Mr. Haferkamp et al., INFLUENCE OF STORAGE, TEMPERATURE, AND LIGHT ON GERMINATION OF JAPANESE BROME SEED, Journal of range management, 47(2), 1994, pp. 140-144
Japanese brome (Bromus japonicus Thunb.), an alien annual grass, is an
important component of some northern mixed-prairie communities. Under
standing the relationship between environment and population dynamics
for this species is critical for efficient management of infested rang
es. Our objective was to determine the germination pattern of seed har
vested in the Great Plains with varying collection dates, storage cond
itions, incubation temperatures, and light regimes. Seeds were collect
ed from inflorescences (nondisseminated seed) during July in Oklahoma
and Montans and during November and December in Montana. July collecti
ons were stored in paper sacks in a laboratory, and November and Decem
ber collections were divided into thirds and stored in an unheated war
ehouse, oven-dried at 46-degrees-C, or frozen at - 18-degrees-C. Seeds
were germinated in 2 regimes, where temperatures alternated every 12
hours and light was provided during the 12 hours of high temperature.
One regime provided 10 days of prechilling (0 and 10-degrees-C) follow
ed by 18 days of a warm temperature (8 and 23-degrees-C) (chilling). A
nother regime consisted of 28 days of the warm temperature (warm). Sam
ples of seeds were also imbibed in the warm regime with 12-hour or int
ermittent periods of light. July collections germinated rapidly to > 9
0% regardless of temperature. November and December collections stored
in the warehouse germinated > 70% in the warm regime, but germination
was reduced to < 20% with chilling, suggesting secondary dormancy was
induced by imbibition at 0-degrees-C. Oven drying was the only treatm
ent that consistently reduced maximum germination. Darkness enhanced 7
-day germination, but light improved 28-day germination, and more rece
ntly collected seeds were more sensitive to light than older ones. The
se and earlier findings from Kentucky suggest Japanese brome seeds gro
wn in different locations respond similarly to changing environmental
conditions.