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How do gametophytes and sporophytes differ in chromosome number?
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Plant
Grandidier's baobas (Adansonia grandidieri) in Madagascar.
In the alternation of generations characteristic of plants, gametophytes and sporophytes differ in their chromosome number as follows:
- Gametophyte: This is the haploid (1n) phase of the life cycle, meaning its cells contain a single set of chromosomes. The gametophyte generation produces gametes through mitosis.123
- Sporophyte: This is the diploid (2n) phase of the life cycle, meaning its cells contain two sets of chromosomes. The sporophyte generation produces spores through meiosis.143
These two generations are separated by the critical processes of syngamy (fertilization), which restores the diploid number when gametes fuse to form a zygote, and meiosis, which reduces the chromosome number by half to produce haploid spores.3