Transcript Mosses Kingdom Plantae Phylum Bryophyta Class Muscopsida

Mosses
Kingdom Plantae
Phylum Bryophyta
Class Muscopsida
Eukaryotic
Cellulose and Pectin Cell walls
Open mitosis, phragmoplast cytokinesis
Chloroplasts with chlorophyll a, b xanthophylls, carotenoids
Starch storage
Diplohaplontic (sporic) life history
Homosporous
The green plant is
the moss
gametophyte
(haploid).
It uses chlorophyll a
and b,
xanthophylls, and
carotenoids for
photosynthesis.
It produces starch
for storage of
photosynthate.
http://upload.wikimedia.org/wikipedia/commons/thumb/4/47/Leucobryum_glaucum_2.jpg/800pxLeucobryum_glaucum_2.jpg
The gametophyte can live in creek beds and dry forests
While many tell about mosses
needing lots of water, mosses
can live on bare rock with
virtually no soil.
It is true that they need some
rainfall to complete the life
cycle and produce the
sporophytes (tan color)
shown here.
Nevertheless they can
tolerate long periods of
desiccation.
http://img5.travelblog.org/Photos/26951/224529/t/1739177-Moss-on-Ice-1.jpg
Talk about a difficult climate, here are mosses living on a glacier!
The sperm found their
way to the egg and
syngamy took place.
These tan structures are
the sporophytes that grow
from the zygote.
The diploid sporophyte is
dependent upon the
haploid gametophyte for
photosynthetic products.
http://www2.lubw.baden-wuerttemberg.de/public/abt2/dokablage/oac_168/typ_02/0201703_1.jpg
These haploid green
moss gametophytes have
produced gametes some
time ago.
The morphology of gametophyte and sporophyte assist in
moss taxonomy. Meiosis takes place inside the capsule
The product of meiosis in the moss capsule is this haploid spore
The moss spore is
a complete haploid
cell with normal
plant cell structure.
Cell Wall
Cell Membrane
Nucleus
Chloroplast
Mitochondrion
Vacuole
Cytosol
The cell wall is
waterproofed with
sporopollenin to
avoid desiccation
http://www.informaworld.com/ampp/image?path=/713648917/743910100/sgra_a_155555fig003.gif
What process is just finishing in the
extremely large chloroplast?
After distribution on wind to a new environment into good
conditions, the spore wall cracks open for germination into a
haploid gametophyte produced by mitosis only.
http://www.cbe21.com/subject/biology/photo/03050501/1008/Young%20protonema.jpg
The spore cell divides
mitotically to produce a
haploid multicellular
gametophyte.
It is initially filamentous with
bright green chlorplasts and
gives every appearance of a
green alga.
The terms “onotogeny
recapitulates phylogeny”
comes to mind!
This filamentous plant body is
called the “protonema” and the
“chloronema” depending upon
how far away in time from
germination one is looking.
Moss protonemata in prepared slides just don’t look so nice.
The cell wall picks up the blue-green dye, masking the
normal phenotype of these cells. But you can see the true
branching.
When moss chloronemata run into bad conditions, bulbils can
be produced to endure the climate until better conditions return.
In good conditions, the moss chloronema can produce
parenchyma that organizes into a “shoot” with “leaves.” You
should notice the spiral phyllotaxy.
A longitudinal section of a
moss “stem” (axis) shows
cortex cells at the far leftedge.
Cells with red walls and
simple pits are called
hydroids. The red-staining
material is not lignin, so
these cells cannot be called
xylem.
Cells with blue walls and
blue cytoplasm conducting
photosynthate through the
plant are called leptoids.
Are mosses vascular?
Ross: YES THEY ARE!
Polytrichum stem cross section
Epidermis
Cortex
Hydroids
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
http://www.botany.ubc.ca/bryophyte/6170.jpg
Leptoids
Moss gametophyte axes has spirally-arranged phyllids
The moss phyllid has a midrib, and expanded blade, and margins
http://en.wikipedia.org/wiki/File:Plagiomnium_affine_laminazellen.jpeg
Moss leaves have differing leaf anatomy
Mnium
mesophyll
hydroids
photosynthetic sheet
leptoids
Polytrichum cutinized
terminal
cells photosynthetic
filaments
cutinized
lower
epidermis
mesophyll
http://www-biol.paisley.ac.uk/bioref/Bryophyta/Polytrichum_leaf_TS2.jpg
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
http://upload.wikimedia.org/wikipedia/commons/thu
mb/1/19/Polytrichum_commune_assimilationslame
llen.jpeg/250pxPolytrichum_commune_assimilationslamellen.jpeg
Polytrichum: male gametophytes have a splash cup of leaves
containing antheridia that produce sperm
http://www.lamedon.de/moosbilder/images/polytrichum_f02.jpg
The first drop
fills the cup.
Water
causes the
sperm to
shed into
that first
drop.
Subsequent
drops cause
the spermwater to
splash out.
