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1999 (2)
1977 (1)
1Author    German MüllerRequires cookie*
 Title    Schadstoff-Untersuchungen an datierten Sedimentkernen aus dem Bodensee II. Historische Entwicklung von Schwermetallen — Beziehung zur Entwicklung polycyclischer aromatischer Kohlenwasserstoffe * Pollution Research on Dated Sediment Cores from Lake Constance II. Historical Evolution of Heavy Metals — Relationship to the Evolution of Polycyclic Aromatic H ydrocarbons  
 Abstract    The vertical distribution of eight heavy metals (Hg, Cu, Zn, Cr, Co, Ni, Pb, Cd) in dated sediments of four sedimentary profiles from the central part of Lake Constance was examined. From 1900 to about 1960 — 1970, a general increase of all heavy metals was observed. After this time, the concentrations of most of the metals decreased. As compared with pre-1900 "natural" metal concentrations, Cd and Pb have been enriched the strongest (enrichment factors 4.0 and 3.8 resp.), whereas Ni and Co exhibit least civilizational influences (enrichment factors 1.5 and 1.9 resp.). Cu, Cr, Zn and Hg were enriched by a factor between 2 — 3. Elements which were not influenced by anthropogenic processes — such as K and Li — remained unaffected over the whole vertical sequence. Polycyclic aromatic hydrocarbons (PAH) which were also studied in the same sediment material by Grimmer and Böhnke show a similar pattern. Within a sedimentary profile the concentration ratio benzo (a) pyrene: cadmium remained about constant. Combustion of coal is believed to be the common source of both heavy metals and PAH and seems to be responsible for the general distribution pattern of both groups of pollutants. In ad­ dition, local sources — both domestic and industrial — are assumed to have delivered additional heavy metal pollution. 
  Reference    (Z. Naturforsch. 32c, 913 [1977]; eingegangen am 12. Juli 1977) 
  Published    1977 
  Keywords    Sediments, Heavy Metals, Polycyclic Aromatic Hydrocarbons, Lake Constance 
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 TEI-XML for    default:Reihe_C/32/ZNC-1977-32c-0913.pdf 
 Identifier    ZNC-1977-32c-0913 
 Volume    32 
2Author    M. Ciscato3 ', J. Vangronsveldb, R. Valcke3Requires cookie*
 Title    Effects of Heavy Metals on the Fast Chlorophyll Fluorescence Induction Kinetics of Photosystem II: a Comparative Study  
 Abstract    The effects of toxic concentrations of Cu, Zn and Cd on the fast induction kinetics of fluorescence from photosystem(PS)II were investigated in a comparative way. The fast fluo­ rescence transient from primary leaves of m etal-treated bean plants was studied. During several days after metal application, the time course of the changes induced by the different metals was monitored. The results evidenced not only a different time course of the changes in fluorescence related parameters for the three metals, but also different effects on the fluorescence induction kinetics, which could possibly be linked to different mechanisms of action of the metals. 
  Reference    Z. Naturforsch. 54c, 735 (1999); received November 8 1998/M arch 10 1999 
  Published    1999 
  Keywords    Cadmium, Chlorophyll Fluorescence, Copper, Heavy Metals, Zinc 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0735.pdf 
 Identifier    ZNC-1999-54c-0735 
 Volume    54 
3Author    Herman Clijsters, Ann Cuypers, Jaco VangronsveldRequires cookie*
 Title    Physiological Responses to Heavy Metals in Higher Plants; Defence against Oxidative Stress  
 Abstract    Depending on the physiological process investigated heavy metal phytotoxicity can be either inhibitory or stimulatory. Photosynthesis and its partial light and dark reactions are inhibited; the activity of various enzymes, located in several cell compartiments, is increased. These enzymes are mostly induced since metals affect the transcription activity. They appear to be related to the plant defence against oxidative stress caused by metal phytotoxicity. Careful examination of the time course of this induction reveals differences in response between the metals applied. 
  Reference    Z. Naturforsch. 54c, 730—7 (1999); received November 22 1998/April 10 1999 
  Published    1999 
  Keywords    Heavy Metals, Photosynthesis, Enzyme Induction, Oxidative Stress, Plant Defence Mechanisms 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0730.pdf 
 Identifier    ZNC-1999-54c-0730 
 Volume    54