The pollen tube plays a crucial role in fertilization in flowering plants. Here's how it works:

1. Pollen Grain Lands on Stigma: When a pollen grain lands on the sticky stigma of a flower, it germinates.

2. Pollen Tube Formation: The pollen grain grows a long, thin tube called the pollen tube. This tube extends down through the style, which is the stalk connecting the stigma to the ovary.

3. Journey to the Ovule: The pollen tube grows towards the ovary, specifically to an ovule within the ovary.

4. Delivering the Sperm: The pollen tube contains two sperm cells. When the pollen tube reaches the ovule, it bursts open, releasing the sperm cells.

5. Fertilization: One sperm cell fertilizes the egg cell within the ovule, creating the zygote which will develop into the embryo. The other sperm cell fuses with two polar nuclei within the ovule, giving rise to the endosperm, which provides nutrients to the developing embryo.

In essence, the pollen tube acts like a pathway or tunnel, guiding the sperm cells from the pollen grain to the egg cell in the ovule, allowing fertilization to take place.

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