Estudos anatômicos em açaí preto (Euterpe oleracea Mart.) e na variedade açaí branco (Euterpe oleracea var. branco)

Abstract

In the Amazon region few studies have been made on the anatomical aspects of the genus Euterpe and especially on its varieties, which may be important to compare and assist in the classification of species and varieties in the genus. The objective was to conduct studies on the anatomical structures of the species Euterpe oleracea Mart, and the variety "açaí branco" for the purpose of structural comparisons. The material for analysis was collected on the island of Combu, municipality of Belém, Pará State, in September 2000. Five 30 cm tall seedlings were collected from the species under study, from which two leaflets and the rootlets were removed and both were sectioned in three regions: apex, middle and base. From each species, two adult leaves were collected from the apex, middle and base regions and two roots were sectioned. For observation of the mesophyll and root structures, the method of (Johansen 1940) and (Braga 1977) was used, mounted on slides and coverslips, in glycerin, protected with colorless enamel; the epidermis was dissected according to the method of (Franklin 1945), washed in water, stained in astrablau and basic fuchsin and dehydrated in alcohol, xylol and mounted on slides and coverslips with Canada balsam. Observations were made with the aid of a ZEISS microscope. The observations showed that the mesophyll of seedlings and adult leaves of black açaí presents triseriate lacunate parenchyma, vascular bundles and aggregated epidermis and elongated uniseriate palisade parenchyma only in adult leaves; in seedlings and adult leaves of white açaí the lacunate parenchyma is biseriate, bundles and thick epidermis and uniseriate palisade parenchyma only in adult leaves; The acai black and acai white present elongated and rectangular cells in the upper epidermis with absence of stomas, however, the lower epidermis of the acai black contains paracitic stomas and the lower epidermis of the acai white presents itself impregnated with tetracytic stomas; the roots and radicles of the acai black and acai white present, median epidermis, sclerotized exodermis, endodermis, discontinuous pericycle, presence of phloem and xylem. It is concluded that the species Euterpe oleracea Mart, and the variety "açaí branco" are similar in root structures, and differ in the mesophyll in relation to lacunose parenchyma and in the epidermis in the type of stomas