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

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Presentation on theme: "Roots, Stems and Leaves Chapter 23 Mr. Bragg 2014."— Presentation transcript:

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

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