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  • Chlorophyll fluorescence  (2)
  • Isoptera  (2)
  • Springer  (4)
  • American Geophysical Union
  • Copernicus
  • PANGAEA
  • 2000-2004
  • 1980-1984  (4)
Collection
Publisher
  • Springer  (4)
  • American Geophysical Union
  • Copernicus
  • PANGAEA
Years
Year
  • 1
    ISSN: 1432-2048
    Keywords: Chlorophyll fluorescence ; Chloroplast development ; Thylakoid protein kinase ; Triticum (chloroplast biogenesis)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The activity of thylakoid protein kinase and the regulation of excitation energy distribution between photosystems I and II was examined during chloroplast biogenesis in light-grown Triticum aestivum (wheat) leaves. The specific activity of the thylakoid protein kinase decreased some six-fold during development from the young plastids at the base of the 7-d-old leaf to the mature chloroplasts at the leaf tip. Appreciable activity was also detected in plastids isolated from etiolated leaves. In mature chloroplasts the majority of phosphate was incorporated into the Mr=26,000 apo-proteins of the light-harvesting chlorophyll a/b-protein complex (LHCP). However, at early stages of chloroplast development and in the etioplast, the phosphate was predominantly incorporated into a polypeptide of Mr=9,000 dalton. Immature thylakoids, isolated from the base of the leaf, had relatively low concentrations of LHCP and could perform a State 1-State 2 transition, as demonstrated by ATP-induced quenching of photosystem II fluorescence. Analyses of photosystem I and photosystem II fluorescence-induction curves from intact leaf tissue demonstrated that this transition occurs in vivo at early stages of leaf development and, therefore, may play an important role in regulating energy transduction during chloroplast biogenesis.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-1561
    Keywords: Isoptera ; Nasutitermitinae ; isolation ; identification ; Curvitermes strictinasus (Mathews) ; defense secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The defense secretion of the soldier termites ofCurvitermes strictinasus Mathews has been analyzed. Seven components have been isolated and identified, including limonene, terpinolene,p-cymen-8-ol, tridecan-2-one, tridecen-2-onecis,trans-farnesal, andtrans,trans-farnesal.
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  • 3
    ISSN: 1432-2048
    Keywords: Carbon dioxide fixation ; Chlorophyll fluorescence ; Photosynthesis, C4 (induction) ; Zea (photosynthesis)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The rate of CO2 fixation (Fc) and 680 nm chlorophyll fluorescence emission (F680) were measured simultaneously during induction of photosynthesis in Zea mays L. leaves under varying experimental conditions in order to assess the validity of fluorescence as an indicator of in vivo photosynthetic carbon assimilation. Z. mays leaves showed typical ‘Kautsky’ fluorescence induction curves consisting of a fast rise in emission (O to P) followed by a slow quenching via a major transient (S-M) to a steady-state (T). After an initial lag, net CO2 assimilation commenced at a point corresponding to the onset of the S-M transient on the F680 induction curve. Subsequently, Fc and F680 always arrived at a steady-state simultaneously. Decreasing the dark-adaption period increased the rate of induction of both parameters. Alteration of leaf temperature produced anti-parallel changes in induction characteristics of Fc and F680. Reducing the CO2 level to below that required for saturation of photosynthesis also produced anti-parallel changes during induction, however, at CO2 concentrations tenfold greater than the atmospheric level the rate of F680 quenching from P to T was appreciably reduced without a similar change in the induction of Fc. Removal of CO2 at steady-state produced only a small increase in F680 and a correspondingly small decrease in F680 occurred when CO2 was re-introduced. The complex relationship between chlorophyll fluorescence and carbon assimilation in vivo is discussed and the applicability of fluorescence as an indicator of carbon assimilation is considered.
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  • 4
    ISSN: 1573-1561
    Keywords: Isoptera ; Nasutitermitinae ; Syntermes species ; defensive secretion ; isolation ; identification ; terpenoid compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The defensive secretions from the frontal glands of soldier termites of the genusSyntermes contain similar mixtures of mono- and sesquiterpene hydrocarbons. The major components inS. dirus, S. molestus, S. brevimalatus, S. peruanus, and a new species (Syntermes sp. n), iscis-β-ocimene. A substantial amount of aristolochene is found inSyntermes sp. n. and is present at lower levels in all the other species;S. brevimalatus contains onlycis-β-ocimene and aristolochene. The four other species also contain minor amounts of epi-α-selinene and germacrene A. The latter compound has been identified on the basis of its rearrangement product β-elemene. The termiteS. grandis differed markedly from the otherSyntermes species in that no terpenoid components were found in the soldier extract. With the obvious exception ofS. grandis, the same soldier-specific mono- and sesquiterpenes occurred in all species. The total amount of secretion per unit weight of soldiers varies with the species and is inversely proportional to the development of the mandibular apparatus. InS. molestus smaller gland size is compensated for by a greater number of soldiers foraging trails.
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