Caracterização Anatômica em Diferentes Frações de Cultivares de Capim-elefante (Pennisetum purpureum Schumach.)

Abstract

The knowledge of the anatomy of tropical forage grasses may help to improve its use as ruminant feed. The aim of this paper was to determine the area occupied by different tissues in stem and leaf in three cultivars of elephantgrass (Pennisetum purpureum Schumach.). Five plants of each cultivar were selected and segmented into three parts (apical, median and basal), this material was collected after ten weeks of regrowth. The stems were separated into two parts and the leaves segmented into sheath, limbo and keel. The phloem, a tissue of high digestibility, represented only 2% of the total tissue area, thus did not affect total plant quality. The area of epidermis and lignified vascular tissues is larger in limbo, mainly in young leaves. In the stem, the area of vascular lignified tissue increases towards the bottom of the plant. The distance between bundle sheaths in the leaf sheath is over 500 μm, while in limbo it is 140 μm. It was difficult to determine the correct distance among bundle sheaths in stems due to their uneven distribution. Limitations were observed in separating cultivars through anatomy profile. Even so, cultivar Testo showed the greatest vascular lignified tissue area and the lowest area of parenchymal tissue. On the other hand, cultivar Areia showed the smallest distance among bundle sheaths in the leaf sheath and keel, and the greatest area of phloem in leaves.