Morphogenesis of “Floating” Stomata in the Fern anemia mandioccana Raddi, Stomatal Pore Formation

Abstract

The stomatal pore opening is one of the most important processes accompanying guard cell (GC) morphogenesis. In angiosperms this process is carried out by the gradual detachment of the median thickened regions of the partner ventral walls (VWs), which starts from the external and/or the internal periclinal walls (PWs) and proceeds inwards [1], [2], and [6]. A different mode of stomatal pore formation operates in the ferns Polypodium vulgare [7] and Adiantum capillus-veneris [3]. In the latter plant the adjacent plasmalemmata at the mid-region of the post-cytokinetic VW of the GC pair move apart from each other forming the central pore aperture, while the PWs remain intact. At a later stage of differentiation the PW regions covering the central aperture are disrupted to complete the stomatal pore. The detailed mechanism by which this type of stomatal pore opens was examined in the fern Anemia mandioccana Raddi. In this study we used light and electron microscope techniques, as described in [1] and