foraging cycle like the otariids, but typically resembles other phocids in length of lactation, rate of mass gain in pups, and in milk fat content. As harbor seals are among the smallest phocids, and only slightly larger than most otariids, it seems likely that maternal size constrains the amount of stored energy harbor seal females can bring to the rookery, forcing them to start feeding during the lactation period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00164180
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Intra-specific variation in growth and P accumulation of Leucaena leucocephala and Gliricidia sepium as influenced by soil phosphate status (1991)
    Springer
    Plant and soil 133 (1991), S. 201-208 
    Details
    ISSN: 1573-5036
    Keywords: isolines ; nodulation ; N2 fixation ; P uptake ; P use efficiency ; provenances ; Rhizobium ; rhizosphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Twenty-three provenances of Gliricidia sepium and eleven isolines of Leucaena leucocephala were examined at a low and at high phosphate levels (20 and 80 mg P kg-1 soil) for growth, phosphate (P) uptake and use efficiency. Large differences in growth at the low P level, and in growth response to the higher P rate occurred among L. leucocephala isolines and G. sepium provenances. Shoot dry weight at low P varied from 1.30 to 3.01 g plant-1 for L. leucocephala and from 1.44 to 3.07 g plant-1 for G. sepium. Leucaena isolines had only half the root weight of G. sepium provenances yet produced approximately 90% of the shoot weight of the corresponding G. sepium treatments, i.e. more than a 2-fold difference in root/shoot ratios. Total P in shoots of G. sepium was some 85% greater than of the respective L. leucocephala isolines in corresponding treatments. Physiological phosphate use efficiency (g shoot/mg P in shoots) (PPUE) was not a simple reciprocal relation, being markedly lower at higher shoot % P and content. However, for the same shoot P both species produced the same shoot weight. Nevertheless, there were apparent genotypic differences within species in the root development, shoot P and PPUE. In another study, the numbers of rhizobia in the rhizosphere of L. leucocephala, nodulation, N2 fixation at five different levels of P were determined. The numbers of rhizobia in the rhizosphere of inoculated L. leucocephala during the first two weeks were lower when P was added but later became similar to those without added P. Nodules formed earlier than inoculated plants fertilized with P and in greater numbers (4- to 5-fold) and dry weights than in those without P. However, the percentage of N2 derived from fixation did not change with increasing levels of P application. These results suggest that the observed P effect did not operate via stimulated growth of rhizobia in the rhizosphere, nor through increased N2 fixation rate. The major effect appeared to be due to effects via plant growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00009192
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Influence of pruning management on P and N distribution and use efficiency by N2 fixing and non-N2 fixing trees used in alley cropping systems (1994)
    Springer
    Plant and soil 167 (1994), S. 219-226 
    Details
    ISSN: 1573-5036
    Keywords: Gliricidia sepiun ; low P soil ; N2 fixation ; Senna siamea ; S. spectabilis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Pruning of hedgerow trees is an important management practice for the successful establishment of an alley cropping system. Although pruning affects biomass production, only meager evidence of this management on distribution of nutrients among the different plant organs after tree regrowth is available. This study examined the effect of pruning on the distribution and use efficiency of N and P in a N2 fixing leguminous tree species, Gliricidia sepium, and two non-N2 fixing leguminous tree species, Senna siamea and S. spectabilis, grown in a field on an Alfisol (low in P) at Fashola (Guinea Savanna Zone), Southwestern Nigeria. Four P rates, 0, 20, 40 and 80 kg P ha−1 as single superphosphate were used and management treatments included pruned versus unpruned plants. The 15N isotope dilution technique was used to measure N2 fixation in G. sepium. Partitioning of total P among different plant organs was influenced by plant species and pruning management, but was not affected by P application rates. The distribution of total P in the various plant organs followed that of dry matter yield while N partitioning had a different pattern. Pruned plants distributed about 118% more total P to branches and had a higher physiological P use efficiency (PPUE) than unpruned plants. Leaves were the biggest sink for total N and N allocation in the other plant organs was influenced by plant species and pruning management, G. sepium had relatively more of its total N and P partitioned into roots (about double that of the non-N2 fixing trees) but had a lower PPUE. Unpruned and pruned G. sepium derived 35 and 54% respectively of their total N from atmospheric N2, with about 54% of the fixed N2 being allocated to leaves and roots. Results showed that N and P pools turned over in the branches during plant regrowth after pruning but the causative factors associated with this phenomenon were not clear.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00007948
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    An investigation of catalytic activity in mixed metal oxide nanophase materials (1993)
    Springer
    The European physical journal 26 (1993), S. 46-50 
    Details
    ISSN: 1434-6079
    Keywords: 82.65.Jv ; 81.20.Lb
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present preliminary evidence for catalytic activity by unsupported mixed metal oxide nanocrystalline materials. The results of this study show that a nanophase form of Li-MgO has begun to exhibit catalytic activity by 300 °C. This is at least 200 degrees below the temperature at which conventional Li-MgO catalysts exhibit comparable activity. Furthermore, at higher temperatures, the same nanophase composition shows enhanced activities and somewhat improved hydrocarbon selectivities over conventional Li-MgO catalysts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01429104
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...