1.
2.
3.
4.
Review What are the three main tissue systems of
plants
Compare and Contrast How do the three main
functions of a plant’s tissue differ
Form and Function How might the presence of
meristems explain the ability of plants to
regenerate from cuttings
Infer With your prior knowledge of the circulatory
system, write a paragraph comparing and
contrasting the structure and function of the
vascular system of a plant to the human
circulatory system
CH 23 PLANT STRUCTURE AND FUNCTION
23.1 Specialized Tissues in Plants
Seed Plant Structure

Three principal organs
of seed plants are roots,
stems, and leaves.
Roots

Anchor plant in ground




Help prevent erosion
Absorb water and
nutrients and transport
to rest of plant
Store food
Hold plant upright.
Stems




Support system for the
plant body
Transport system that
carries nutrients
Defensive system to
protect against
predators and disease
Produces leaves and
flowers.
Leaves


Main photosynthetic
organs
Regulates water by
controlling air exchange.
Plant Tissue Systems

Three main tissue systems:
 Dermal
 Vascular
 Ground.
Dermal Tissue


Protective outer covering of a plant
Epidermis
 Single

layer of cells that makes up the dermal tissue
May have tiny hair like projections on leaves and
roots.
Vascular Tissue


Supports the plant body
Transports water and
nutrients
 Xylem
 Phloem
 Consist
of long, slender cells
that connect almost like
sections of pipe.
Xylem

Tracheids
 Xylem
cells
 Leave cell walls made of
lignin when they die
 Openings allow water
movement from cell to
cell.
Xylem

Vessel elements
 Wider
than tracheids
and are arranged end
 After cell dies, cell walls
allow water to move
freely.
Phloem



Alive at maturity
Transports sugar throughout plant
Sieve tube elements
Arranged end to end with ends having
many small holes
 Lose nuclei and organelles as they
mature
 Kept alive by companion cells.

Phloem

Companion cells
 Supports
sieve tube element.
Ground Tissue




Produces and stores sugars
Contributes to physical support of plant
Neither dermal nor vascular
Three types of ground tissue:
 Parenchyma
 Collenchyma
 Sclerenchyma.
Parenchyma



Main type of ground tissue
Have thin cell walls
Contain many chloroplasts in leaves.
Collenchyma


Strong, flexible cell walls that help support plant
organs
Middle cell wall thickness.
Sclerenchyma


Extremely thick, rigid cell walls
Makes ground tissue such as seed coats tough and
strong.
Meristems


Regions of unspecialized cells in which mitosis
produces new cells
Found in tips of stems and roots.
Apical Meristems



Meristem at tip of a stem
or root
Cells divide rapidly
Increases plants length.
Floral Meristems


Produces flowers specialized cells
Develop from apical meristem.