Induction of Germination in Dormant Barnyardgrass (Echinochloa crus-galli) Seeds by Wounding

Abstract

Various surgical cuts were used to induce germination of dormant barnyardgrass [Echinochloa crus-galli(L.) Beauv. # ECHCG] caryopses. Greater percentages of germination were obtained when the cuts were made closer to the embryo. However, removal of only the caryopsis coat covering the coleoptile or midembryo axis induced up to 10% germination compared to 70% germination for caryopses with the coat covering the radicle removed. Dormancy of barnyardgrass was not caused by the inability of the embryo to imbibe, imposed mechanical resistance of the caryopsis coat, or presence of an inhibitor. A wounding response, other than ethylene production, by the cut caryopses was possibly responsible for stimulating germination. Similar responses to cutting observed in afterripened caryopses were consistent with the suggested hypothesis.