Longitudinal section through splash cup reveals many antheridia
all tissues
here are
haploid!
antheridium sterile jacket
spermatogentic tissue
stalk
sperm
http://www.biology.duke.edu/bryology/LiToL/Images/Liverwort%20Life%20Cycle/Blasia.sperm.jpg
Bryophyte spermatozoid
Sketch by K. Renzaglia
http://upload.wikimedia.org/wikipedia/commons/thumb/3/30/Polytrichum_j
uniperinum.jpg/800px-Polytrichum_juniperinum.jpg
Polytrichum female gametophytes lack the splash cup
The terminal
phyllid tufts
include the
archegonia.
cap cell
open
neck
archegonium
neck
neck
canal
cells
ventral
canal
cell
egg
zygote
venter
stalk
immature
archegonium
young
sporophyte
The moss sporophyte develops at expense of the gametophyte
haploid archegonium
neck and venter
tissue (calyptra)
elongating diploid
sporophyte tissue
photosynthetic
haploid phyllid
tissue
Developing
sporophytes
show at least
some green
color.
haploid calyptra
shrouds the
diploid capsule
(sporangium)
within
diploid seta
haploid
gametophytes
haploid phyllids
shroud the
embedded
diploid foot
“Exploded” view of
Polytrichum sporophyte
and gametophyte
calyptra
cross-section of diploid seta
cutinized
epidermis
capsule
cortex
seta
leptoids
hydroids
foot
gametophyte
Polytrichum capsule (sporangium) longisection
cap
All these diploid
diaphragm
sporophyte cells initially
peristome teeth
surrounded diploid
columella
sporocytes.
haploid spores
sterile jacket
seta attachment
The sporocytes were
diploid cells that
underwent meiosis.
Each sporocyte
produced four haploid
cells that develop
desiccation resistant
walls to become spores
When the
calyptra and
cap desiccate
and abscise
the operculum
is exposed.
The peristome
teeth are
revealed.
The peristome
teeth respond to
humidity to shed
spores only in dry
air for dispersal
The peristome teeth can be used to help identify moss species
Genus Tetraphis
Genus Tortula
Funaria peristome teeth are attached
to a small diaphragm and twist like
Venetian blinds to release spores
http://farm2.static.flickr.com/1341/1152673291_6e64d9e9db.jpg?v=0
Atrichum peristome teeth are
attached to a wide diaphragm and lift
the diaphram in dry air to release
spores.
http://stapper.monheim.de/orthotrichum%20pulchellum.jpg
http://www.stapper.monheim.de/ortpat_BLAM.jpg
Orthrotrichum patens
Splachnum is a dung moss
The peristome teeth reflex like the
petals of a flower and are colorful.
The sterile jacket shrinks
downward revealing the
columella.
The spores are brightly colored
and sticky (insect dispersed).
Splachnaceae Moss
Apophysis Color
Dung Collected
Haplodon wormskjolffi
Brown purple
Human, lemming
Splachum ampullaceum
Light Purple
Reindeer, moose, cattle,
sheep
Splachnum luteum
Yellow
Reindeer, moose
Splachnum rubrum
Dark red
Reindeer, moose
Splachnum ovatum
Dark purple
Cattle
Splachnum vasculosum
Dark purple
Sheep, reindeer
Tayloria longicollis
Brownish green
Human
Tetraplodon ongustatus
Light brown
Carnivores
Tetraplodon mnioides
Purplish black
Sheep, reindeer, yak
Data from Bequaert (1921), Crum (1972), Iwatsuki & Steere
(1975), Koponen & Koponen (1978), Nyholm (1954), Steere
(1973), Watson (1955).
http://i2.tinypic.com/t8xc1e.jpg
Splachnum rubrum/luteum growing on moose dung
http://rbg-web2.rbge.org.uk/bbs/meetings/mtgs03images/TETRAPLODON4.jpg
Tetraplodon mnioides growing on moose dung
http://www.mun.ca/biology/pmarino/t_mirabilis_chile.jpg
Tayloria
mirabilis
growing on
cattle dung
The phyllid color
difference here has
to do with water in
empty cells rather
than air refracting
light.
Sphagnum moss
sporophytes (shown
attached to
gametophytes)
explode to blast their
spores into the air.
unshed
shed
Longitudinal section of a Sphagnum
sporophyte
pressure-containing sterile jacket
spores
pressure chamber has air for driving spores
seta
drying out
Sphagnum moss gametophytes with attached sporophytes
unshed
shed
Physcomitrium capsules open into a cup-like form
The pyriform (pearshaped) capsule
opens.
The peristome
flares out to form a
funnel-like opening
Air moving across
the peristome lifts
dry spores into the
air for dispersal.
This is a Bernouilli
effect.
When is a “moss” not a moss?
These hanging plants are often
called “Spanish moss”.
The plant is not a bryophyte.
It produces small flowers and
small fruits.
The plant is a relative of
pineapple and bromeliads.
http://farm1.static.flickr.com/17/22957467
_5a894e620e.jpg?v=0
Tillandsia usneoides is the
name of this flowering plant.