The invasive behavior of Melaleuca quinquenervia in wetlands seems attributable to its inherently aggressive regeneration strategies associated to massive seed production. The knowledge of the germination physiology of weed seeds can contribute significantly to the development of strategies for their management. This work aimed to evaluate the possible effects of water and salt stress on the germination of M. quinquenervia seeds. Four replications with 0.05 g of seeds were sown in paper moistened with solutions with the potential of 0.0; -0.2; -0.4 and -0.8 MPa, induced with polyethylene glycol (PEG 6000) and NaCl. Germination test was carried out at 25 ºC in the presence of light. The percentage of normal seedlings was obtained seven days after sowing (first count) and, weekly, up to 28 days. The speed of germination index was calculated. The results allowed to conclude that water stress causes a greater reduction in germination speed and accumulated germination of M. quinquenervia seeds than saline stress, and that, regardless of the substance used for stress induction, germination limit is between -0.4 and -0.8 MPa.
osmotic stress; weed; osmotic potential; salinity; vigor
