PARENT SESSION
Poster Session #71: Plant Ecology: Physiology and Function.
Friday, August 9. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC

Physiological evidence for ecotypes of Schizachyrium scoparium.

Johnson, Jennifer^*,1, Wallace, Linda², ¹ Jornada Experimental Range, Las Cruces, NM² University of Oklahoma, Norman, OK

ABSTRACT- The Salt Plains National Wildlife Refuge in north central Oklahoma appears to be a very stressful habitat for plant growth. Soil salinity averages 10 meq and pH averages 9.8. Vascular plants that do occupy this habitat occur on small hummocks. We noted morphological differences between Schizachyrium scoparium plants growing in the Salt Plains soils versus glycophytic soils located nearby. To determine whether plants growing in the Salt Plains were a distinct ecotype, plants collected from the glycophytic soils, a Texas salt marsh and the Salt Plains were grown in a common garden design in the greenhouse. Some plants were reciprocally transplanted into alternate soil types. Physiological parameters were measured using a LI-6400 over 6 weeks following acclimation in the various soils for 6 months. No differences in physiology were found based on the soil of origin. However, the transfer soil significantly affected photosynthesis, stomatal conductance and transpiration with values in plants in the Texas soil significantly less than those for the other two soil types. No significant soil of origin by transfer soil interactions were noted indicating that these plants were not distinct ecotypes but rather represent an example of the extremely plastic nature of this species.

KEY WORDS: salinity, pH, Oklahoma