1. Parts of the plant and their functions
Intro to Horticulture
Parts of the plant and their functions
By Ryan Talton
Georgia Ag Ed Curriculum Office
May 2004

2. Functions of leaves
1. Critical for photosynthesis (the process by which plants produce their food).
2. Aid in the process of transpiration which is necessary in order for plants to cool themselves.

3. 3. Leaves can store some food which
can later be transferred to other areas of
the plant.
4. Sometimes, leaves can be used in asexual or vegetative propagation.

4. External Leaf Structures
Leaves are consist of petiole and blade
Blade is comprised of veins and a midrib
The veins of the leaf form its structural framework

5. Internal Leaf Structures
Epidermis
Cuticle
Waxy substance covers the leaves and stems
Waterproof layer that keeps water in plants

6. Principal Tissues of the Leaf
Epidermis (cont)
Stomata
Openings in the epidermis mainly located on underside of leaves
Exchange of gases
Guard Cells
Two cells located on each side of stomata
Open and closes stomata

7. Chloroplast Cells in the center of the leaf
The chloroplast contains chlorophyll which gives the plants the green color
Manufactures food for the plant though Photosynthesis
Beginning of the food chain for all living things

8. Photosynthesis
CARBON DIOXIDE + WATER + LIGHT ENERGY = GLUCOSE + OXYGEN
Food manufactured by this process goes down to the roots thought the stem. It is either used by the plant or stored as a starch, sugar, or protein

9. Respiration Plants respire 24 hours/day just as animals
In this process they consume oxygen and give off oxygen

10. What is the purpose of the stems?
Two main Functions
The movement of materials- water, minerals, food
Support the leaves and reproductive structures
Can be used for food storage
Ex. Irish potato

11. What are the types of stems?
1) Woody Stem: trees, shrubs, woody perennials
2) Grass Stem: hollow or filled
3) Herbaceous Stem: like woody but softer (clover, alfalfa)
4) Modified Stem:

12. Types of Modified Stems
Bulbs: (onion)
Tubers: (potato)
Stolons: above ground runner (strawberry)
Rhizomes: below ground runners (field bindweed or creeping jenny)

13. What is the Terminal Bud for?
Terminal bud tries to make plant grow taller or longer
if we remove terminal bud, the plant will be shorter and thicker
Can you think of why we would want to do this??
What kind of plants could we do this on??

14. Internal Stem Structure
What does the Xylem Carry
Water and minerals travel up
What about the Phloem
Manufactured food travels down the plant
What does the Cambium do?
Separates the xylem and the phloem
Thin, green, actively growing tissue located between the bark and the wood of a plant

15. What is the difference in monocot and dicot and why should I care?
Dicot stem may continue to increase in diameter because the cambium builds new phloem cells on the outside and new xylem cells on the inside
Ex. Trees
Monocot have vascular bundles which contain both xylem and phloem and no cambium
This would make it more limited in size
Ex. corn

16. Why should we care? The stems of some plants we use as food
Irish potato and asparagus
Others are used in building materials
Lumber from the tree trunks

17. Roots Roots function Anchor the plant and hold it upright
Absorb water and minerals from the soil and conduct them to the stem
Store large quantities of plant food
Propagate or reproduce some plants

19. Fibrous root vs. tap root
Fibrous root system
Much easier to transplant
More spread out
Tap root system
Longer fewer roots
End of root contains many root hairs

20. Functions of Fruit:
1. Protect the seeds inside the ripened ovule (fruit).
2. Provide nutrients to the soil and
to a newly germinated seedling.

21. Animals eat the fruit and seeds. After the
3. Aid in the dissemination/spreading of seed by providing food for animals.
Animals eat the fruit and seeds. After the
fruit is digested, the seeds pass out in the
animal’s feces at another location.

22. 4. Some plants have dry, dehiscent fruits
which split open to disseminate seeds.

23. What is the purpose of seeds
To continue the plant process
There are two types
Monocots
dicots

24. Monocot and dicot