1. Plant Structures Original PowerPoint crated by Mr. Morgan Modified by Georgia Agriculture Education Curriculum Office June 2002

2. What Are primary parts of plants? • Leaves • Stems • Roots • Flowers

3. What are the functions of leaves? • Capture light • Exchange gases • Provide a site for photosynthesis • Some leaves store food and water • Some form new plants and provide support

4. What is photosynthesis? • It is a process by which plants combine water and carbon dioxide in the presence of chlorophyll and sunlight and produce carbohydrates and release oxygen.

5. Why is photosynthesis important? • Light is the most important source of energy for living things. Photosynthesis converts light into nutrients that can be used by plants and animals. • Releases oxygen

6. Photosynthesis • Light+6CO2+12H20-Sunlight-> C6H1206+6O2+6H20

7. There are two parts of photosynthesis--the light and dark reactions. • The light reactions produce chemical energy from light. • The dark reactions convert carbon dioxide into carbohydrates.

8. Leaves in gas exchange • Oxygen, Carbon Dioxide, and Water exchanged from Stomata • Pores open in day to transpire H2O and allow gases to enter • Close during dry conditions to prevent H2O loss.

9. External Parts of Leaves • Petiole- Stalk of leaf that attaches to stem • Midrib- Main vein of vascular tissue • Blade- Photosynthetic site of leaf

11. Stomata • Openings on the epidermis • allows air into leaf • allows H2O and oxygen out of leaf

12. Stems • Water and mineral transport by capillary action and cohesion to the leaves. • Transport food to the roots • Gas exchange • Produce and support new leaves, branches, and flowers

13. Internal parts of stem • Phloem • Xylem • Cambium • Pith • Cortex

14. Functions • Phoem-Sugar and carbohydrates to roots • Xylem- Water and nutrients • Cambium- Growing part of stem

15. Function Cont’ • Pith-Occupies the central area of the stem • Cortex- Composed of several layers of thick-walled cells

16. External parts of stem • Buds • Nodes • Internodes

17. Modified Stems • Rhizomes- Horizontal underground stems(Bermuda Grass • Stolons- Horizontal above ground stems(strawberries) • Tubers- Greatly enlarged tip of underground stem

18. Cont. • Bulbs- budlike structure consisting of a small stem (onion) • Corms- Fleshly leaves underground stems with few nodes(gladiolus)

19. Functions of Roots • Anchor plants in soil • Absorb water and nutrients • Some store reserves for future uses(Potato) • Propagation

20. Advantages Penetrates deeper Obtain water from other levels Anchor plant Disadvantages Difficult to remove or harvest do not stabilize well Taproots

21. Advantages Shallower, better for fertilization & Water Stabilize in soil better Disadvantage Less drought resistant Tend to get exposed during cultivation Fibrous

22. Primary Roots • Grow down into the soil and may branch repeatedly into lateral roots • Taproot is a primary root

23. Lateral Roots • Called Secondary roots • grow horizontally away from the primary root • Some grow downward

24. Adventitious • Came from stems or leaves instead of another root • Prop root of corn and grapes are examples that give support

25. Fibrous Root • Root structures in which the primary and lateral roots develop equally so there is not a definite taproot.

26. Storage Roots • Are structures such as those of carrots and sweet potatoes which are used for food storage.

27. What do stems and roots have in common? • Both have xylem and phloem cells for transport.

28. Male flowers and their parts and functions. • Stamen- has two parts- filament and antherFilament- supports the anther • Anther- Produces pollen grains

30. Female parts and their functions • Ovule-develops into a seed • Ovary- surrounds the ovule, later becomes the fruit • Style-supports the stigma • Stigma- receives the pollen grain • Pistil- All three female parts together

32. Other parts of flower • Receptacle- enlarged part of the flower stalk where floral part is. • Sepals- outer protective parts of buds • Petals- the colored part of the flower used to attract insects

33. Complete Flower • Both have Male and Female parts

34. Incomplete Flowers • Have either male or female parts but not both

35. Monoecious • Plants that have male and female flower parts on separate plants

37. Dioecious • Have both parts on the same plant.

39. Pollination • The transfer of pollen from one anther to anther stigma. • Two ways- self-pollination & Cross-pollination • Bees and Wind

40. The End