Pollination in the Antarctic flowering plant Colobanthus quitensis (Kunth) Bartl.

Colobanthus quitensis forms chasmogamic and cleistogamic flowers. Their structure signals the possibility of both cross-pollination and self-pollination. In favorable conditions (natural or laboratory), flowers open creating a possibility for cross-pollination. The occurrence of cleistogamy in the investigated species may be conditioned by abiotic factors: low temperature, high air humidity, and strong wind. In closed flowers, a part of pollen grains reaches the stigma surface, and the rest remains inside the microsporangium. Pollen grains germinate on the stigma surface or inside the microsporangium. Often, two or more pollen tubes grow from a single pollen grain. Closed flowers and the direct contact between the style stigma and anther prove the preference for autogamy. Autogamy ensures the reproductive success of the investigated plant in the exceptionally harsh Antarctic environment