[EN]: Formation of the special wall of callose during microsporogenesis was studied simultaneously using a general stain for light microscope, a specific technique for this material (aniline blue) and transmission electronic microscope. The use of aniline blue with epifluorescence, however, does not show the presence of another type of material which starts to accumulate before the formation of the first indications of callose, and which continues to accumulate throughout meiosis. This may be "precallosic" material, i. e. relatively unpolymerized glucide precursors of callose, which are clearly distinguishable from the callose itself. This material does not reveal secondary fluorescence with aniline blue, and under transmission electron microscopy is much more electron translucent in comparison to the greyish color of the callose.

[ES]: Se ha realizado un estudio sobre la formación de la pared especial de calosa durante la microsporogénesis en Olea europaea L. simultaneando el empleo de una tinción de tipo general para microscopio optico, con una técnica específica para detectar este material (azul de anilina) y microscopia electrónica de transmisión.

Este estudio ha sido financiado por la Comisión Asesora para la Investigación Científica y Técnica y CSIC (Proyecto nº 1-179-2ID 181/906).

7 páginas, 10 figuras.-- Trabajo presentado al VII Simposio de Palinología.

Peer reviewed