Plant Cells, Tissues and Organs

1. Plant Cells, Tissues and Organs

2. Cell Specialization & Cell Differentiation http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookplantanat.html http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookplantanat.html http://earthsky.org/human-world/nate-lewis-on-artificial-photosynthesis http://www-plb.ucdavis.edu/labs/rost/tomato/Roots/rootcell.html

3. Specialized Cells & Tissues in Plants • Tissue: group of specialized cells • Organ: Group of several types of tissues working towards a specific function • Meristem: unspecialized cell that can form specialized cells in plants

4. Tissues in Plants

5. Repairing & Replacing Specialized Cells • Buds: Swelling of the stem • Terminal Bud – most active growth, produce Auxin • Lateral Bud – dormant regions, inhibited by Auxin

6. Plant Organs • Leaf • Stem • Root • Flower

7. The Leaf • Dermal tissue • Palisade tissue • Mesophyll tissue • Vascular bundles

8. The Leaf – Tissues • Dermal tissue • Waxy cuticle – limits water loss • Protects the leaf • Palisade tissue • Prime site of photosynthesis – palisade cells and chloroplast • Mesophyll tissue • Loosely packed cells • Spaces contain gases such as H2O, CO2 and O2 • Vascular tissue • Xylem – transports water to the photosynthesizing cells • Phloem – transports sugar throughout the plant • Small vein branches – every cell gets water and nutrients

9. The Leaf – Lower epidermis • Exchange of gases • Guard cells • Control opening and closing of stomata • Stomata • Connected to spongy mesophyll • CO2 enters, O2 and H2O exits through them • Transpiration – evaporation of water from leaves

10. Chloroplast

11. The Stem • Provides physical support and transports sap • Composed mainly of xylem tissue • Dead tubular hollow cells fortified with lignin • Vascular bundle • Phloem (living porous cells) exchanges materials with neighbouring cells

12. The Roots • Anchor a plant to the ground • Allow water and minerals uptake from the soil • Some also act as plant’s storage area

13. The Roots • Dermal tissue • Root hair – increase surface area for absorption • Ground tissue • Cortex – provide support • Pericycle – vascular tissue

14. Types of Roots Fibrous root • Large surface area to absorb water • Stabilize soil • Prevent erosion & landslides Tap root • Allows plant to reach far underground for water • Anchors the plant

15. Plants Under Attack

16. The Flower • Reproduction - pollen and eggs • Pollination: transfer of pollen to female parts of flower • Seeds are produced and embedded in fruits • Hormone called ethylene stimulates ripening of fruits

17. Homework  • P. 69 # 1, 3, 5 - 7