Cambridge (CIE) AS Your notes
Biology
Structure of Transport Tissues
Contents
Plant Transverse Sections
Xylem & Phloem Distribution
Xylem Vessels Elements
Phloem Sieve Tube Elements
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, Plant Transverse Sections
Your notes
Transverse Sections: Stems, Roots &
Leaves
Dicotyledonous (dicots) plants
Dicotyledonous (dicots) plants have:
Seeds that contain two cotyledons (seed leaves)
Network of veins
Leaves that typically have broad blades (leaf surface) and petioles (stalks)
Tap root with lateral branches
Herbaceous dicots have a relatively short life cycle (one growing season) and non-
woody tissue
Transport systems
Plants need transport systems to meet their metabolic demands (glucose, hormones,
mineral ions are required for various processes within plants), to efficiently move
substances up and down, e.g.
Glucose from photosynthesis needs to be transported to parts of the plant that
cannot photosynthesise
Water from the roots needs to be transported to the upper parts of a plant
Plants may store glucose in storage organs, e.g. tubers, and need to release this
glucose and transport it to metabolically active parts of the plant
Plants consist of many layers of cells and so cannot rely on diffusion from cell to cell to
supply all their needs, as this would be too slow
Plants therefore have a vascular system which involves a network of vessels (vascular
tissue) running through the leaves, stem and roots. These three parts are the main
organs involved in transport
The vascular system is comprised of two distinct types:
Xylem transports water and mineral ions from the roots to the rest of the plant
Phloem transports substances from the source (e.g. a leaf) to the sink (e.g. root)
The xylem and phloem are arranged together in vascular bundles
The bundles are laid out differently in the leaves, stem and roots
Dicotyledons Plan Diagrams
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, Your notes
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Biology
Structure of Transport Tissues
Contents
Plant Transverse Sections
Xylem & Phloem Distribution
Xylem Vessels Elements
Phloem Sieve Tube Elements
© 2025 Save My Exams, Ltd. Get more and ace your exams at savemyexams.com 1
, Plant Transverse Sections
Your notes
Transverse Sections: Stems, Roots &
Leaves
Dicotyledonous (dicots) plants
Dicotyledonous (dicots) plants have:
Seeds that contain two cotyledons (seed leaves)
Network of veins
Leaves that typically have broad blades (leaf surface) and petioles (stalks)
Tap root with lateral branches
Herbaceous dicots have a relatively short life cycle (one growing season) and non-
woody tissue
Transport systems
Plants need transport systems to meet their metabolic demands (glucose, hormones,
mineral ions are required for various processes within plants), to efficiently move
substances up and down, e.g.
Glucose from photosynthesis needs to be transported to parts of the plant that
cannot photosynthesise
Water from the roots needs to be transported to the upper parts of a plant
Plants may store glucose in storage organs, e.g. tubers, and need to release this
glucose and transport it to metabolically active parts of the plant
Plants consist of many layers of cells and so cannot rely on diffusion from cell to cell to
supply all their needs, as this would be too slow
Plants therefore have a vascular system which involves a network of vessels (vascular
tissue) running through the leaves, stem and roots. These three parts are the main
organs involved in transport
The vascular system is comprised of two distinct types:
Xylem transports water and mineral ions from the roots to the rest of the plant
Phloem transports substances from the source (e.g. a leaf) to the sink (e.g. root)
The xylem and phloem are arranged together in vascular bundles
The bundles are laid out differently in the leaves, stem and roots
Dicotyledons Plan Diagrams
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, Your notes
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