B4: Plant Structure

B4: Plant Structure

1. Phloem

   • These cells are living
   • Stacked on top of one another in tubes
   • Transport food substances made in the leaf to all other parts of the plant.

2. Xylem

   • These cells are dead
     • Have a hollow cavity called the lumen
   • Are stacked on top of one another to form long hollow tube-like vessels
   • Transport water and dissolved minerals from the roots to the shoots and the leaves

3. Support in Plants

   • Xylem cells have particularly thickened, strengthened cellulose cell walls.
     • Help support the plant
   • The location of the Xylem and the vascular bundles helps them carry out their functions:
     • In the root the vascular bundles are located in the centre of the root. This helps the root act like an anchor and allows it to bend as the plant moves in the breeze or is tugged from above.
     • In the stem the vascular bundles are around the outer edge of the stem.
       • Provides strength to resist bending of the stem in the breeze.
     • In the leaf the vascular bundles form a network which supports the softer leaf tissues.

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