roots, stems and leaves chapter 23 biology – miller levine

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  • Slide 1
  • Roots, Stems and Leaves Chapter 23 Biology Miller Levine
  • Slide 2
  • Specialized Tissue in Plants The three organs of a plant are the roots, stems and leaves The three organs of a plant are the roots, stems and leaves The three tissue systems of a plant are dermal tissue, vascular tissue, and ground tissue The three tissue systems of a plant are dermal tissue, vascular tissue, and ground tissue A special type of tissue called meristematic tissue is the only plant tissue that can produce new cells by mitosis A special type of tissue called meristematic tissue is the only plant tissue that can produce new cells by mitosis Found in the tips of shoots and roots Found in the tips of shoots and roots
  • Slide 3
  • Dermal Tissue The outer covering of a plant The outer covering of a plant Consists of a single layer of epidermal cells Consists of a single layer of epidermal cells Cuticle a waxy layer that often covers the epidermis Cuticle a waxy layer that often covers the epidermis Provides protection against water loss & injury Provides protection against water loss & injury May include specialized structures such as root hairs and guard cells May include specialized structures such as root hairs and guard cells
  • Slide 4
  • Vascular Tissue Transports water and nutrients throughout the plant Transports water and nutrients throughout the plant Xylem transports water; composed of dead cells Xylem transports water; composed of dead cells Phloem transports nutrients; composed of living cells called sieve tube elements Phloem transports nutrients; composed of living cells called sieve tube elements
  • Slide 5
  • Ground Tissue Lies between the dermal and vascular tissues Lies between the dermal and vascular tissues Parenchyma has thin cell walls and large central vacuoles Parenchyma has thin cell walls and large central vacuoles Collenchyma has strong, flexible cell walls and is found in larger plants Collenchyma has strong, flexible cell walls and is found in larger plants Sclerenchyma has extremely thick, rigid cells walls Sclerenchyma has extremely thick, rigid cells walls
  • Slide 6
  • Roots Types of roots: Types of roots: Taproot - A thick primary root that grows long and is found mainly in dicots Taproot - A thick primary root that grows long and is found mainly in dicots Fibrous roots branch extensively and are found mainly in monocots Fibrous roots branch extensively and are found mainly in monocots
  • Slide 7
  • Root Structure & Growth Root hairs tiny projections from the epidermis that increases the surface area for absorption of water Root hairs tiny projections from the epidermis that increases the surface area for absorption of water Cortex layer of ground tissue Cortex layer of ground tissue Endodermis layer of tissue that encloses the vascular tissue Endodermis layer of tissue that encloses the vascular tissue Root cap protects the root as it forces its way through the soil Root cap protects the root as it forces its way through the soil
  • Slide 8
  • Root Structure & Function
  • Slide 9
  • Root Function Anchor a plant in the ground Anchor a plant in the ground Absorb water and dissolved nutrients from the soil Absorb water and dissolved nutrients from the soil
  • Slide 10
  • Stem Function & Types Three important functions: Three important functions: Produce leaves, branches and flowers Produce leaves, branches and flowers Hold leaves up in the sunlight Hold leaves up in the sunlight Transport substances between roots and leaves Transport substances between roots and leaves Two types: Two types: Monocot has vascular bundles that contain the xylem & phloem scattered randomly Monocot has vascular bundles that contain the xylem & phloem scattered randomly Dicot have vascular bundles organized in a ringlike pattern Dicot have vascular bundles organized in a ringlike pattern
  • Slide 11
  • Monocots and Dicots
  • Slide 12
  • Stem Structures Nodes where leaves are attached Nodes where leaves are attached Internodes regions between the nodes Internodes regions between the nodes Buds contain undeveloped tissue that can produce new stems and leaves Buds contain undeveloped tissue that can produce new stems and leaves
  • Slide 13
  • Leaf Structure Blade thin, flattened section Blade thin, flattened section Petiole thin stalk that attaches the leaf to the stem Petiole thin stalk that attaches the leaf to the stem Veins contain the xylem and phloem Veins contain the xylem and phloem
  • Slide 14
  • Leaf Structure Palisade mesophyll tightly packed cells that absorb light Palisade mesophyll tightly packed cells that absorb light Spongy mesophyll loosely packed cells with air spaces Spongy mesophyll loosely packed cells with air spaces Stomata pore-like openings for taking in CO 2 and releasing O 2 Stomata pore-like openings for taking in CO 2 and releasing O 2 Guard cells cells that open and close the stomata Guard cells cells that open and close the stomata
  • Slide 15
  • Leaf Structure
  • Slide 16
  • Leaf Functions Photosynthesis takes place in the mesophyll cells of the leaf 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) 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 Gas exchange taking in carbon dioxide and releasing oxygen