Title page for etd-0628100-031109


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URN etd-0628100-031109
Author Shuo-Tsang Chang
Author's Email Address tsang@cdpa.nsysu.edu.tw
Statistics This thesis had been viewed 4604 times. Download 3235 times.
Department Biological Sciences
Year 1999
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Changes in Cytokinin and Gibberellin Levels Before, During and After Floral Initiation in Polianthes tuberosa
Date of Defense 2000-06-18
Page Count 50
Keyword
  • gibberellins
  • cytokinins
  • Polianthes tuberosa
  • flowering
  • Abstract    We studied how the endogenous and exogenous cytokinin and gibberellin functions in floral
    initiation and development in tuberose. In the aspect of cytokinins. The contents of endogenous
    cytokinin in tuberose corms (Polianthes tuberosa L. cv. Double) at vegetative, early floral
    initiation, and flower development stages were investigated. We also determined the influence of
    exogenous cytokinin treatment on the corm apex at three different growth stages in relation to
    floral initiation and development in tuberose. The exogenous cytokinin effectively induced
    floral initiation and development, especially at the early floral initiation and flower
    development stages. Endogenous cytokinins were higher in early floral initiation and development
    stages in comparison to the vegetative stage. During floral initiation stage, the zeatin and
    dihydrozeatin increased significantly, while the cytokinins, zeatin riboside, dihydrozeatin
    riboside, 6N-(δ2-isopentenyl) adenine, and 6N-(δ2-isope -ntenyl) adenine riboside at consistently
    low levels. The increase of cytokinin levels in tuberose corms during floral induction suggests a
    role for cytokinins in tuberose apex evocation. Moreover, these results indicate that cytokinins
    seem to promote the development of flower buds rather than inducing flowering in tuberose.
       Endogenous gibberellins (GAs) in tuberose corms were isolated using high performance liquid
    chromatography, bioassay and identified by combined capillary gas chromatography-mass
    spectrumetry. Gibber -ellins A19, A20 and A53 were quantified at the vegetative, early floral
    initiation and flower differentiation stages. The identification of these 13-hydroxylated GAs
    indicates the presence of the early-13-hydroxy -lation in tuberose corms. An increase in GA20 and
    decrease in GA19 coincided with the transition from the vegetative phase to the stages of early
    floral initiation and flower differentiation. GA53 maintained at constant levels at three
    different growth stages. When GA3, GA4, GA20 and GA32 were applied to corms at vegetative stage
    (plants about 5 cm in height ), floral initiation was induced and/or promoted by several, most
    notably by GA3, GA20 and GA32. It is suggest that hydroxylated C-19 GAs play an important role in
    flower induction in tuberose.
    Advisory Committee
  • - chair
  • Li-Jen Liao - co-chair
  • Wen-Shaw Chang - advisor
  • Files
  • V131815O.pdf
  • indicate access worldwide
    Date of Submission 2000-06-28

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