Self-Incompatibility, Protandry, Pollen Production and Pollen Longevity in Banksia menziesii

Abstract

Controlled self- and cross-pollination indicated that a natural population of Banksia menziesii (Proteaceae) was self-incompatible. Flowers were protandrous. Deposition of pollen into the stigmatic cavity was regulated by opening of the stigmatic groove. Stigmatic grooves opened 24-48 h after the flowers opened. Pollen production was high and the pollen:ovule ratio was approximately 10000. Over 90% of pollen grains were viable when flowers first opened. Viability decreased rapidly with time and most pollen was inviable within 24 h. These results indicate that B. menziesii requires pollen vectors to produce seed and suggest that pollinators may have influenced the evolution of the reproductive traits that were examined.