Bumblebee removal occurs when bumblebees come in contact with the anthers of a flower while collecting nectar. When it enters a flower, the bumblebee's body hairs receive a dusting of pollen from the anthers. In queens and workers this is then groomed into the corbiculae (pollen baskets) on the hind legs where it can be seen as bulging masses that may contain as many as a million pollen grains. Male bumblebees do not have corbiculae and do not purposively collect pollen. Bumblebees are also capable of buzz pollination, in which they dislodge pollen from the anthers by creating a resonant vibration
Pollen tube by recognition and hydration of the pollen that allows for germination of the tube and ultimate growth. In the pollen grain, the generative cell gives rise to the sperm, whereas the vegetative cells have a tube cell that grows the pollen tube. There is competition in this step as many pollen grains may compete to reach the egg. The stigma plays a role in guiding the sperm to a receptive ovule, in the case of many ovules. Only compatible pollen grains are allowed to grow as determined by signaling with the stigma. Some plants have mechanisms in place to prevent