Plants Part 4

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Plants Part 4

• Roots

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Roots

• Serve 3 important functions anchors, absorb
  minerals and water, and they transport those
  minerals and water
• Two main types of roots
• Taproots are long and thick and have secondary
  roots emerging from that root. Dicots have
  taproots.
• Fibrous roots are many roots of about the same
  size, each with secondary roots. Monocots have
  fibrous roots.

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• Another type of root called the adventitious
  roots are when the roots emerge from other
  tissues like the stem and leaves, and prop up the
  plant in support.
• Tuberous roots are a lateral root that is
  specialized to store carbohydrates. Example
  yams, cassava

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Types of Tissues in Roots

• Epidermis is one cell layer thick and is the
  outermost layer of the root. It protects and
  absorbs water and mineral from the soil. Has
  specialized cells that form root hairs that
  increase surface area.
• The cortex is a layer of cells found just below
  the epidermis and has some cells that store
  molecules like starch, transport water and
  minerals from the epidermal cells to the centre
  of the root by osmosis.
• Cortex has a wax coating on the inner layer
  called the endodermis.

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• The Casparian strip surrounds the endodermal
  cells, prevents water from entering back into the
  cortex. Minerals must be pumped by active
  transport into the vascular cylinder. This layer
  controls the movement of water and minerals.

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• The vascular cylinder contains the plants
  conducting tissues the xylem and the phloem.
• The xylem conducts water and minerals to the
  leaves
• The phloem conducts the sugars from the leaves to
  other parts of the plant.
• Monocot root vs dicot root