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mods:
  schema location: http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
  title info:
    title: Studies on the cytokinin physiology of senescent and nonsenescent grain sorghum cultivars
  name:
    name part: Ambler, John Richard
    name part: 1945-
    role:
      role term: creator
  name:
    name part: Jordan, Wayne R.
    role:
      role term: degree supervisor.
  name:
    name part: Morgan, Page W.
    role:
      role term: degree supervisor.
  name:
    name part: Miller, Frederick R.
    role:
      role term: degree committee member.
  name:
    name part: Van Bavel, Cornelius H. M.
    role:
      role term: degree committee member.
  name:
    name part: Texas A & M University
    role:
      role term: degree granting institution.
  type of resource: text
  genre: bibliography
  genre: Academic theses
  origin info:
    place:
      place term: xx
    date issued: 1988
    issuance: monographic
  language:
    language term: eng
  physical description:
    form: print
    extent: xiv, 289 leaves : illustrations ; 29 cm
  abstract: Nonsenescent sorghums have characteristics that resemble cytokinin responses; therefore, their cytokinin physiology was compared with that of senescent sorghums. First, effects of kinetin on chlorophyll retention of disks from mature leaves placed in the dark for 5 days were studied. Two nonsenescent sorghums, 'Tx2817' (tropically-adapted) and 'SC599-6' (late-season drought resistant), had maximal retention at lower concentrations than did senescent 'RTx7000' and 'BTx378' and in some cases had greater responses to 10^-8 M kinetin and to 10^-5 M gibberellic acid. SC599-6 had high initial chlorophyll content and low loss of chlorophyll without kinetin; RTx7000 and Tx2817 showed characteristics opposite of this, and BTx378 was intermediate. Second, xylem sap from Tx2817 and RTx7000 was analyzed for cytokinins using high-performance liquid chromatography (HPLC). Bioassay studies on HPLC-fractionated sap from vegetative plants indicated that zeatin (Z), zeatin riboside (ZR), and a substance eluting similar to ZR 5'-monophosphate were probably responsible for most of the eell-division type of cytokinin activity. HPLC analyses showed that zeatin riboside, zeatin, and isopentenyl adenosine were present in sap from mature plants. The amount of Z + ZR was 51% higher for Tx2817 than that of RTx7000 on a shoot dry weight basis but only 17% higher on green leaf dry weight basis. For vegetative plants grown with solution culture, Z + ZR amounts in sap per g shoot fresh weight were consistent between duplicates. When RTx7000 and Tx2817 were grown with high N and high light, they had nearly the same Z + ZR amounts. However, they differed greatly with moderately suboptimal treatments of 10% N and 50% light for 7 or 8 days. Suboptimal N caused Z + ZR to be 30% and 59% of the control for RTx7000 and Tx28I7, respectively. Suboptimal light decreased Z + ZR for RTx7000 to 55% of the control but increased that of Tx2817 to 136%. The results with suboptimal light may indicate that Tx2817 h…
  note: Typescript (photocopy).
  note: Vita.
  note: "Major subject: Plant Physiology."
  note: Ph. D. Texas A & M University 1988
  note: Includes bibliographical references (leaves 159-186).
  subject:
    topic: Sorghum
    topic: Physiology
  subject:
    topic: Cytokinins
  subject:
    topic: Plant hormones
  subject:
    topic: Major plant physiology
  identifier: http://gateway.proquest.com/openurl
  identifier: http://proxy.library.tamu.edu/login
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    location:
      url: http://proxy.library.tamu.edu/login
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    location:
      url: http://gateway.proquest.com/openurl
  record info:
    record content source: TXA
    record creation date: 891031
    record change date: 20200904152412.0
    record identifier: in00000786736
    language of cataloging:
      language term: eng