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Unit 7 Chapter 23 Plant Structure and Function

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1 Unit 7 Chapter 23 Plant Structure and Function

2 Typical plant cell

3 Plant Tissues 1) Dermal Tissue
For covering and protection, and controlling water loss Examples: epidermis, including cuticle of leaves, guard cells & stomata

4 Plant Tissues 2) Vascular tissue
For transport of food, minerals and water Examples: Xylem (for transporting upward from roots) Phloem (for transporting downward from leaves) Phloem Xylem

5 Plant Tissues 3) Ground tissue
cortex 3) Ground tissue For storage, food production, strengthening and support Examples: cortex, pith, mesophyll pith

6 Plant Tissues 4) Meristematic tissue For production of new cells
Apical Meristem of Shoot 4) Meristematic tissue For production of new cells Examples: growing tips in roots and stems (shoots)

7 Roots To anchor, absorb, and conduct Types of root systems: 1) taproot
One main root with branches Ex: carrot 2) fibrous Many small branching roots Ex: grass

8 Root Structure 1) Root cap Protective covering of root tip
2) Apical Meristem Region of cell division (where mitosis occurs)

9 Root Structure 3) Epidermis
cortex 3) Epidermis May contain root hairs for increasing surface area 4) Cortex Ground tissue for storage of food and water

10 Root Structure 5) Endodermis
Waterproof cells that control flow of water into vascular tissue 6) Pericycle Produces lateral roots

11 Root Structure 7) Xylem (star-shaped center) Transports water upward
8) Phloem (between rays of star) Transport food downward

12 Stems To support, conduct, and store Arrangement of Vascular Bundles:
Monocots Randomly scattered Dicots Radially arranged Can you classify these stems?

13 Woody stems Bark Wood Pith (young stems)
Composed of cork, phloem, & vascular cambium Wood Composed entirely of xylem tissue Contains annual growth rings Pith (young stems) Pith

14 Pith

15 Translocation The movement of sugars through the phloem, from the source (origin) to the sink (storage area, such as root or fruit)

16 Leaves For photosynthesis and transpiration
1) Blade (flat green portion) Simple One undivided blade Compound Blade divided into leaflets 2) Petiole (stalk) Contains vascular tissue, attaches to stem

17 Leaf structure 3) Epidermis
Upper epidermis produces waxy cuticle to prevent water loss Lower epidermis contains guard cells & stomata to control water loss cuticle

18 Leaf structure 4) Mesophyll
Photosynthetic tissue made up of palisade & spongy cells 5) Veins Contains xylem & phloem cells

19 Transpiration Evaporation of water through stomata
Plants lose 90% of the water they transport from the roots by transpiration. What happens to the other 10%? When water enters the guard cells, pressure causes them to bow, opening the stoma When water leaves the guard cells, pressure is lost and the cells come together, closing the stoma

20 Plant hormones Like animals, plants produce hormones to regulate growth & development Hormones are chemicals produced in one part and transported to another to effect a change Examples of plant hormones are Auxin, Gibberellins, Cytokinins, & Ethylene (Without) (With) Gibberellin

21 Tropic responses in plants
Tropism is a plant’s response toward a stimulus, such as gravity (gravitropism), light (phototropism) or touch (thigmotropism) Ex: phototropism is the growth of a plant toward light

22 Nastic responses in plants
Nastic movements are NOT dependent on the direction of the stimulus For example: in a Venus’s fly-trap, the insect triggers sensitive hairs on the surface and the leaf snaps shut

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