Temperature-Dependent Physiology of Poa secunda, a Cool Season Grass Native to the Great Basin, United States

摘要: Poa secunda Presl. is one of the few native perennial bunchgrasses in Intermountain West to persist and co-occur with invasive annual Bromus tectorum L. following widespread overgrazing frequent wildfires. To identify potential mechanisms responsible for co-occurrence P. B. tectorum, respiration rates (\(R_{\operatorname{CO} _2 }\)) eight populations were measured at 10, 20, 30°C on laboratory-grown plants by infrared gas analysis. In addition, \(R_{\operatorname{CO} }\) metabolic heat (q) nine field-grown 10 20°C using calorimetry dates over a growing season compare temperature-dependent physiology previous published patterns tectorum. Laboratory suggest considerable intraspecific variation physiological response temperature. Changes slope q steeper 20 than 10°C , suggesting that are more capable maintaining steady metabolism low high temperatures. However, growth relatively lower those 10°C. Calculations efficiency converting substrate carbon into biomass consistently remained positive, while rapidly declined temperatures above These data broad range plant communities may be partially explained having similar ability maintain positive stable rate greater higher allow this grass compensate relative