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'Cell Culture' in keywords Facet   section ZfN Section C:Volume 051  [X]
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1996 (2)
1Author    Gerold Reila, RalfG. Ünter BergerhRequires cookie*
 Title    Accumulation of Chlorophyll and Essential Oils in Photomixotrophic Cell Cultures of Citrus sp  
 Abstract    Heterotrophically or photomixotrophically initiated callus cultures o f Citrus paradisi, C. limon and C.aurantifolia were grown on different nutrient media and under different light regimes. Calli of C.paradisi that contained > 1 4 0 mg chlorophyll per kg wet weight accumu­ lated about 40 volatile mono-and sesquiterpene hydrocarbons, oxigenated terpenes and ali­ phatic aldehydes. Upon five subcultivations the best yielding callus contained about 5% (186 mg x k g 1 wet wt) of the volatiles found in peel tissue (exo/m esocarp section), and about the twentyfold amount of that found in the fleshy endocarp. The com position of the essential oils from most of the cell cultures equalled grapefruit peel oil, but was shifted to a more fruit flesh-like composition, after the concentration of gellan gum in the medium was increased from 3 to 9 g per L. C. limon produced 11 m onoterpenes and n-nonanal (40 mg x kg"1 wet wt max.), and C.aurantifolia yielded limonene only (4.4 mg x kg'1 wet wt max.). For all of the indicated species chlorophyll content and accumulation of volatiles were positively corre­ lated. Addition of exogenous valencene to suspended cells of C.paradisi led to a stable con­ centration of the conversion product nootkatone. This stably maintained level suggested that a decreased catabolism of available carbon sources might have accounted for the significant accumulation of essential oil constituents. 
  Reference    Z. Naturforsch. 51c, 657—6 (1996); received March 12/June 18 1996 
  Published    1996 
  Keywords    Citrus, Cell Culture, Photomixotrophy, Oligoprenoids, Limonene 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0657.pdf 
 Identifier    ZNC-1996-51c-0657 
 Volume    51 
2Author    KlausP B Ad Er, Judith SchülerRequires cookie*
 Title    Inhibition of the Photosynthetic Electron Transport by Pyrethroid Insecticides in Cell Cultures and Thylakoid Suspensions from Higher Plants  
 Abstract    Synthetic pyrethroid insecticides with different molecular structures have been investigated with respect to their effect on photosynthetic electron transport reactions in chloroplast sus­ pensions and cell cultures from higher plants. The fluorescence induction curves of tobacco (Nicotiana tabacum) leaves and tomato cells were substantially affected by permethrin and cypermethrin resulting in a strong increase of the maximum fluorescence. Application of different concentrations (0.3-1.2 m M) of the respective chemical abolishes virtually any ki­ netics of the normal Kautsky effect. Oxygen evolution from cell cultures from tomato (Ly-copersicon peruvianum) was completely inhibited by cypermethrin. Analysis of partial reac­ tions of the photosynthetic electron transport showed that both a methylviologen-mediated Mehler reaction and a ferricyanide-driven Hill reaction were quantitatively inhibited by e.g. fenvalerate. On the other hand, neither a silicomolybdate-driven Hill reaction nor a methylvi-ologen-driven Mehler reaction using dichlorophenol indophenol/ascorbate as electron donors could be inhibited by the pyrethroid. The analyses suggest that pyrethroid insecticides in­ terfere with the photosynthetic electron transport at the same site as urea-type herbicides do. Depending on the molecular structure and on the halogen compound in the molecule, however, different pyrethroids are more or less phytotoxic to the investigated photosynthetic membranes -cypermethrin with two Cl-substituents requires much higher concentrations to be applied for significant inhibition of the electron transport reactions than the Br-derivative deltamethrin does. Moreover, qualitative differences have to be taken into account. In the case of fenvalerate the effect seems to exist in a type of all-or-nothing reaction when the reaction centres are inhibited by the pyrethroid. None of the S-states nor the transition probabilities are specifically influenced by increasing concentrations of fenvalerate. In the case of deltamethrin, however, it was found that the overreduced state S_i is significantly increased at the expense of both Si and S(). Moreover, the miss parameter a is increased in the case of deltamethrin addition. The results and the significance of different substituents for the investigated pyrethroids are discussed. 
  Reference    Z. Naturforsch. 51c, 721—728 (1996); received April 25/June 20 1996 
  Published    1996 
  Keywords    Photosynthesis, Electron Transport, Oxygen Evolution, Pyrethroid Insecticide, Cell Culture 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0721.pdf 
 Identifier    ZNC-1996-51c-0721 
 Volume    51