Nichole Edelman, Masters
Advisor: Dr. Michelle Jones
“Evaluating ethylene sensitivity using mature plant screens and the seedling hypocotyl response”
Abstract: Ethylene (C2H4) is a gaseous hormone produced by plants in response to environmental stress and during growth and development. Sensitive seedlings exposed to ethylene gas will exhibit an exaggerated apical hook, thickened hypocotyl, and reduced hypocotyl elongation. Collectively these symptoms are known as the triple response, and have been used as a screen to identify ethylene mutants. Exposure to ethylene gas at the mature plant stage can induce flower, bud, or leaf abscission, flower senescence, leaf chlorosis (yellowing), or leaf epinasty (downward curvature). Sensitivity can vary between species and by developmental stage or tissue (flower vs leaf). Ethylene can damage plants during production, shipping, and retailing. The objectives of this research were 1) to determine if the seedling hypocotyl elongation screen could be used to predict the sensitivity of mature plants at the marketable stage; 2) to identify ethylene sensitivity differences (levels of sensitivity and symptoms) between accessions within Solanaceae; and 3) to identify ethylene sensitivity differences at different developmental stages (seedling, younger vegetative, and mature plants). Seedlings were germinated on filter paper saturated with 1-aminocyclopropane-1-carboxylic acid (ACC) and sensitivity was determined based on the hypocotyl lengths relative to the control (0 μM ACC). Mature plants were treated with 10 μL·L-1 ethylene gas for 24 hours, and the severity of the response was used to classify ethylene sensitivity. The first experiment evaluated 18 bedding plant species while the second evaluated 40 Solanaceous accessions. A classification of low, medium or high sensitivity to ethylene was assigned to plants at both developmental stages. The results showed that the seedling hypocotyl elongation screen did not consistently predict mature plant sensitivity. Ethylene sensitivity varied between species and cultivars within the Solanaceae family, and sensitivity also varied by developmental stage. Information from this research can be used by growers to identify insensitive or low ethylene sensitive varieties for long-distance shipping and to identify medium to highly sensitive varieties that would benefit from treatment with ethylene inhibitors (1-MCP). Plant breeders and scientists can also use this information to identify breeding lines with lower ethylene sensitivity.
Tuesday November 19, 2013 10:00 – 11:00 am
In Research Services 130 (Wooster)
video linked to
Kottman Hall 202F (Columbus)