1. Flower > Reproduction of the species
Fertilized flowers produce fruits containing seeds that will germinate and produce new plants.
2. Stem > Transportation of sap
The nutrients absorbed or synthesized by the plant are transported through the conducting vessels in the stem.
3. Leaf > Respiration and photosynthesis
Using the chlorophyll in its leaves, the plant fixes (using light) CO2 from the atmosphere, releases O2 back into the atmosphere and creates nutrients: this is photosynthesis.
4. Root > Anchoring, absorption and storage
Roots allow the plant to anchor itself to the ground, absorb water and mineral salts from the ground and store energy reserves.