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'Triazine Resistance' in keywords
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1993 (1)
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1990 (3)
1Author    V. Ictor, B. Curw, G. Ert, S. Chan Sk Er, O. Scar, J. De, V. Os, J. S. Van RensenRequires cookie*
 Title    Comparison of Photosynthetic Activities in Triazine-Resistant and Susceptible Biotypes of Chenopodium album  
 Abstract    Triazine-resistant and susceptible Chenopodium album plants were grown at low and at high light irradiances. A t the lower light irradiance the dry m atter production of the resistant and the susceptible plants were almost similar. At the higher irradiance the resistant biotype had a significantly lower production. Fluorescence studies showed that the photochemical yield and the photosystem II electron transport rate were lower in the resistant biotype. It could be demonstrated in intact leaves that the lower productivity of the resistant biotype is caused by a higher sensitivity to photoinhibition. However, when studying effects of photoinhibition on electron flow and photophosphorylation in isolated thylakoids o f the two biotypes, no signifi­ cant differences between resistant and susceptible plant materials were observed. It is suggest­ ed that the difference between resistant and susceptible biotypes connected with processes pro­ tective against photoinhibition in intact leaves, are lost during the isolation of thylakoids. 
  Reference    Z. Naturforsch. 48c, 278 (1993); received November 26 1992 
  Published    1993 
  Keywords    Chloroplasts, Triazine-Resistance, Photosystem II, Photoinhibition, Fluorescence 
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 TEI-XML for    default:Reihe_C/48/ZNC-1993-48c-0278.pdf 
 Identifier    ZNC-1993-48c-0278 
 Volume    48 
2Author    Dirk Naber, Udo Johanningmeier, JackJ S Van Rensen, D. N., J.J S V RRequires cookie*
 Title    A Rapid Method for Partial mRNA and DNA Sequence Analysis of the Photosystem II psbA Gene  
 Abstract    Single amino acid substitutions in the D 1 protein of photosystem II may cause resistance to various herbicides. In all organisms studied these substitutions are located in or between hel­ ices IV and V of the protein. The increasing number of herbicide-resistant organisms necessi­ tates development of a rapid methodology to characterize deviations from the wildtype se­ quence. Here, two procedures are described to identify mutations in the psbA gene, which is coding for D 1. These procedures involve the isolation and amplification of D N A and RN A and subsequent sequencing reactions without the need to clone the psbA gene. A triazine-re-sistant and a -susceptible biotype of Chenopodium album were used as model species. An A to G transition, giving rise to a serine to glycine mutation at position 264 in the D 1 protein, is found in the resistant plant. 
  Reference    Z. Naturforsch. 45c, 418—422 (1990); received November 3 1989 
  Published    1990 
  Keywords    Triazine Resistance, Sequence Analysis, Polymerase Chain Reaction, Chenopodium album 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0418.pdf 
 Identifier    ZNC-1990-45c-0418 
 Volume    45 
3Author    R. Hain, J. E. ThomzikRequires cookie*
 Title    Segregation of Triazine-Resistant Chloroplasts after Introduction into Winter Type Oilseed Rape (Brassica napus L.) by Protoplast Fusion  
 Abstract    Triazine-resistant chloroplasts o f the Canadian spring oilseed rape variety OAC Triton were transferred into four German winter oilseed rape lines and two cultivars o f double-low quality by means o f protoplast fusion. X-irradiation has been used to reduce the am ount o f nuclear D N A o f the spring type cultivar and to promote cybrid formation. RFLP-analysis showed that some regenerants and their progeny carried both types o f chloroplasts. In som e instances regenerants and progeny containing mixtures o f both chloroplasts not kept under selective conditions lost their triazine-resistant chloroplasts completely during further plant growth. Preliminary results o f greenhouse and field experiments indicate that volunteer plants can be eliminated by application o f 1 5 0 -3 0 0 g/ha metribuzin (SencorR, Bayer A G) in a stand o f triazine-resistant oilseed rape o f double-low quality. 
  Reference    Z. Naturforsch. 45c, 478 (1990); received September 8 1989 
  Published    1990 
  Keywords    Brassica napus, Somatic Hybridization, Triazine resistance, Chloroplast segregation, RFLP-analysis 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0478.pdf 
 Identifier    ZNC-1990-45c-0478 
 Volume    45 
4Author    J.Dirk Naber, JackJ S Van RensenRequires cookie*
 Title    Activity of Photosystem II Herbicides Is Related with Their Residence Times at the D 1 Protein  
 Abstract    The reversible binding kinetics o f atrazine, diuron and ioxynil were measured via their bind­ ing and release parameters during steady state inhibition o f electron transport. The parameters were determined in isolated chloroplasts o f peas and o f triazine-resistant and -susceptible bio­ types o f Chenopodium album using a kinetic model. This model is based on the flash-induced oxygen evolution patterns o f isolated broken chloroplasts. It was found that the binding parameters were always significantly higher in the case o f an oxidized acceptor quinone complex as compared with a semi-reduced complex. Triazine resist­ ance seems to originate from a significant increase o f the release kinetics. The release parame­ ters could be used to calculate the residence times o f the herbicides at the D 1 protein. The values o f these residence times were always much higher for the herbicides than for Q B; this explains the inhibition o f electron transport. The only exception was the residence time o f atra­ zine in the resistant biotype, where the value was close to that o f Q B. It is concluded that the "on" kinetics o f a com pound to its binding environment at the D 1 protein are determined principally by the accessibility o f the niche to the com pound. The dif­ ferences in activity between herbicides are mainly due to variations in the release kinetics. 
  Reference    Z. Naturforsch. 46c, 575—5 (1991); received March 18 1991 
  Published    1991 
  Keywords    Chloroplasts, Photosystem II, D 1 Protein, Herbicides, Triazine Resistance 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-0575.pdf 
 Identifier    ZNC-1991-46c-0575 
 Volume    46 
5Author    MarcelA K Jansen, Klaus PfisterRequires cookie*
 Title    Conserved Kinetics at the Reducing Side of Reaction-Center II in Photosynthetic Organisms; Changed Kinetics in Triazine-Resistant Weeds  
 Abstract    The decay o f chlorophyll variable fluorescence after a "single turnover" flash is generally assumed to represent the reoxidation o f the reduced quinone Qa. We have observed that the kinetics o f this decay are very similar in a wide variety o f species. Comparing 28 different spe­ cies, we found an average half decay time o f 314 ± 4 6 (isec. N o systematic correlations were found between the decay rate and biochemical or physiological specializations such as C 2, C 4 or C A M . This indicates that structural as well as functional factors controlling photosystem II electron transfer between Qa and Qb are highly conserved. Apparently, the freedom for natural structural variations in this region is very limited. Triazine resistant plants, characterized by an altered amino acid sequence o f the D 1 protein, have clearly decreased rates o f Qa/Q b electron transfer. We found an average half decay time o f 946 ± 100 jisec (5 species). However, this three-fold decrease is much less than previously re­ ported. Therefore, if alterations o f photosystem II electron transfer efficiency contributes to an often reported reduction o f "ecological fitness", this contribution is smaller than was hitherto assumed. 
  Reference    Z. Naturforsch. 45c, 441—4 (1990); received November 27 1989 
  Published    1990 
  Keywords    Chlorophyll Fluorescence, Evolution, Photosystem II, Triazine Resistance, p sb A Conservation 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0441.pdf 
 Identifier    ZNC-1990-45c-0441 
 Volume    45