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'C hronobiology' in keywords Facet   section ZfN Section C  [X]
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1990 (1)
1987 (1)
1Author    JackD. Ekker, Barbara WestfallRequires cookie*
 Title    A Temporal Phase Mutation of Chlorophyll Fluorescence in Triazine-Resistant Brassica napus  
 Abstract    The objectives o f this study were to determ ine if there were variations in triazine-resistant and -susceptible Brassica napus leaf disc chlorophyll fluorescence (LCF) intensity in terms of: age of leaf on the plant and time o f day. In growth room and field experim ents triazine-susceptible B. napus cv. "T ow er", and triazine-resistant B. napus cv. "O A C Triton" were used. Chlorophyll fluorescence intensity m easurem ents were made 30 min after disc removal. In both environm ents, two periods o f reduced photosynthetic efficiency occurred in the diurnal. The tim es that these periods occurred during the diurnal differed between biotypes. A phase shift in LCF maxima betw een resistant and susceptible biotypes resulted in two periods, early and late in the light period o f the diurnal, o f increased LCF in resistant tissue. This differential pattern in LCF is support for the hypothesis that triazine resistance chloroplast alterations could imply an alteration in the temporal organization o f chloroplast physiological function. 
  Reference    Z. Naturforsch. 42c, 775 (1987); received Novem ber 11 1986 
  Published    1987 
  Keywords    C hronobiology, Chronoresistance, Chronomutant, Circadian Clock, R apeseed, Photosynthetic Electron Transport 
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 TEI-XML for    default:Reihe_C/42/ZNC-1987-42c-0775.pdf 
 Identifier    ZNC-1987-42c-0775 
 Volume    42 
2Author    Jack Dekker, RonaldG. BurmesterRequires cookie*
 Title    Differential Pleiotropy in a psbA Gene Mutant of Brassica napus Implies Altered Temporal Photosynthesis and Thermal Tolerance  
 Abstract    Studies were conducted to test the hypothesis that the mutation to the psbA. plastid gene that confers s-triazine resistance (R) also results in an altered diurnal pattern o f photosynthetic car­ bon reduction (CER) relative to that o f the susceptible (S) wild-type. In all experiments CER approximated the increasing and decreasing light levels during the diurnal. S C ER exceeded that o f R during the midday period, but R CER was greater early and late in the diurnal at 25 °C. R CER exceeded that o f S for most o f the diurnal at 35 °C and in older, crowded, nitrogen-starved plants. These studies support the stated hypothesis and indicate a more complex model o f photosynthetic productivity than previously observed. An assessment o f the photosynthetic competence o f either biotype may be a function o f the time o f day or the environmental condi­ tions the plants are exposed to, especially temperature. 
  Reference    Z. Naturforsch. 45c, 474 (1990); received October 18 1989 
  Published    1990 
  Keywords    Photosystem II, D -l Protein, Electron Transport, C hronobiology, Diurnal Rhythms 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0474.pdf 
 Identifier    ZNC-1990-45c-0474 
 Volume    45