Plant transport systems

Dicotyledons

• cotyledons

  • food stores for the developing embryo in the seed

  • form the first leaves after germination which photosynthesise until true leaves grow

Types of dicotyledon

• herbaceous dicot

  • soft tissues/short life cycle

  • die back at end of season

• woody (arborescent) dicot

  • lignified tissues

  • long lifecycles

  • eg. trees

Metabolic remands

• only green parts of the plant photosynthesise

• all cells respire so need oxygen and glucose transported to them

• waste products also need to be removed from cells

• other useful molecules need to be moved from where they are made to where they are needed

• water and mineral ions also need to be moved from where they are absorbed to where they are needed

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Size

• plants continue to grow throughout life cycle

• large range in size

• need to be able to move substances from roots to very top of plant

SA:V

• leaves have large sa:v ratio

• other parts of the plant are very complex and overall have small sa:v ratio

• plants cant rely on diffusion alone to supply their cells

Vascular system

• dicots have transport vessels throughout the stem, roots and leaves

  • vascular bundles containing xylem and phloem

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Vascular bundle

• area containing both xylem and phloem