Plant Parts and their Functions

1. Plant Parts and their Functions 13.00 Describe principles of plant science as related to horticulture 14.00 Compare the anatomical parts and distinguishing characteristics of horticultural plants

2. Plant Sciences • Biology-the branch of science that deals with both plant and animal organisms and life processes • Zoology-the part of biology that deals with animals • Botany the part of biology that deals with plants

3. Plant Sciences • Applied plant sciences are based on the purposes for which the plants are grown • Agronomy • Forestry • Horticulture

4. Agronomy The science and practice of growing field crops such as cotton, wheat, tobacco, corn and soybeans.

5. Forestry The science and practice of growing, managing and harvesting trees for building materials and other products.

6. Horticulture The science and practice of growing, processing and marketing fruits, vegetables, and ornamental plants

7. Life Cycles of Plants • Annual-a plant that completes its life cycle in one year • Biennial-a plant that completes its life cycle in two years • Perennial-a plant that lives more than two years

8. Leaf Retention • Deciduous-loses leaves during the dormant season • Evergreen-keeps leaves and remains green year-round

9. Plant Hormones • Several types of hormones are used to help plants work more efficiently. • Inhibitors • cytokinins • gibberellias • auxins

10. Inhibitors • Inhibitors hasten fruit ripening, retain seed germination and stem elongation.

11. Cytokinins • Hormones that work with auxins to stimulate cell division.

12. Gibberellias • Hormones that stimulate cell elongation, premature flowering, and breaking of dormancy.

13. Auxins • Hormones that speed plant growth by stimulating cell enlargement

14. Moisture in Plants • Turgid-plant is swollen or filled with moisture • Wilted-plant is limp because it does not have enough moisture

15. Plant Parts • Leaves • Stems • Roots • Flowers

16. Leaves-External • Petiole-leaf stalk or part that connects the leaf to the stem • Blade-the large, flat part of the leaf • Midrib-the large center vein • Veins-the structural framework of the leaf • Margin-the edge of the leaf

17. Leaves-External

18. Leaves-Internal • Upper and lower epidermis-skin of the leaf that prevents the loss of too much moisture • Stomates-small openings under the leaf for breathing or transpiration • Guard Cells-open and close stomates

19. Leaves-Internal • Chloroplasts-small green particles that contain chlorophyll • gives leaves their green color • necessary for photosynthesis

20. Leaves-Internal

21. Leaves-Internal

22. Stems-External • Lenticels-breathing pores • Bud scale scars-show where terminal buds have been located • Leaf Scars-show where leaves were attached • Terminal bud-bud on the end of a stem • Axillary or lateral bud-bud on side of stem

23. Stems-Internal • Xylem-tissue that transports water and nutrients up from the roots to stems and leaves • Phloem-tissue that transports food down from leaves to roots

24. Stems-Internal Phloem Phloem Xylem

25. Stems-Internal • Cambium-thin, green, actively growing tissue located between bark and wood and produces all new stem cells • Bark-old inactive phloem • Heartwood-old inactive xylem • Sapwood-new active xylem

26. Stems-Internal Bark Cambium Sapwood Heartwood

27. Stems-Internal • Monocota-plant stems have vascular bundles that contain both xylem and phloem in each bundle • examples: corn, grasses • Dicata-plant stems have the phloem layer and xylem layer separated by cambium • example: trees

28. Stems-Internal Monocot Dicot

29. Roots-External • Root cap-indicates growth of new cells • Root hairs-absorb moisture (water) and minerals Root images from a rice plant

30. Roots-Internal • Much like stems in that they have a phloem, cambium, and xylem layer • Phloem-the outer layer that carries food down the root • Xylem-the inner layer that carries water and minerals up to the stem

31. Layers of Roots • Fibrous-many branched shallow roots • are easier to transplant • Tap-long root with few branched ones • more difficult to transplant

32. Flowers • Sepals-Green parts that cover and protect flower bud before it opens • Petals-are really leaves that are modified to attract insects for flower pollination, the pretty part that we call flowers • Stamen-male part of the flower • Pistil-female part of the flower

33. Flowers

34. Parts of the Stamen • Filament-short stalk that holds up the anther • Anther-a sac-like structure that contains pollen, the male sex cells

35. Parts of the Pistil • Ovules-the eggs or female sex cells that become seeds if fertilized • Ovary-if fertilized becomes a fruit or seed coat • Style-holds up the stigma and connects it to the ovary • Stigma-sticky part on top of style where insects leave pollen

36. Parts of the Pistil Stigma Style Ovary

37. Complete-vs-Incomplete • Complete flowers have both male and female parts • Incomplete flowers have only male or female parts

38. What are the functions of these plant parts?

39. Functions of Leaves • Photosynthesis-manufactures food in green plants which is the beginning of the food chain for all living things • Photosynthesis is the process by which carbon dioxide and water in the presence of light are converted to sugar and oxygen

40. Functions of Stems • Translocation-moves water and minerals from roots up to the leaves and move food from the leaves down to the roots • Supports branches, leaves, flowers, fruits and seeds

41. Functions of Roots • Absorption-take water and nutrients from the soil and conduct them to the stem • Anchor the plant and hold it upright • Store food for plant use • Asexual reproduction in some plants

42. Functions of Flowers • Produce seeds used for sexual reproduction • Attract insects for pollination (Pollination is the transfer of pollen from anther to stigma.) • Produce fruit to protect, nourish and carry seeds