A quantitative analysis of seed dormancy and germination in the winter annual weed Sinapis arvensis (Brassicaceae)

The aims of this study were to determine the effects of burial on germination and longevity, and of water stress and temperature on germination and dormancy induction of the weed Sinapis arvensis L. During exposure to the high temperatures of summer, seeds buried in the field became nondormant, but low water potential and supra-optimal temperatures (constant not alternating) induced them into secondary dormancy. The threshold temperature for dormancy induction (TTDI) was about 19 degrees C when water was not limiting germination, and it decreased with a slope of 10 degrees C per MPa as water potential decreased. Seeds had minimum dormancy (D-min) when T < TTDI, and D-min decreased by 81.5% per MPa increase in water potential. Dormancy induction increased linearly with a slope of 13.23% for each additional centimetre of burial depth from 1.0 to 5.19 cm. Dormancy was induced to its highest level (96%) in seeds buried at a depth of >= 5.19 cm; the remaining seeds were dead or were presumed to be dead Sinapis arvensis can form a persistent soil seed bank, and either water stress or conditions associated with increased burial depth can promote induction of secondary dormancy in the seeds.