Dwarf mutants ofBrassica: Responses to applied gibberellins and gibberellin content

  • Karen P. Zanewich
  • Stewart B. Rood
  • Carol E. Southworth
  • Paul H. Williams
Article
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Abstract

Eight rapid-cyclingBrassica genotypes differing in height were treated with gibberellins (GAs) by syringe application to the shoot tip. The height of two genotypes ofBrassica napus, Bn5-2 and Bn5-8, andB. rapa mutants,dwarf 1 (dwf1) anddwarf 2 (dwf2), was unaffected by exogenous GA3 at dosages up to 0.1 μg/plant, a level which increased shoot elongation of normal genotypes. Thus, these dwarf mutants are “GA-insensitive.” In contrast to theB. napus dwarfs, twoB. rapa mutants,rosette (ros), anddormant (dor), elongated following GA3 application. The dwarfros was most sensitive, responding to applications as low as 1 ng GA3/plant. Furthermore,ros also responded to GA1 and some of its precursors with decreasing efficacy: GA3>ent-kaurenoic acid ≥GA1>GA20≥GA19=GA44≥GA53. Endogenous GAs were measured by gas chromatography-selected ion monitoring using [2H2]GA internal standards for calibration, from shoots of the GA-insensitive genotypes Bn5-2, Bn5-8 which contained theB. napus mutantdwarf 1, and from a normal genotype Bn5-1. Concentrations of GA1 and GA20 averaged 3.2- and 4.6-fold higher, respectively, and GA19 levels also tended to be higher in the dwarfs than in the normal genotype.

Keywords

Petiole Length Dwarf Mutant Normal Genotype Kaurenoic Acid Brassica Genotype 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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Copyright information

© Springer-Verlag New York Inc. 1991

Authors and Affiliations

  • Karen P. Zanewich
    • 1
  • Stewart B. Rood
    • 1
  • Carol E. Southworth
    • 1
  • Paul H. Williams
    • 2
  1. 1.Department of Biological SciencesUniversity of LethbridgeLethbridgeCanada
  2. 2.Department of Plant PathologyUniversity of Wisconsin-MadisonMadisonUSA

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