Transcript 04 Bryophytes

Bryophytes
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Bryophytes
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Ubiquitous
Moist temperate and
tropical locations
 Dominate Arctic Tundra
 Antarctica
 Above the treeline
 Dry deserts
 Some aquatic
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Important colonizers
with lichens
Sensitive to air pollution
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Hypnum
MOSS
Nowellia
LEAFY LIVERWORT
Lichen
Photo by Alan Heilman
Hypnum sp. - Moss on fallen log. GSMNP
Bartramia pomiformi
(apple moss) + Peltigera, a
lichen.
Photo by Alan Heilman
Mosses
Liverworts
Hornworts
Features shared with Charophytes
Other algae
Multicellular specialization (tissues)
Cell walls made of cellulose
Pigments:
a. Chlorophyll a
b. Chlorophyll b
Primary storage substance: starch
Oogamous -- Male gamete is motile &
asymmetrical
Breakdown of nuclear membrane
Zygotes retained
Liverworts
Hornworts
Mosses
Xylem and phloem
Outer layer on spores
Stomata
Ability to distinguish D-methionine
from L-methionine
Zygote retained by gametophyte
Flavenoids
Bryophytes
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Transitional between Charophytes and Vascular
Plants
Synapomorphies for land plants
Antheridia and archegonia with protective layer
 Retention of zygote & multicellular embryo
 Presence of multicellular diploid sporophyte
 Multicellular sporangia
 Meiospores with sporopollenin
 Apical meristem
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Bryophytes
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“Autapomorphies”
Lack of xylem and phloem
 No lignin
 Gametophyte generation dominant; free-living
 Sporophyte nutritionally dependant
 Sporophyte unbranched with single sporangium
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Ubc.edu
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Bryophyte Structure
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Thalloid -- Hornworts & (some) liverworts
Differentiated -- Mosses & (some) liverworts
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Not true leaves/stems
o
o
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Gametophyte generation
No xylem & phloem
Rhizoids
Mosses – multicellular
 Liverworts & hornworts – unicellular
 Only anchor plant
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Plasmodesmata
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Bryophyte Structure
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Hornworts – single plastid
Sperm only flagged cell – water required
Gemmae cups
Gametophytes often
sexed
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Sex chromosomes 1st
in bryophytes!
Photo by Alan Heilman
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Reproductive Structures
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Antheridium
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Each cell  single
sperm
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Reproductive Structures
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Archegonia
Single egg
 Zygote persistent
 Matrotrophy
 Enlarged venter 
calyptra
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Nearly Mature Sporophyte
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Embryophytes
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Matrotrophy + placenta  multicellular
sporophyte (produced by ……
More divisions between fertilization and meiosis
Larger sporophyte
 More spores
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Sporophytes of hornworts & mosses 
stomata
Sporopollenin – survival value
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Spore generates  protonema
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THE PHYLA OF BRYOPHYTES
The three phyla are:
• Bryophyta – Mosses
• ca. 10,000+ sp.
• Hepatophyta – Liverworts
• ca 6000 sp.
• Leafy liverworts
• Thallose liverworts
• Anthophyta – Hornworts
• ca 100 sp.
