QUIZ Diagram

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QUIZ Diagram
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Plant Structure Leaves

• Plant leaves

• Organs attached to stems of vascular plants

• Usually site of photosynthesis

• Today...

• Leaf structure

• Types of leaves

• Leaf arrangements

• Types of leaf venation

• Internal leaf anatomy

• Types of modified leaves

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Plant Structure Leaves

• Leaf structure

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Plant Structure Leaves

• Type of leaves

• Simple blade not divided into smaller leaflets

• Compound blade divided into smaller parts that
  look like small leaves (but lack axillary buds)

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Plant Structure Leaves

• Type of leaf venation

• Monocots such as Families Agavaceae and
  Orchidaceae

• Palmate and pinnate occur in dicots such as
  Families Moraceae and Euphorbiaceae

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Plant Structure Leaves

• Type of leaf arrangements (on stem)

• Alternate leaves occur at nodes singly

• Opposite leaves occur at nodes in pairs

• Whorled more than 2 leaves at each node

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Plant Structure Leaves

• Internal leaf anatomy

• Cuticle

• Epidermis

• Pallisade cells

• Spongy mesophyll

• Stomata

• Guard cells

• Xylem phloem

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Plant Structure Leaves

• Stomata

• Stomata pores in epidermis used for gas exchange

• CO2 into cell for photosynthesis

• H2O out of leaf by evaporation to facilitate
  transpiration (process by which water pulled up
  plant)

• Guard cells epidermal cells that open and close
  stomata

• Stomata open when guard cells swell with water

• Stomata close when guard cells collapse together
  (shrivel)

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Plant Structure Leaves

• Types of modified leaves

• Bulb leaves leaves wrapped around short,
  swollen stem of bulb (e.g. onion)

• Bracts large, colorful leaves surrounding
  flowers (e.g. poinsettas)

• Spines sharp projections (e.g. cacti)

• Insectivorous leaves leaves designed to trap
  insect (e.g. venus flytrap)