1. Roots, Stems and Leaves
Chapter 23
Mr. Bragg
2014

2. EQ: How are plant tissues organized?
Objectives:
Identify the main organs of vascular plants
Explain the functions of the main tissues
Contrast meristems with other plant tissues

3. A. Specialized Tissue in Plants
Plants have 3 main organs
a. Roots
b. stems
c. leaves

4. 2. Plants have three tissue systems:
a. dermal tissue
b. vascular tissue
c. ground tissue

5. 3. A special type of tissue called meristematic tissue is the only plant tissue that can produce new cells by mitosis
a. Found in the tips of shoots and roots

6. 4. Dermal Tissue a. The outer covering
b. single layer of epidermal cells
Cuticle – a waxy layer that often covers the epidermis
Provides protection against water loss & injury
c. May include specialized structures such as root hairs and guard cells

8. Stomata Function Allows for taking in of CO2 for photosynthesis
Drawback = loss of water vapor (transpiration)
Larger leaf area = more water loss

9. 5. Review - Vascular Tissue
a. Transports water and nutrients throughout the plant
Xylem – transports water; composed of dead cells
Phloem – transports nutrients; composed of living cells called sieve tube elements

10. 6. Ground Tissue
Lies between the dermal and vascular tissues

11. Activity/lab Work in pairs No more than 4 people / lab table
Follow handout procedure
Finish lab portion in class
Take home the questions- due tomorrow

13. Do Now - Review 1. Compare and contrast gymnosperms and angiosperms.
2. What are the 3 main tissues found in vascular plants?
3. What are the 3 main organs of plants?

14. EQ: How do the structure and function of the 3 main organs help a plant to carry out life processes?
Objectives:
Describe the different functions of the 3 main organs in plants.

15. Root Function Anchor a plant in the ground
Absorb water and dissolved nutrients from the soil

16. Root Structure & Growth
Root hairs – tiny projections from the epidermis that increases the surface area for absorption of water

17. 1. Cortex – layer of ground tissue
a. Cells in this layer may contain:
stored carbohydrates
Resins
Latex
Essential oils
Tannins

18. Endodermis – layer of tissue that encloses the vascular tissue; may be important for fluid transport

19. Root Structure & Function
Root cap – protects the root as it forces its way through the soil
Apical meristem – actively growing part of root; protected by cap

20. Modified Roots Why are they important?
Food storage and/or increases fitness (adaptations)
Modified Roots

21. Stem Function Three important functions:
Produce leaves, branches, and flowers
Hold leaves up to the sunlight
Transport substances between roots and leaves

22. Stem types: Monocots and Dicots
Two types:
Monocot – has vascular bundles that contain the xylem & phloem scattered randomly
Dicot – have vascular bundles organized in a ringlike pattern

23. Stem Structures Nodes – where leaves are attached
Internodes – regions between the nodes
Buds – contain undeveloped tissue that can produce new stems and leaves

24. Specialized or Modified Stems
Includes:
Stolons
Tubers
Rhizomes
Bulbs
Why are they important?
Food storage or exploiting new territory

25. Leaf Functions
Photosynthesis – takes place in the mesophyll cells of the leaf
Transpiration – the loss of water from a plant through its leaves (helps to pull water up from the roots)
Gas exchange – taking in carbon dioxide and releasing oxygen

26. Leaf Structure Blade – thin, flattened section
Petiole – thin stalk that attaches the leaf to the stem
Veins – contain the xylem and phloem

27. Leaf Structure
Palisade mesophyll – tightly packed cells that absorb light
Spongy mesophyll – loosely packed cells with air spaces
Review
Stomata – pore-like openings for taking in CO2 and releasing O2
Guard cells – cells that open and close the stomata

28. Leaf Structure

29. Modified Leaves Why are they important?
Exploiting new territory, protection, nutrient acquisition

30. Closing What are the 3 functions of stems?
What are the 2 functions of roots?
Give an example of a modified plant organ. Why did some plants evolve these modifications?

31. Hormones
Defined: a chemical signal produced in one part of the body and transported to other parts of the body, where it can act on target cells