2. 9/24/13
2
WHAT IS A TRACHEOPHYTE (VASCULAR PLANT)?
A Land Plant (embryophyte) with:
vascular tissue (xylem & phloem)
-functions in conduction of water/sugars
TRACHEOPHYTES ALSO HAVE:
Sporophyte dominant & independent
Supportive tissue (lignified 2˚ cell walls;
sclerenchyma)
Roots
Shoots (w/ sporophytic leaves) }extant
3. 9/24/13
3
LIGNIN
¢ Polymer of complex compound
¢ Incorporated into secondary wall
4. 9/24/13
4
SECONDARY CELL WALL
- CELLULOSE + LIGNIN
-FORMS BETWEEN 1˚ CELL WALL AND
PLASMA MEMBRANE
- ADDS STRUCTURAL SUPPORT
- FOUND IN TRACHEIDS, VESSELS, FIBERS
(ALL DEAD CELLS)
LIGNIFIED SECONDARY CELL WALL
5. 9/24/13
5
Sclerenchyma
¢ Secondary cell wall (+ primary)
¢ Dead at maturity (usually)
1. Fibers
Elongate, sharply tapering
6. 9/24/13
6
FIBERS
¢ Mechanical support
¢ Occur in groups or bundles
¢ Components of vascular tissues
Sclerenchyma
• Permits the plant to attain greater stem of height
2. Sclereids
- Isodiametric to irregular
- Branched
7. 9/24/13
7
What is the function of tracheary elements?
In what tissue are the tracheary elements found?
8. 9/24/13
8
TRACHEARY
ELEMENTS
Tracheids - Imperforate Vessels - Perforate
Angiosperms (most)
Gnetales
A few Monilophytes
SIEVE ELEMENTS
Sieve cells - No sieve plates
Sieve tube members - Sieve plates
=Apomorphy of Angiosperms
23. 9/24/13
23
Lepidodendron
EXTINCT LYCOPODS
WERE TALL TREES:
MAKE UP SOME OF COAL
DEPOSITS
LYCOPODS ALIVE TODAY
ARE SMALL - ALL HAVE
LYCOPHYLLS /
MICROPHYLL
- (1 VEIN, INTERCALARY
MERISTEM)
40. 9/24/13
40
MARATTIALES- POLYCYCLIC
SIPHONOSTELE
MarattiaEusporangia
- Relatively large; derived from several epidermal cells;
sporangial wall surrounded by many layers of cell
41. 9/24/13
41
Ophioglossaceae
Ophioglossum californicum Calif. Adder’s
Tongue
fertile
sterile
LEPTOSPORANGIATE FERNS
= POLYPODIALES
Leptosporangium:
- Develops from one cell
- one cell thick
- spores ejected
42. 9/24/13
42
spor ophyte
(2n)
gametophyte
(n)
young
spor ophyte
(2n)
sperm cell
(n)
egg cell
(n)
archegonium
antheridium
spore
(n)
rhizomesori
leptosporangium
gametophyte
(n)
annulus
spores
(n)