Fern Life Cycle

Fern Life Cycle - Plants that belong to the division Fern are to some extent complex, and better modified to a land environment, rather than mosses, even though still constrained to growth in the moist areas. These plants have certain specialized vascular tissue and just as all vascular plants, have an overriding sporophyte generation.

The fern life cycle is stunning and compound, but with a bit of study, one can understand it.

i. Ferns usually live in damp, cool places covered with shade. These perennial, evergreen plants possess an rhizomatous stem that runs underground, the leaves are large and aerial and the roots are adventitious. The young leaves of a fern generally illustrate circinate ptyxis.

ii. The process of vegetative reproduction in ferns occurs through the fragmentation of the rhizome and its adventitious buds.

iii. During some seasons the ventral portion of a full-grown leaflets bear sporangia in bunches called sori. Sori containing leaflets as well as leaves are known as sporophylls. Sporangia usually develop within these and froms a parenchymatous cushion called the placenta, finishing the undulation of generations.

iv. Within each of the sporangium 8 to 16 mother cells of the spore separate by the method of meiosis and produce sixty four or lesser than that number of haploid spores. The sporangium contains biconvex capsule which is crammed with a throng containing spores and multicellular stalk. The thin, single layer of the capsule has a noticeable strip, known as annulus, whose cells are condensed along the radial and the inner walls that are tangential in nature. The slender walled region of the annulus is known as stomium, alongside which the sporangium bursts to discharge the spores.

v. The spores sprout to structure the generation of gametophyte called prothallus. Gametophyte of the fern is known as the prothallus which is commonly very small, slender, plane, has a shape like heart, green in color and photosynthetic in nature. It also possesses root-like rhizoid that project downwards to fasten the plant.

Situated ventrally are male antheridia. The sperms develop and mature within this, and at the same time the eggs develop within the female archegonia.

Its nature is haploid, and it bears gametes. It replicates sexually by these gametes. For this process, it generates the archegonia and the antheridia, which is known as the homothallic condition.

vi. The nature of the antheridium is extremely sessile and it encloses spirally coiled male gamates known as multiflagellate antherozoids. Rain stimulates swelling of the antheridia, resulting them to rupture and liberate multiflagellated sperm which are then transported by the means of water droplets to the egg. One of theses mingles with the nucleus of the egg, which results in forming one diploid zygote.

vii. The zygote after developing a substantial wall is called the oospore. It segregates at a later stage to form an embryo within the archegonium.

viii. The newly formed young embryo at a later stage grows into a young sporophyte. Typically the fern sporophyte comprises of a horizontal stem, known as rhizome; the roots; and the conspicuous erect leaves, known as fronds. The adult sporophyte contains a rosette with leafy fronds. This plant is recognized as a fern.

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