In the plant kingdom, life cycles refer to the alternation of generations between a haploid (gametophyte) stage and a diploid (sporophyte) stage. This process is seen across various plant groups, and the dominance of either stage varies.
Here are four examples of plant life cycles:
1. **Algae** (e.g., *Spirogyra*):
– Haploid-dominant, with gametophyte as the dominant phase.
– Sexual reproduction involves the fusion of gametes to form a zygote.
2. **Bryophytes** (e.g., *Moss*):
– Gametophyte-dominant, where the main plant is haploid, and sporophytes grow from the gametophyte.
3. **Pteridophytes** (e.g., *Fern*):
– Sporophyte-dominant life cycle, with independent, small gametophytes.
4. **Angiosperms** (e.g., *Flowering Plants*):
– Sporophyte-dominant life cycle with a highly reduced gametophyte (pollen and embryo sac).