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

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

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

6. Principal Tissues of the Leaf Epidermis (cont) 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 Cells in the center of the leaf The chloroplast contains chlorophyll which gives the plants the green color The chloroplast contains chlorophyll which gives the plants the green color Manufactures food for the plant though Photosynthesis Manufactures food for the plant though Photosynthesis Beginning of the food chain for all living things Beginning of the food chain for all living things

8. Photosynthesis 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 CARBON DIOXIDE + WATER + LIGHT ENERGY = GLUCOSE + OXYGEN

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

10. What is the purpose of the stems? Two main Functions Two main Functions –The movement of materials- water, minerals, food –Support the leaves and reproductive structures Can be used for food storage 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) Bulbs: (onion) Tubers: (potato) Tubers: (potato) Stolons: above ground runner (strawberry) Stolons: above ground runner (strawberry) Rhizomes: below ground runners (field bindweed or creeping jenny) 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 Terminal bud tries to make plant grow taller or longer if we remove terminal bud, the plant will be shorter and thicker 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 What does the Xylem Carry –Water and minerals travel up What about the Phloem What about the Phloem –Manufactured food travels down the plant What does the Cambium do? 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 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 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 The stems of some plants we use as food –Irish potato and asparagus Others are used in building materials Others are used in building materials –Lumber from the tree trunks

17. Roots Roots function 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 Fibrous root system –Much easier to transplant –More spread out Tap root system 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. 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 To continue the plant process There are two types There are two types –Monocots –dicots

24. Monocot and dicot