Ecophysiological, anatomical and nutritional characteristics of Urochloa spp. Mulatto II under different canopy structures

The objective was to evaluate the ecophysiological, anatomical and nutritional responses of Urochloa spp. (syn. Brachiaria) Mulato II simulating continuous stocking during periods of water and drought. The treatments were composed of four heights, maintained at 10, 20, 30 and 40 cm. The photosynthetic efficiency was higher in the pastures kept at 20 and 30 cm height, consequently higher levels of soluble carbohydrates were observed in the base of the stem and in the roots, which resulted in a greater accumulation of forage. As for leaf anatomy, it was verified that the heights of 10 and 20 cm had the lowest proportion of lignified tissues, which could have resulted in greater disappearance of the chlorophyll tissue and phloem on the leaf blade. Regarding the CP, NDF, ADF and IVDMD levels, the 10 cm handled grass presented the highest levels of CP, lower levels of NDF and ADF, and higher IVDMD. It was concluded that the pastures of Urochloa spp. (syn. Brachiaria) Mulato II managed at heights between 10 and 30 cm had better morphophysiological, anatomical and qualitative responses.CNPq - Conselho Nacional de Desenvolvimento Científico e TecnológicoTese (Doutorado)Objetivou-se avaliar as respostas ecofisiológicas, anatômicas e nutricionais da Urochloa spp. (syn. Brachiaria) Mulato II simulando lotação contínua nos períodos das água e da seca. Os tratamentos foram constituídos de quatro alturas, mantidas a 10, 20, 30 e 40 cm. A eficiência fotossintética foi maior nos pastos mantidos a 20 e 30 cm de altura, consequentemente verificou-se maiores teores de carboidratos solúveis tanto na base do colmo como nas raízes, o que resultou em maior acúmulo de forragem. Quanto à anatomia foliar, verificou-se que as alturas de 10 e 20 cm apresentaram a menor proporção de tecidos lignificados, o que pode ter resultado no maior desaparecimento do tecido clorofiliano e floema na lâmina foliar. Com relação aos teores de PB, FDN, FDA e DIVMS, o capim manejado a 10 cm foi o que apresentou maiores teores de PB, menores teores de FDN e FDA, e maior DIVMS. Conclui-se que os pastos de Urochloa spp. (syn. Brachiaria) Mulato II mantidos nas alturas entre 10 e 30 cm tiveram melhores respostas morfofisiológicas, anatômicas e qualitativas