|
Submitted to: Weed Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/24/2003 Publication Date: 1/2/2004 Citation: Foley, M.E. 2004. Leafy spurge (Euphorbia esula) seed dormancy. Weed Science. v. 52. p. 74-77. Interpretive Summary: Although seed dormancy is a key characteristic of weedy plants, mechanism governing seed dormancy are unknown. To begin to understand seed dormancy in leafy spurge, we determine which seed component(s) is responsible for dormancy and characterize conditions that lead to breaking of dormancy. From this research, we determined that dormancy in leafy spurge is imposed by the seed coat and afterripening occurs slowly under warm, moist or cool, moist conditions. Technical Abstract: Leafy spurge is a herbaceous perennial weed that reproduces asexually through adventitious vegetative buds and sexually by seed. Seeds can remain viable in the soil for up to 8 yr. The objectives of this research were to identify seed components which restrict germination and to determine if afterripening treatments affect germinability. Germination of non-afterripened intact seeds was 30% after 28 d of incubation. Afterripening seed for 12 wk under warm, moist conditions provide nearly a two-fold stimulation in germination after 21 d compared to the control and other afterripening treatments. Depending on the year the seeds were harvested, afterripening under warm, moist or cool, moist conditions for an additional 12 wk provide nearly complete germination within 7 to 21 d. Germination of seeds after removal of the seed coat (dehulled) and dehulled seed in which the endosperm surrounding the embryo was removed led to rapid germination, approaching 80 to 90% in 5 d. Fructose did not enhance germination of dehulled seeds or embryos. Thus, leafy spurge displays coat-imposed seed dormant that can be overcome by afterripening under moist conditions. |
