Roots,%20Stems,%20Leaves,%20Tissues

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Roots, Stems, Leaves, Tissues

• BSC 2011L

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Review of difference between monocots and dicots
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Organization of Flowering Plants

• 3 vegetative organs that dont have to do with
  reproduction
• Root anchor the plant, and absorb water and
  minerals
• Stem supports leaves
• Leaves carry on photosynthesis
• 3 major tissues of vegetative organs
• Dermal tissue
• Outer protective coating of organ
• Ground tissues
• Interior of plant organ
• Vascular tissue
• Xylem (transports water) and phloem (transports
  sugars)
• Transports, supports

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Ground Tissue

• 3 cell types according to cell wall structure
• Parenchyma
• Large vacuoles
• Important roles
• Photosynthesis in leaves
• Storage of proteins in fruits
• Storage of starch in roots
• Collenchyma
• Generally elongated
• Provide support to leaf petioles, nonwoody stems,
  growing organs
• Sclerenchyma
• Thickened cell walls for support
• Undergo programmed cell death often and offer
  support then (in wood and bark)

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Growth

• Primary Growth
• Increases length of plant
• Secondary Growth
• Increases girth of plant

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Growth - Apical Meristem

• Located at terminal end of stem, branches, root
  tip
• Continuous growth

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Growth Lateral Meristem

• The roots and stems of some Eudicots develop
  secondary plant body tissues referred to as
  wood and bark
• 2 Lateral Meristems
• Vascular Cambium supplies cells of secondary
  xylem and phloem which eventually become wood and
  bark
• Cork cambium waxy protective cells that become
  bark

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Root System

• Eudicot Root

• Monocot Root

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Roots

• Note location of
• Root cap
• Zone of cell division
• Zone of elongation
• Zone of maturation

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Root Diversity

• Types of roots
• Taproots main root is larger and often serves
  as food storage
• Fibrous roots all of the roots approximately
  same size

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Stems

• Monocots
• Usually herbaceous (non-woody)
• Dicots
• Some are herbaceous
• Trees - woody

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Stems

• Dicot

• Monocot

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Stem Diversity

• Other examples
• Rhizomes horizontal underground stems that can
  give rise to new shoots
• Bamboo
• Bulbs stems with many fleshy layers of leaves
  that store nutrients
• Lilies, onions

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Anatomy of woody stems only in dicots

• Primary growth
• Apical meristem within termnial bud is active
• Secondary growth
• Vascular cambium is active
• Produces new xylem and phloem each year
• Build-up of this every year is called wood

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Woody Stems
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Leaves
Dicot
Monocot
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Leaves
Petiole