Themes > Science > Botanical Sciences > Plant Reproduction and Development > Ferns Reproduction and Life Cycle












Although not to the extent of mosses, ferns exhibit several characteristics that tie them to their aquatic origins:
  • A primitive vascular system permits the transport of water and nutrients. Consequently, true leaves (megaphylls) capable of photosynthesis are present.
  • Ferns possess flagellated (swimming) sperm.
  • Both the sporophyte and gametophyte generations are free-living.
  • The gametophyte stage is greatly reduced, although not to the extent of the moss gametophyte.
  • Reproduction is by homosporous spores rather than seeds.
  • Ferns rely on rhizomes, rather than true roots, for support.

The following diagram is representative of a typical fern life cycle:



Arbitrarily begin with the production of haploid spores as diploid sporogenous tissue within the sporangia undergoes meiosis. Photosynthetic haploid gametophytes evolve from the germinating spore. The gametophyte is generally amorphous to heart-shaped with root-like rhizoids projecting downward to anchor the plant. Also located ventrally are male antheridia within which sperm develop and mature, and female archegonia within which eggs develop and mature. Rain induces swelling in the antheridia, causing them to burst and release multiflagellated sperm that are transported via water droplets to the egg. Fertilization results in a diploid zygote that matures into an adult sporophyte consisting of a rosette of leafy fronds. This is the plant one usually recognizes as a fern. Sori develop on the ventral portion of pinnae (leaflets), and within these sporangia form, completing the alternation of generations.


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