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– SWAMPS– MARSHES– NEAR STREAMS, – RAINFORESTS– ALONG THE WEST COAST OF BC & STATES

Unique to Bryophytes

• have no lignin usually • are small, low-lying,

(generally) moisture-loving 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

• SCARCER THAN MOSSES• NEED TO LIVE IN

PLACES THAT ARE CONSTANTLY WET

• LOOK LIKE FLAT LEAVES GROWING ALONG THE GROUND

LIVERWORTS

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 bio-indicators of pollution and environmental degradation