Anatomia foliar de Ocimum gratissimum L., com ênfase na caracterização dos tricomas secretores e conteúdo do óleo essencial

Abstract

The objective of this study was to describle the anatomy of the leaf of Ocimum gratissimum L. witch emphasis in the characterization of the secretory structure responsible for the production of essencial oils and analyses their chemistry composition using histochemical tests. The samples were collected in the Reconcavo of Bahia: in Conceição do Almeida city and Cruz das Almas city. Botanic material was fixed in FAA50 (GL), SFF and FNT e mounted in permanent lamina for the anatomic study. Transversal sections were realized to free hand for histochemistry tests. Essential oil of species studied was extracted by water-distillation. It observed in leaf non-glandular trichomes and peltate and capitate glandular trichomes, diacytic stomatas on both epidermis faces and dorsiventral mesophyll, collenchyma in the midrib and collateral vascular bundle. Glandular trichomes of O. gratissimum were development in new leaves and in totally expanded leaves the immature trichomes are absentee. The major steps of the development of the trichomes are: extend of volume of cell protodermic, later periclinal division, periclinal division of upper cell formed and forming os secretory head. Secretion peltate trichomes of O. gratissimum have lipidic nature and it was a terpenoid compound certificated by positive results with the lipophilic compounds. There wasn‟t statistic significative difference in tenor of oil of samples collected in two cities. Anatomic and histochemistry characteristics are commons to that registered for the family can be utilized as diagnostic to their identification. Environment in witch the samples were collected offers similar condition for production of essential oil.