Fern Reproduction and Life Cycle

Fern Reproduction

• Ferns are a group of seedless, vascular plants with approximately 20,000 species, occupying a wide range of habitats from temperate to tropical.
• They prefer shady, moist environments and have roots, stems, and leaves called fronds.
• Ferns reproduce through spores, undergoing two generations of plants to complete the life cycle, known as alternative generation.

Alternative Generation

• Alternative generation refers to lifecycles that alternate between haploid and diploid individuals, common in algae and terrestrial plants.
• Haploid cells contain one set of chromosomes (n), while diploid cells have two sets of chromosomes (2n).

Fern Sexual Reproduction

• Spores are found on the underside of the blade or pinnae, containing genetic material needed to grow a new plant.
• Spores are coated in sporangia, often brown, yellow, or red in color.
• When spores are released in optimal growing conditions, they form a haploid, multicellular gametophyte through mitosis.
• The gametophyte contains either antheridia (male structure) or archegonia (female structure).

Fertilization and Sporophyte Development

• With the presence of water, antheridia use flagella to swim to archegonia and fertilize, creating a diploid sporophyte.
• The sporophyte contains two sets of chromosomes (2n) and can produce haploid spores through meiosis.
• The sporophyte develops into an adult spore-producing fern.

Fern Asexual Reproduction

• Apogamy occurs when a sporophyte grows from a gametophyte without fertilization, often in dry environments.
• Ferns can also reproduce from bulbets, small vegetative buds that grow from proliferous frond tips.
• Bulbets will either fall off the frond or be pressed into the ground, developing rhizomes that grow into the soil.

Fern Life Cycle

• The life cycle of a fern has two distinct life stages: diploid and haploid.
• The fern undergoes two generations to complete the life cycle, known as alternative generation.
• The haploid stage begins with a spore undergoing mitosis to create a gametophyte.
• The gametophyte develops male and female structures that produce gametes, which fertilize to form a zygote.
• The diploid stage begins with the development of a sporophyte from the zygote, which grows into a mature fern producing new spores.