Root: Functions

1
Root Functions

• Uptake of plant nutrients
• Active transport of minerals requires ATP!
• Movement into the vascular cylinder Casparian
  strip waterproof strip that surrounds plant
  endodermis cells
• Root pressure

2
Stem Structure and Function

• Produce leaves, branches and flowers
• Hold leaves up in the sunlight
• Transport substances between roots and leaves

3
Stem Structure and Function

• Node point on a stem where a leaf is attached
• Internode region between nodes on plant stems
• Bud plant structure containing undeveloped
  tissue that can produce new stems and leaves

4
Monocot and Dicot Stems

• Monocot Stems vascular bundles are scattered
  throughout the stem
• Dicot Stems (and most gymnosperms) vascular
  bundles are arranged in
  
  a cylinder
• Pith parenchyma
  cells inside
  the ring
  of vascular tissue
  in
  dicot stems

5
Primary Growth of Stems

• Type of plant growth that occurs at the tips of
  roots and shoots
• Cell divisions in the apical meristem
• Takes place in all seed plants

6
Secondary Growth of Stems

• Pattern of plant growth in which stems increase
  in width
• Enables the plant to support more weight and more
  fluid through the vascular tissues

7
Formation of the Vascular Cambium

• New layers of vascular tissue are created each
  year after secondary growth begins
• New meristematic tissue forms between the xylem
  an phloem of each vascular bundle
• Divisions in the vascular cambium give rise to
  new layers of xylem and phloem

8
Formation of Wood

• Most of what we call wood is actually layers of
  xylem
• Heartwood older xylem near the center of a woody
  stem that no longer conducts water darkens with
  age
• Sapwood area in plants that surrounds heartwood
  and is active in fluid transport lighter in
  color
• Heartwood and sapwood make up tree rings

9
Formation of Bark

• Tree structure that includes all tissues outside
  the vascular cambium, including phloem, the cork
  cambium, and cork

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11
Leaf Structure

• Optimized for absorbing light and carrying out
  photosynthesis
• Blade thin, flattened section of a plant leaf
  that collects sunlight
• Petiole thin stalk by which a leaf blade is
  attached to a stem

12
Leaf Functions

• Photosynthesis
• Transpiration
• Gas Exchange

13
Water Transport in Plants

• Root pressure
• Capillary Action
• Transpiration
• Together provide enough force to move water
  through the xylem tissue of even the largest
  plant!

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15
Capillary Action

• Tendency of water to rise in a thin tube
• Adhesion attraction between unlike molecules

16
Transpiration

• The evaporation of water from leaves
• Controlled by the guard cells
• The biggest contributor to moving water in the
  plant

17
Nutrient Transport

• Water is pulled upward in plants nutrients are
  pushed through phloem
• Phloem In cold climates, sugar is stored in the
  roots in the winter and in the trunk and branches
  in the springhow does it move?

18
Movement from Source to Sink

• Pressure-Flow Hypothesis When nutrients are
  pumped into or removed from the phloem system,
  the change in concentration causes a movement of
  fluid in that same direction
• As a result, phloem is able to move nutrients in
  either direction to meet the nutritional needs of
  the plant