Anthesis and pollen dispersal of holcus lanatus L. and Festuca rubra L. in relation to climate factors

Anthesis and pollen dispersal of H. lanatus and F. rubra were related to climate factors during a field investigation on Schiermonnikoog. In both species the anthesis showed a diurnal periodicity and could be connected to air temperature, relative air humidity, and light intensity. In the pollen release of both species no daily periodicity was found. This pollen release appears to be dependent on neither the temperature nor the light intensity. It could be related to only one of the measured climate factors, viz. the relative air humidity. It was discussed that anthesis is an active process based on physiological and ecological properties of the plant, whereas the pollen dispersal is only a mechanical process.