Plant transport system is usually taught at Primary 5 under the theme, Systems. In Primary 4, you would have learnt about the parts and functions of a plant and understand why plant need food and water to survive. Water is needed for plants to make food for themselves, yes, the process of photosynthesis
These 3 main concepts you must know are:
- What do the tubes transport?
- Where are the tubes found?
- What happens to the plant if the tubes are removed?
Plants have two transport tubes to transport food and water throughout the plant.
- Water-carrying tubes or phloem
- Food-carrying tubes or xylem
*Note that phloem and xylem are not terms taught in Primary School syllabus
What are the water-carrying & food-carrying tubes?
Water-carrying tubes carry/transport water and mineral salts from the roots to the rest of the plant.
Food-carrying tubes carry/transport food and nutrients from the leaves/ green parts to the rest of the plant.
A simplified diagram of the plant transport system and the substances they transport.
This is a common diagram of the transport tubes. [Cross Section View]
Always remember WIFO (Water in , Food Out)
What happens when the FOOD-CARRYING tubes are removed?
In this example, food made at Part A cannot be transported down to the roots and excess food would accumulate at the cut part of the stem and it will swell as food carrying tubes were removed at Part X. The part below the cut stem will not swell because food made at Part B can still be transported down to the roots.
MUST write excess food (starch)
Fruits can be made bigger with the removal of food-carrying tubes as fruits are storage organs of the plant.
Farmers use this method to get bigger and juicier fruits.
Take note of these keywords:
1.Food-carrying tubes were removed
2.Food made at Part A cannot be transported down to the roots/ other parts of the plant
3.Excess food is accumulated
A second part of the question can be…
(b) What will happen to the leaves at part A after a week?
[x] Nothing. [This is WRONG, because you have to write exactly what will happen]
[x] The leaves will die. [This is also WRONG, because the leaves can still receive water and make food for themselves]
[✓] The leaves will continue to absorb the water to photosynthesise and make its own food. [Correct!]
What happens when the WATER-CARRYING tubes are removed?
There is no swelling like food-carrying tubes. Without water, the leaves cannot photosynthesize and will die. Other parts of the plant will dry up and die too.
Now you have covered all the essential concepts about Plant Transport System! you are ready to do some common exam questions. Click here to go to the Study Notes [Common Exam Questions Primary 5 Students Must Know About Plant Transport System]