Transcript Nonvascular Plants

Nonvascular Plants
Page 35
(Bryophytes)
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Bryophytes
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Seedless
Nonvascular
Plants
Spore Capsules
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Simplest land plants
Evolved from green alagae
Can grow in a wide range of
Environments
When environment dries so does the
plant
Moss
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General Characteristics
• Lack vascular tissue (xylem &
phloem) to carry water and food
• Water and food move in the
plant by diffusion
• No strengthening tissue (xylem)
so they cannot grow tall
• Most are between 2 and 20 cm
high
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General Characteristics
• Have no true leaves or roots
• Have rhizoids – fine outgrowths
of the stem to anchor the plant
• Have simple ‘leaf like structures’
that contain chlorophyll for
photosynthesis
• Can absorb water through the
surface of the plant
• Have no cuticle
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General Characteristics
• Reproduce by means of spores
produced in sporangia of the
sporophyte
• Which grows out of the visible plant
• Are homosporous = spores are all the
same size
• Germinate immediately and grow into
the green plant we can see
(gametophyte)
• That produces male and female
gametes
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General Characteristics
• Depend on water for fertilisation
• Male gametes have to swim in a
film of water to reach the
female gamete (egg)
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General Characteristics
• Two gametes fuse to form a
zygote
• That develops into an embryo
• Which grows into the sporophyte
• Go through Alternation of
generations (sporophyte &
gametophyte stage)
• Gametophyte is dominant stage
• Reproduce by spores
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Do Learning Activity 5 Page 43
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Division - Bryophyta
Sporophytes
Gametophytes
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Mosses
• Division Bryophyta
• Small, nonvascular
plants
• NO true roots,
stems, or leaves
• Grow in moist areas
(brick walls, as thick
mats on the forest
floor, on the sides
of trees)
Moss gametophytes
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Mosses
• Some can survive
short dry spells
• Must grow close
together for their
life cycle
• H2O moves by
diffusion from cell
to cell
• Sperm must swim
to egg through
drops of water
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Moss growing on Moist tree trunk
Diagram page 36
Mosses
• Have a outer waxy
Cuticle to prevent
water loss
• Have root like Rhizoids
to anchor the plant,
but NOT absorb water
• Leaf like gametophyte
supports sporophyte
with spore capsule
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Sphagnum Moss
• Known for its
moisture holding
capacity
• Absorbs 20 times
its weight in water
• Used by florists to
keep plant roots
moist
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EXTRA STUFF
Uses for Moss Plants
• Help decompose dead wood
• Serve as pioneer plants on bare
rock or ground
• Help prevent erosion
• Provide shelter for insects & small
animals
• Used as nesting material by birds
• Peat moss is burned as fuel
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Asexual Reproduction in
Moss
• The spore capsule is
full of spores that
must mature
• Once mature, the
spore cap
(operculum) comes
off releasing spores
• Spores germinate
(grow) when they
land on moist soil
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Sexual Reproduction in Moss
• Moss alternate between a dominant
haploid (1n) Gametophyte and a
diploid (2n) Sporophyte
• Gametophytes produce gametes (eggs
& sperm) containing half the
chromosome number
• Sporophytes have a complete set of
chromosomes & produces spores by
meiosis
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Sexual Reproduction in Moss
• The sporophyte is
smaller & attached to
the gametophyte
• Sporophyte lacks
chlorophyll & gets food
from the gametophyte
• Sporophyte has a long,
slender stalk (setae)
topped with a spore
producing capsule
Spore
Capsule
setae
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Sexual Reproduction in Moss
• Eggs are large &
immobile
• Produced in
structures called
archegonia
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Sexual Reproduction in Moss
• Antheridia forms
many sperm cells
• Sperm cells
capable of
swimming to egg
• Sperm follow a
chemical trail
released by the
egg
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Sexual Reproduction in Moss
• Fertilized egg (zygote)
undergoes mitosis to
develop Sporophyte
• Spore capsule of
sporophyte makes haploid
spores by meiosis
• Spores germinate into
juvenile plants called
protonema
• Protonema becomes the
gametophyte
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Not in the
syllabus
Division - Hepatophyta
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Liverworts
• Nonvascular
• Reproduce by spores
• Alternation of
generations with
sporophyte attached
to gametophyte
• Green, leafy
Gametophyte
dominant
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Liverworts
• Need abundant water
for fertilization
• Grow on moist soil,
rocks, or other moist
surfaces
• Reproduce asexually
by gemmae or by
growing new branches
• Reproduce sexually
by haploid spores
Gemmae Cups
Capsule
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Not in the syllabus
Division Anthocerophyta
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Hornworts
• Small, nonvascular
bryophytes
• Gametophyte leafy
and dominant like
liverworts
• Archegonia &
antheridia form
inside the plant
• Zygotes develop into
long, horn-shaped
Sporophytes
Sporophytes
Gametophytes
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Hornworts
• Horn-shaped
Sporophyte capable
of photosynthesis
• Sporophyte attached
to, but NOT as
Sporophyte
dependent on
Gametophyte
Gametophyte
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TO DO
• In your workbook draw the moss
plant on page 36
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• The End
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