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How do flowering plants achieve fertilization without swimming sperm?
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Reproduction
Fungi produce billions of spores that give rise to new generations of fungi.
Flowering plants (angiosperms) do not require swimming sperm for fertilization because they have evolved a specialized mechanism to deliver male gametes directly to the egg through the growth of a pollen tube.12
The process occurs as follows:
- Pollination: Pollen grains are transferred from the anther to a receptive stigma via external agents such as wind, water, or animals.12
- Tube Growth: Upon landing on the stigma, the pollen grain germinates and produces a pollen tube. This tube elongates and grows through the style’s tissues, nourished by specialized secretions, until it reaches the ovule.2
- Delivery: The pollen tube enters the ovule through an opening called the micropyle. It penetrates a synergid cell, where it discharges the two male gametes.12
- Double Fertilization: Flowering plants undergo a unique process called double fertilization. One male gamete fuses with the egg to form a diploid zygote, while the second male gamete fuses with the central cell's fusion nucleus to create a triploid endosperm nucleus, which provides nourishment for the developing seed.13