University of SaskatchewanHARVEST
  • Login
  • Submit Your Research
  • About
    • About HARVEST
    • Guidelines
    • Browse
      • All of HARVEST
      • Communities & Collections
      • By Issue Date
      • Authors
      • Titles
      • Subjects
      • This Collection
      • By Issue Date
      • Authors
      • Titles
      • Subjects
    • My Account
      • Login
      JavaScript is disabled for your browser. Some features of this site may not work without it.
      View Item 
      • HARVEST
      • Electronic Theses and Dissertations
      • Graduate Theses and Dissertations
      • View Item
      • HARVEST
      • Electronic Theses and Dissertations
      • Graduate Theses and Dissertations
      • View Item

      Germination thresholds of the Mixed-grass Prairie species as affected by global climate change: A FACE study.

      Thumbnail
      View/Open
      LI-THESIS.pdf (1.461Mb)
      Date
      2014-02-13
      Author
      Li, Jin
      Type
      Thesis
      Degree Level
      Masters
      Metadata
      Show full item record
      Abstract
      The effects of global climate change on seed germination and plant regeneration have been reported in many species. However, there are no consistent trends in how seed quality and germination are affected by these conditions. Seeds of four native, one invasive, and two pairs of native/invasive species were collected from the USDA-ARS Prairie Heating and CO2 Enrichment Experimental plots in 2007 to 2009, located in the Mixed-grass Prairie near Cheyenne, WY. Field treatments include ambient (385 ppm, c) and elevated (600 ppm, C) CO2 concentrations, control temperature (t) and heating (1.5/3.0°C warmer day/night, T), and deep (ct-d) and shallow (ct-s) irrigation. Seed quality was evaluated and germination tests were conducted under alternating temperatures (10/0, 12.5/2.5, 15/5, 20/10, 25/15, 30/20, 35/25°C). Thermal time requirements (θ50) and base temperatures (Tb) for germination were determined using thermal time models. Elevated CO2 concentrations reduced seed fill and viability, germination and germination rate in Grindelia squarrosa. Heating increased seed viability in Koeleria macrantha from 56% to 79%. Heating, when combined with elevated CO2 concentrations, increased germination while CO2 alone decreased germination by about 14% in Bouteloua gracilis. Heating tended to enhance Tb and to reduce θ50 in Bouteloua gracilis, which may slow the initiation of germination but seeds germinate faster in spring. Elevated CO2 concentrations tended to increase but CT tended to decrease Tb in Centaurea diffusa, but not θ50. Heating tended to increase but all the other treatments tended to reduce Tb in Lanaria dalmatica, leading to a possible earlier start of germination. Irrigation treatments tended to show similar trend of effects on seed quality and germination as that in elevated CO2 concentrations. Species specific changes in seed quality and germination were observed, which may exert substantial cumulative effects on community composition in the long run. Invasive species may be more competitive under future climatic conditions compared with native species. However, the distribution and abundance of some native species, specifically Bouteloua gracilis, may be favored by climate change.
      Degree
      Master of Science (M.Sc.)
      Department
      Plant Sciences
      Program
      Plant Science
      Supervisor
      Bai, Yuguang
      Committee
      Coulman, Bruce; Romo, Jim; Tanino, Karen; Morgan, Jack
      Copyright Date
      December 2013
      URI
      http://hdl.handle.net/10388/ETD-2013-12-1331
      Subject
      climate change
      grass
      regeneration
      thermal time model
      Mixed-grass Prairie
      Collections
      • Graduate Theses and Dissertations
      University of Saskatchewan

      University Library

      © University of Saskatchewan
      Contact Us | Disclaimer | Privacy