1. Chapter 22/23
Plants

2. Bryophytes
• Life cycle that depends on water to reproduce,
lacking vascular tissue, these plants can draw
up water by osmosis only a few centimeters
• Include mosses, liverwort, and hornworts
• Gametophyte is the dominant recognized stage
of the life cycle and is the state that carries out
most of the plant photosynthesis
• Low growing plants
• First plants on earth

3. Seedless Vascular Plants
• Tracheids were an evolutionary innovation
that allowed vascular tissue to form: resist
pressure
• Xylem and phloem are vascular tissue that
can move fluids through the plant body
against the force of gravity
• Xylem – carries water upward
• Phloem -moves nutrients and carbohydrates
produced by photosynthesis

4. Cont.
• Allows plants to grow to great heights
• Changed the surface of earth, allowed for
the growth of forests
• Mosses, horsetails and ferns
• Have life cycle in which the diploid
sporophyte is the dominant stage

5. Seed plants
• Adaptations that allow seed plants to
reproduce without water include flowers
(angiosperms) and cones (gymnosperms),
the transfer of sperm by pollination and
the protection of embryos in seeds

6. Gymnosperms
• Ancient surviving seed plants
• Gnetophytes: cycads (tropical &
subtropical), ginkgoes (rare), conifers
(most common), as old as the fossil record
• Conifers; evergreen (do not loose their
leaves in winter)

7. Angiosperms
• Develop unique reproductive organs
known as flowers
• Contain ovaries, which surround and
protect the seeds, which becomes the fruit
• Excellent way to reproduce – animals eat
fruit, travel, excrete seeds, new plant
• Diversity- type and variation of plants:
woody, herbaceous,
• Life span: annuals, biennials, perennials

8. Characteristics
• Monocot • Dicot
• Single cotyledon (1st • Two cotyledons
leaf) • Branched veins
• Parallel veins • Floral parts often in
• Floral parts often in multiples of 4 or 5
multiples of 3 • Vascular bundles
• Vascular bundles arranged in ring
scattered throughout • taproot
stem
• Fibrous roots

9. Seed Plant Specialized tissue
• Roots; absorb water and dissolve
nutrients
• Stems; support for plant body
• Leaves; main photosynthetic system
• Dermal tissue; like “skin”
• Vascular tissue; xylem and phloem
• Ground tissue; lies between dermal and
vascular, most photosynthesis happens

10. Growth
• Meristems; clusters of tissue that are
responsible for growth
• Meristematic tissue; undifferentiated cells
that can become anything
• Meristematic tissue is the only plant tissue
that produces new cells by mitosis

11. Roots
• Two main types are taproots (mainly
dicots) and fibrous roots (mainly
monocots)
• Has outside layer, epidermis, a central
cylinder of vascular tissue, with large area
of ground tissue between
• Anchor plant in the ground and absorb
water and dissolve nutrients from soil (N,
P, K, Mg, Ca)

12. Stems
• 3 important functions; 1.) produce leaves,
branches and flowers; 2.) hold leaves up
to sunlight; 3.) transport substances
between roots and leaves
• Monocot: vascular bundles are scattered
throughout the stem
• Dicot: vascular bundles are arranged in
ring in stem

13. Cont.
• Primary growth: stems (length) is
produced by cell division in the apical
meristem, takes place in all seed plants
• Secondary growth: stems (width) lateral
meristematic tissue called vascular
cambium and cork cambium (eventually
becoming tree “rings”

14. Leaves
• Structure of leaf optimized for absorbing light
and carrying out photosynthesis
• Functions: photosynthesis, transpiration, gas
exchange
• Stoma – where gas exchange takes place
• Guard cells – allows stoma to open and close
• Plants keep stomata open just enough to allow
photosynthesis to take place but not enough to
allow for excessive loss of water

15. Transport
• Combination of root pressure, capillary action,
and transpiration provides enough force to move
water through the xylem of even the tallest plant
(pulls up)
• when nutrients are pumped into or removed
from the phloem system, the change in
concentration causes movement of fluid in that
same direction resulting in nutrients being able
to move in either direction depending on the
needs of the plant