Leaf blades and stem segments at two stages of development (day of leaf ligule exposure and 20 days thereafter) and two insertion levels on tillers (lower and upper) of signalgrass (Brachiaria decumbens), molassesgrass (Melinis minutiflora) and tifton 85 bermudagrass (Cynodon sp), were sampled in two seasons of the year (summer and autumn). The anatomical and chemical traits, and in vitro dry matter digestibility of blades and stems segments were evaluated. The correlations among these variables were established to associated values observed in leaf blade and stem, and to each fraction. The cell wall thickness was the anatomical trait to exhibit the highest correlation with all the chemical components, being positive with neutral detergent fiber, acid detergent fiber and lignin contents and negative with crude protein content. The proportion of mesophyll correlated positively with crude protein and negatively with acid detergent fiber content, while the proportion of sclerenchyma showed positive correlation with neutral detergent fiber content. The chemical components showed strong correlation among themselves and with the IVDMD. From the anatomical traits, the cell wall thickness was the only one to exhibit a significant correlation with the IVDMD, independent of fraction. The IVDMD correlated positively with leaf blade mesophyll and negatively with stem xylem.
Brachiaria decumbens; cell wall thickness; Cynodon sp; in vitro dry matter digestibility; Melinis minutiflora; tissue proportion
