Transcript Plant Lecture in Power Point

Kingdom Plantae
Lower Plants,
Organization, Morphology and
Reproduction
Plant Evolution
Ancestor = Charophytes  member
of the green algae
Problems associated with movement to land
1.
2.
3.
4.
5.
Desiccation (dehydration)
Gas exchange
Support of multicellular structures
Reproduction
Spore or seed dispersal
Alternation of Generations
Alternation of generations
Diploid
• Full # chromosomes
• 2n
• All non-gamete
cells
• Can’t be gametes
• Human = 46
•
•
•
•
•
Haploid
½ # chromosomes
n
Gametes
At fertilization
become diploid
zygote
• Human = 23
Alternation of generations
Two Generations:
1. Sporophyte stage (spore-plant)
a. Diploid stage (2n)
b. Produces haploid spores by meiosis
c. Spores grow into gametophyte
containing male or female repro
structures.
Alternation of Generations
Alternation of generations con’t.
Two Generations:
2. Gametophyte (n) (gamete plant)
a. haploid stage
b. Male: has antheridia, makes sperm
c. Female: has archegonia, makes eggs
d. gametes produced via MITOSIS
e. Sperm swim
f. Fertilization produces zygote
g. Grows into Sporophyte
Alternation of Generations
Bryophytes
(nonvascular
land plants)
Hepatophyta
Anthocerophyta
Bryophyta
Liverworts
Hornworts
Mosses
The Liverworts (Hepatophyta) - Marchantia sp.
Female Gametophyte
Gemmae cups-asexual
Archegonia
The Hornworts
(Anthocerophyta)
Anthoceros sp.
Moss plants – Bryophyta
gametophyte & sporophyte generations
See fig 27.12, Russell*
Adaptation to Land
Problems associated with movement to land
1.
2.
3.
4.
5.
Desiccation (dehydration)
Gas exchange
Support of multicellular structures
Reproduction
Spore or seed dispersal
Adaptation to Land (desiccation, gas xchge)
1. Stomata:
a. Openings in leaf surface
b. control H2O loss
b. allow for gas exchange
Adaptation to Land (desiccation,transport)
1. Stomata:
2. Vascular Structures
a. Xylem-H2O up from Roots
b. Phloem-sugar around
Adaptation to Land (dessication)
1. Stomata:
2. Vascular
3. Cuticle
a. H2O proof
b. prevents dessication
Cuticle
(made of cutin)
Adaptation to Land (support)
1. Stomata:
2. Vascular Structures
3. Support
a. Lignin in cell walls
b. allows for branching and larger
size
Bryophytes
No true roots or vascular tissue
- 2 cm tall
Still have a need for water (Repro)
Vascular Plants
Dominant stage = sporophyte
(Gametophyte hidden)
Specialized organs
a. Roots
-
rhizomes
b. Stems
c. Leaves
Vascular plants con’t.
Branching
Some contain lignin
a. structural support
Vascular tissues
a. Xylem
b. phloem
Vascular Bundles in
Monocot stem
Vascular plants con’t.
Two types of growth – apical meristem
a. Primary growth
b. Secondary growth
Sperm still flagellated
Maintained stomata & cuticle
Nonseed
Vascular
Plants
Lycophyta
Psilotophyta
Sphenophyta
Pterophyta
Lycophyta
Psilotophyta
Lycopodium sp.
Psilotum sp.
(microphylls)
(stems only)
Sphenophyta
Equisetum sp.
Pterophyta – the ferns
Sori on the underside of sporophylls
Vascular
Seed Plants
Coniferophyta
- the gymnosperms
Anthophyta
- the angiosperms
Seed plants
Purpose of the seed:
A. means of dispersal of offspring
B. Survive unfavorable conditions
C. Stores food for embryo
D. Protection from predators
E. Remember “Seedy Side of Plants”
Seed plants (con’t.)
Non-flagellated sperm
a. pollen
b. Moved by water, wind, insects, and
animals
c. Forms pollen tube for sperm
Egg cells
a. Called ovules  located inside the
ovary
Seed plants con’t.
Reduced gametophyte
a. composed only of sperm or egg
Maintained:
a.vascular tissue,
b.Cuticle
c.stomata
Gymnosperms
A. Needle-like leaves
B. Found in moderately cold & dry
regions
C. Direct pollination  ovules NOT
enclosed by tissue of the
sporophyte (gym= naked)
Gymnosperm Life Cycle
Gymnosperms – naked seed plants
Phy: Cycadophyta
Phy: Ginkophyta
Cycads (Sego palm)
Strobili: sporophylls (leaves with sporangia)
Ginkgo biloba
Phylum: Gnetophyta
Welwitschia
Ephedra
Coniferophyta
Angiosperms
1. Produce flowers, seeds and fruit
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