The study of the botanical characters of weeds can be valuable in the decision - making process for the control methods to be used. The objective of this work was to verify the vegetative growth of Egeria najas plants from 5 cm plant fragments. The experiment was developed at Nova Estrela Farm, located at 20º30'19.7'' latitude and 51º14'56.3'' longitude, in Pereira Barreto, in Northwestern São Paulo. The experiment was arranged in randomized blocks, with four treatments and five replications. The treatments consisted of different positions of the plant fragments. In treatment 1, the plant fragments were removed from the apex (0 to 5 cm); in treatment 2, from fragments removed 5 to 10 cm; in treatment 3, from 10 to 15 cm and in treatment 4, from 15 to 20 cm. The fragments were tied with thin nylon cords, fixed in an iron support, and returned to the pond, and kept there until the end of the experiment. Growth evaluation was accomplished at 12 days after the treatments. Regardless of their position, all the fragments had at least one sprouting, confirming the high vegetative activity of E. najas. The fragments removed from the apex were significantly more active in retaking growth, providing a larger number of sprouts and greater length.
aquatic plant; weed; morphology; reproduction
