2. Specialized Tissues in Plants Plant Organs: Roots, Stems, and Leaves Roots Anchor the plant and absorb nutrients and water Mutualistic relationship with mycorrhizae and rhizobacteria Transport Nutrients to the plant Store Food

3. Specialized Tissues in Plants Stems Support the plant Transport water and nutrients Protect against predators and disease

4. Specialized Tissues in Plants Leaves Conduct photosynthesis Increased SA:V with leaf size Protect against water loss Waxy cuticle Stomata and Guard Cells

5. Specialized Tissues in Plants Plant Tissues: Dermal, Vascular, and Ground Tissue

6. Specialized Tissues in Plants Dermal Tissue Covers the plant Epidermis (epi = upon) – single layer of cells on the outside of the plant Cuticle – layer of wax that covers the epidermis and prevents water loss (polarity?) Trichomes – tiny hairlike projections for protection Bark – covers the epidermis in woody plants Root hair cells are found on the epidermis of roots to help absorb water (SA:V)

7. Specialized Tissues in Plants Vascular Tissue Vessels that transport water and nutrients Plant “bloodstream” Xylem – carries water Phloem – carries nutrients

8. Specialized Tissues in Plants Ground Tissue Produces and Stores food (sugars) Composes most of the edible portions of plants Contributes to the physical support of the plant

9. Plant Growth and Meristems Meristems – regions of specialized plant cells in which mitosis produces new cells ready for differentiation The undifferentiated cells produced are much like the stem cells of animals Located in parts of plants that undergo rapid growth Allow even the oldest trees to produce new leaves and new reproductive organs each year

10. Apical Meristem – located at the end (apex) of a root or stem. Leads to increase in root or stem length Once produced, the new cells differentiate into new dermal, vascular, and ground tissue

11. Floral Meristems Produce the tissues of flowers Includes the plant’s reproductive organs as well as the colorful petals that surround them

12. Tropism The (growth or turning) movement of a plant in response to an environmental stimulus Includes – Phototropism Gravitropism Thigmotropism Taxis The movement (or migration) of an animal in response to an environmental stimulus Includes – Hydrotaxis Thermotaxis Magnetotaxis Phototaxis

13. Phototropism The growth or movement of a plant in response to light Positive phototropism is expressed when a plant moves toward the light (stems and leaves) Negative phototropism is expressed when a plant moves away from the light (roots)

14. Gravitropism (geotropism) The growth or movement of a plant in response to gravity Positive gravitropism is expressed when a plant moves with the pull of gravity (roots) Negative gravitropism is expressed when a plant moves against the pull of gravity (stems and leaves)

15. Thigmotropism The growth or movement of a plant in response to touch Positive thigmotropism is expressed when a plant moves towards touch (venus fly trap and vines) http://www.youtube.com/watch?v=hGCg5bhV1X4http://www.youtube.com/watch?v=hGCg5bhV1X4 Negative thigmotropism is expressed when a plant moves away from touch (stems and leaves) http://www.youtube.com/watch?v=BLTcVNyOhUchttp://www.youtube.com/watch?v=BLTcVNyOhUc