Roots, Stems and Leaves Roots, Stems and Leaves
Chapter 23Chapter 23
Mr. BraggMr. Bragg
20142014
EQ: How are plant tissues organized?EQ: How are plant tissues organized?
Objectives:Objectives: Identify the main organs of vascular plantsIdentify the main organs of vascular plants Explain the functions of the main tissuesExplain the functions of the main tissues Contrast meristems with other plant tissuesContrast meristems with other plant tissues
A. Specialized Tissue in PlantsA. Specialized Tissue in Plants
1.1. Plants have 3 Plants have 3 main organsmain organs
a. Rootsa. Roots
b. stems b. stems
c. leavesc. leaves
2. Plants have three tissue systems:2. Plants have three tissue systems:
a. dermal tissuea. dermal tissue
b. vascular tissueb. vascular tissue
c. ground tissuec. ground tissue
3. A special type of tissue called 3. A special type of tissue called meristematicmeristematic tissue is the only plant tissue that can produce tissue is the only plant tissue that can produce new cells by mitosisnew cells by mitosis
a. Found in the tips of shoots and rootsa. Found in the tips of shoots and roots
4. Dermal Tissue4. Dermal Tissue
a. The outer covering a. The outer covering
b. single layer of epidermal cellsb. single layer of epidermal cellsCuticleCuticle – a waxy layer that often covers the epidermis – a waxy layer that often covers the epidermis
Provides protection against water loss & injuryProvides protection against water loss & injury
c. May include specialized structures such as root hairs c. May include specialized structures such as root hairs and guard cellsand guard cells
Stomata FunctionStomata Function
Allows for taking in of CO2 for Allows for taking in of CO2 for photosynthesisphotosynthesis
Drawback = loss of water vapor (transpiration)Drawback = loss of water vapor (transpiration) Larger leaf area = more water lossLarger leaf area = more water loss
5. Review - Vascular Tissue5. Review - Vascular Tissue
a. Transports water and a. Transports water and nutrients throughout the nutrients throughout the plantplantXylemXylem – transports – transports water; composed of dead water; composed of dead cellscellsPhloemPhloem – transports – transports nutrients; composed of nutrients; composed of living cells called sieve living cells called sieve tube elementstube elements
6. Ground Tissue6. Ground Tissue Lies between the dermal and vascular tissuesLies between the dermal and vascular tissues
Activity/labActivity/lab1.1. Work in pairsWork in pairs
2.2. No more than 4 people / lab tableNo more than 4 people / lab table
3.3. Follow handout procedureFollow handout procedure
4.4. Finish lab portion in classFinish lab portion in class
5.5. Take home the questions- due tomorrowTake home the questions- due tomorrow
Do Now - ReviewDo Now - Review
1. Compare and contrast gymnosperms and 1. Compare and contrast gymnosperms and angiosperms. angiosperms.
2. What are the 3 main tissues found in vascular 2. What are the 3 main tissues found in vascular plants?plants?
3. What are the 3 main organs of plants?3. What are the 3 main organs of plants?
EQ: How do the structure and function of the 3 EQ: How do the structure and function of the 3 main organs help a plant to carry out life main organs help a plant to carry out life processes?processes?
Objectives:Objectives: Describe the different functions of the 3 main Describe the different functions of the 3 main
organs in plants. organs in plants.
Root FunctionRoot Function
Anchor a plant in Anchor a plant in the groundthe ground
Absorb water and Absorb water and dissolved nutrients dissolved nutrients from the soilfrom the soil
Root Structure & GrowthRoot Structure & Growth
Root hairsRoot hairs – – tiny tiny projections projections from the from the epidermis that epidermis that increases the increases the surface area surface area for absorption for absorption of waterof water
1. Cortex1. Cortex – layer of ground tissue – layer of ground tissue
a. Cells in this layer may contain:a. Cells in this layer may contain:stored carbohydrates stored carbohydrates ResinsResinsLatexLatexEssential oilsEssential oilsTanninsTannins
EndodermisEndodermis – layer of tissue that encloses the – layer of tissue that encloses the vascular tissue; may be important for fluid vascular tissue; may be important for fluid transporttransport
Root Structure & FunctionRoot Structure & Function
Root cap – protects the root as it forces its way through the soilApical meristem – actively growing part of root; protected by cap
Modified RootsModified Roots
Why are they important?Food storage and/or increases fitness (adaptations)
Stem FunctionStem Function
Three important Three important functions:functions: Produce leaves, Produce leaves,
branches, and branches, and flowersflowers
Hold leaves up to Hold leaves up to the sunlightthe sunlight
Transport Transport substances between substances between roots and leavesroots and leaves
Stem types: Monocots and DicotsStem types: Monocots and Dicots
Two types:Monocot – has vascular bundles that contain the xylem & phloem scattered randomlyDicot – have vascular bundles organized in a ringlike pattern
Stem StructuresStem Structures
NodesNodes – where – where leaves are attachedleaves are attached
Internodes Internodes – regions – regions between the nodesbetween the nodes
BudsBuds – contain – contain undeveloped tissue undeveloped tissue that can produce new that can produce new stems and leavesstems and leaves
Specialized or Modified StemsSpecialized or Modified Stems
1.1. Includes:Includes:
a.a. StolonsStolons
b.b. TubersTubers
c.c. RhizomesRhizomes
d.d. BulbsBulbs
Why are they important?Food storage or exploiting new territory
Leaf FunctionsLeaf Functions
Photosynthesis – takes place in the mesophyll Photosynthesis – takes place in the mesophyll cells of the leafcells of the leaf
Transpiration – the loss of water from a plant Transpiration – the loss of water from a plant through its leaves (helps to pull water up from through its leaves (helps to pull water up from the roots)the roots)
Gas exchange – taking in carbon dioxide and Gas exchange – taking in carbon dioxide and releasing oxygenreleasing oxygen
Leaf StructureLeaf Structure
BladeBlade – thin, flattened section – thin, flattened section PetiolePetiole – thin stalk that attaches the leaf to the – thin stalk that attaches the leaf to the
stemstem VeinsVeins – contain the xylem and phloem – contain the xylem and phloem
Leaf StructureLeaf Structure
Palisade mesophyllPalisade mesophyll – tightly packed cells that – tightly packed cells that absorb lightabsorb light
Spongy mesophyllSpongy mesophyll – loosely packed cells with air – loosely packed cells with air spacesspaces
ReviewReview StomataStomata – pore-like openings for taking in CO – pore-like openings for taking in CO22
and releasing Oand releasing O22
Guard cellsGuard cells – cells that open and close the – cells that open and close the stomatastomata
Leaf StructureLeaf Structure
Modified LeavesModified Leaves
Why are they important?•Exploiting new territory, protection, nutrient acquisition
ClosingClosing
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?
HormonesHormones Defined: a chemical signal produced in one Defined: a chemical signal produced in one
part of the body and transported to other parts part of the body and transported to other parts of the body, where it can act on target cellsof the body, where it can act on target cells