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Revista Brasileira de Zootecnia

On-line version ISSN 1806-9290

Abstract

BRITO, Cláudio José Freixeiro Alves de; RODELLA, Roberto Antonio  and  DESCHAMPS, Francisco Carlos. Quantitative anatomy of leaves and stems of Brachiaria brizantha (Hochst. ex A. Rich.) Stapf and B. humidicola (Rendle) Schweick. R. Bras. Zootec. [online]. 2004, vol.33, n.3, pp. 519-528. ISSN 1806-9290.  http://dx.doi.org/10.1590/S1516-35982004000300001.

The forage digestion characteristics can better be understood when associated with studies of tissue anatomy of forage species. Aiming at new focus to this issue, the area of several tissues present in leaves and stems of B. brizantha and B. humidicola, were determined at three different regions of the plant. The assay was carried out at greenhouse, with plants growing in pots with sterilized sand, receiving nutritive solution of macro and micronutrients. After 70 days of growing period, the segment of leaf and stem localized in the center of each of three different insertion planes was collected. The samples were fixed in FAA, embedded in GMA, sectioned in microtome, stained and photographed. The pictures were digitalized and the areas measured with Image Tool software. It was observed that the limbo at bottom plane presents lower area of lignified vascular tissue. On the other hand, at the sheath and stem of B. brizantha, a larger area of parenchymal tissue is found. Compared to B. humidicola, B. brizantha showed greater area of lignified vascular tissue at the limbo, sheath and stem, while the greatest distance among bundle sheath is found at the limbo and sheath, where the number of bundle sheath was higher at the limbo and stem.

Keywords : cellulose; forage; grasses; lignin; plant anatomy.

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