With a polyclonal antibody raised against calreticulin (CRT) the locations where the protein occurs in unpollinated and pollinated styles of Petunia hybrida were localized. The epitopes binding the CRT antibody were immunolocalized preferentially in pollen tubes. In transmitting tract cells, both before and after pollination, the level of CRT was low. The protein was mainly localized in the cytosol and around dictyosomes of transmitting-tract cells. In pollen tubes, a high level of CRT was found at their tips rich in endoplasmatic reticulum, cisternae piles of reticular and/or dictyosomal origin, and vesicles. Binding sites of the CRT antibody were also found in the internal callosic cell wall of the pollen tube. These results indicate a role of CRT in cells directly participating in pollen-pistil interaction.