The objective of this work was to evaluate the morphogenetic and structural characteristics of Brachiaria brizantha and decumbens submitted to different nitrogen doses (N). The experiment was carried in a greenhouse. The treatments consisted of four N doses (0, 75, 150 and 225 mg/dm³ of N) and two grasses (Brachiaria brizantha and decumbens). Nitrogen fertilization was subdivided into three applications. A completely randomized block experimental design with five repetitions was used. For the morphogenetic and structural characteristics, the daily foliar structure emergence, total number of leaves and number of tillers per B. decumbens plant was higher for B. brizantha. However, for phyllochron, the daily foliar prolongation and life duration of the B. brizantha leaf were higher. B. decumbens and brizantha responded increasingly up to 190 mg/dm³ of nitrogen in relation to the majority the available characteristics. The process senescence is accelerated with increase of the nitrogen doses, reducing the life duration of leaves.
Brachiaria brizantha; Brachiaria decumbens; phyllochron; tillering
