Plant Anatomy

1. Plant Anatomy Unit 1 Horticulture PFHS

2. Plant Types • Mosses and ferns – Bryophytes and Filicineae

3. Plant Types • Seed Plants • Tracheophytes Ex. Trees, grasses, vines, shrubs, flowering herbs, pond weeds, crop plants

4. Plant Types • Seed Plants • Cone-bearing plants – Gymnospermae – ginkgoes, conifers

5. Plant Types • Seed Plants • Flowering plants – Angiospermae

6. Plant Types • Seed Plants • Flowering plants – Angiospermae • Monocotyledon – cattail, grass, iris, orchid, cereal grains, onion

7. Plant Types • Seed Plants • Flowering plants – Angiospermae • Dicotyledon – walnut, peanut, bean, tomato, dandelion

8. Plant Types • Annuals – plants that live only 1 season – zinnia, marigold, petunia, bean, grain cereals

9. Plant Types • Biennial – plants that live 2 growing seasons – beets, carrots, cabbages

10. Plant Types • Perennials – plants that live more than 2 seasons – lilies, iris, trees, shrubs

11. Specialized Tissues of a Seed Plant • Meristematic tissue – small thin-walled cells that are capable of unlimited reproduction • Epidermal tissue – covering layer, usually one cell layer thick, found on surfaces of roots, stems, and leaves

12. Specialized Tissues of a Seed Plant • Cork – covering tissue found on surfaces of woody roots and stems • Parenchyma tissue – found in flower petals, leaves and various regions of roots and stems

13. Specialized Tissues of a Seed Plant • Strengthening tissues – found in roots and stems, stalks, and larger veins of leaves • Vascular tissues – serve as channels of conduction • Sieve tubes – end walls perforated and serve as channels of food conduction principally downward in leaves, stems, and roots • Vessels – paths for transport for water and minerals upward in roots and stems, and outward through stalks and veins of leaves • Tracheids – smaller and act as channels of water and mineral conduction as well as supporting cells, especially stems.

14. Specialized Tissues of a Seed Plant

15. Specialized Tissues of a Seed Plant • Phloem – includes sieve tubes, bast fibers, and parenchyma. In woody stems, phloem is a bark tissue • Xylem – often called wood – vessels, tracheids, fibers, and parenchyma and forms prominent region in roots and stems

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17. Plant Form • Plants need oxygen, carbon dioxide, water, minerals, and light • Specialized organs help them to obtain their needs • Most plant species appear similar, since all four organs are present in approximately the same form and have the same major functions. • Root • Stem • Leaf • Flower

18. Plant Form I. Root In most species the functions of the root system are to take up water and minerals from the growing medium and to anchor the plant in the growing medium

19. Plant Form 2 types of root system: • taproot – single large root (usually maintains direction of growth in response to gravity – geotropism) with many small lateral roots, used for food storage. The primary root is dominant. Ex. Chrysanthemum, carrot • Primary root – the first main one, Secondary root – branch off the primary root

20. Plant Form 2 types of root system: • fibrous root – many roots growing out form the base of the stem, used for water absorption and anchorage – Ex. Grasses, wheat, cactus

21. Plant Form Functions: • absorption of water and minerals from the soil • anchor plant in the ground • storage area for food

22. Plant Form Types: • aerial – absorb moisture from air – orchids, cypress trees in swampy areas • climbing – ivy • prop or brace – corn

23. Plant Form Structure: • root cap • root hair • epidermis • cortex • xylem • phloem • cambium • vascular tissues (center of the root)

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26. Plant Form II. Stem – usually cylindrical and support and produce leave of plants. • Also bear buds that give rise to flowers. • Roots never do.

27. Plant Form Types: • Herbaceous – without woody tissues, soft and easily broken. No strong supporting tissues. Depends on turgor pressure. Do not grow to be very tall and diameter of stem does not increase much. • Strengthening and vascular tissue reduced to strands and bundles

28. In monocot stems vascular bundles are scattered. In dicot stems vascular bundles are in a ring. They all have the same tissue layout within the stem in their first year.

29. Plant Form Types: • Woody stems – with woody tissues, large amounts of strong supporting tissue. • The stem grows in diameter as well as in height. • Large amount of strengthening and vascular tissue

30. Plant Form Structure: • buds – give rise to flowers • lenticels – small pores in bark through which there is an exchange of oxygen and carbon dioxide • scars – where leaves, buds, or fruit were once attached

31. Plant Form Structure: • pith – filling middle of stem – contains stored food • epidermis – outer most layer; • cutin – a waxy outer substance – protects against loss of water • guard cells – control opening and closing of pores (stomata) • cortex • bark – woody stems

32. Plant Form Structure: • annual rings

33. Secondary Growth of Stem Demonstrated

34. Plant Form Function - transport water and dissolved materials, stores food and in case of herbaceous may carry on photosynthesis, and to physically support the leaves and flowers. • There is a variety of design. . .

35. Potato

36. Strawberry

37. Climbing Vine

38. Corn

39. Plant Form Many stems or modified stems such as bulbs, rhizomes, corms, tubers, store food to tide the plant through dormancy, start its growth in spring or bring forth its flowers and seeds.

40. Bulb

41. Rhizome

42. Corm

43. Tuber

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45. 3 tissue types: Dicotyledonous stem • Epidermis – outer protective layer of the stem, leaves, and roots. • Consists of single layer of cells; allow gas exchange, otherwise impermeable • Cortex – zone of tissues found inside the epidermis and reaches inwards to the inner edge of the vascular bundles • Pith – central zone of the stem • mainly parenchyma cells

46. 3 tissue types: • Collenchyma and sclerenchyma cells are usually found to the inside of the epidermis, responsible for support • Both have thickened walls (made of cellulose) • Collenchyma cellulose increased for extra strength • Sclerenchyma lignin is added to wall for thickness, are long and tapered, interlock for additional strength • consist only of cell walls

48. 3 tissue types: Cortex contains a number of tissues • Parenchyma – thin walled and maintain shape by osmotic pressure • Mass of parenchyma cells combine to maintain plant shape. • The lack of water seen as wilting. • Function – contain chlorophyll and so are able to photosynthesize. Can act as food stores and can undergo cell division. • (Useful for cuttings that are being propagated).

49. 3 tissue types: Review of terms: Vascular bundles – contain two vascular tissues that are responsible for transport • Xylem – contains long, wide, open-ended cells, lignified walls, withstands high pressure • Phloem – found to be on the outside of xylem in most species • consists of long, tube-like cells • transports food made by leaves, carries it to the rest of the plant. • Walls are soft cellulose, end walls are sieve-like structures.

50. 3 tissue types: • Companion cells regulate the flow of liquids down the sieve tube • Cambium tissue – contains actively dividing cells producing more xylem and phloem tissues as the stem grows.