The fine structure of Azotobacter vinelandii has been studied by means of electron microscopy of ultrathin sections made of the encysting and germinating cells. The organisms were fixed with KMnO(4) and embedded in epoxy resin. On an encystment medium the rod-shaped bacteria begin to assume an almost spherical form and then bark-like exine appears in 1(1/2) to 2 days. The exine thickens and an ...

To elucidate the IgE binding site of mugwort (Artemisia vulgaris r.) pollen, pollen grains were frozen and fixed using a cryocut. They were incubated with antibodies according to the following sequence: Sera pool of individuals who showed mugwort-RAST class 3 or 4, biotin-labeled goat anti-human IgE antibody, streptavidin-peroxidase and diaminobenzidine. Then, they were observed under electron ...

The pollen morphology and exine structure of 17 species of Lippia L. were investigated in this work using light and scanning electron microscopy. Among the species studied, 14 showed tricolporate pollen grains, two had tri- and tetracolporate pollen grains and a single species exhibited, only tetracolporate pollen. The amb ranged from triangular to square, and the shape varied from oblate-spher...

Recent molecular phylogenetic studies of Camphorosmoideae (Chenopodiaceae) demonstrated that Camphorosma is monophyletic. Palynomorphological peculiarities are used in taxonomy as additional diagnostic features and pollen analysis. Pollen morphology was studied using light scanning electron microscopy, based on 13 specimens belonging to four species (C. annua, C. lessingii, monspeliaca songoric...

Synthesis of lipidic components in anthers, including of the pollen exine, is essential for plant male reproductive development. Plant lipid transfer proteins (LTPs) are small, abundant lipid-binding proteins that have the ability to exchange lipids between membranes in vitro. However, their biological role in male reproductive development remains less understood. Here, we report the crucial ro...

Sporopollenin is the main constituent of the exine layer of spore and pollen walls. The anther-specific chalcone synthase-like (ASCL) enzyme of Physcomitrella patens, PpASCL, has previously been implicated in the biosynthesis of sporopollenin, the main constituent of exine and perine, the two outermost layers of the moss spore cell wall. We made targeted knockouts of the corresponding gene, PpA...

Pollen morphology characterization is important in taxonomy, conservation and plant breeding, and pollen viability studies can support breeding programs. This study investigated pollen morphology and male fertility in 18 species of Bromeliaceae with ornamental potential. For morphological characterization, pollen grains were acetolyzed and characterization of exine was done using scanning and t...