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Plant Cells and Tissues
Chapter 23.1
• Plants are composed of cells which
contain:
– Cell wall
– Central vacuole
– Chloroplasts
Plant Tissues
• There are four types
of tissues in plants:
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–
–
–
Dermal tissue
Vascular tissue
Ground tissue
Meristematic tissue
Dermal Tissue
•
•
•
•
Also called the epidermis
Composed of flattened cells
Protects and covers the body of the plant
Produces the cuticle
Located in the Epidermal Layer…
• Stomata:
– Opening in leaf tissue
– Help control water loss from plant
• Guard Cells:
– Controls the opening/closing of stomata
• Trichomes:
– Hairlike projections on stem and leaf
– Reduces evaporation of water from plant
Vascular Tissue
• Main function is to transport water, food
throughout plant
• Two types of vascular tissue
– Xylem
– Phloem
Xylem
• Transports water from
roots to plant
• Composed of
tracheids
– Tubular cells tapered
at each end
Phloem
• Transports sugars to
all parts of the plant
• Made up of tubular
cells joined end to
end
Ground Tissue
• In charge of
photosynthesis,
storage, and
secretion
• Found throughout
plant
Meristematic Tissue
• Produces most of a
plant’s new cells
• Located in regions of
actively dividing cells
Roots, Stems, and Leaves
Chapter 23.2
Roots
• Anchor, absorb nutrients, contain vascular
tissue to transport materials
• Can be short or long, thick or thin
• Have root hairs
– Tiny extensions
– Increase surface area of root
Stems
• Support leaves and flowers, contains
vascular tissue to transport materials
• Arrangement of vascular tissue:
– Monocots: Xylem and phloem scattered
throughout stem
– Dicots: Xylem and phloem in a circle that form a
ring
Growth of Stem
• Primary growth
– Increase in length
• Secondary growth
– Increase in diameter
Ex: Woody Stem:
Leaves
• Primary function: Photosynthesis
• Some leaves joined directly to stem
– Example: grass blade
• In some leaves, a stalk called a petiole
joins the leaf blade to the stem
• Simple leaf
– Blade that is not divided
• Compound leaf
– Blade divided into leaflets
• Transpiration:
– Loss of water through
the stomata
• Leaf venation:
– Patterns of veins in the
leaves
• Parallel
• Pinnate
• Palmate
Plant Responses
Chapter 23.3
Plant Hormones
• Plants have hormones that regulate
growth and development
• Auxins and Gibberellins (2 hormones) that
promote growth in plants
Plant Responses
• Why do stems grow up and roots grow
down?
• Tropism
– Plant’s response to an external stimulus
• Phototropism
– Plant growth toward light
• Gravitropism
– Plant growth in response to gravity