1. Slide 1
Structure of
Plants

2. A. Functions of Roots Anchor & support plant in the ground
Slide 2
A. Functions of Roots
Anchor & support plant in the ground
Absorb water & minerals
Hold soil in place
Fibrous Roots
Root Hairs

3. B. Root Types
Slide 3
Tap Root
1. Fibrous Roots: branching roots hold soil in place to prevent soil erosion
Ex. Grasses
2. Tap Roots –larger central root reaches deep water sources underground
Ex. Trees, Carrots, & Dandelions

4. C. The Structure of a Root
Slide 4
Root Hairs
Root Hairs: increase surface area for water & mineral absorption
Meristem: region where new cells are produced
Root Cap: protects tip of growing root
Phloem
Xylem
Meristem
Root Cap

5. A. Functions of Stems Support system for plant body
Slide 5
Support system for plant body
Transport system carries water & nutrients
Holds leaves & branches upright
Looking at the picture to the left:
What years had the most rain?
What years experienced the worst drought?
Each light and dark tree ring equals one year of annual growth. Light rings for fast spring growth, dark for slow summer growth.
Smaller rings tell of past droughts that have occurred.

6. Need for transport systems
Plants need sugars and water to stay alive
Water needs to travel from the roots to the leaves
Sugars need to travel from the leaves to the rest of the plant

7. Xylem Hollow dead tubes
Water and minerals transported in an upwards direction
Made of lignin
Very strong so help support the plant

8. Phloem Transports sugar around plant Made of living cells
Companion cells provide the energy for the tube cells.
The end walls of the tube cells have pores through which food is transported from cell to cell in the form of dissolved sugars

11. A. Functions of Leaves Main photosynthetic organ
Slide # 6
Main photosynthetic organ
Broad, flat surface increases surface area for light absorption
Have systems to prevent water loss
Stomata open in day but close at night or when hot to conserve water
waxy cuticle on surface
System of gas exchange
Allow CO2 in and O2 out of leaf
Elephant Ear Plant

13. Helps to catch more light energy
Structure
Wide
Helps to catch more light energy
Thin
Help get carbon dioxide from bottom to top of leaf for photosynthesis

14. B. Leaf Structures Leaf Cross-Section
Slide # 7
Leaf Cross-Section
Cuticle: waxy layer; covers upper surface
Protects leaf against water loss
Veins: transports water, nutrients and food
Made of xylem and phloem
Mesophyll: contains cells that perform photosynthesis
b/c they contain Chloroplasts.
Cuticle
Veins
Mesophyll
Stoma
(Opening)
2 Guard Cells
Surround
each
Stoma
Stoma- singular
Stomata-plural

15. cells that open and close the stoma
More Plant Parts…
Slide # 8
Guard cells:
cells that open and close the stoma
Stomata: openings in leaf’s surface; when open:
GAS EXCHANGE: Allows CO2 in & O2 out of leaf
TRANSPIRATION: Allows excess H2O out of leaf
Guard Cells
Stoma

16. Leaf structure
Greener on top
CO2 gets in here

17. Leaf diagram – palisade layer
Most chlorophyll
CO2

18. Leaf cell - palisade Position? Upper surface of leaf Features?
Box shape
Chloroplasts
Function?
Photosynthesis

19. Gas exchange
Leaves are designed to allow carbon dioxide to get to the main chlorophyll layer at the top of the leaf
They have small holes called stomata on the under surface
Each hole is open & closed by 2 guard cells

20. Leaf diagram – stoma and guard cells

21. Stoma position

22. Stoma is a small hole Its size is controlled by 2 guard cells closed
open

23. Stoma function is for gas exchange in the leaf
oxygen
Guard cell
Provided plant is photosynthesising
Carbon dioxide

24. Stomata open and close at different times of the day
When it is light the plant needs CO2 for photosynthesis so the stoma open
At night (darkness) they close

25. Gas exchange

26. Function of Stomata
Slide # 9
What process involves using CO2 and H2O releasing O2 as a waste product?
Photosynthesis
What is the plant using this process to make?
Carbohydrates-glucose
If the plant needs water for photosynthesis, why is water coming out of the stoma?
Guard Cells
Guard Cells
What goes out? O2
H2O
CO2
What goes in?
Stoma Open
Stoma Closed
Stoma

27. Function of Guard Cells
Slide # 10
These stomata (leaf openings) naturally allow water to evaporate out.
Why would the plant close stomata with guard cells?
Prevent excess water loss through transpiration. (conserve water)
So what is the point of having stomata?
Allow gas exchange for photosynthesis
Guard Cells
Guard Cells
Stoma Open
Stoma Closed
Guard cells open by inflating with extra water. They do this by pumping K+ ions into the cell, which causes water to rush in via osmosis to diffuse the high ion concentration.

28. C. Plants find a use for Transpiration
Slide # 11
Transpiration: loss
of excess water from plant leaves
2. Significance:
Transpiration causes enough pressure to help pull water (& required nutrients) up stem from roots.
As part of the water cycle, trees transpire water back into the atmosphere.
Transpiration provides much of the daily rain in rainforest. A B
A average size maple tree can transpire 200 liters of water per hour during the summer.
Transpiration is the #1 driving force for pulling water up stems from roots.