AP BIOLOGY

Detailed explanation-1: -During the process of fertilization, pollen lands on the stigma, a tube grows down the style and enters the ovary. Male reproductive cells travel down the tube and join with the ovule, fertilizing it. The fertilized ovule becomes the seed, and the ovary becomes the fruit.

Detailed explanation-2: -Pollen-tube pathway During the pollination process of higher plants, after the pollen germinates on the stigmatic surface, a pollen tube is formed from the pollen and extends down the style into the ovule; nuclei from the pollen travels through the pollen tube to fertilize the ovule.

Detailed explanation-3: -The pollen tube structure rapidly descends down the length of the style via tip-directed growth, reaching rates of 1 cm/h, whilst carrying two non-motile sperm cells. Upon reaching the ovule the pollen tube ruptures, thereby delivering the sperm cells to the female gametophyte.

Detailed explanation-4: -…and gives rise to a pollen tube, which grows down through the pistil toward one of the ovules in its base.