Zhiyu, He , Holaday, A. Scott .
Potential Variability of Heat Tolerance for a Cool-season, Invasive Grass, Phalaris arundinacea.
Phalaris arundinacea (reed canary grass) is a cool-season perennial grass that is classified as an invasive species in wetlands of the northern U.S.A. and Canada. We hypothesize that high temperature limits the southern extent of P. arundinacea. Given predicted global climate change, we want to determine whether P. arundinacea exhibits enough variabilty with respect to its response of photosynthesis to high temperature to maintain its invasive status. There are reports of genetic variability among P. arundinacea populations that may contribute to its invasive potential. Some genetic variability is the result of the existence of three cytotypes, diploid, tetraploid, and hexaploid, of which the tetraploid is thought to compose much of the invasive populations of North America and the hexaploid is possibly heat tolerant. We have plants from the central portion of the speciesí range in the U.S. (northern IN), Iran, Morocco, and Portugal (two populations). Other collections in northern TX/OK are planned. We have determined that the plants in northern IN are diploid, as are those from Morocco, whereas one population from Portugal is tetraploid and the other is hexaploid. From preliminary gas-exchange analyses, the optimum temperature for photosynthesis was 30 oC for hexaploid and diploid plants. These data suggest that populations of P. arundinacea may not vary with respect to the photosynthetic response to moderate heat stress.
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1 - Texas Tech Univeristy, Biological Sciences, Flint & Main Streets, Lubbock, Texas, 79409-3131, U.S.A
2 - Texas Tech Univeristy, Biological Sciences
Reed canary grass.
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM