Transcript Evolution and Diversity of Green and Land Plants Michael G. Simpson cellulose: beta form of glucose.

Evolution and Diversity of
Green and Land Plants
Michael G. Simpson
cellulose:
beta form
of glucose
Cellulosic cell wall
made of cellulose microfibrils
cell wall
chloroplasts
Elodea (Hydrocharitaceae - Alismatales)
amyloplasts (starch grains):
alpha-1,4-glucopyranoside
chloroplast:
chlorophyll a & b
grana
starch
2 forms of
glucose
How did chloroplasts
evolve?
By endosymbiosis:
Charales - oogamy
oogonium
Coleochaete
Nitella
Chara
cell wall:
cellulosic
plasmodesmata (in some Green Plants)
-allow cell-to-cell communication
The Land Plants
=Embryophyta (embryophytes)
• The first colonization of plants on land
during the Silurian period, ca. 400 million
years ago.
• Land Plants now dominate the earth.
sporophyte:
- allowed for many more propagules (spores) produced
- sporophyte (diploid) shields against deleterious recessives
cuticle
cell wall
epidermal cell
cuticle:
protects against desiccation
parenchyma:
solid mass of tissue; cells:
1) are elongate to isodiametric;
2) have a primary (1˚) cell wall only (rarely a 2˚ wall);
3) living at maturity, capable of continued cell divisions.
antheridium
antheridium
sperm cells
Marchantia (liverwort)
Mnium (moss)
egg cell
neck
archegonium
Marchantia (liverwort)
“Bryophytes” paraphyletic
Hornworts
Liverworts
Mosses
“Bryophytes”
Liverworts Hepaticae
Two basic forms:
-thalloid
-leafy
Thalloid (Conocephalum sp.)
Leafy (Bazannia)
-3 rows of leaves,
lower usu. reduced
archegoniophore
-specialized structure that bears
archegonia
antheridiophore
-specialized structure that bears
antheridia
pore
pore
gemmae
gemma cup
Marchantia
elaters
sporophyte
Marchantia
spores
stomate
Mosses
(Musci)
spore
(n)
protonema
gametophyte (n)
meiosis
fertilization
sporophyte (2n)
archegonium
antheridium
Economically important mosses:
Sphagnum Peat Moss
Sphagnum - Peat moss:
Leaves have tiny pores that retain water
chlorophyllous cells
hyaline cell
pore
Sphagnum - Peat moss:
Plants make ground water acidic, form extensive bogs
Sphagnum Peat Moss
Peat = partially decomposed
Sphagnum
- Used in
potting media
- Used as a
fuel
Peat = partially decomposed
Sphagnum
- “Tolland” man:
- preserved
remains in bog,
405-100 B.C.
Hornworts
(Anthocerotae)
Hornworts