Download Lecture 26 - MSU Billings

I. Terrestrial Invasion
A. Mineral absorption
1. N K S Ca P Mg
I. Terrestrial Invasion
A. Mineral absorption
1. N K S Ca P Mg
2. mycorrhizae
I. Terrestrial Invasion
A. Mineral absorption
1. N K S Ca P Mg
2. mycorrhizae
B. Water conservation
1. waxy cuticle (on exposed areas)
- prevents water loss
- water enters at roots
I. Terrestrial Invasion
A. Mineral absorption
1. N K S Ca P Mg
2. mycorrhizae
B. Water conservation
1. waxy cuticle (on exposed areas)
- prevents water loss
- water enters at roots
2. stomata
a. passages in the cuticle
b. allow gas exchange
c. water vapor
C. Reproducing
1. plants are immobile
- creates problem for sexual reproduction
- how can sperm get from one plant to another?
- pollen
2. spores
a. a cell that can develop into another organism without
fusing with another cell
b. basically asexual
c. resist drying
D. Structural support
1. gravity vs. water
2. lignin: chemical that strengthens plant cell walls
E. Life cycle changes
1. alternation of generations
- diploid alternates with haploid
2. sporophytes (diploid generation)
- form haploid spores my meiosis
- sporophyte grows by mitosis
- most vascular plants
3. gametophytes (haploid generation)
- form haploid gametes by mitosis
3. gametophytes (haploid generation)
- form haploid gametes by mitosis
- fused gametes (fertilization) form the sporophyte
F. Vascular system (found in 9 of 12 plant phyla)
1. roots and shoots
2. tall plants need good plumbing (vascular systems)
- vascular plants
- highly successful (>250,000 species)
G. Avascular plants (bryophytes)
1. first land plants
- still the simplest
2. lack lignin
- still have some conducting tubes
- limited size
3. liverworts, hornworts, mosses
4. still have flagellated sperm
Liverwort
Sphagnum Moss
Thalloid Liverwort
Hornwort
II. Vascular Plants
A. Features
1. dominant sporophyte
2. specialized conducting tissues
- reinforced cell walls (lignin)
- vascular bundles
3. specialized body form
- roots, stems, leaves
B. Conducting systems
1. phloem
- living cells
- transports carbohydrates
B. Conducting systems
1. phloem
- living cells
- transports carbohydrates
B. Conducting systems
1. phloem
- living cells
- transports carbohydrates
2. xylem
a. hard-walled cells
- dead
b. transport water and minerals
Vascular Bundles
G. Growth
1. indeterminate
- most plants
- growth for duration of life span
2. determinate
- most animals
- growth until a certain size is reached
3. primary
a. cell division at tips of roots and stems
b. from apical meristems
c. taller but not wider
4. secondary
a. new cells laid around periphery
b. increased diameter
- allows increase in height
c. from lateral meristems (2 of them)
- vascular cambium
- cork cambium
d. wood
- secondary xylem
- lignin provides the rigidity
d. wood
- secondary xylem
- lignin provides the rigidity
e. rings
- vary in size according to amount of growth each season
D. Seedless varieties
1. dominated the Carboniferous period (360-299 MYA)
- coal
D. Seedless varieties
1. dominated the Carboniferous period (360-299 MYA)
- coal
2. water required for fertilization
- sperm must swim
3. ferns (most abundant)
a. independent sporophyte (diploid) and gametophyte
(haploid) forms
b. gametes from gametophyte unite  zygote
c. zygote develops into sporophyte (diploid)
- produces haploid spores
- spores released
d. spores develop into gametophyte (haploid)
e. fern gametophyte: small, thin, photosynthetic, heart-shaped
f. fern sporophyte
- large, complex
- fronds