Glossary:
1. non-vascular plants
2. vascular plants
3. spore
4. sporophyte
5. gametophyte
6. fertilization
7. antheridium
8. archegonium
Nonvascular Plants: eukaryotic, multicellular, autotrophic.
Nonvascular plants - “bryophytes” transition between aquatic algae and land
plants
Non-vascular General Information
Non-vascular plants are the simplest of all land dwelling plants. Their closest
ancestor is the green algae, and like the green algae, they lack an internal means for
transporting water. Non-vascular plants do not produce seeds or flowers. In terms
of physical appearance, non-vascular plants typically only reach a height of one or
two centimeters due to their lack of the woody tissue necessary for support on land.
They are almost always found in damp, shady places. Because these plants lack
vascular tissue, they must absorb the water on their surfaces and then distribute it
through the considerably slower means of capillary action, diffusion, and
cytoplasmic streaming. Non-vascular plants cannot survive for long in habitats
which are not constantly moist. Non-vascular plants have never covered much of
the earth's surface.
Reproduction in Non-Vascular Plants
Non-vascular plants can reproduce both sexually and asexually. Asexual
reproduction is the less common method and basically involves the regeneration of
plant material, leaves or other parts, that fall to the ground and create secondary
plants which have new buds. Most non-vascular plants reproduce sexually and
create gametes.
ALTERNATION OF GENERATIONS: an alternation of multi-cellular haploid
and diploid forms in the life history of an organism
SPOROPHYTE: the diploid individual which produces reproductive cells called
spores
GAMETOPHYTE: the haploid individual which produces gametes
note: the two generations alternate taking turns producing one another .Spores
released from sporophytes germinate to form gametophytes, which in turn produce
gametes.Then the union of two gametes (fertilization) results in a diploid zygote
which gives rise to a new sporophyte.
Phylums of Non-Vascular Plants
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Phylum Chlorophyta (green algae)
Phylum Rhodophyta (red algae)
Phylum Phaeophyta (brown algae, the kelps)
Phylum Bryophyta (primitive land plants, mosses and liverworts)
Mosses
Kingdom Plantae
Seedless Nonvascular Plants
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Includes mosses, liverworts and hornworts
Lack vascular tissue (xylem and phloem) to carry water and food
Have a Sporophyte and Gametophyte stage known as alternation
of generations
Gametophyte is dominant stage
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Reproduce by spores
Division Bryophyta
Mosses:
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Small, nonvascular land plants
No true roots, stems, or leaves
Most common bryophyte
Grow on moist areas (brick walls, and on the trees)
Some survive periodic dry spells, revive when H2O becomes
available
Must grow close together and have H2O to complete life cycle
Sperm swims to egg through drops of water during fertilization
H2O moves cell-to-cell by osmosis
Sphagnum moss is known for its moisture holding capacity,
absorbing up to 20 times its dry weight with water.
LIFE CYCLE OF MOSSES:
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Mosses alternate between a haploid (n) gametophyte stage and a
diploid (2n) sporophyte stage
Gametophyte is the dominant generation
Moss Gametophyte
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Moss Sporophyte
Called alternation of generations
The haploid gametophyte stage contains half the chromosome
number and produces gametes (egg and sperm)
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Gametophyte stage is dominant in the moss's life cycle
Gametophytes are photosynthetic and have root-like rhizoids
The diploid sporophyte has a complete set of chromosomes and
produces spores by meiosis
Sporophyte of a moss is smaller than, and attached to the
Gametophyte
Sporophytes lack chlorophyll and depend on the photosynthetic
gametophyte for food
Sporophyte has a long, slender stalk topped with a capsule
Capsule forms haploid (n) spores
Moss Capsules
Sexual Reproduction in Moss:
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Mosses produce 2 kinds of gametes (egg and sperm)
Gametes of Bryophytes are surrounded by a jacket of sterile
cells that keep the cells from drying out
Female gametes or eggs are larger with more cytoplasm & are
immobile
Flagellated sperm must swim to the egg through water droplets
for fertilization
Moss gametes form in separate reproductive structures on the
Gametophyte Archegonium and Antheridium
Archegonium
Antheridium
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Each Archegonium forms one egg, but each Antheridium forms
many sperm
Fertilization can occur only after rain when the Gametophyte is
covered with water
Sperms swim to the egg by following a chemical trail released by
the egg
A zygote (fertilized egg) forms that undergoes mitosis and
becomes a Sporophyte
Cells inside mature Sporophyte capsule undergoes meiosis and
form haploid spores
Haploid spores germinate into juvenile plants called protonema
Protonema begin the Gametophyte generation
Protonema
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Spores are carried by wind & sprout on moist soil forming a new
Gametophyte
Asexual reproduction in Mosses:
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Asexual reproduction in moss may occur by fragmentation or
gemmae
Pieces of a Gametophyte can break off and form new moss plants
(fragmentation)
Gemmae are tiny, cup shaped structures on the Gametophytes
Raindrops separate gemmae from the parent plant so they can
spread and form new Gametophytes
Uses for Moss:
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Help decomposer dead logs
Serve as pioneer plants on bare rock or ground
Help prevent erosion
Provide shelter for insects and small animals
Used as nesting materials by birds and mammals
Sphagnum or peat moss forms peat bogs (wet ecosystem)
Peat is burned as fuel in some areas
Liverworts:
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Nonvascular
Undergo alternation of generations with Sporophyte attached to
Gametophyte
Gametophytes are green and leafy and the dominant generation
Liverwort
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Need abundant water for fertilization
Reproduce by spores
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Grow on moist rocks or soil
Reproduce asexually by gemmae and by growing new branches
Hornworts:
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Small, nonvascular bryophytes
Gametophyte leafy like liverworts
Archegonia and antheridia form inside the plant
After fertilization, zygotes develop into long, horn-shaped
Sporophytes
Horn-shaped Sporophytes capable of photosynthesis so not
completely dependent on Gametophyte
Hornwort