title: Stylar peroxidase and incompatibility reactions in Petunia hybrida.
abstract: Self-, cross- and non-pollinated styles of Petunia hybrida were treated with 3-3'-diaminobenzidine for the ultrastructural localization of peroxidase activity. Wall peroxidases were absent in cross-pollinated styles, but they were detectable as an osmiophilic deposit on the cell walls of the outer portion of the transmitting tissue in self- and non-pollinated styles. The cell layer showing peroxidase activity was thicker in the self-pollinated styles than in the non-pollinated ones. In accordance with current hypotheses on the mechanism involved in pollen incompatibility process, it is suggested: that wall peroxidases present in the cells of the outer portion of the transmitting tissue are involved in the gametophytic self-incompatibility of Petunia; that self-pollination causes an increase in the number of cells involved in the rejection process; that non-pollinated styles, which are characterized by the presence of cell wall peroxidases in the outer portion of the transmitting tissue, are 'prepared' to a certain extent for the rejection of incompatible pollen tubes. The removal of peroxidase activity thus seems to be an important step in the compatible pollination process.
mesh_terms: D002473:Cell Wall / Q000201:enzymology / Q000648:ultrastructure; D005306:Fertilization; D008854:Microscopy, Electron; D010544:Peroxidases / Q000378:metabolism*; D010944:Plants / Q000201:enzymology* / Q000648:ultrastructure
chemical_list: D010544:Peroxidases