Anatomy of the nectaries, colleter, and stgma of Rodriguezia venusta (Lindl.) Rchb. f. (Orchidaceae) / Anatomia dos nectarios, do coleter e do estigma de Rodriguezia venusta (Lindl.) Rchb. f. (Orchidaceae)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Rodriguezia venusta is an orchid with ornamental potential, native to Brazil and Peru. This specie belongs to subtribe Oncidiinae that is in Epidendroideae, the notorioas biggest Orchidaceae s subfamily. Although the wide morphology and taxonomy studies on this family, the works concerning anatomy are rare, specially focusing the secretory structures, in order that is the objective of the present work. Floral buds, bracts and expansion leaves samples were carried out to microscopy analysis. ln the abaxial side of the bract subtending each flower, especially at the portion of they insertion, there are material secreting trichomes that react positive to carbohydrates and mucilage histochemical tests. Due the probable lubricant action of this secretion during the floral bud growth passing aver the bract, it is expected that "colleters" is the most convenient term to designate these structures. ln the flowers, the stigmatic and transmitting tissues have similar cellular types characterized by the elongated shape. The cellular unions only at the terminal walls give a net shape to the structure. ln the intercellular spaces copious secretion occurs constituted predominantly of mucilage. There is a cuticle on the stigma surface and at the canal delimited by transmitting tissue in it apical region. ln addition, R. venusta has extrafloral nectaries in the growing leaves and in the floral bud subtending bract, and also a floral nectary inserted at the lip base. The extrafloral nectaries are anatomically similar, whereas floral nectary is more complex structurally, being covered by nectariferous trichomes

ASSUNTO(S)

rodriguezia rodriguezia orchidaceae nectaries orchidaceae coleteres plant anatomy anatomia vegetal colleters nectarios

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