Kingdom Plantae
Plant Morphology
Plant Evolution
Ancestor = Charophytes  member
of the green algae
Evidence that supports this idea:
1. Homologous chloroplasts
Similarity in characteristics d/t common
ancestry
2.
3.
4.
5.
Biochemical similarity
Similarities in cytokinesis
Sperm cell ultrastructure
Genetic relationships
Problems associated with movement to land
1.
2.
3.
4.
5.
Desiccation
Gas exchange
Support of multicellular structures
Spore or seed dispersal
Reproduction
Alternation of generations
Two Generations:
1. Sporophyte stage
a. Diploid stage
b. Sporo = spore (n) plant
a. sporopollenin
c. Spores produced via meiosis
d. Sporangium  sporocytes (2n)
Alternation of generations con’t.
Two Generations:
2. Gametophyte
a. haploid stage
b. gameto = gamete plant
c. gametes produced via MITOSIS
Monocots
Dicots
Angiosperms
Gymnosperms
ovary
no ovary
seeds
Sporophyte dominates
life cycle
Cryptogams
spores
vascular
Bryophytes
nonvascular
land
Bryophytes
(nonvascular
land plants)
Hepatophyta
Anthoceros
Bryophyta
Liverworts
Hornworts
Mosses
Bryophytes
Gametangia = structures where
gametes are produced
a. Archegonia - egg cells
b. Antheridia – sperm cells
* Sporophyte cannot live independently
Moss plants – gametophyte & sporophyte generations
The Liverworts (Hepatophyta) - Marchantia sp.
The Hornworts
(Anthocerophyta)
Anthoceros sp.
Bryophytes con’t
Stomata
a. openings in leaves that allow for
gas exchange
Bryophytes con’t
Cuticle
(made of cutin)
Bryophytes con’t.
No fundamental difference between
above and below ground parts
- 2 cm tall
Still have a need for water
Vascular Plants - Tracheophytes
Dominant stage = sporophyte
Specialized organs
a.
b.
Stems
Leaves
- megaphyll
- microphyll
c.
Sporophylls: specialized leaf to house
meiosporangia
- Many cone shaped
- Homosporous & heterosporous
d.
Roots
- rhizomes
Vascular plants con’t.
Branching  increased sporangia
Some contain lignin
a. structural support
Vascular tissues
a. Xylem
b. phloem
Vascular plants con’t.
Two types of growth – apical
meristem
a. Primary growth
b. Secondary growth
Sperm still flagellated
Maintained stomata & cuticle
Vascular Plants - Tracheophytes
 plants w/ pipes
Broken up into two groups:
1. Reproduce by spores
Cryptogams: crypto: hidden, gam: sex
2. Reproduce by seeds
Gymnosperms: naked seed plants
(cones)
Angiosperms: seed surrounded by
ovary (flowers)
TracheophytesCryptogams
Lycophyta
Psilotophyta
Sphenophyta
Pterophyta
Innovations of the Cryptogams
1.
Roots
- uptake water, minerals, nutrients, and gases
2.
Vascular tissue
- xylem & phloem arranged in bundles
3.
Division of labor
- specialized tissues and organs
4.
Lignin
- infused in xylem  support against gravity
5.
Hormones
- regulate plant development
P: Lycophyta
C: Lycopodiopsida
(microphylls)
P: Lycophyta
C: Sellaginellopsida
Sellaginella – The resurrection plant
l.s. strobilus
P: Psilotophyta
* stems only
P: Sphenophyta
Equisetum sp. - Horsetail
Aerial stem in c.s.
Equisetum gametophyte & sporophyte stages.
Equisteum strobilus (cone: compact group of meiosporangium-bearing structures).
Left: whole mount and Right: cross section showing sporangiophore: stem-like
structure bearing sporangium (container in which spores are borne).
P: Pterophyta – the ferns
Gametophytes
Sori (cluster of meiosporangia) on the underside of
sporophylls (specialized leaf that bears meiosporangia) aka
fronds.
Sori in c.s.
Note – indusium: layer of tissue protecting meiosporangia
filled with meiospores. Annulus (head portion of
meiosporangia) also present.
Left: fern gametophyte (prothallium) with archegonia and
antheridia. Right: sporophyte growing out of gametophyte.
Rhizoids present.
Vascular Seed Plants
• Gymnosperms – naked seed plants
• Angiosperms – flowering plants
Seed plant characteristics
• Seeds
• Reduced gametophytes – microscopic
- Gametophytes develop from spores
retained in sporangia of parental
sporophyte protects female gametophyte
from environmental stresses
- Gametophyte obtains nutrients from
sporophytes
Seed plant characteristics con’t.
• Heterospory
– Megasporangia: produce megaspores that give
rise to female gametophytes
• egg within ovule
– Microsporangia: produce microspores that
give rise to male gametophytes
• sperm within pollen
Seed plants con’t.
• Non-flagellated sperm
a. pollen
b. Moved by water, wind, insects, and
animals
•
Egg cells
a. Called ovules  located inside the
ovary
Seed plants
• Purpose of the seed:
A. means of dispersal
B. Survive unfavorable conditions
C. Stores food for embryo
D. Protection from predators
Seed plants con’t.
• Characteristics Maintained:
-vascular tissue
-cuticles
-stomata
Gymnosperms
Cycadophyta
Ginkgophyta
Gnetophyta
Coniferophyta
Gymnosperms
•
•
•
Needle-like leaves
Found in moderately cold & dry
regions
Direct pollination  ovules NOT
enclosed in ovaries
P: Cycadophyta
i.
dioecious: seeds & pollen produced on different sporophytes
ii. strobili: micro and megasporophylls
Phylum: Ginkgophyta
Ginkgo biloba – single species in the phylum.
i. dioecious
ii. male pollen cone w/ 2 microsporangia (whole & l.s.)
iii. no seed cone  ovules on end of branches
Phylum: Gnetophyta
Welwitschia – found in the deserts of Africa
i. dioecious
Phylum: Gnetophyta con’t.
pollen cone: note microsporangia
(compound strobilus)
Ephedra
seed cone: will produce two seeds
Phylum:Coniferophyta
Conifer characteristics
• largest group of gymnosperms (600 spp.)
• most are evergreen, monoecious, trees or
shrubs
• needle or scale-like leaves
• compound seed cones (ovules on cone scales)
• Simple or clustered pollen cone
Needle-like leaves
-Curled bracts
- fasicle (group of needle-like leaves attached to a single shoot)
bundled in a papery sheath
Angiosperms
1. Produce seeds and flowers
2. Petals  brightly colored to
attract pollinators
3. Dominate the landscape
The anatomy of a flower
Flower anatomy con’t.
Angiosperms con’t.
1.
2.
3.
4.
Pollination
Pollen grain lands on stigma and
germinates
Pollen tube grows down through
style into ovary  releases sperm
into ovules (egg cells)
Mature ovary = fruit
Mature ovule = seed
Pollination
Monocots vs. Dicots
Mono
1. 1 cotyledon
2. Parallel vein
3. Fibrous root
4. Flwr parts in 3
5. Scattered bundles
(in the stem)
Dicot
2 cotyledons
net-like vein
tap root
flwr parts in 4-5
bundles in ring