Edexcel IGCSE Biology: Double Science 复习笔记 2.8.2 Transport Systems in Flowering Plants

Edexcel IGCSE Biology: Double Science 复习笔记 2.8.2 Transport Systems in Flowering Plants

Xylem

 

  • The rootsstem and leaves form a plant organ system for the transport of substances around the plant
  • Plants also possess two specialist transport vessels called the xylem and phloem
  • The xylem and phloem are arranged throughout the root, stem and leaves in groups called vascular bundles

 

 

Structure and function of the xylem

  • Xylem vessels transport water and minerals (pronounced: zi-lem) from the roots to the stem and leaves
  • The xylem has some key structural features
    • It is composed of dead cells which form hollow tubes
    • Xylem cells are strengthened by lignin and so are adapted for the transport of water in the transpiration stream

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