The Apertural Wall in Pollen of Linum grandiflorum

Publisher Website
Google Scholar
Abstract
The apertural wall in tricolpate pollen of Linum grandiflorum was investigated in order to understand its functioning during desiccation and rchydration. Whole and sectioned pollen grains were studied with light or electron microscopy and by cytochemical means. The areas of the apertures were examined in fresh dry pollen, in grains moistened on agar gel or removed from compatible stigmas, and in pollen from mature undehisced anthers The intine was found to consist of an inner β-glucan layer and an outer pectic layer. At the apertures the pectic layer is thickened and overlaid by a β-glucan layer. The pectinaceous intine stains red with basic fuchsin. The presence of a third wall layer, the medine, was not confirmed. The apertural intine thickenings possess considerable imbibitional capacity and at rehydration they appear as swollen lenticular bodies A procedure is described for obtaining intact exine free grains (EFG's) and whole, separated exines of L. grandiflorum. Invariably, the released EFG's consisted of protoplasts encased in the cellulosic intine. In most grains the outer intine remained attached to the separated exine In L. grandiflorum the outer wall of the aperture expands while the protoplast and endintine are still infolded. Apparently, the exintine becomes detached from the endintine during desiccation and re-attaches at rehydration. It is suggested that the transient detachment controls the influx of water into the vegetative cell Except for morph-specific exine processes no differences in structure of the aperture wall or its functioning at rehydration were observed between pin and thrum grains

This publication has 1 reference indexed in Scilit: