Fern Reproductive Cycle

Fern Reproductive Cycle

The Sporophyte is the dominant phase of the Life Cycle for Ferns. Their Gametophytes are Microscopic.

Ferns are also Homosporous.

Upper surface of a typical Fern Leaf

Lower surface of the Leaf on the left. The Yellow-brown dots are Sori. Each Sorus contains numerous Sporangia.

Most Ferns bear Sporangia on the lower surfaces of their Leaves. Such Leaves are called Sporophylls!

The Sporangia are minute and are often grouped into areas which are called a Sorus.

The Sori appear like yellow-brown dots on the right-hand Leaf Above & Below.

Head of a Solitary Sporangium containing Meiospores

SorusCloseUp240.jpg (36409 bytes)
Magnified view of a Sorus From above. Each helmet-like Entity is a Sporangium.

Meiosis occurs inside the Sporangium and produces
Haploid Meiospores.

Highly magnified view of a Fern Spore. It is Green and thus Autotrophic. It must find light and moisture in order to Germinate. These spores are like Moss spores in that they can't survive for long on their own.

Young Fern Gametophyte: Ferns tend to produce Photosynthetic Gametophytes. These are barely visible with the naked eye. They are often heart-shaped and have an Apical Cell in the Notch. They do not have Organs or Vascular Tissues.

Mature Fern Gametophyte: The Dark objects along the central axis of the Gametophyte are Gametangia. Antheridia are produced first. Archegonia are produced later. These Gametophytes are Bisexual.

Ferns are Homosporous & produce one type of Spore.

The Spores germinate and produce Photosynthetic Gametophytes.

These produce Rhizoids which Absorb Water and provide Anchorage.

An Apical Cell develops and resides in the Apical Notch.

Gametangia

Antheridia are produced first and are found amid the Rhizoids.

Fern Gametophyte with Globular Antheridia
Here is the most recent competition for the 3 Tenors, the 3 Antheridia!	Close-up of an Antheridium containing nearly mature, coiled Sperm
	Globular Antheridia occur on the lower side of the gametophyte.

Microscopic view of Antheridia
Intact Antheridium	Sperm Release!

Light Microscope Image of Fern Sperm	SEM Image of a Fern Sperm: The Sperm have many Flagella

Archegonia are produced later and are found near the
Apical Notch.

Fern Gametophyte near the Apical Notch. The dark objects are Archegonia.	Fern Archegonia with Open Neck, receiving Sperm.
Archegonia with their Necks protruding from the Gametophyte.
Microscopic Section through 2 Archegonia	Whole Mount of an Archegonium

Once Fertilization occurs the Embryo develops within the Archegonium in a Prone or lateral orientation. They are neither Endoscopic nor Exoscopic. This is unique in the plant kingdom!

The Embryo develops into a Sporophyte that remains attached to the Gametophyte for some time.	The Sporophyte has a Root and Shoot Apical Meristem. The latter produces a Leaf early in development. The Sporophyte grows rapidly and becomes independent from the Gametophyte.
The Shoot Apical Meristem Produces Simple Leaves. A Root develops opposite the Shoot.
The Sporophyte continues to grow while the Gametophyte Dies.	Fern Life Cycle
Fern Life Cycle