Title page for ETD etd-04122007-121853

Type of Document Master's Thesis
Author Sosa Nan, Sergio J
Author's Email Address ssosa1@lsu.edu
URN etd-04122007-121853
Title Effects of Pre- and Postharvest Calcium Supplementation on Longevity of Sunflower (Helianthus annuus cv. Superior Sunset)
Degree Master of Science (M.S.)
Department Horticulture
Advisory Committee
Advisor Name Title
Jeff S Kuehny Committee Chair
Charles J Graham Committee Member
Marc A Cohn Committee Member
  • membrane degradation
  • water balance
  • senescence
  • calcium
  • postharvest physiology
  • Sunflower
  • Helainthus annuus
  • specialty cut flower
  • water deficit
  • longevity
Date of Defense 2007-04-02
Availability unrestricted
The sunflower is one of the most important specialty cut flowers produced. Sunflowers have a short and variable postharvest longevity that is dependent upon cultivar. Research in postharvest physiology of cut flowers indicates that calcium (Ca) may be involved in delaying flower senescence by postponing cell membrane degradation. Cut flowers with intact cell membrane structure and function maintain their water balance and last longer. This study was developed to determine the effects of Ca supplementation on longevity of fresh cut sunflowers. The cultivar ‘Superior Sunset’ was used in this study; the sources of Ca were Ca(NO3)2, CaCl2 or a chelated Ca at 125 (low), 250 (medium), or 500 (high) mg/l amounts of Ca. The chelate minus Ca and sodium nitrate (NaNO3) were used as control treatments. Untreated flowers were included in all the experiments; means and standard errors were calculated for comparison with treatments. Ca was applied prior to harvest as a foliar spray or a weekly drench. Results indicated that the Ca treatments did not increase postharvest longevity of sunflower when treated preharvest; however, there was an increase in Ca concentration of stem tissue content compared to the untreated plants. Postharvest application of Ca chelate supplied as a 2-h pulse increased postharvest longevity of sunflower by up to 2 d compared to untreated flowers. Sunflowers treated with Ca also had a greater increase in fresh weight after 8 d in postharvest and improved water retention. Sunflowers treated with Ca had a greater concentration of the cation compared to the untreated flowers.
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