PARENT SESSION
Oral Session #45: Biogeography and Metapopulations.
Presiding: T. Miller
Tuesday, August 6. 1:00 PM to 4:45 PM. Grand Ballroom Central, Radisson.
Calorimetric studies of several populations of winterfat (Krascheninnikovia lanata) with different metabolic responses to temperature.
THYGERSON, TONYA*,1, SMITH, BRUCE1, HANSEN, LEE1, PENDLETON, ROSEMARY2, BOOTH, D. TERRANCE3, 1 Brigham Young University, Provo, UT2 Forestry Sciences Laboratory, Albuquerque, NM3 High Plains Grassland Research Station, Cheyenne, WY
ABSTRACT- Krascheninnikovia lanata (Pursh) Guldenstaedt.[ Eurotia lanata (Pursh) Moq.] (winterfat) is a cold-desert subshrub, seldom more than 2ft. tall, and grows in dry climates at cooler temperatures. Stem, leaves, and seed dispersal units called diaspores are covered with a dense mix of short and long white hairs that aid in water retention. It is excellent forage for both wildlife and domestic cattle. Populations were collected from western United States (CO, NM, WY, UT) and Canada (Sask). Seeds were soaked and placed on moistened filter paper in petri dishes. At the time of radicle emergence (ca.3mm), seeds were placed in ampules in a microcalorimeter. Heat-rate (Rq) was measured at a given temperature, then a vial containing NaOH was added to measure the rate of CO2 evolution (RCO2) for the same tissue at the same temperature. This procedure was repeated for each population at temperatures ranging from 0 to 35 C. From these measurements, predicted specific growth rates and metabolic efficiency were calculated. The response to temperature of seedlings reflected adaptation to the environment at their site of origin.
KEY WORDS: calorimetry, metabolism, temperature, winterfat