BRAINCAKEPhloem
Phloem transports assimilates such as sucrose and amino acids. Unlike xylem, it is made mainly of living cells. It contains sieve tube elements, companion cells, fibres and parenchyma.
Sieve tube elements are joined end to end to form long sieve tubes.
1. Their end walls are perforated to form sieve plates, which let the phloem sap flow from one element to the next.
2. As they mature, they lose their nucleus and most of their organelles. Only a thin layer of cytoplasm lines the walls, leaving more space for the sap to flow.
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More in Transport in Plants
- Xylem and Phloem
- Xylem
- Evidence for the Movement of Water Through Xylem
- Root Hair Cells
- Symplast Pathway
- Apoplast Pathway
- Transpiration
- Cohesion-Tension Theory
All 21 lessons in Transport in Plants · All Edexcel AS-level Biology topics