Aerodynamics of wind pollination in a zoophilous flower, Brassica napus

1. The flower of Brassica napus L. appears to be typically zoophilous (suited to animal pollination) because of its visually attractive petals, robust stigma and nectaries. Pollination by wind is feasible, however, and its likely effectiveness is not immediately foreseeable because of the complexity of interactions between objects and windborne particles. 2. Computational fluid dynamics (CFD) and wind-tunnel experiments were used to investigate the aerodynamic interactions between the flower and a windborne suspension of its pollen. 3. The flower's petals handicapped wind pollination by reducing the target efficiency of the upwind-facing stigma. For downwind-facing flowers, pollen reception was negligible. 4. Several aspects of the plant's architecture (floral structure, pollen cohesiveness, inflorescence structure) are uncompromisingly zoophilous. Estimates of the amount of wind pollination suggest that it is unlikely to be important for the long-distance dispersal of B. napus genes such as those from genetically modified varieties. 5. This study illustrates how CFD may become a powerful tool in future analyses of wind pollination.