| Mohamed Nasri and Paul S. Doescher |
| Authors are former graduate research assistant and associate professor at Oregon State University, Corvallis 97331-2218. |
Abstract |
| Development of deep and extensive root systems especially at cold temperatures has been considered an advantage to successful establishment of grass species in arid environments. This study determined the effects of temperature on seedling root and shoot growth of cheatgrass (Bromus tectorum L.) and 5 collections of Idaho fescue (Festuca idahoensis Elmer). Four collections of Idaho fescue were from degraded sites while the fifth Idaho fescue collection was from a site in high ecological condition. Seedlings were grown in environmental chambers (16 hours day/8 hours night) at 5, 10, and 15oC. Root depth was recorded weekly for 9 weeks, and seedlings were harvested after 63 days. Tiller and leaf number, below and above-ground biomass, and total root length were evaluated. At temperatures of 5, 10, and 15oC, cheatgrass grew faster and produced a greater mass of roots and shoots than Idaho fescue. Root and shoot growth were similar for the 5 Idaho fescue collections at all temperatures. Idaho fescue collections produced more tillers than cheatgrass, except at 5oC. These results indicated that cheatgrass produces greater root and shoot growth mass, but tillers less at warmer temperatures than Idaho fescue. |
| Key Words: Bromus tectorum, Festuca idahoensis, growth chambers, root and shoot growth, population ecology |