Cyperus giganteus or "piri", constitutes a vegetable community denominated "Pirizal", in the Pantanal. It is considered an amphibious or mesophyte species, because it grows in ponds or dry soils. In the tip root there is the calyptrogen, from which the root cap originates; the promeristem, the protoderm, the procambium and the fundamental meristem are also evident in this part. During the differentiation of the protoderm and of the fundamental meristem from promeristem, the initial cell of both tissues can be observed. The external cortex is constituted by the hypodermis and the inner cortex is formed from the precursory layer of the endodermis. The endodermis presents Casparian strip, suberin lamella, thickened walls and phenolic compounds. In successive phases the inner cortex presents schizo-lysigenous aerenchyma. Precocious metaxylem elements are observed in the vascular cylinder followed by the protoxylem elements differentiation. During the development of the rhizome, the roots arise from the pericycle, that constitutes the innermost layer of the primary thickening meristem (PTM). The disposition of the aerenchyma, the multiple hypodermis and idioblasts with phenolic componds are the most representative characters in the root organization for the family Cyperaceae.
Cyperaceae; Cyperus giganteus; root anatomy
