Transcript Bryophytes P.P.

Bryophytes
Bryophytes
• Bryophytes are nonvascular plant; examples
are mosses and their relatives.
WHERE THEY ARE FOUND
• THRIVE IN WET ENVIRONMENTS OR IN AREAS
WHERE THERE IS LOTS OF RAINFALL AT LEAST PART
OF THE YEAR
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SWAMPS
MARSHES
NEAR STREAMS,
RAINFORESTS
ALONG THE WEST COAST OF BC & STATES
Unique to Bryophytes
• have no lignin usually
• are small, low-lying,
(generally) moistureloving plants
• have no roots, only
filamentous rhizoids
THE ONLY LAND PLANTS WITH A DOMINANT GAMETOPHYTE! The
sporophyte is parasitic on the gametophyte. This stems from the embryo
being retained in the female sex organ of the gametophyte.
Groups of bryophytes
• Bryophytes included mosses, liverworts, and
hornworts.
Mosses
Liverworts
Hornworts
LIVERWORTS
• SCARCER THAN MOSSES
• NEED TO LIVE IN PLACES
THAT ARE CONSTANTLY
WET
• LOOK LIKE FLAT LEAVES
GROWING ALONG THE
GROUND
HORNWORT
• LOOK LIKE
GAMETOPHYTE OF
LIVERWORT
• SPOROPHYTE LOOKS
LIKE A HORN
Mosses
• The most common bryophytes are mosses, which
are members of the phylum Bryophyta.
• Mosses grow most abundantly in areas with
water-in swamps and bogs, near streams, and in
rain forests.
BRYOPHYTES LACK SEVERAL CRITICAL
ADAPTATIONS TO DRY PLACES
• LACK WATER CONDUCTING TUBES
– IN BRYOPHYTES, WATER PASSES FROM CELL TO
CELL BY OSMOSIS & BY MEANS OF SURFACE
TENSION AROUND THE STEMS
– WHAT DOES THIS MEAN?
WHAT ELSE?
• BRYOPHYTES LACK PROTECTIVE SURFACE
COVERING TO KEEP WATER FROM
EVAPORTAING FROM THEIR CELLS
• WHAT DOES THIS MEAN?
THERE IS MORE
• THEY LACK TRUE ROOTS
– ROOTS CONTAIN WATER CONDUCTING TUBES
THAT ENABLE A PLANT TO ABSORB AND
TRANSPORT WATER EFFICIENTLY
• THEY HAVE RHIZOIDS INSTEAD
– WHAT IS THEIR FUNCTION?
Rhizoids
• Rhizoid are in fungi, a root like hypha that
penetrates the surface of an object; in mosses,
a long, thin cell that anchors the moss to the
ground and absorbs water and minerals from
the surrounding soil.
Protonema
• Protonema is the mass of tangled green
filaments in mosses that forms during
germination.
Antheridia
• Antheridum is the male reproductive structure
in some algae and plants.
Archegonia
• Archegonium is the female reproductive
structure in some plants, including mosses
and liverworts.
• During at least one stage of their life
cycle, bryophytes produce sperm
that must swim through water to
reach eggs of other individuals.
• Therefore, they must live in places
where there is rainfall or dew for at
least part of the year
Role of Bryophytes
• Many are pioneer plants, growing on bare rock and
contributing to soil development.
• In bogs and mountain forests they form a thick carpet,
reducing erosion.
• In forest ecosystems they act like a sponge retaining
and slowly releasing water
• They provide habitat for other plants and small animals
as well as microorganisms like N2-fixing blue-green
bacteria
• Lacking a cuticle and transport tissue they readily
absorb whatever is around them and can serve as bioindicators of pollution and environmental degradation