A CUTIN FLUORESCENCE PATTERN IN DEVELOPING EMBRYOS OF SOME ANGIOSPERMS

A cuticle visualized by auramine O fluorescence appears on the develop ing embryos of 9 species belonging to Cruciferae, Caryophyllaceae, Pla ntaginaceae, Linaceae and Papilionaceae. In the investigated species t he formation and extent of fluorescing and non-fluorescing embryonic a reas follow a similar pattern. At first the cutin fluorescing layer is formed on the apical part of the proembryo without delimited protoder m. This layer extends and at the late globular stage envelops the embr yo proper, except for a cell adjoining the suspensor. Fluorescing cuti n persists during the heart stage but disappears from the torpedo embr yo. During these stages there is no cutine fluorescence on suspensoria l cells. Continuous cutin fluorescence appears again on the surface of the whole embryo by the late torpedo stage. Then fluorescence disappe ars from the radicular part of U-shaped embryos, but persists on the s hoot apex, cotyledons and at least on the upper part of hypocotyl. It is assumed that polarization and nutrition of the embryo may be influe nced by cuticular changes.