Flower primary purpose of a flower is reproduction. Since the flowers are the reproductive organs of plant, they mediate the joining of the sperm, contained within pollen, to the ovules — contained in the ovary. Pollination is the movement of pollen from the anthers to the stigma. The joining of the sperm to the ovules is called fertilization. Normally pollen is moved from one plant to another, but many plants are able to self pollinate. The fertilized ovules produce seeds that are the next generation. Sexual reproduction produces genetically unique offspring, allowing for adaptation. Flowers have specific designs which encourages the
Pollen tube This is a gene level regulation in which gene loci of the gynoecium allow either self pollen to slowly grow, stop growing or burst while faster growth of outcrossed pollen occurs, increasing genetic diversity. The main component is that this step determines which pollen grains are compatible to grow and parts of the style, and female embryo contribute in determining. Using hybrid species and crossing pollen, the interaction with the style and pollen was found to influence growth of the pollen tube based on compatibility. Pollen tube growth begins from when the pollen attaches to the stigma. It is followed