- One laboratory experiment was carried out in order to determine relationship between water absorption levels and dormancy of Brachiaria plantaginea (Link) Hitchc. seeds germination rate, a crop weed. Two seed lots collected in the 1992 and 1993 growing seasons were used. Imbibition periods were of 6, 12, 18, 24 and 48 hours, at 20ºC . Afterwards seeds electric conductivity was determined. Seed treatments were disposed in a germinator with temperatures of 30/20ºC , cycles of 14/10 hours, 90% RU and diffuse fluorescent light. Four replications of 100 seeds/gerbox were disposed in a completely randomized experimental design. Results showed that B. plantaginea seeds, with higher state of dormancy (most recently collected), present higher rate of water absorption, higher electrolytic lixiviation and lower rate of germination. Seed germination rate is not directly related to water absorption capacity, but to the state of dormancy or storage period. State of dormancy is not due to the tegument impermeability, once dormant seeds present water absorption somewhat higher as non-dormant seeds. Seed imbibition period needed to a higher germination is lower after breaking of dormancy.