1. Specialized Tissue in Plants
Chapter 23
ROOTS, LEAVES & STEMS
Specialized Tissue in Plants

2. Basic Parts of a Plant
Roots
Stem
Leaves
Flower

3. Section 23-2
Roots

4. Types of Root Systems Taproot System Fibrous Root System
Primary roots grow down from the stem with some secondary roots forming.
Fibrous Root System
Small lateral roots that spread out just below the soil surface.

5. Four Root Functions Absorption of water and nutrients.
Transportation of water and nutrients to stem.
Anchor plant to maintain stability.
Store food and wate.r

6. Parts of a Root

7. Parts of a Root Epidermis Cortex
Outermost layer of cells, like the skin of the root.
Cortex
Tissue inside epidermis that stores starch and other substances for the growth of the root.

8. Parts of a Root Root Cap Root Hairs Vascular Tissue
Provides protection for the root tip.
Root Hairs
Site of absorption.
Vascular Tissue
Within cortex, contains cells that transport water, nutrients, and minerals to all parts of the plant.
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9. Parts of a Root

10. Section 23.3
Stems

11. Function of Stems Transport water and nutrients from roots to leaves.
Supports/produces leaves, branches, and fruit/flowers.
Food storage.
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12. Types of Stems Woody: Herbaceous:
Thick cell walls that support the plant.
Trees, shrubs, and vines.
Herbaceous:
Stems are smooth, supported by hydrostatic pressure (turgor).
Dandelions, zinnias, petunias.

13. Types of Stems
Woody Stem
Herbaceous Stem

14. Parts of a Stem Node Internode Xylem Phloem
Areas where side branches and leaves develop.
Internode
Area between nodes.
Xylem
Carries water up.
Phloem
Carries nutrients throughout plant.

15. Monocot & Dicot Stems
Monocot: vascular bundles scattered throughout the stem.
Dicot (and most gymnosperms): vascular bundles are arranged in a cylinder.

16. Cross-Section of Stems
Woody Stem
Dicot Stem
Monocot Stem

17. Growth of Stems
Primary growth of stems is produced by cell divisions in the apical meristem.
It takes place in all seed plants.
In conifers and dicots, secondary growth takes place in the lateral meristematic tissues called the vascular cambium and cork cambium.

18. Woody Stems Actual wood part of the stem is xylem tissue.
Heartwood (pith): stores food.
Sapwood: active in fluid transport; xylem and phloem.
Cambium: producing new tissue, vascular.
Cork: bark

19. Formation of Bark

20. Section 23.4
Leaves

21. Function of Leaves Photosynthesis Transpiration
The structure of a leaf is optimized for absorbing light and carrying out photosynthesis.
Photosynthesis
Process that plants use to produce their food.
6CO2 + 6H2O  C6H12O6 + 6O2
Transpiration
Loss of water and exchange of carbon dioxide.

22. Parts of a Leaf Cuticle Mesophyll
Waxy outer surface; retains moisture.
Mesophyll
Middle layer of leaf where photosynthesis occurs.
Palisade layer (upper)
Spongy layer (underside)

23. Parts of a Leaf Epidermis Stomata
“Skin” of leaf - responsible for gas exchange
Upper and lower
Stomata
Outside layer of leaf opening in epidermis where gas and water exchange (controlled by guard cells)

24. Leaves

25. Leaves Letter Structure Color Function A Cuticle Yellow
Waxy outer surface; retains moisture. B
Epidermis
Orange
“Skin” of leaf - responsible for gas exchange. C
Vein (Xylem)
Blue
Pumps water up from soil through roots. D
Vein (Phloem)
Red
Moves nutrients and carbohydrates throughout the plant. E
Mesophyll
Green
Middle layer of leaf where photosynthesis occurs. F
Stomata
Pink
Outside layer of leaf opening in epidermis where gas and water exchange. G
Guard Cells
Brown
Control stomata; trigger when water is scarce causing stomata to become flaccid and pores close.

26. Leaves
Dicot Leaf

27. Turgor Pressure Turgor pressure (water pressure)
Stomata close automatically when supplies of water from roots start to dry up
Guard cells trigger when water is scarce causing stomata to become flaccid and pores close

28. Leaf Venation

29. Leaf Adaptations

30. Section 23.5
Transport in plants

31. Capillary Action The tendency of water to rise in a thin tube.
The result of the water molecules’ ability to stick to one another (cohesion) and to the walls of the tube (adhesion); contributes to the movement of water up the cells of the xylem tissue.