Liverworts: Phylum Hepatophyta
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Ca. 6000 species
Mostly terrestrial
Some have protonema-like structure
Apical meristem
3 major groups
Complex thalloid liverworts
 Simple thalloid liverworts
 Leafy liverworts
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Complex Thalloid Liverworts
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Marchantia, Riccia, Ricciocarpus
Terrestrial
Thallus 10-30 cells thick
Upper layer -- air pores
 Middle layer -- chloroplast rich
 Lower layer – carbohydrate
storage & rhizoids
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Riccia sporophytes
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Little more than a sporangium
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Marchantia sporophytes
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Gametangia -- stalked specialized structures
Sporophyte – foot, seta, and capsule
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archegoniophore (part of
gametophyte, not a
sporophyte)
Conocephalum conicum thallus + archegoniophore,
with dev. sporophyte
Photo by Alan Heilman
Marchantia
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Mature capsule contains elaters (green strands)
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Aid in spore dispersal
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Asexual Reproduction
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Fragmentation
Gemmae – splash cups
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Marchantia Life Cycle
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Photo by Alan Heilman
Marchantia polymorpha - antheridiophores male
Marchantia polymorpha archegoniophores female
Photo by Alan Heilman
Photo by Alan Heilman
Ricciocarpus natans - floating aquatic liverwort
Photo by Alan Heilman
Riccia fluitans - floating aquatic liverwort
Photo by Alan Heilman
Conocephalum conicum - detail of upper
surface of thallus with pore
Leafy Liverworts
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Very diverse
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> 4000 of the 6000 species
More tropical
Diagnostic …
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Moss leaves
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Spiral
Midrib
Entire
Liverwort leaves
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Distichous
Highly dissected
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Photo By Paul Davison
Frullania
Photo By Paul Davison
Cephalozia
Moss
Leafy Liverwort
Margin teeth
Mid Vein
Moss and Liverwort Leaves
Sporophyte of leafy liverwort
Capsule
Seta
Photo by Alan Heilman
Hornworts: Phylum Anthocerophyta
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ca 100 species
Gametophytes similar to
liverworts
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Large single chloroplast
Phylogenetically most
closely related to
vascular plants
Nostoc is symbiont -- N
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Gametophytes
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Rosette-like
Unisexual and bisexual
Clustered antheridia
Single gametophyte –
many sporophytes
wikipedia
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Sporophytes
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Sporophytes
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Life cycle
wikipedia
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Anthoceros laevis hornwort, habitat view
Photo by Ken McFarland
Phaeoceros sp.
Mosses: Phylum Bryophyta
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Things that are NOT mosses ….
Reindeer moss – lichen
 Scale moss – leafy liverworts
 Club moss – Lycopodium (Fern ally)
 Spanish moss – bromeliad (like pineapple …..)
 Spike moss – Selaginella (Fern ally)
 Sea moss (or Irish moss) – red alga (Carrageenan!)
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Mosses: Phylum Bryophyta
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3 groups discussed in text
Sphagnidae – peat mosses
 Andreaeidae – granite mosses
 Bryidae – true mosses
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Peat Mosses – Sphagnidae
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Sphagnum
Earliest diverging moss
Unusual
Protonema a “plate” w/ marginal meristem
 Distinctive leaf morphology
 Distinctive sporophytes
 Gametophytes -- clusters of branches
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Diapers and wound dressings
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20x dry weight in water (cotton only 4-6x)
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Sphagnum
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Unique leaf morphology
Antheridia and
archegonia at tips of
specialized branches
Unique sporophyte
morphology
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Granite Mosses -- Andreaeidae
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Mountainous or Arctic regions
Protonema & rhizoids – 2 rows of cells
Unusual sporangial dehiscence
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True Mosses -- Bryidae
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Filamentous protonema
Multicellular rhizoids
Leaves one cell thick
Specialized tissues
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Hadrom & Leptom
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Found in seta
Water conducting tissue – hydroids
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Similar to tracheids no protoplast but no lignin
Food conducting tissue – leptoids
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Similar to sieve tubes
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Sexual Reproduction
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Male and female gametangia
Branch tips
 Lateral branches
 Unisexual & bisexual
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Antheridia in splash cups
Capsules – 6-18 months to mature!
Maternally nourished sporophyte
Specialized spore dispersal
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Sexual Reproduction
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Mnium
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Archegonia and Antheridia
paraphyses
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Antheridial Splash Cups
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Peristome Teeth
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Control release of
~ 50 million spores
Characteristic of Bryidae
Taxonomically
important
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peristome teeth
operculum
calyptra
Photo by Alan Heilman
Eurhynchium serrulatum
Dehiscing operculum
Dicranella varia
Photo by Alan Heilman
Peristome teeth of
Dicranum flagellaria
Photo by Alan Heilman
Dicranella varia
spores
Photo by Alan Heilman
Grimmia gracilis
peristome teeth
open
Photo by Alan Heilman
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