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Introduction to Plant Reproduction - Coggle Diagram
Introduction to Plant Reproduction
Vegetative reproduction
is a form of asexual reproduction
in which new plants grow from parts of an existing plant
Alternation of Generations
diploid (2n) sporophyte
stage
haploid (n) gametophyte
stage
Life cycles
Conifer Reproduction
Conifers are heterosporous
heterosporous plants make two types of spores that
develop into male and female gametophytes.
Pine trees are examples of the sporophyte generation of
conifer plants.
Each scale of a female cone has two ovules at its base.
Within each ovule, meiosis produces four megaspores
Cells in these sporangia undergo meiosis and
form microspores.
A pollen grain is made of four cells and
develops from microspores.
Fern reproduction
Spore-producing structures called sori are found on a fern’s lacy fronds.
Each sorus consists of sporangia
The zygote is the first cell of the sporophyte stage.
The resulting spores begin a
new gametophyte generation
Most prothalli develop both antheridia and archegonia
it can grows a form of tiny heart shaped gametophyte called prothallus
later the prothallus dissolves and the sporophyte develops fronds and a rhizome
A rhizome is a thick underground stem that
produces roots and supports the fronds.
Moss reproduction
the gametophyte stage is the dominant
generation
Gametophytes can produce archegonia
and antheridia
The archegonium of some moss species produces one egg.
The archegonium of other moss species produces many eggs.
Antheridia produce sperm that have flagella. These sperm
need water to move to the archegonium.
sperm exhibits chemotaxis because they respond to
chemicals produced by archegonia
The fertilized egg forms
the first cell of the sporophyte stage, called the zygote
A protonema can develop into the gametophyte plant,
and the cycle repeats
Pollination
The opening of a female cone’s
ovule is called the micropyle
Pollination occurs when a pollen grain from one species of seed plant lands on the female reproductive structure of a plant of the same species.
Seed development
When one sperm fertilizes an egg, a zygote is
formed
The outside layer of the ovule forms a seed coat. The female
cone opens and releases mature seeds.
Seed development can take as long as three years