Environmentally induced dormancy in Bromus tectorum. Armstrong, Jeremiah ^*,1, Johnson , Robert ^*,1, Anderson, Val ^*,1, ¹ Integrative Biology, Provo, UT

ABSTRACT- The extent of environmentally induced dormancy in cheatgrass Bromus tectorum and the dynamics of its seedbanking capabilities were studied. The ability of cheatgrass to persist in the environment has been partially attributed to its seedbanking capability. The relationship between the dormancy and the environment has not been studied. Knowledge of the seedbanking abilities of cheatgrass will enable land managers to more effectively treat cheatgrass problems. Four sites representing various cheatgrass environments were sampled. The four sites consisted of a recently burned valley, a south facing slope, and the interspace and understory of a shrub dominated site. Seeds were collected from the unshattered cheatgrass plants and the various litter substrates. Seeds were separated by substrate and condition class. Three conditions were found: new seeds in good condition that were likely to be viable, seeds in a slightly eroded condition that were possibly viable, and seeds in poor and degraded condition that were unlikely to be viable. Of these seed conditions it was found that the slightly eroded seeds were the most common in the seedbank. The second most common were the seeds in good condition followed by the poor condition seeds. Germination trials determined that the seeds in new, good condition contribute the most to the viable seedbank. The seeds from the eroded and poor condition classes had insignificant germination. It was determined that the current seasons seed production contributes the most to recruitment of new cheatgrass plants.

KEY WORDS: Bromus tectorum, Dormancy