Transmission electron microscopy was used to investigate the development
and ultrastructure of the cuticles of the bladder primordium and other
parts of Utricularia, the stem of Cuscuta gronovii, and
the leaves of Athanasia parviflora. In all materials investigated,
except the apical meristem of Cassytha pubescens, the first formed
cuticle, named the procuticle, was very electron dense and apparently
amorphous in texture. Later, the procuticle changed its ultrastructural
appearance: in all species having a procuticle it lost much of its electron
density. Simultaneously, it developed into a lamellar structure in U.
lateriflora and Cuscuta, and became part of a lamellar cuticle
proper. In U. sandersonii and Athanasia the procuticle
generally remained without visible structure. The velum of the pavement
epithelium of Utricularia is considered to be a slightly modified
procuticle which has become loosened from the epithelial cells and stretched.
Key words: Athanasia - Cassytha - Cuscuta -
Cuticle (development, ultrastructure) - Procuticle - Utricularia