Changes in Dormancy and Viability of Weed Seeds in Soils

Abstract

Seeds of several weed species, each with initially known responses to light and temperature, were buried in soil in an open field at 2.5, 7.6, and 15.2-cm depths during November. At 3-month intervals during the following year, the seeds were recovered in the dark and reexamined for their response to light and temperature, and their viability. Loss in viability occurred fastest with seeds having little initial dormancy and with shallow placement of seeds. Phytochrome was important in controlling germination of the recovered weed seeds, and manifested itself as an acquired type of dormancy, as well as an initial one. However, other factors in the soil environment appear to interact with the phytochrome system in the control of germination of weed seeds in soils.