Pollen tube through wind, water or pollinators. The last step before fertilization is the growth of the pollen tube to transfer non-motile sperm to the protected egg. Pollen tubes are unique to plants and their structure had evolved over plant history. The pollen tube formation is complex and the mechanism is not fully understood, but is of great interest to scientists. Pollen is produced by the stamen, the male reproductive organ of the flower. Each pollen grain contains a vegetative cell, and a generative cell that divides to form two sperm cells. The pollen is delivered by the opening of anthers for
Pollen basket Pollen basket The pollen basket or corbicula (plural corbiculae) is part of the tibia on the hind legs of certain species of bees. They use the structure in harvesting pollen and carrying it to the nest or hive. Other species of bees have scopae instead. Bees in four tribes of the family Apidae, subfamily Apinae: the honey bees, bumblebees, stingless bees, and orchid bees have corbiculae. The corbicula is a polished cavity surrounded by a fringe of hairs, into which the bee collects the pollen; most other bees possess a structure called the scopa, which is similar in function, but