Bryophytes
Lecturer: Asst. Prof. Dr. İsmail EKER
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General
characteristics
of
bryophytes
Bryo- gr. moss. & ~16,000 species.
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Non-vascular plants
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Advancements over algae: cuticle, multicellular
gametangia, stomata
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Habitat: they require moist environment for active
growth and sexual reproduction
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The diverse bryophytes are not a monophyletic group.
Several lines of evidence indicate that these three
divisions diverged independently early in plant
evolution, before the origin of vascular plants.
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Mosses are the bryophytes most closely related to
vascular plants.
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The gametophyte is the dominant generation in the
life cycles of bryophytes
Note, the name Bryophyta refers only to one division,
but the informal term bryophyte refers to all
nonvascular plants.
Bryophytes are represented
by three phyla:
Hepatophyta – liverworts;
Anthocerophyta – hornworts;
Bryophyta - mosses
Division Bryophyta (Mosses)
sporophyte
• the largest and most diverse divison of
bryophytes, with more than 9,000 species.
• has green “leafy stems” and root-like
structures called rhizoids, for anchoring (not
true roots!), and leaf like structures
(phyllids)
• some mosses such as members of the
Polytrichaceae family contain
- Hydroids-transporting water and minerals
- Leptoids-transporting sugars and other
nutrients
gametophyte
• absence of vascular tissue prevents
bryophytes from having true roots, stems or
leaves.
(phyllid)
Bryophyte reproduction
• Sexual and asexual
• Asexual reproduction by fragmentation and gemmae.
• Gametophyte plant (n) produces multicellular sex organs: Archegonia –
produces egg (female) and Antheridia – produces motile sperms (male)
• Motile biflagellated sperm must swim to archegonia.
• Sporophyte (2n) occurs after egg is fertilized by sperm. Sporophyte
matrotrophic and short lived (6-16 weeks).
• Sporophyte grows in the archegonium of the gametophyte plant – it’s
dependent on it
• Mature sporophyte consists of: Foot (point of attachment), Seta (stalk),
Capsule (spore case)
• Sporocytes within the Sporophyte undergo meiosis to produce a single kind
of haploid spore
• If spore lands on suitable place, it will germinate
into a protonema, the initial stage of the gametophyte plant.
Bryophyte sexual reproduction
sporophyte
Gametophyte with
orange antheridia
Gametophyte
and attached
sporophyte
gametophyte
Gametophyte with excised
leaves making visible the
sporophyte with embedded
foot.
Gametangia and gametes can be embedded in the gametophyte tissue as shown here, or
attached at the surface of the gametophyte.
Gametangia –organs that produce gametes.
Antheridium (Sperm-bearing
Organ) with an outer row of
sterile (nonsperm-forming)
cells enclosing inner fertile
cells, each of which becomes
a sperm gamete.
• The male plant produces clusters of elongate antheridia
which contain thousands of flagellated sperm.
Archegonium (Egg-bearing Organ)
with a long neck extends beyond the
venter, capped at the tip with cover
cells.
• The female produces vase-shaped archegonia, each
containing a single egg.
Moss spore capsule (Tortula muralis var. muralis) SEM
Coloured scanning electron
micrograph (SEM) of part of
the opening mouth of a
capsule (spore case) of
moss. Mosses reproduce by
means of spores at certain
times during their life cycle.
The spores are dispersed
from the mouth of the
capsule, dispersal aided by
the wind. Magnification
x1380
Sphagnum sp.
Polytricum sp.
Tortula sp.
Marchantiophyta (Hepaticophyta)- liverworts
• Hepato- gr. liver. & 6,000 species.
• Gametophytes thalloid or leafy, often bilaterally symmetrical and lobed
• Simplest of all living plants.
• Rhizoids single celled.
• Reproduction:
- Asexual- with pieces of tissue call gemma, which are bounced by rain out of
gemma cups.
- Sexual- haploid gametophyte, diploid sporophyte
• Sporophytes without stomata, but have pores.
• Specialized conducting tissue absent.
• Sporangium with dehiscent capsule, elaters present in some to disperse spores.
• Most cells contain numerous chloroplasts.
• Habitat- moist, some aquatic, temperate and tropical. Examples- Marchantia and
Riccia.
gemma cups
• asexually with pieces of tissue
call gemma, which are bounced
by rain out of gemma cups.
Reproduction of Marchantiophyta
Antheridial stalk
Antheridial head
Antheridiophore
Male reproductive "umbrella"
Archegoniophore
Female reproductive "umbrella"
Archegonial stalk
Archegonial head
the sporophyte generation consists of a small stalk with a
podlike capsule, the sporangium, on top.
Marchantia sp.
Anthocerotophyta- hornworts
• Antho- gr. flower, keras- gr. horn. & 100 species
• Hornworts are similar to liverworts except each
cell only has one large chloroplast rather than
many smaller ones, and the sporophytes are
elongated capsules.
• Rhizoids single celled.
• Gametophytes thalloid.
• Specialized conducting tissue absent.
• Sporophytes with stomata.
• Sporangia dehisce to disperse spores, elater-like
structures present.
• Habitat- moist temperate and tropical.
• Example- Anthoceros
Magnification approximately 200x
The long, slender
sporophyte generations
grow upward from the
thallus and are typically
0.5 to 12 centimeters in
height.
Hornworts often have long,
pointed sporophytes
(resembling horns) that
rise from the thalloid
gametophytes.
Reproduction of Anthocerophyta
Anthoceros sp.
Bryophyte significance
• Bryophytes are small and inconspicuous, but important part of the biosphere
• Food for mammals, birds
• Important to prevent soil erosion along streams
• Commercially – peat moss (Sphagnum) is used as fuel, soil conditioner, by florists,
also it is used in potting soil for better water-holding capabilities. Its organic
materials does not decay readily because of resistant phenolic compounds and
acidic secretions that inhibit bacterial activity.
• Sphagnum has been used in the past as diapers and a natural antiseptic material for
wounds.
• Today, it is harvested for use as a soil conditioner and for packing plants roots
because of the water storage capacity of its large, dead cells.
• Peatlands, extensive high-latitude boreal wetland occupied by Sphagnum, play an
important role as carbon reservoirs, stabilizing atmospheric carbon dioxide levels.
• Ethnobotanically- Liverworts look like liver. They were used as medicine to help
the liver in the middle ages in Europe because of this.
Tollund Man
• May 8th, 1950 the police in Silkeborg received an
alarming message. On the previous Saturday a body
had been discovered in a bog close to Bjældskovdal,
an area located approximately 10 kilometres west of
Silkeborg/Denmark. Accordingly, the body was
discovered on May 6th, 1950.
•The Tollund Man was alive during the first part of
the iron age, 300-400 years B.C.
• The antibiotic effect of Sphagnum moss prevent
decay of it with humic acid (alsom known as "bog
acid”. The acid in the peat, along with the lack of
oxygen underneath the surface, had preserved the
soft tissues of his body.
• at the Silkeborg Museum of Denmark
http://www.tollundman.dk/