What am I???

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What am I???
Diagram a Diagram b
Diagram c
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Module 2Exchange and transport

• 1.2.13 Transport in plants-

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• Learning Objectives

• Success Criteria

• Describe the structure and function of xylem
  vessels, sieve tube elements and companion cells

• Define xylem and phloem
• (Grade D C)
• Describe the structure and function of a xylem
  and phloem (Grade C B)
• Compare the structure of xylem and phloem,
  linking it to their importance (Grade B A)

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How is xylem adapted for transportation?
Water and minerals travel in xylem vessels.
Xylem vessels have thick cellulose cell walls,
strengthened waterproofed by lignin. The inside
of the cell is hollow. Xylem vessels are dead
cells. In some places lignification is
incomplete, there are pores in the wall called
pits/bordered pits that allow water to leave one
vessel to the next
Xylem vessels transport water and minerals from
the roots to the shoot and leaves. This transport
only occurs in one direction.
The thick walls of xylem cells also help support
plants.
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How is phloem adapted to transportation?
Phloem is made of columns of living cells. They
transport food, in the form of sugars.
Sugars are carried from the leaves to the growing
and storage parts of the plants. This movement
takes place in both directions.
Phloem cells consist of sieve tubes. Cells are
joined by small holes in the cell wall at the end
of each cell, forming a continuous system. The
end cell walls are called sieve plates.
Companion cells carry out living functions for
both themselves and sieve cells. Providing energy
fro the active transport of sugars