EN
Stigma receptivity of Platanthera chlorantha was examined in a laboratory experiment. Flowers were hand-pollinated at bud stage and at different intervals between the beginning and the 14th day of anthesis. Afterwards, pollen tube growth was examined by fluorescence microscopy. Stigma receptivity was also tested for the presence of peroxidase using the Peroxtesmo Ko test. The efficiency of hand-pollination in flowers of varying ages was confirmed by capsule formation. Pollen tubes started to germinate 6 h after pollination. The stigma was overgrown with pollen tubes 24 h after pollination. The stigma became receptive at the bud stage. Receptivity lasted 15 days on average. Pollen did not germinate on stigmas with a dry surface, in flowers with a dehiscent perianth. Pollination did not affect stigma receptivity. Pollen tubes germinated from pollinaria deposited on the stigma additionally 6 days after the first pollination. Fluorescence microscope observations of pollen tube germination produced results corresponding to those obtained with the Pertexmo Ko test.