Britannica
Sources used in this answer
Why do bryophytes need water for fertilization?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
bryophyte
Bryophyte moss growing on oak trees.
Bryophytes require water for fertilization because they produce motile, flagellated sperm that must swim to reach the egg located within the female sex organ, known as the archegonium.12
This process is facilitated by the following mechanisms:
- Release of Gametes: When the plant is sufficiently moist, the male sex organ, or antheridium, ruptures to release the sperm into the surrounding water.1
- Chemical Signaling: Mature archegonia release a fluid that creates a chemical gradient. The flagellated sperm swim through the water toward the site of the highest concentration of this fluid, effectively guiding them down the neck canal of the archegonium to the egg.1
- Evolutionary Context: This reliance on water for gamete transport is considered a vestige of the bryophyte-ancestral link to aquatic green algae, as these plants have adapted to land but have not evolved the pollen-based fertilization mechanisms found in many other terrestrial plants.2