A comparison of cumulative-germination response of cheatgrass (Bromus tectorum L.) and five perennial bunchgrass species to simulated field-temperature regimes

作者：Hardegree Stuart P^*; Moffet Corey A; Roundy Bruce A; Jones Thomas A; Novak Stephen J; Clark Patrick E; Pierson Frederick B; Flerchinger Gerald N

来源：Environmental and Experimental Botany, 2010, 69(3): 320-327.

DOI：10.1016/j.envexpbot.2010.04.012

• Seed
• Germination
• Temperature
• Model
• Bromus tectorum
• Elymus multisetus
• Elymus elymoides
• Pseudoroegneria spicata
• Leymus cinereus
• Poa secunda

Cheatgrass (Bromus tectorum L) has come to dominate millions of hectares of rangeland in the Inter-mountain western United States. Previous studies have hypothesized that one mechanism conferring a competitive advantage to this species is the ability to germinate rapidly at low temperatures in the fall, winter and spring and, therefore, initiate growth and establishment more rapidly than more desirable perennial bunchgrass species. In this experiment, we developed thermal-germination-response models for multiple seedlots of cheatgrass and five perennial grass species. We conducted sensitivity analysis on potential-cumulative-germination response to a 38-year simulation of field-variable conditions of seedbed temperature and moisture. Cheatgrass uniformly germinated at a higher rate, and required significantly less time to complete germination than any of the perennial species for all but the slowest seed subpopulations. A germination-rate-sum index was used to integrate relative response characteristics over time. This index showed that germination rate of the most rapidly germinating subpopulations of cheatgrass was 2-5 times higher than for the other species tested. Model simulations of this type provide a more ecologically relevant basis for seedlot evaluation as they allow comparisons across a wide range of potential conditions that may be experienced in the field. Published by Elsevier B.V.

• 出版日期2010-12