P5 Plant Transport System (Concept Map)
Primary 5 Science — Concept Map
Created by Miss Clarissa Ng · www.clartutors.com
Plant Transport System
plants transport food, water and mineral salts through tubes in the stem
two sets of tubes
Food-carrying tubes (phloem)transport food (sugar) made by the leaves · up or down
Water-carrying tubes (xylem)transport water + mineral salts from the roots · up only
what is transported
Food (sugar → starch)used for growth; excess stored in fruit, stem and roots
Water + mineral saltsabsorbed by the roots, transported up to all parts
the experiments
Food-carrying tubes removedleaf above healthy · stem swells · roots starve → dies
Water-carrying tubes removedleaf above dies · leaf below stays healthy
gaseous exchange at the leaf
Stomata (day)open · CO₂ in, O₂ out · water vapour escapes
Stomata (night)closed · reduce water loss · respiration only
Tiny openingsleaves have many tiny openings called stomata
Gases move in and outstomata allow gaseous exchange with the air
the food-tube experiment
Food tubes cuta whole ring of food-carrying tubes is removed
Leaf above stays healthyWater still travels up, so the leaf above keeps making food.
The stem swellsfood collects above the cut, so the stem swells
Then no water is absorbeddead roots cannot absorb water, so the plant dies
the water-tube experiment
Water tubes cuta ring of water-carrying tubes is removed
Leaf above diesno water reaches it, so it dies
Leaf below survivesThe leaf below is still fed by the roots, so it stays healthy.
comparing the two
The leaf above suffers firstwater comes up from the roots, so the top leaf suffers first
Which part starves?In the food-tube test the roots starved, not the leaf above.
stomata open or closed
Open in sunlightopen: carbon dioxide in, oxygen out
Mostly closed at nightmostly closed, so less water vapour is lost