3. Specialized Cells & Tissues in Plants
Tissue: group of specialized cells
Organ: Group of several types of
tissues working towards a specific
function
Meristem: unspecialized cell that can
form specialized cells in plants
5. Repairing & Replacing Specialized
Cells
Buds: Swelling of the
stem
◦ Terminal Bud – most
active growth, produce
Auxin
◦ Lateral Bud – dormant
regions, inhibited by
Auxin
8. The Leaf – Tissues
Dermal tissue
◦ Waxy cuticle – limits water loss
◦ Protects the leaf
Palisade tissue
◦ Prime site of photosynthesis – palisade cells and chloroplast
Mesophyll tissue
◦ Loosely packed cells
◦ Spaces contain gases such as H2O, CO2 and O2
Vascular tissue
◦ Xylem – transports water to the photosynthesizing cells
◦ Phloem – transports sugar throughout the plant
◦ Small vein branches – every cell gets water and nutrients
9. The Leaf – Lower epidermis
Exchange of gases
Guard cells
◦ Control opening and closing of stomata
Stomata
◦ Connected to spongy mesophyll
◦ CO2 enters, O2 and H2O exits through them
Transpiration – evaporation of water from leaves
11. The Stem
Provides physical
support and transports
sap
Composed mainly of
xylem tissue
◦ Dead tubular hollow
cells fortified with lignin
Vascular bundle
◦ Phloem (living porous
cells) exchanges
materials with
neighbouring cells
12. The Roots
Anchor a plant to the
ground
Allow water and
minerals uptake from
the soil
Some also act as
plant’s storage area
13. The Roots
Dermal tissue
◦ Root hair – increase
surface area for
absorption
Ground tissue
◦ Cortex – provide
support
◦ Pericycle – vascular
tissue
14. Types of Roots
Tap root
• Allows plant to
reach far
underground for
water
• Anchors the plant
Fibrous root
•
Large surface area
to absorb water
•
Stabilize soil
•
Prevent erosion &
landslides
16. The Flower
Reproduction - pollen and
eggs
Pollination: transfer of pollen
to female parts of flower
Seeds are produced and
embedded in fruits
Hormone called ethylene
stimulates ripening of fruits
