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
Grains of Selim Grains of Selim Grains of Selim are the seeds of a shrubby tree, "Xylopia aethiopica", found in Africa. The seeds have a musky flavor and are used as a spice in a manner similar to black pepper, and as a flavouring agent that that defines , the dominant style of coffee in Senegal. It is also known as Kani pepper, Senegal pepper, Ethiopian pepper, and (historically) Moor pepper and Negro pepper. It also has many names in native languages of Africa, the most common of which is in the Wolof language (this is the name used on most packages of