This document discusses plant cells, tissues, and organs. It describes how plant cells can be specialized into tissues for specific functions. The major plant organs are then examined in more detail: leaves contain tissues like palisade and mesophyll for photosynthesis; stems provide structure and transport through vascular bundles; roots absorb water and minerals through root hairs and vascular tissue; and flowers facilitate reproduction through pollination and seed production. The roles of meristem, buds, and plant hormones in growth and repair are also outlined.

1. PLANT CELLS, TISSUES, &
ORGANS

2. PLANT CELLS, TISSUES, & ORGANS

3. SPECIALIZED CELLS & TISSUES IN PLANTS

4. •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
SPECIALIZED CELLS & TISSUES IN PLANTS

5. Plant organs:
•Leaf
•Stem
•Root
•Flower
PLANT ORGANS

6. Leaf:
•Dermal tissue
•Palisade tissue
•Mesophyll tissue
•Vascular bundles
PLANT ORGANS: LEAF

7. 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
PLANT ORGANS: LEAF

8. PLANT ORGANS: LEAF
Leaf: Palisade tissue
• Contains chloroplasts that perform photosynthesis

9. 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
PLANT ORGANS: LEAF

10. 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
PLANT ORGANS: STEM

11. Roots:
•Anchor a plant to the
ground
•Allow water and
minerals uptake from
the soil
•Some also act as plant’s
storage area
PLANT ORGANS: ROOTS

12. Fibrous root
• Large surface area
to absorb water
• Stabilize soil
• Prevent erosion &
landslides
Tap root
• Allows plant to
reach far
underground for
water
• Anchors the plant
PLANT ORGANS: ROOTS

13. •Dermal tissue
• Root hair – increase
surface area for
absorption
•Ground tissue
• Cortex – provide
support
• Pericycle – vascular
tissue
PLANT ORGANS: ROOTS

14. •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
PLANT ORGANS: FLOWERS

15. Buds: Swelling of the stem
• Terminal Bud – most active
growth, produce Auxin
• Lateral Bud – dormant regions,
inhibited by Auxin
• Auxin = class of plant growth
substances (hormones)
REPAIRING & REPLACING SPECIALIZED CELLS

16. PLANTS UNDER ATTACK