20: Bryophytes

bryophytes

non-vascular plants

not a monophyletic group

relationship to each other and vascular plants are unresolved

is bryophytes monophyletic?

false

paraphyletic

cause of unresolved relationship to vascular plants

common ancestors to land plants

protists

bryophyte

no vascular system and reproduce via spores.

importance of moss

-can inhabit diverse and extreme environments

• common in moist forests and wetlands

  • helps retain nitrogen in soil - nutrient cycling

Sphagnum - peat moss

forms extensive deposits of partially decayed organic material - PEAT

acidifies soil

peat

source of fuel/ imp global reservoir of organic carbon

over geological time

lots of moss-compress-peat moss - potting soil

continues to press - coal

sporophyte

multicellular diploid form of plant body

2n

gametophyte

structure that produces haploid gametes in plants

n

sporangium

structure where meiosis occurs

haploid spores develop

n

antheridia

structure where gametes develop in male structures of plants

polyp - male structure of plants found here

n

archegonia

structure where gametes develop in female structures of plants

eggs found hereand fertilization occurs.

6 main traits of bryophytes

dominant gametophytic phase (1n)

no xylem/phloem

no roots

no leaves

no cuticle

sporophyte dependent on female gametophyte for nutrition

bryophyte - repoructive

small sporophyte

gametophyte dominant - haploid dominant

Moss life cycle

tiny haploid spores inside capsule - wind dispersal

spores develop into male and female gametophytes

rhizoid

produce flagellated sperm in antheridia

produce egg in archegonium

• sperm swim through water to reach and fertilize egg

no cuticle

nutrients move freely into body

rhizoid

anchor that absorbs water and nutrients

anchor to substrate

help transfer nutrients

do moss lifecycle show alternation of generations?

yes

fertilization happens in

archegonium

how do sperms reach egg

The sperm swim through water to reach the egg within the archegonium.

sporangium

has a capsule - where spores develop

capsule explodes so spores released in env via wind dispersion

bryophyte sporophyte made up of

foot

seta

sporangiumand capsule

foot

receives nutrients from female gametophyte

seta

elongated stalk

dispersal

sporangium

site of meiosis

sporocyte (2n) - spores (1n)

hornworts and moss sporophytes vs liverworts

hornwors and moss sporophytes have stomata for gas exchange - liverworts do not

gametophyte in pic

green fuzzies

that are the dominant stage in bryophytes, producing gametes for reproduction.

moss spore disposal

teeth of peristome - flick spore away for dispersal

spores from cap explodes - haircap moss

liverworts - hepatophyta

liver shaped/ leafy gametophyte

smallest sporophytes

male and female gametangia on separate plants

archegonia and antheridia are developed on gametangia elevated on gametophores/ stalk

miniature sporophytes can be seen on undersurface of female gametangia

no stomata

bryphytes vs liverworts

b: have stomata

l: no stomata

liverwort structure

small, v close to ground cause no vascular system

looks like coconut trees

liverworts sporophyte made of

seta

foot - anchors

capsule (sporangium)

thallus

The main body of a liverwort, often flat and ribbon-like, that functions in photosynthesis and nutrient absorption.

Hornworts

anthocerophyta

“horny”plants with elongated sporophytes

sporophyte has no seta

• entire length will explode spores

hornworts

group of non-vascular plants

found in damp and humid env

horizontal gametophytes

long taperd sporophytes

no seta only sporangium

relatively unexplored group