Within the gametophyte, sperm is produced within a structure called an antheridium. The egg is produced within a similar structure called an archegonium. When water is present,
sperm use their flagella to swim to an egg
and fertilize it. The fertilized egg remains attached to the prothallus.
How do Fern sperm get from the Antheridia to the egg?
Fertilization
is attained by the ejection of sperm from antheridia. The sperm swim through free water toward simple organic acids released at the opening of the archegonium, the neck of which spreads apart at the apex, permitting the neck cells to be extruded and the sperm to swim in and penetrate the egg.
How do the sperm of mosses and ferns move to reach the egg cell?
Because the plant is already haploid, these gametes can be created by mitosis, simple cell division. The
sperm swims to the archegonia through a thin film of water, drawn by a chemical attractant produced by the female plant
, then swims down the neck of the archegonia to the egg.
How do Fern sperm sense the location of the egg?
How do sperm know where the archegonia (and eggs) are?
Sperm are attracted to chemical substances (positive chemotaxis) that are contained in a small drop of liquid that is discharged from the necks of receptive archegonia
. One sperm eventually succeeds in fertilizing each egg.
How do sperm get to the eggs in moss plants?
They swim using two threadlike tails. Some successfully end up on female gametophyte moss plants and are chemically attracted to the
archegonium
. Each archegonium holds one egg, in a swollen section called the venter. The sperm enter the archegonium through the narrow channel in its neck.
Do ferns have male and female parts?
Unlike most flowering plants,
individual ferns are either male or female — not both
. Their sex doesn’t become fixed until after germination, in their early growth stages. … These plants absorb it and finish the job, turning it into full-blown gibberellin, which leads them to develop into males.
Where do ferns grow best?
Woodland ferns do best in
high or dappled shade
. The open shade of mature trees or the north side of the house or a wall, open to the sky, provide nearly ideal light conditions. Most woodland ferns will adapt to relatively low light levels, but no ferns thrive in deep shade.
What is the shape of fern sperm?
Antheridium. The antheridium is the male sex organ. These are
small spherical
structures that produce flagellate sperm.
What is the final stage in the fern life cycle?
The life cycle of the fern has two different stages;
sporophyte, which releases spores, and gametophyte, which releases gametes
. Gametophyte plants are haploid, sporophyte plants diploid. This type of life cycle is called alternation of generations.
What is the fern life cycle?
The life cycle of the fern has two different stages;
sporophyte, which releases spores, and gametophyte, which releases gametes
. Gametophyte plants are haploid, sporophyte plants diploid. This type of life cycle is called alternation of generations.
Do Antheridia produce sperm?
The male sex organ, the antheridium, is a saclike structure made up of a jacket of sterile cells one cell thick; it encloses many cells, each of which, when mature,
produces one sperm
. The antheridium is usually attached to the gametophyte by a slender stalk.
What is always necessary for sperm to reach archegonia?
Getting sperm to
egg
Once an antheridium has matured
and contains viable sperm, the sperm need to get to the eggs in archegonia. The first step for the sperm to get out of the antheridia and the second is to then travel to the archegonia and fertilize the eggs within. Water is essential for both steps.
What is the medium necessary for moss sperm to swim to egg?
Moss sperm are produced in great numbers, but each tiny cell has a vanishingly small chance of ever finding an egg. Unlike the peepers who call so strenuously to their mates, moss sperm have no signal to guide them to their destination and so swim
at random in the water film
.
What’s the difference between male and female ferns?
Unlike most flowering plants,
individual ferns are either male or female — not both
. Their sex doesn’t become fixed until after germination, in their early growth stages. … If the hormone is present in large enough quantities as the plant develops, the fern usually becomes a male, and if it isn’t, it becomes a female.
Do ferns reproduce asexually?
Most ferns reproduce through the alternation of generations
, alternating successive generations of sexual and asexual forms. … The second form of asexual reproduction occurs by spores. These form on the undersides of the leaves in clusters of spore cases called sporangia, or sori (singular, sorus).
Do all ferns multiply?
Natural vegetative reproduction occurs in many fern species.
It is the only way nonfertile hybrids can multiply
. These ferns can make new plants along their underground rhizomes. Most ferns that are cultivated in homes and gardens are propagated in this way to help renew old plants and create more ferns.
